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Here's why some scientists think Pluto should still be a planet

  • Pluto was considered a planet through the early 90s, but then scientists discovered Eris, Pluto's twin, along with other nearby objects. 
  • These new worlds looked and behaved like Pluto, but they were completely different from every other planet in our solar system. So astronomers created a new definition of what makes a planet a planet.
  • In 2006, the International Astronomical Union decided to reclassify Pluto as a dwarf planet, to the fury and confusion of the American public.
  • Visit Business Insider's homepage for more stories.

Following is a transcript of the video.

Narrator: Back in the '90s, most people took Pluto for granted. Fast-forward to 2006. Suddenly, Pluto was all Americans were talking about. Or rather, yelling about. Some people were so angry, they were giving astronomers death threats.

Thierry Montmerle: People were so angry that they said that all the astronomers should be put on the wall and shot at.

Narrator: That's Thierry Montmerle. He's former general secretary for the International Astronomical Union. The same organization of the world's astronomers that changed Pluto's status from planet to dwarf planet in 2006. And today, over 12 years later, people still have strong opinions whenever you ask: Should Pluto be a planet again?

- No.

- Yes.

- No.

- No.

- Yeah.

- Yes.

- No.

- Yes.

- I'm not really sure that I have an opinion of whether or not Pluto should be a planet.

Narrator: There's obviously some confusion going on here. So we did the next logical step. We went to the experts to settle this once and for all.

That's Alan Stern. He leads NASA's New Horizons mission, which flew by Pluto in 2015.

Alan Stern: And in planetary science, where the experts in planets are, we call small planets "planets." We call large moons "planets." We call all the planets around other stars "planets." And the astronomer's definition wouldn't allow any of those to be planets.

Narrator: OK, so basically Stern says it depends on context. But why? Back in the early '90s, Pluto was a planet, period. No context needed. So what changed? By the late '90s, it was becoming clear that Pluto wasn't alone. Astronomers had discovered other worlds in the same region, called the Kuiper belt. And some of them looked awfully similar to Pluto. Then in 2005, astronomers discovered Eris, which estimates at the time suggested was even larger than Pluto.

Mike Brown: On January 8 of this year, while looking through some old data that we had taken with the Samuel Oschin Telescope at Palomar Observatory, we found, much to our surprise, an object three times further away than Pluto. This will absolutely rewrite the history of astronomy textbooks.

Narrator: And while these new worlds looked and behaved like Pluto, they were completely different from every other planet in our solar system. Something had to be done. It was clear that astronomers were in need of something they never had before: a good definition for what makes a planet a planet. So in the wake of these new discoveries, the IAU came up with a checklist. A planet must orbit the sun, have a nearly round shape, and have cleared its neighborhood, meaning no other large objects are nearby. And that last requirement boots Pluto off Team Planet. Yes, it orbits the sun. Yes, it's spherical. But Pluto isn't always the dominant gravitational force in its neighborhood. For one thing, Eris shares the region and isn't stuck in Pluto's orbit. The end result? Pluto is bumped from "planet" to "dwarf planet." Now, Stern argues that a dwarf planet is a kind of planet. Just like how

Stern: The bonsai tree is still a tree. And a Chihuahua is still a dog.

Narrator: But other experts, like Montmerle, prefer to think of dwarf planets as their own class. So where does that leave us? Well, in the grand scheme of things, it doesn't really matter what Pluto's official designation is.

Montmerle: If people don't like it, they don't use it, period.

Narrator: Which is exactly what planetary scientists do.

Stern: So everyone's using the planetary scientist's definition in the written, refereed scientific literature. And using it at the podium in giving scientific presentations. That's the kind of consensus that's very powerful in science.

Narrator: So maybe Pluto isn't a planet the same way that Earth and Jupiter are planets. But that doesn't mean we should ignore it. Besides, there's more to this dwarf planet than meets the eye. The New Horizons mission has found evidence of ice volcanoes, hidden oceans.

Stern: There are evidence for icefalls and floes and glaciers. Just tremendous stuff.

Narrator: And that's true, no matter what you call it.

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How NASCAR's banked turns help cars go faster

  • Many NASCAR tracks use banked turns that are sloped to keep race cars tilted inwards. These banks are both safer and faster than flat roads.
  • The race cars, which can reach speeds faster than 200 mph at NASCAR's fastest tracks, would fling outwards and off the track if not for the banked turns.
  • Watch the video above for a deeper dive into the physics of NASCAR's banked turns.
  • Visit Business Insider's homepage for more stories. 

Following is a transcript of the video. 

In 1959, something happened that revolutionized NASCAR's stock-car racing: the introduction of Daytona International Speedway.

Daytona was unlike any race track before it because of these: banked turns. The turns had towering walls that sloped downwards to the center. Walls that NASCAR's stock cars would drive onto. Daytona's banks were a whopping 31 degrees, significantly steeper than the relatively flat 12-degree banks at Martinsville or Occoneechee Speedways.

In the first year of Daytona, stock-car drivers qualified at speeds of more than 140 mph. And today, at the same track, that speed is more like 200 mph — in large part because of the steep banks. Which raises the question: How do banked walls help cars go faster?

Detractors of NASCAR joke that, to finish a race, all you have to do is turn left. To NASCAR fans' chagrin, it's somewhat true. For the majority of NASCAR tracks, most of the lap is completed while turning, or cornering. What critics misunderstand is that it's the turns where good drivers earn their keep. Oftentimes, viewers will see stock cars rocket past each other in the straightaways and think that the faster car had more horsepower. The speed that driver uses to pass, however, comes largely from the momentum they collect in the curve they just left.

The winningest NASCAR drivers, then, are the ones that understand the corners the best, change direction the fastest, pick the best lines, and apply power at the right times to navigate the corners better than their competitors. It's the corners where the races are won. Going straight is easy. Newton's law of inertia tells us that an object going straight will keep going straight until something makes it change direction.

So driving a stock car on a straightaway, even at 180 mph, would be fairly easy for you or I. It's turning that presents some challenges. To turn, a force needs to push the car sideways. That force is centripetal force. Imagine a ball attached to a string. When I twirl the ball in a horizontal circle, the tension in the string provides the centripetal force needed to make the weight curve.

Our stock cars do not have strings attached to them. The centripetal force needed to move the car left is caused, instead, by friction at the tires. But at high speed, the force of traction at the tires alone is not enough to pull the car to the left.

Let me explain by example. Think about turning sharp circles in a flat parking lot. The faster you go, the more unsteady the car will be. With enough speed, the car will slide out. For cars traveling above 180 mph, friction at the tires alone is not enough to get the cars moving to the left. For example, taking the first turn at Bristol Motor Speedway at 130 mph requires an immense 16,000 pounds of force to move the car to the left. That's where high banks come in handy. When an object presses onto a surface, the object feels an equal force in the opposite direction. So for a stock car on a flat track, the track will push up with a force equivalent to the weight of the car.

On a banked track, however, only part of the force from the track goes straight up. The angle of the track directs the rest of the force towards the center. And that's exactly the direction the driver is trying to turn. The extra force from the banked track, combined with the friction from the tires, is enough to turn the car safely. So the steep, banked turns let drivers maintain greater speeds into and through the turns.

While the banked track isn't the only thing helping the car corner — aerodynamic downforce too helps the car generate lateral force — it is one of the most important factors keeping stock cars cornering at speed. NASCAR's banks are for cars going at race speeds. At lower speeds, the 33 degree bank at Talladega Superspeedway would be enough to slide a car down to the bottom of the track. In fact, if you or I wanted to take a lap around Talladega in a street car, we'd constantly be turning right to just stay up on the wall.

But you don't need to be a stock-car driver to test a banked turn for yourself. Banked turns exist on our roads, too, on freeway on-ramps and interchanges. For heavy vehicles like trucks and buses, friction alone may not provide enough force to turn safely, especially if the driver doesn't slow down enough. A slightly banked turn, with a gentle grade of 15 degrees or less, can help push the vehicle into the turn.

So, for NASCAR, banked turns simultaneously create lateral force that, in addition to friction force at the tires, create enough centripetal force in total to get stock cars moving to the left but also enable them to travel at higher speeds without sliding or flying off the track.

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Satellite collisions may set off a space-junk disaster that could end human access to space. Here's how.


space junk debris trash orbiting earth kessler syndrome effect event shutterstock_233084350

  • One of SpaceX's new Starlink internet satellites risked hitting a European spacecraft on Monday. The ESA moved its satellite, called Aeolus, and avoided a 1-in-1,000 chance of collision.
  • As more spacecraft are launched, the chances of satellite collisions — and the creation of dangerous space debris— will go up. Deliberately destroying satellites also won't help.
  • Experts worry that debris orbiting Earth could lead to a "Kessler syndrome" domino effect that cuts off human access to space for hundreds of years.
  • Visit Business Insider's homepage for more stories.

As humanity launches more stuff into space, the odds of spacecraft bumping into each other will go up.

SpaceX and the European Space Agency (ESA) got the most recent and talked-about taste of the problem on Monday. On that day, there was a 1-in-1,000 chance of collision between one of SpaceX's new Starlink internet satellites and the ESA's wind-monitoring Aeolus spacecraft.

The ESA decided to fire a thruster on Aeolus and avoid risking a hit, but there will inevitably and always be more close calls in the future — and sometimes deliberate incidents, such as India's satellite shoot-down in May — that generate countless tiny pieces of space junk.

The US government tracks about 23,000 human-made objects floating in space that are larger than a softball. These satellites and chunks of debris zip around the planet at more than 17,500 mph — roughly 10 times the speed of a bullet. Until April 1, the list of space junk even included China's school-bus-size Tiangong-1 space station, which burned up in Earth's atmosphere.

However, there are millions of smaller pieces of space junk— sometimes called micrometeoroids — orbiting Earth, too.

"There's lots of smaller stuff we can see but can't put an orbit, a track on it," Jesse Gossner, an orbital-mechanics engineer who teaches at the US Air Force's Advanced Space Operations School, told Business Insider in 2018.

As companies and government agencies launch more spacecraft, concerns are growing about the likelihood of a "Kessler syndrome" event: a cascading series of orbital collisions that may curtail human access to space for hundreds of years.

Here's who is keeping tracking of space junk, how satellite collisions are avoided, and what is being done to prevent disaster on the final frontier.

This story has been updated. It was originally published on March 27, 2018.

SEE ALSO: A spacecraft graveyard exists in the middle of the ocean — here's what's down there

DON'T MISS: Elon Musk's plan to blanket Earth in high-speed internet may face a big threat: China

Thousands of launches since the dawn of the Space Race have led to a growing field of space debris. Most space junk is found in two zones: low-Earth orbit, which is about 250 miles up, and geostationary orbit, about 22,300 miles up.

In addition to 23,000 objects the size of a softball or larger — like rocket stages, satellites, and even old spacesuits — there are more than 650,000 objects that are softball-to-fingernail-size.

Another 170 million bits of debris as small as a pencil tip may also exist — including things like explosive bolts and paint flecks.

Source: ESA

Countless pieces of tiny debris were added to orbit in 2007, when China intentionally smashed one of its old satellites with a "kill vehicle." Then in 2009, an old Russian satellite and US satellite collided, adding even more dangerous junk.

India also generated thousands of bits of debris with its "Mission Shakti" anti-satellite missile test on March 27, 2019.

Leftover rocket bodies often have fuel remaining. As the harsh environment of space weakens the rocket parts over time, fuels can mix, explode, and spray more debris every which way.

No piece of space debris is insignificant, since each one travels at speeds high enough to inflict catastrophic damage to vital equipment. A single small hit could be deadly to astronauts aboard a spacecraft.

Jack Bacon, a senior scientist at NASA in 2010, told Wired that a hit by a 10-centimeter sphere of aluminum would be akin to detonating 7 kilograms of TNT.

If the space junk problem were to spiral out of control, one collision could beget other collisions, and in turn spread even more debris: a chain of crashes known as a Kessler event.

Astrophysicist Donald J. Kessler, who used to work for NASA's Johnson Space Center, penned the idea in a 1978 study. Kessler and his NASA colleague Burton G. Cour-Palais calculated that more and more launches in the coming decades would increase the risks of collisions in space.

In the study, titled "Collision Frequency of Artificial Satellites: The Creation of a Debris Belt," they also described important sources of space debris and possible sinks that'd remove dangerous junk from orbit.

As Kessler's study explains, the more massive an object, the more space debris it can create if hit. Thus, large objects pose a much higher risk of fueling a cascade of collisions if there are many other satellites in similar orbits.

A Kessler syndrome event could create an Asteroid Belt-like field of debris in large regions of space around Earth. These zones may be too risky to fly new satellites or spaceships into for hundreds of years, severely limiting human access to the final frontier.

Source: Inter-Agency Space Debris Coordination Committee

The Kessler syndrome plays center-stage in the movie "Gravity," in which an accidental space collision endangers a crew aboard a large space station. But Gossner said that type of a runaway space-junk catastrophe is unlikely.

"Right now I don't think we're close to that," he said. "I'm not saying we couldn't get there, and I'm not saying we don't need to be smart and manage the problem. But I don't see it ever becoming, anytime soon, an unmanageable problem."

There is no current system to remove old satellites or sweep up bits of debris in order to prevent a Kessler event. Instead, space debris is monitored from Earth, and new rules require satellites in low-Earth orbit be deorbited after 25 years so they don't wind up adding more space junk.

"Our current plan is to manage the problem and not let it get that far," Gossner said. "I don't think that we're even close to needing to actively remove stuff. There's lots of research being done on that, and maybe some day that will happen, but I think that — at this point, and in my humble opinion — an unnecessary expense."

A major part of the effort to prevent a Kessler event is the Space Surveillance Network (SSN). The project, led by the US military, uses 30 different systems around the world to identify, track, and share information about objects in space.

Many objects are tracked day and night via a network of radar observatories around the globe.

Optical telescopes on the ground also keep an eye out, but they aren't always run by the government. "The commercial sector is actually putting up lots and lots of telescopes," Gossner said. The government pays for their debris-tracking services.

Gossner said one major debris-tracking company is called Exoanalytic. It uses about 150 small telescopes set up around the globe to detect, track, and report space debris to the SSN.

Telescopes in space track debris, too. Far less is known about them because they're likely top-secret military satellites.

Objects detected by the government and companies get added to a catalog of space debris and checked against the orbits of other known bits of space junk. New orbits are calculated with supercomputers to see if there's a chance of any collisions.

Diana McKissock, a flight lead with the US Air Force's 18th Space Control Squadron, helps track space debris for the SSN. She said the surveillance network issues warnings to NASA, satellite companies, and other groups with spacecraft, based on two levels of emergency: basic and advanced.

The SSN issues a basic emergency report to the public three days ahead of a 1-in-10,000 chance of a collision. It then provides multiple updates per day until the risk of a collision passes.

To qualify for such reporting, a rogue object must come within a certain distance of another object. In low-Earth orbit, that distance must be less than 1 kilometer (0.62 mile); farther out in deep space, where the precision of orbits is less reliable, the distance is less than 5 kilometers (3.1 miles).

Advanced emergency reports help satellite providers see possible collisions much more than three days ahead. "In 2017, we provided data for 308,984 events, of which only 655 were emergency-reportable," McKissock told Business Insider in an email. Of those, 579 events were in low-Earth orbit (where it's relatively crowded with satellites).

When a space company receives a SSN alert, they typically move their satellite into a different orbit — and out of harm's way — by burning a little propellant.

Although companies like SpaceX are launching more and more objects into space, McKissock said "our everyday concern isn’t something as catastrophic as the Kessler syndrome."

The biggest priority is avoiding damage to multimillion-dollar satellites and keeping astronauts safe. "It's just a matter of watching and, with our active satellites that we do control, avoiding collisions," Gossner said. "It becomes a very important problem not just for that satellite, but then for the debris that it would create."

So any time something massive returns to Earth, like China's 9.4-ton Tiangong-1 space station did in April, it's a cause for celebration — not despair.

The next very large object to fall to Earth after Tiangong-1 may be NASA's 12.25-ton Hubble Space Telescope, which could be deorbited as soon as 2021.

Like other objects that can be guided toward their doom, Hubble (as well as the International Space Station, eventually) will be deorbited in the "spacecraft graveyard": the most remote point of the Pacific Ocean.

Source: Business Insider

The first day of fall has arrived. Here's how the equinox marks the changing of seasons.


FILE PHOTO: This color image of Earth, taken by NASA's Earth Polychromatic Imaging Camera, a four megapixel CCD camera and telescope on July 6, 2015, and released on July 20, 2015.   REUTERS/NASA/Handout via Reuters/File Photo

  • This year's fall or autumnal equinox happens Monday, September 23.
  • Earth's rotation does not cause the fall equinox. Rather, equinoxes occur because the planet has a tilted axis.
  • Fall comes when the sun's warming rays line up perpendicular to Earth's axial tilt. During an equinox at Earth's equator, the sun appears almost directly overhead.
  • Visit Business Insider's homepage for more stories.

Monday is this year's fall equinox.

Also called the September or autumnal equinox, this astronomical event signals the arrival of fall, summer's end, and a trend toward increasingly cold and dark days as winter comes.

At least, that's the case for people who live in Earth's northern hemisphere, which roughly 90% of all human beings call home. (Blame Earth's shifting land masses for that fun fact.)

For those in the southern hemisphere, the milestone marks the official beginning of spring. The days down under are growing longer, the weather is warming, and sunlight is growing brighter as winter approaches.

Two factors drive these all-important seasonal shifts: Earth's tilted axis and the planet's orbit around the sun.

How the fall equinox works

The Earth orbits the sun once every 365 days and 6 hours. Our planet also rotates once per day around a tilted axis.

That tilt is about 23.5 degrees (for now), which means different parts of the world get bathed with various intensities of light over the course of a year. Meanwhile, the planet's rotation keeps the heating even — it's sort of like a 7,917-mile-wide rotisserie chicken made of rock and a little water.

The fall equinox occurs when the sun's warming rays line up perpendicular to Earth's axial tilt:

Earth during equinox

If you were to stand directly on the equator at the moment the equinox peaks — which came at precisely 3:50 a.m. ET Monday morning, according to the National Weather Service—  the sun would appear more or less directly overhead. Your shadow would also be at its absolute minimum. The sun sets and rises roughly 12 hours apart on this day, too.

But this moment doesn't last, since the Earth makes its way around the sun at a speed of roughly 66,600 mph.

Uneven seasons

Our planet's orbit is elliptical and its center of gravity slightly offset from the sun, so the time it takes to cycle through the seasons isn't perfectly divvied up.

Read more: The speed of light is torturously slow, and these 3 simple animations by a scientist at NASA prove it

About 89 days and 19 hours after the fall equinox, the Earth will reach its winter solstice — when the most direct sunlight strikes the Southern Tropic (or Tropic of Capricorn). Another 89 days later, the spring or vernal equinox will occur.

Then it's another 93 days and 18 hours to the summer solstice — when the most direct rays of the sun reach their northernmost latitude, called the Northern Tropic (or Tropic of Cancer) — and another 92 days and 16 hours to get back to the fall equinox.


Earth equinoxes and solstices graphic

The animation below, from NASA's Goddard Space Flight Center, shows this seasonal progression.

It was created using geosynchronous satellite images taken over Africa; such satellites fly around Earth in a geosynchronous orbit, which means they move fast enough to hover above one spot on the planet. This creates a great opportunity to photograph Earth over the course of the year and see how the the angle of sun changes.

Take a look:


The truth about the egg-balancing trick

While we're talking about equinoxes and solstices — that whole business of only being able to balance an egg on-end during a solstice is a myth. You can balance an egg any time you please, thanks to very small pores in its shell.

Those pores create nearly invisible dimples in the shell upon which a (very, very) patient person can stand up the egg.

Don't look for any gravitational interplay between Earth and the sun to help you out either; that's far too weak to make a noticeable difference.

This is an updated version of a story that was originally published on March 20, 2019.

SEE ALSO: A new image of a mysterious object careening toward our solar system strongly suggests it's the first comet from another star system

DON'T MISS: An amateur astronomer accidentally recorded a rare flash on Jupiter. The culprit turned out to be a 450-ton meteor.

Join the conversation about this story »

NOW WATCH: If Earth spun sideways, extreme winters and summers would doom life as we know it

The moon has been drifting away from Earth for 4.5 billion years. A stunning animation shows how far it has gone.


moon earth

  • The moon is moving away from Earth at a rate of 3.8 centimeters (1.5 inches) per year, but the speed of its retreat has varied over time.
  • A new animation by planetary scientist James O'Donoghue shows the moon's 4.5-billion-year journey from a fiery ball of magma looming over Earth to the cold, distant rock it is today.
  • Some of the moon's fastest retreat speeds line up with major geological changes on Earth, like supercontinents breaking up and the mass melting of glaciers.
  • Visit Business Insider's homepage for more.

The moon is slowly moving away from us.

About 4.5 billion years ago, a Mars-sized object (or perhaps a series of many smaller objects) crashed into Earth, sending bits of Earth's crust into space. They fell into the planet's orbit and eventually coalesced, forming our moon. That newborn moon — a ball of molten rock covered in a magma ocean — was nearly 16 times closer to Earth than it is today.

As it cooled, the moon backed away, retreating thousands of miles into the distance. A new animation depicts that process with unprecedented clarity.

The video's creator, James O'Donoghue, works as a planetary scientist at the Japan Aerospace Exploration Agency (JAXA). He told Business Insider that he set out to create an accurate picture of the moon's creation, but got carried away and wound up animating its entire history.

The sequence starts with the moon's current position and follows it back in time to its birth, tracking its distance from Earth, apparent size relative to our planet, and the speed of its retreat over time.


O'Donoghue said he only recently learned how to create scientific animations like this — his first were for a NASA news release about Saturn's vanishing rings. After that, he moved on to animating other difficult-to-grasp space concepts, like the torturously slow speed of light.

"My animations were made to show as instantly as possible the whole context of what I'm trying to convey," O'Donoghue previously told Business Insider, referring to those earlier videos. "When I revised for my exams, I used to draw complex concepts out by hand just to truly understand, so that's what I'm doing here."

The moon's retreat has been inconsistent

Today, the moon is pulling away from Earth at about 3.8 centimeters (1.5 inches) per year. Scientists refer to this as "lunar retreat." The pace of this motion hasn't always been constant: The moon started out moving away at 20.8 centimeters (8.2 inches) per year, and its drift has fluctuated from between 0.13 centimeters (0.05 inches) per year to 27.8 centimeters (10.9 inches) per year.

"I didn't appreciate how many different past rates of lunar 'retreat' there were until this week," O'Donoghue said, adding, "this is the most researched animation I've made to date."

But you can't see every rate of retreat in his video, he noted, because it quickly moves through millions of years.

"I use the main average rates to avoid it flickering over values that people can't read in time," he said.

Much of the variation in the moon's pace of movement comes from lunar meteorite impacts and major geological changes on Earth.

Such events have coincided with three notable spikes in the pace of lunar retreat. One spike came around the same time as some of the earliest evidence of ocean tides — about 3.2 billion years ago. At that time, the moon started retreating at 6.93 centimeters per year.

Similarly, about 900 million years ago, the moon's speed of retreat spiked to 7 centimeters per year as it got bombarded with meteors. It continued racing away at that rate as the supercontinent Rodinia broke apart on Earth.

The third spike was roughly 523 million years ago: As life was exploding on Earth following millions of years of fluctuation between ice ages and hothouse conditions, the moon retreated at 6.48 centimeters per year.

The reason that changes in Earth's climate can impact the moon's retreat is that the formation and melting of glaciers affects the oceans, which then affect the moon.

asteroid meteor

The fates of Earth's oceans and the moon's location in space are connected because the moon's gravity pulls on ocean water, creating a "tidal bulge" that stretches slightly towards the moon. In turn, Earth's tidal bulge exerts gravity on the moon. The Earth spins faster than the moon orbits it, so as the bulge rotates away, it pulls the moon along with it.

The moon pulls back, and that slows the Earth's rotation. All this dragging back and forth creates friction around Earth's tidal bulge, which pushes the moon outward and makes its orbit larger.

That's why researchers look to the imprints of ancient ocean tides to determine how fast the moon has retreated at different periods in time.

SEE ALSO: NASA's future missions will explore an icy moon of Jupiter, collect samples on Mars, and more. Here's what's coming in the next 10 years.

DON'T MISS: A 'ridiculous' yet simple animation by a NASA scientist shows how long it takes light to reach Pluto. If you plan to watch it, take a day off work.

Join the conversation about this story »

NOW WATCH: NASA's $30 billion Artemis missions will attempt to set up a moon base

Coin flips aren't actually random. An app called Universe Splitter is, though — here's how it works.


coin flip

  • Coin flips may seem random, but the outcome is governed by predetermined forces like gravity and the strength of your finger flick. So physics formulas could be used to calculate how a coin will land.
  • To be truly random, the outcome of a coin flip would need to be determined on a quantum level. That's the term for the universe of subatomic particles that are constantly and randomly splitting.
  • Astrophysicist Sean Carroll recommends an app called Universe Splitter, which cleaves quantum particles in two.
  • Visit Business Insider's homepage for more stories.

Our lives are filled with decisions: Order cheese or pepperoni pizza? Wear a sweater or a jacket? Take the train or the bus?

Sometimes we flip a coin, allowing chance to decide for us. 

But the notion that a coin flip is random and gives a 50-50 chance of either heads or tails is, unfortunately, fallacious. 

That's because the mechanics that govern coin flips are predictable.

Determinism versus randomness

In physics-speak, scientists categorize a coin flip as deterministic, since the outcome is determined by factors that are in place before the coin lands. Those factors include the angle at which the coin starts out on your thumb, the force your hand exerts on the coin, the pull of gravity, friction in the air, and more.

All of those forces governing the coin's motion could, hypothetically, be calculated based on the laws of physics.

coin flip toss odds probability

Of course, likely nobody can control all of those factors precisely enough to predict the outcome in real time, so for day-to-day decisions, a coin flip gets the job done. 

But even so, the heads or tails you'd see can't be considered a fully random result. 

So according to astrophysicist Sean Carroll, author of the new book "Something Deeply Hidden," people who want to find true randomness should look to quantum mechanics, which governs the nanoscopic universe of photons, electrons, and other particles smaller than atoms.

These tiny particles don't follow those orderly cause-and-effect rules that govern the world we can see; instead, subatomic particles are constantly and spontaneously decaying into many other particles. Those decaying events can't be predicted with certainty; the best we can do (so far at least) is calculate probabilities about the chances certain atoms have of decaying, and when. 

A subatomic world that's truly random

In his book, Carroll explains that although we can't predict the behavior of subatomic particles, once researchers go to measure that behavior, the act of measuring causes the set of probabilities about whether and when particles will split to collapse down to only one.

Schrödinger's cat is the thought experiment many physicists use to illustrate this concept. Simplified, it goes like this: A cat is in a box along with some kind of poison, and the animal could be alive or dead. As long as we can't see inside the box, the cat is simultaneously both alive and dead. Upon opening the box, however, there remains only one possibility, and the cat's state becomes set. 

But according to Carroll, a different theory of quantum mechanics is preferable, one called the "Many Worlds Interpretation (MWI)."

Proponents of this line of thinking argue that all the permutations of decaying atoms (which we can't accurately predict or measure) get realized, each in a different universe. So every time an atom decays — or the cat-containing box is opened — another universe branches off from this one. Another you exists in it, living out a different life.


"There are infinite versions of us that exist in an infinite number of worlds," Carroll told Business Insider.

Many worlds — and versions of you

According to Carroll, the Many Worlds Interpretation can be used to get a truly random result to a binary question. 

In his book, he recommends an iPhone app (sorry, Android users) called "The Universe Splitter," which lets users input two actions, like accepting a job offer or not, into two text boxes. Then you click "Split," and the app sends a signal to a laboratory in Switzerland, where a single photon gets hurtled toward a splitter.

Put simply, the photon can either go left or right. The copy of the iPhone user in the branch of the universe in which the photon veered left sees their app say: "Take the job." And in the universe branch in which the photon went right, their screen will say: "Don't take it."

Presuming that the version of you in each branch heeds that answer, there will be one world in which you take a new job, and another in which a version of you is still looking for work, Carroll wrote in his blog.Universe Splitter

These "many worlds" exist simultaneously, but the beings in them can't contact each other, Carroll added: "It's impossible to interact or talk with your alternative selves. You're separate people with a common past but different futures."

In that sense, the "Universe Splitter" app gives a fully random result, but it doesn't choose which of two outcomes gets realized (like a coin toss might). Instead, it reports which of those two universes you are currently living in.

SEE ALSO: The highly anticipated Cotton Bowl began with the worst coin 'flip' you'll ever see

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NOW WATCH: Here's why some coins have ridges on their side

Physicists say they found new evidence for a mysterious 5th force of nature. It could be the bridge between dark matter and the visible universe.


dark matter

  • Physicists say they may have uncovered a new force of nature, called X17 — a reference to its unique mass.
  • The physicists first spotted it when they studied a decaying beryllium isotope's unexpected behavior. Scientists around the world suggested that a whole new fundamental particle, or boson, could explain it.
  • The new study, which has not yet been peer reviewed, examines similar behavior in a helium atom.
  • If confirmed, the discovery could be the missing piece for understanding how invisible dark matter interacts with all the matter we can see.
  • Visit Business Insider's homepage for more stories.

Everything in our universe is held together or pushed apart by four fundamental forces: gravity, electromagnetism, and two nuclear interactions. Physicists now think they've spotted the actions of a fifth physical force emerging from a helium atom.

It's not the first time researchers claim to have caught a glimpse of it, either. A few years ago, they saw it in the decay of an isotope of beryllium. Now the same team has seen a second example of the mysterious force at play - and the particle they think is carrying it, which they're calling X17.

If the discovery is confirmed, not only could learning more about X17 let us better understand the forces that govern our universe, it could also help scientists solve the dark matter problem once and for all.

Attila Krasznahorkay and his colleagues from the Institute for Nuclear Research in Hungary suspected something weird was going on back in 2016, after analyzing the way an excited beryllium-8 emits light as it decays.

If that light is energetic enough, it transforms into an electron and a positron, which push away from one another at a predictable angle before zooming off.

Based on the law of conservation of energy, as the energy of the light producing the two particles increases, the angle between them should decrease. Statistically speaking, at least.

Higgs Boson

Oddly, this isn't quite what Krasznahorkay and his team saw. Among their tally of angles there was an unexpected rise in the number of electrons and positrons separating at an angle of 140 degrees.

The study seemed robust enough, and soon attracted the attention of other researchers around the globe who suggested that a whole new particle could be responsible for the anomaly.

Not just any old particle; its characteristics suggested it had to be a completely new kind of fundamental boson.

That's no small claim. We currently know of four fundamental forces, and we know that three of them have bosons carrying their messages of attraction and repulsion.

The force of gravity is carried by a hypothetical particle known as a 'graviton,' but sadly scientists have not yet detected it.

This new boson couldn't possibly be one of the particles carrying the four known forces, thanks to its distinctive mass of 17 megaelectronvolts (or about 33 times that of an electron), and tiny life span (of about 10 to the minus 14 seconds … but hey, it's long enough to smile for the camera).

So all signs point to the boson being the carrier of some new, fifth force. But physics isn't keen on celebrating prematurely. Finding a new particle is always big news in physics, and warrants a lot of scrutiny. Not to mention repeated experiment.

Fortunately, Krasznahorkay's team haven't exactly been sitting on their laurels over the past few years. They've since changed focus from looking at the decay of beryllium-8 to a change in the state of an excited helium nucleus.

Similar to their previous discovery, the researchers found pairs of electrons and positrons separating at an angle that didn't match currently accepted models. This time, the number was closer to 115 degrees.

Working backwards, the team calculated the helium's nucleus could also have produced a short-lived boson with a mass just under 17 megaelectronvolts.

To keep it simple, they're calling it X17. It's a long way from being an official particle we can add to any models of matter.

While 2016's experiment was accepted into the respectable journal, Physical Review Letters, this latest study is yet to be peer reviewed. You can read the findings yourself on arXiv, where they've been uploaded to be scrutinized by others in the field.

But if this strange boson isn't just an illusion caused by some experimental blip, the fact it interacts with neutrons hints at a force that acts nothing like the traditional four.

dark matter

With the ghostly pull of dark matter posing one of the biggest mysteries in physics today, a completely new fundamental particle could point to a solution we're all craving, providing a way to connect the matter we can see with the matter we can't.

In fact, a number of dark matter experiments have been keeping an eye out for a 17 megavolt oddball particle. So far they've found nothing, but with plenty of room left to explore, it's too early to rule anything out.

Rearranging the Standard Model of known forces and their particles to make room for a new member of the family would be a massive shift, and not a change to make lightly.

Still, something like X17 could be just what we're looking for.

This research is available on arXiv ahead of peer review.

SEE ALSO: A handful of new telescopes are about to transform the hunt for alien life and our understanding of the universe itself

DON'T MISS: The universe is expanding faster than scientists thought, a study confirms — a 'crisis in cosmology' that could require a 'new physics'

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NOW WATCH: Scientists have solved one of the biggest problems with space colonization

There is no permanent dark side of the moon, and this simple animation by a former NASA scientist explains why


far dark side moon lighting day night visualization nasa gsfc svs s3m 1920

Contrary to what you may have heard, there is no mysterious dark side of the moon.

Yes, there is a side of the moon that we never see from Earth, but it's not dark all the time.

James O'Donoghue, a former NASA scientist who now works at the Japanese space agency (JAXA), made a new animation to explain how that works.

"Remember not to say 'dark side of the moon' when referring to the 'far side of the moon,'" O'Donoghue said on Twitter. "This graphic shows the dark side is always in motion."

The video shows how sunlight falls across the moon as it orbits Earth. In one orbit of about 29.5 days, all sides of the moon are bathed in sunlight at some point.

We always see the same side of the moon from Earth

The moon is tidally locked with Earth, which means that we are always looking at the same side of it. The other side — the far side — isn't visible to us, but it's not in permanent darkness.

The video shows our view from Earth as the moon passes through its month-by-month phases, from full moon to new moon. At the bottom right corner, the animation also tracks the boundary of sunlight falling across the moon as it rotates.

So, half of the moon is in darkness at any given time. It's just that the darkness is always moving. There is no permanently dark side.

"You can still say dark side of the moon, it's still a real thing," O'Donoghue said on Twitter. "A better phrase and one we use in astronomy is the Night Side: It's unambiguous and informative of the situation being discussed."

Here's what it looks like from Earth's southern hemisphere:


In the last year, O'Donoghue has created a slew of scientific animations like this. His first were for a NASA news release about Saturn's vanishing rings. After that, he moved on to animating other difficult-to-grasp space concepts, like the torturously slow speed of light.

"My animations were made to show as instantly as possible the whole context of what I'm trying to convey," O'Donoghue previously told Business Insider, referring to those earlier videos. "When I revised for my exams, I used to draw complex concepts out by hand just to truly understand, so that's what I'm doing here."

SEE ALSO: When the Andromeda galaxy crashes into the Milky Way, this is what it could look like from Earth

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NOW WATCH: What living on Earth would be like without the moon

How NFL quarterbacks throw perfect spirals

  • NFL quarterbacks like Tom Brady, Aaron Rodgers, and Drew Brees make throwing a perfect spiral look easy, but it's far more complicated than it seems.
  • To take a closer look, we spoke to NCAA football coach Ryan Larsen, who breaks down the steps that go into throwing a perfect spiral, as well as the common mistakes that can lead to inaccurate passes.
  • Finally, Union College Physics Professor Chad Orzel helps us dive into the science and physics at play in a spiraling football to understand why a well-thrown spiral is vital to the success of every attempted pass.
  • Visit Insider's homepage for more stories.

Following is a transcription of the video.

Narrator: In 2018, NFL quarterbacks attempted over 17,000 passes. Of those, 64.9% were completed. That's the highest completion percentage in league history. And if you look closely, all of those successfully completed passes had one thing in common: They were thrown with a nice, tight spiral. But throwing a perfect spiral isn't as easy as it looks. Here's what it takes.

First, we have to answer one basic question: How exactly do you throw a spiral? To answer that, we went to an expert.

Ryan Larsen: My name's Ryan Larsen, and I'm the quarterbacks coach here for Columbia University.

Narrator: Larsen says that the first key to throwing a spiral is the grip. No matter a quarterback's hand size, there are really only two fingers that are crucial to how they hold the ball.

Larsen: We're gonna orient the best we can our middle finger and our thumb in a straight line on the ball, and then we're just gonna wrap our fingers down and let them rest in control.

Narrator: After that, the quarterback's goal is to build up force behind the ball. So, first, they'll load the ball back, with their elbow above their armpit. This helps to ensure that the quarterback is what's called being "on top of the ball." That's important because, otherwise, the quarterback won't be able to throw as far.

Larsen: The second you're low, now you're, yet again, you're pushing the ball. So when you try to drive that ball deep down the field, you're underneath it, and you're lacking arm strength.

Narrator: After that, the quarterback uses their other arm to twist their upper body while stepping forward into the throw as they prepare to release the ball. But a quarterback could complete all of these steps and never end up with a spiraling football. Getting that spiral comes down to the very last thing the quarterback does in the split second before they release the ball, and it comes back to the grip. Because, in order to generate a good spiral, the last finger that should touch the ball as the hand releases it is the quarterback's index finger.

Larsen: The spiral's created by that final flick, that last finger. You really want that last finger to come off of it and then finish down, and that's that spin that you're trying to get to create the spiral.

Narrator: But here's the problem. Even the slightest of errors in how the quarterback lets go of the ball can affect the throw.

Larsen: If you're finishing with the ball on your wrist, you're finishing like that, now your index finger's not the last finger. Now you've got multiple ones, and that's when you start to get balls that get wobbly.

Narrator: And wobbly footballs are a quarterback's worst nightmare.

Chad Orzel: Really, precision in the release and in the flight of the ball is absolutely critical to success if you're gonna be a passing quarterback. My name is Chad Orzel, and I am a professor at Union College in the department of physics and astronomy.

Narrator: When it comes to how well a football flies through the air, there are two key elements: spin rate and velocity. Let's start with spin. On average, a good spiral has a spin rate of roughly 600 rotations per minute. That's as fast as an electric screwdriver.

Orzel: If you get the ball spinning rapidly, the ball will tend to stay with its axis of spin, pointing in the same direction all the time. So if it's spinning fast and moving nose-on through the air, it's going to feel a smaller air-resistance force, and that means it'll go a little bit farther because of that.

Narrator: The reason a rapidly spinning football stays on course better than a slower-spinning ball is due to its angular momentum. Angular momentum measures how likely a ball is to wobble through the air or not.

Orzel: The more angular momentum something has, the harder it is to change the orientation of that object. Something with a lot of angular momentum wants to keep its spin axis always pointing in exactly the same direction. The faster you make the ball spin, the better it will hold its orientation, the more angular momentum it'll have.

Narrator: So a rapidly spinning football will fly straighter than one that isn't spinning as quickly, and it will even help it fly a little farther. How far, however, mostly depends on the velocity of the ball flying through the air.

Orzel: The initial velocity that the ball's given pretty much determines everything about the flight. It determines, all right, how high is the pass going to go in the air, the arc that it's gonna follow, it determines how far it's going to go.

Narrator: And building that velocity behind the ball is pretty straightforward. It's all about muscle strength.

Larsen: The most important thing in generating velocity, and therefore what you would call a great spiral, right, is using your strongest muscles in your body. Your strongest muscles in your body are gonna be in your quads, your hamstrings, your glu tes, and then your core.

Narrator: However, velocity can be a double-edged sword. Because trying to increase the velocity behind a throw can sometimes compromise the integrity of the ball's spiral.

Orzel: If you're trying to throw the ball really, really hard, sometimes that means you can't get as much spin on it as you would like, and then the ball ends up not going as far as it could, just because it doesn't hold its orientation, and it tumbles in the air, and it's not as accurate.

Larsen: The lower body is what creates everything in terms of that velocity, but if you have bad mechanics in your upper body, you're not gonna be able to have a spiral to get the ball downfield.

Narrator: So, ultimately, the best throws come down to:

Larsen: Having a tighter spiral, and more velocity behind that spiral is gonna give you the ability to make throws on the field to be successful.

Narrator: So, if throwing the perfect spiral is just a matter of the right grip and sufficient strength, what distinguishes the mediocre quarterbacks from the greats?

Orzel: The key is getting just the right balance of precisely controlled velocity and a good spin rate on the ball.

Narrator: And, as the saying goes, practice makes perfect.

Larsen: Anytime you're doing things repetitively, over and over and over, and creating that consistency, that's gonna now give you accuracy. The second that your mechanics go out the door, your accuracy goes out the door, because now every throw is different.

Narrator: Of course, repeating those exact mechanics perfectly every time is easier said than done. Especially when your target is moving at 20 miles an hour and 300-pound defensive tackles are barreling toward you. But for the all-time greats, that skill is what makes them so special.

Larsen: You think about some of the most accurate quarterbacks of all-time, you think about Dan Marino. Unbelievable arm talent, unbelievably strong, could make every throw, his mechanics are perfect. People talk about Dan Marino having the quickest release they've ever seen, well, he has a quick release because there's no inefficiencies in his throwing motion. Tom Brady is unbelievably meticulous with his mechanics, whether it's footwork or how he's throwing, yet again, it's the consistency in your mechanics that's gonna create accuracy.

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The 39 most awe-inspiring scientific discoveries of the decade include the 'God particle,' the first image of a black hole, and the ability to edit the human genome


black hole neutron star

In the last decade, scientists around the world pulled off impressive feats: They imaged a supermassive black hole for the first time, discovered new human ancestors, and launched probes to distant asteroids, comets, and moons.

Researchers also invented reusable rockets, sent two landers to explore Mars, and identified possibly habitable planets outside our solar system.

These and other accomplishments are improving scientists' understanding of our history, the planet, and the cosmos.

As 2020 — and a new decade — approaches, here's a look back at some of the most awe-inspiring scientific discoveries made during the last 10 years.

SEE ALSO: The most mind-boggling scientific discoveries of 2019

In March 2010, anthropologists discovered a tiny, lone finger bone in the Denisova cave in Siberia. They determined it belonged to previously undiscovered species of human ancestor.

Genetic analysis revealed that Denisovans (named after the cave in which they were found) were an enigmatic offshoot of Neanderthals.

Thus far, fossilized Denisovan remains have only been found in Siberia and Tibet. The species disappeared about 50,000 years ago but passed some of their genetic makeup to Homo sapiensDenisovan DNA can be found in the genes of modern humans across Asia and some Pacific islands; up to 5% of modern Papua New Guinea residents' DNA shows remnants of interbreeding with Denisovans. 

People in Tibet today also possess some Denisovan traits — and these traits appear to help Sherpas weather high altitudes.

Just after anthropologists discovered Denisovans, geneticists finished sequencing the entire Neanderthal genome.

Scientists discovered that both Neanderthals and Denisovans interbred with modern humans extensively.

While 2010 was a watershed year for anthropology, 2011 was all about achievements in space. NASA sent a new rover to Mars named Curiosity.

Curiosity is the largest and most capable rover ever sent to Mars. It joined fellow rover Opportunity in searching the red planet for signs of water and clues about whether Mars was capable of supporting microbial lifeforms.

In November 2011, NASA announced that its planet-hunting Kepler space telescope had spotted its first potentially habitable planet, Kepler 22-b.

The Kepler mission was charged with finding and identifying Earth-like planets in our galaxy that existed within a star's "Goldilocks," or habitable, zone. Kepler 22-b is 600 light-years away.

Planets in habitable zones are capable of hosting liquid water, one of the requisites for being considered Earth-like.

Impressive achievements in space exploration continued into 2012. In November of that year, NASA's Voyager 1 probe left our solar system and crossed into interstellar space.

NASA launched Voyager 1 in 1977. After flying by Jupiter and Saturn, Voyager 1 crossed into interstellar space. It continues to collect data to this day.

In 2019, Voyager 1's successor, Voyager 2, also entered interstellar space. Both probes have been flying longer than any other spacecraft in history.

Voyager 2 has beamed back unprecedented data about previously unknown boundary layers at the far edge of our solar system— an area known as the heliopause. The discovery of these boundary layers suggests there are stages in the transition from our solar bubble to interstellar space that scientists did not previously know about.

In May 2012, Elon Musk's aerospace company, SpaceX, made history by sending the first-ever commercial spacecraft to dock with the International Space Station (ISS).

SpaceX's groundbreaking spaceship was called Dragon.

Previously, only four governments — the United States, Russia, Japan, and the European Space Agency — had achieved this challenging technical feat.

Seven years later, SpaceX launched Dragon's successor, Crew Dragon, into orbit for the first time. Crew Dragon is designed to ferry astronauts to the ISS; its 2019 trip marked the first time that a commercial spaceship designed for humans had ever left Earth. 

Other scientific disciplines made incredible headway in 2012, too. Physicists reported the detection of a new type of particle called the Higgs Boson.

The Higgs Boson is nicknamed the "God particle" because it gives mass to all other fundamental particles in the universe that have mass, like electrons and protons. 

Scientists knew a particle akin to the Higgs Boson had to exist — otherwise nothing in the universe would have mass, and we wouldn't exist — but had failed to find evidence of such a particle until 2012.

The same year, the patent for utilizing CRISPR-Cas9 gene-editing technology was approved.

Crispr-Cas9 technology enables researchers to edit parts of the genome by removing, adding, or altering sections of DNA. Since 2012, scientists have edited mosquito, mushroom, and lizard DNA, among others. In 2018, a Chinese scientist announced he had edited the genetic information of two human embryos.

In 2013, NASA astronomers observed plumes of water vapor being ejected from the frigid, icy surface of Jupiter's moon, Europa.

This discovery made Europa only the second known oceanic world in our solar system aside from Earth; NASA observed jets of water vapor spewing from Saturn's moon Enceladus in 2005.

The presence of liquid water and ice make these two moons ideal places to search for life in our corner of the galaxy.

Since 2013, water has also been discovered on the dwarf-planet Pluto, a moon of Neptune called Triton, and multiple other moons of Jupiter and Saturn.

That year, NASA's Curiosity rover uncovered evidence that the red planet not only once held liquid water, but may also have been habitable.

In September 2012, NASA announced its Curiosity rover had identified gravel made by an ancient river in Mars' Gale Crater.

Then in March 2013, scientists found chemical ingredients for life — sulfur, nitrogen, hydrogen, oxygen, phosphorus, and carbon — in powder that Curiosity had drilled from rock near the ancient streambed.

"A fundamental question for this mission is whether Mars could have supported a habitable environment," Michael Meyer, who worked as the lead scientist for NASA's Mars Exploration Program at the time, said in a press release about the finding. "From what we know now, the answer is yes."

In the following years, evidence has mounted that the planet was once home to a vast ocean.


Since then, evidence has continued to mount that Mars still hosts liquid water today in at least one underground lake.

After three years of studying Mars, Italian scientists determined in July 2018 that it's possible the red planet has a 20-kilometer-wide lake of liquid water at its polar ice cap today.

"If these researchers are right, this is the first time we've found evidence of a large water body on Mars," Cassie Stuurman, a geophysicist at the University of Texas, told the Associated Press.

Other parts of Mars are too cold for water to stay liquid ⁠— unless it's deep underground.

In a March 2019 study, researchers suggested that seasonal flow patterns in Mars's crater walls could come from pressurized groundwater 750 meters below the surface, which travels upward through cracks in the ground.


In November, physicists discovered 28 strange particles called neutrinos buried deep under the Antarctic ice. These neutrinos, they concluded, had come from outside our solar system.

Researchers found the particles using the IceCube Neutrino Observatory, an array of sensors embedded in Antarctic ice. Neutrinos are nearly mass-less and unstoppable; they move at the speed of light and get discharged in the aftermath of exploding stars.

Scientists can use neutrinos to understand events happening in distant galaxies. In 2018, they found more of the particles in Antarctica, then traced them back to the source: a rapidly spinning black hole, millions of times the mass of the sun, that's gobbling up gas and dust.

Researchers also achieved a food industry milestone in 2013 when scientists successfully served the first-ever lab-grown hamburger.

The burger — which took two years and $325,000 to make — consists of 20,000 thin strips of cow muscle tissue that were grown in a Netherlands laboratory. 

Since 2013, the lab-grown meat industry has grown in popularity and dropped in price. In 2015, one of the researchers responsible for the first lab-grown burger, said the per-pound cost had dropped to $37


The European Space Agency got some time in the spotlight in 2014. In November, the agency's Rosetta space probe was able to land on a comet 372 million miles from Earth called 67P/Churyumov-Gerasimenko.

It took Rosetta 10 years to reach and orbit the comet, then launch a lander down to the surface.

Rosetta's lander, Philae, took the first-ever surface images of a comet. 

In 2015, anthropologist Lee Berger announced that his team had discovered a new human ancestor species called Homo Naledi in South Africa.

Two spelunkers had accidentally stumbled across the Homo naledi fossils two years earlier, in a hidden cave 100 feet below the surface.

All told, the chamber contained 1,550 bones belonging to at least 15 individuals who all lived between 330,000 and 250,000 years ago.

2015 was also the year that scientists mapped the human epigenome for the first time.

The epigenome is made up of chemicals and proteins that can attach to DNA and modify its function — turning our genes on and off. 

An individual's lifestyle and environment —  factors like whether they smoke or what their diet looks like — can prompt sometimes deadly changes in their epigenome that can cause cancer.

Mapping the epigenome may help scientists understand how tumors develop and cancer spreads.

Humanity visited Pluto for the first time in 2015, when NASA's New Horizons probe flew by the dwarf planet.

New Horizons spent 15 minutes flying close to the dwarf planet and collecting as much information as possible. After that, it moved on for close encounter with Pluto's largest moon, Charon.

Another NASA spacecraft, Cassini, achieved new heights that same year. In September, astronomers announced that they had confirmed a liquid ocean exists under the icy crust of Saturn's moon Enceladus.

NASA's Cassini spacecraft found that Enceladus emits plumes of water into space following the probe's arrival in 2004. But in 2015, scientists confirmed that the source of these plumes was a giant saltwater ocean hidden beneath the moon's icy crust. 

Later that year, Space X launched and recovered the first-ever reusable rocket: the Falcon 9.

After the first-stage portion of the Falcon 9 launched was recovered, it was repurposed and re-launched in March 2017. 

In 2016, an artificial intelligence program from Google's DeepMind division named AlphaGo beat the world champion in four out of five matches of Go, a strategy game.

That wasn't the first time AI beat humans in a complex game.

In 2011, IBM's supercomputer, Watson, defeated two "Jeopardy!" champions — including Ken Jennings — in a three-day contest.

A year after AlphaGo's success, an AI named Libaratus beat four of the world's top professional players in 120,000 hands of no-limit, two-player poker. Then, in 2019, another DeepMind AI program named AlphaStar bested 99.8% of human players in the popular video game "Starcraft II." 

Physicists rejoiced in 2016 when they detected two black holes colliding a billion light-years away.

The catastrophic collision created ripples in space-time, also known as gravitational waves. Einstein predicted the existence of these gravitational waves in 1915, but he thought they'd be too weak to ever pick up on Earth. New detection tools have proved otherwise.

This collision was the first event scientists observed using gravitational-wave detectors. Then in 2017, they observed two neutron stars merging. In August 2019, astrophysicists detected the billion-year-old aftermath of a collision between a black hole and a neutron star (the super-dense remnant of a dead star).

The same year, astronomers also spotted evidence that a mysterious planet or object 10 times the size of Earth orbits in the outer solar system. They nicknamed it "Planet 9."

"For the first time in over 150 years, there is solid evidence that the solar system's planetary census is incomplete,"one of the planet's discoverers said

In 2017, geologists announced they'd discovered a new continent, called Zealandia, hidden under the Pacific Ocean.

The lost land of Zealandia sits on the ocean floor between New Zealand and New Caledonia.

It wasn't always sunken – researchers have found fossils that suggested novel kinds of plants and organisms once lived there. Some argue that Zealandia should be counted alongside our (more visible) seven continents.

In 2019, scientists found that another ancient continent had slid under what is now southern Europe about 120 million years ago. The researchers named this continent Greater Adria. Its uppermost regions formed mountain ranges across Europe, like the Alps.

That year brought a new breakthrough in genetics, too: Scientists successfully created synthetic DNA.

All living creatures' DNA is made up of two types of amino acid pairs: A-T (adenine – thymine) and G-C (guanine – cytosine). This four-letter alphabet forms the basis for all genetic information in the natural world.

But scientists invented two new letters, an unnatural pair of X-Y bases, that they seamlessly integrated into the genetic alphabet of E. coli bacteria.

Floyd Romesburg, who led the research, previously told Business Insider that his invention could improve the way we treat diseases. For example, it could change the way proteins degrade inside the body, helping drugs stay in your system longer. Romesburg said his team will be investigating how the finding might help cancer treatments and drugs for autoimmune diseases.

It was also a breakthrough year for self-driving car technology.

In September 2017, Audi announced it had produced the world's first "Level 3" autonomous car — meaning its self-driving mode requires no human feet, hands, or eyes. The A8 sedan can wholly, safely control itself in self-driving mode, only needing a human to take over in the event of bad weather or disappearing lane lines.

Tesla Autopilot drivers, for comparison, have to be ready to take over at any moment, so they're counseled to keep their eyes on the road at all times.

Just two months later, Waymo — the autonomous vehicle division of Alphabet, Google's parent company — revealed that it was testing self-driving minivans in the streets of Arizona without any humans at all behind the wheel. In 2018, Waymo launched the first fully autonomous taxi service in the US.

Astronomers also witnessed another interstellar collision in 2017. When two neutron stars collided, scientists were able to see how all the gold in the universe was created.

The two massive, exploded stars hit each other at one-third the speed of light and created gravitational waves. Scientific instruments on Earth picked up the waves from that crash, an event astronomers say only happens once every 100,000 years.

The crash happened 130 million light years away from Earth, researchers discovered. It caused the formation of $100,000,000,000,000,000,000,000,000,000 worth of gold and produced huge stores of silver and platinum, too.

That year, researchers at a Hawaiian astronomical observatory also observed the first interstellar object ever seen in our solar system, named 'Oumuamua.

Scientists only had a few weeks to study the interstellar interloper before it got too far, and too dim, to see with Earth-based telescopes.

Guesses as to what the object is run the gamut from comet to asteroid to alien spaceship. One Harvard University astronomer, Avi Loeb, has speculated that 'Oumuamua was an extraterrestrial scout, but nearly all other experts who have studied 'Oumuamua say that hypothesis is extraordinarily unlikely.

2017 was also a bittersweet year for astronomers who had to say goodbye to NASA's Cassini spacecraft, which took a fatal dive into Saturn in October.

Cassini had been exploring Saturn and its moons for 13 years before the probe plunged to its death on September 15. Scientists planned the crash to ensure that Cassini wouldn't one day run out of fuel and hit one of Saturn's potentially habitable moons (thereby contaminating it with Earthly bacteria).

During its final dive, Cassini beamed back amazing photos of Saturn as we'd never seen the planet before. That last portion of the mission began with a flyby of the planet's moon, Titan. Then Cassini jetted through a 1,200-mile opening between Saturn and its rings of ice — an unprecedented feat.

The spacecraft then angled down into the planet's clouds and burned up.

Toward the end of 2017, the US Food and Drug Administration (FDA) approved a new gene therapy treatment for blind people.

The cure for a form of hereditary blindness called leber congenital amaurosis is the first gene therapy approved by the FDA for an inherited disease.

The treatment, called Luxturna, is a one-time virus dose that gets injected into a patient's retina. The corrected gene in the virus taps out the flawed, blindness-inducing gene in the eye, and produces a key vision-producing protein that patients with the disease normally can't make.

People start noticing a difference in their sight within a month. In clinical trials of the treatment, 13 out of 20 patients saw positive results. The treatment could cost as much as $1 million for a single injection, however.

The following year, genetics news of a very different nature came out: Chinese geneticist He Jiankui announced he had successfully genetically modified human embryos.

Jiankui claimed to have edited genes in a pair of twins born in China in November. By using the DNA-editing technique called CRISPR, he said, the babies were born immune to HIV.

This type of genetic manipulation is banned in most parts of the world, since any genetic mutations that the babies may have would get passed on to their offspring, with potentially disastrous consequences. 

In 2019, the MIT Technology Review released excerpts from Jiankui's research. The unpublished manuscripts revealed that in the process of trying to manipulate the babies' HIV resistance — which some experts say was unsuccessful— Jiankui may have introduced unintended mutations.

In 2018, NASA launched another rover to the red planet. InSight touched down on November 26.

NASA's InSight lander spent more than six months careening through space before it landed safely on Martian soil.

The robot is charged with exploring Mars' deep interior and helping scientists understand why Mars wound up a cold desert planet while Earth did not.

InSight has given scientists the unprecedented ability to detect and monitor Mars quakes— seismic events deep inside the planet.

On Earth, scientists have made monumental — though often troubling — discoveries throughout the decade. In 2018, scientists found that atmospheric carbon dioxide had reached its highest level in at least 800,000 years.

Fossil fuels like coal contain carbon dioxide, methane, and other compounds that trap heat from the sun. When we extract and burn these fuels for energy, that releases those gases into the atmosphere, where they accumulate and heat up the Earth over time.

That's what made 2016 the hottest year on record. So far, 2019 is the second-hottest year since records began 140 years ago, with July being the hottest month ever recorded.

A landmark report by the Intergovernmental Panel in Climate Change (IPCC) warned that slashing greenhouse-gas emissions in the next decade is crucial in order to avoid the worst consequences of severe climate change.

Climate researchers have also found that the Antarctic and Greenland ice sheets are melting at unprecedented rates.

An April 2019 study revealed that the Greenland ice sheet is sloughing off an average of 286 billion tons of ice per year. Two decades ago, the annual average was just 50 billion.

In 2012, Greenland lost more than 400 billion tons of ice

Antarctica, meanwhile, lost an average of 252 billion tons of ice per year in the last decade. In the 1980s, by comparison, Antarctica lost 40 billion tons of ice annually.

What's more, parts of Thwaites Glacier in western Antarctica are retreating by up to 2,625 feet per year, contributing to 4% of sea-level rise worldwideA study published in July suggested that Thwaites' melting is likely approaching an irreversible point after which the entire glacier could collapse into the ocean. If that happens, global sea levels could rise by more than 1.5 feet.

On January 1, 2019, NASA's nuclear-powered New Horizons spacecraft flew past a mysterious, mountain-sized object 4 billion miles from Earth.

The object, called MU69, is nicknamed Arrokoth, which means "sky" in the Powhatan/Algonquian language (it was previously nicknamed Ultima Thule). It's the most distant object humanity has ever visited.

The New Horizons probe took hundreds of photographs as it flew by the space rock at 32,200 miles per hour.

Images revealed that Arrokoth is flat like a pancake, rather than spherical in shape. The unprecedented data will likely reveal new clues about the solar system's evolution and how planets like Earth formed, though scientists are still receiving and processing the information from the distant probe.

Over 5.5 million miles from Earth, a Japanese spacecraft landed on the surface of an asteroid called Ryugu in July.

The Japan Aerospace Exploration Agency (JAXA) launched its Hayabusa-2 probe in December 2014. Hayabusa-2 arrived at Ryugu in June 2018, but didn't land on the asteroid's surface until this year.

In order to collect samples from deep within the space rock, Hayabusa-2 blasted a hole in the asteroid before landing. The mission plan calls for the probe to bring those samples back to Earth. By studying Ryugu's innermost rocks and debris — which have been sheltered from the wear and tear of space — scientists hope to learn how asteroids like this may have seeded Earth with key ingredients for life billions of years ago.

2019 was also a watershed year for the study of black holes. In April, the Event Horizon Telescope team published the first-ever image of a black hole.

The unprecedented photo shows the supermassive black hole at the center of the Messier 87 galaxy, which is about 54 million light-years away from Earth. The black hole's mass is equivalent to 6.5 billion suns. 

Though the image is somewhat fuzzy, it showed that, as predicted, black holes look like dark spheres surrounded by a glowing ring of light.

Scientists struggled for decades to capture a black hole on camera, since black holes distort space-time, ensuring that nothing can break free of their gravitational pull — even light. That's why the image shows a unique shadow in the form of a perfect circle at the center.

NASA scientists also discovered an exoplanet that could be our best bet for finding alien life outside our solar system.

In September, scientists announced they'd detected water vapor on a potentially habitable planet for the first time. The planet, K2-18b, is a super-Earth that orbits a red dwarf star 110 light-years away.

NASA's planet-hunting Kepler space telescope discovered K2-18b in 2015, three years before the telescope was shut down. During its nine-year mission, Kepler discovered more than 2,500 exoplanets.

But K2-18b is the only known planet outside our solar system with water, an atmosphere, and a temperature range that could support liquid water on its surface. That makes it our "best candidate for habitability," one researcher said.

After three decades of research and development work, the world's first malaria vaccine program began in April.

In the pilot program, children up to 2 years old in Malawi, Ghana, and Kenya can receive the vaccine. The new vaccine prevented 4 in 10 malaria cases in clinical trials, including 3 in 10 life-threatening cases.

Malaria kills about 435,000 people each year, most of them children. 

"We need new solutions to get the malaria response back on track, and this vaccine gives us a promising tool to get there," Tedros Adhanom Ghebreyesus, director-general of the World Health Organization, said in a release. "The malaria vaccine has the potential to save tens of thousands of children's lives."

In December, the World Health Organization (WHO) prequalified an Ebola vaccine for the first time, a critical step that will help speed up its licensing, access, and roll-out.

The vaccine comes in addition to two experimental treatments proven to dramatically boost Ebola survival rates.

The two new treatments, called REGN-EB3 and mAb-114, are cocktails of antibodies that get injected into people's bloodstreams. These therapies saved about 90% of new infected patients in the Congo after the WHO declared the Ebola outbreak in Africa to be a global health emergency.

Morgan McFall-Johnsen contributed to this story.

What if Santa really delivered presents in one night?

  • If Santa really delivered presents on Christmas Eve, he'd need to fly over a thousand times faster than the world's faster jet fighter to visit  about 240 million homes. If every kid received one mid-sized LEGO set, the gifts would weigh a whopping 600,000 tons.
  • Just like a spacecraft heats up when re-entering the atmosphere, the reindeer would heat to blistering temperatures that would turn vaporize them! Meanwhile, a force tens of thousands of times stronger than gravity would pin him to the sleigh, smashing his bones and internal organs into jelly.
  • On the brighter side, Santa would snack on 720 million sugar cookies and drink enough milk to fill 23 Olympic sized swimming pools!
  • Visit Business Insider's homepage for more stories.

Following is a transcript of the video.

Narrator: Every Christmas Eve, certain traditions say that Santa has just one night to deliver presents to millions of children around the globe. Now, this might seem unreasonable from a scientific perspective. But we wondered, exactly how unreasonable is it?

Overall, it's difficult to determine how many people around the world celebrate a Santa-centric Christmas on December 25th. But if we consider certain religious and cultural traditions, we get a rough estimate of about 600 million people. Now, let's say each household has, on average, two and a half kids. So Santa only needs to visit 240 million homes. Even better? He has more time to get the job done than you might think. Legend has it that he drops by when the kids are asleep. So that gives him eight hours, right? Well, hold up. We mustn't forget about time zones. There are 24 broad time zones worldwide, each one hour apart. So factor in the different Christmas Eve start times across the planet, and Kringle's got a luxurious 31 hours to make his deliveries.

Unfortunately, this is where his luck runs out. Because just to reach every house, he'll have to fly 1,200 times faster than the world's fastest jet fighter. That's a lot to ask of nine reindeer, which can only gallop up to 80 kilometers per hour on average. Way too slow.

But to be fair, that's the best they can do on the ground. Since we don't know exactly how fast a reindeer can fly, let's assume they can manage those incredible speeds. Even then, the load they have to lug is much too heavy for them. If every kid receives a single mid-sized Lego set, the bag alone would weigh a whopping 600,000 tons, or about 20 Statue of Liberties. Meanwhile, the average reindeer can pull up to twice their weight, or about 225 kilograms. So those deer aren't going anywhere. And even if they could, well, it wouldn't be pretty.

For starters, the team would create a massive sonic boom as they hurdle through the air at 3,000 times faster than the speed of sound, deafening any bystanders on the ground below. Merry Christmas folks! But it gets worse. Once Rudolph and Co. take off, they vaporize before they reach their first house. Just like how a rocket heats up when it reenters the atmosphere at tremendous speeds, the reindeer would heat to blistering temperatures that would turn them into venison jerky.

And Santa wouldn't fare much better because he's sitting on what amounts to the worst roller-coaster ride on Earth. When a typical coaster accelerates, you get pushed back against your seat. But in Santa's case, to accelerate to those extreme speeds makes for a much stronger push. A force tens of thousands of times stronger than gravity would pin into the sleigh, smashing his bones and internal organs to jelly.

But it's not all doom and gloom. Let's assume Santa and friends miraculously survive this ordeal. He slips his conveniently boneless body through chimney after chimney, drops off the gifts, and now gets to munch on his well-deserved treats. A lot of treats. If every household offers him three sugar cookies and one 8-ounce glass of whole milk, that's 720 million cookies and enough milk to fill 23 Olympic swimming pools total. Now, that adds up to 396 billion calories. Plenty to see him through his hibernation until Christmas comes round again.

SEE ALSO: What if the Earth stopped orbiting the Sun?

Join the conversation about this story »

An incredible animation by a planetary scientist shows how fast each planet spins by putting them in one giant globe


planet rotations animation

Every planet turns to its own beat, and a new animation from a video-savvy scientist shows just how different those rotations are.

James O'Donoghue, a planetary scientist at the Japanese space agency (JAXA) and formerly at NASA, spends his free time making animations of space concepts like the history of the moon and the vastness of our solar system.

He recently created a video showing slices of each planet spinning at its own speed — all in one giant globe.

"I had the idea to make this back in December last year but I didn't think people would be interested in it," O'Donoghue said on Twitter when he shared a clip of the animation. As of Friday, that version of the video had over 215,000 views.

The animation, below, shows how quickly the planets spin on their axes relative to one another. Jupiter, for example, rotates 2.4 times faster than Earth.

As one commenter pointed out on Twitter, it can be weird to watch Africa and South America making their rounds near the North Pole of this stitched-together globe. Earth's position falls there, however, because O'Donoghue lined up the planets in their order from the sun, from Mercury to Neptune.

"I picked the slices of latitude of each planet that were most interesting," he explained. 

O'Donoghue picked the piece of Jupiter that has its Great Red Spot, the part of Neptune where its darkest storm brews, and a slice of Saturn that shows high contrast between its clouds.

You might also notice that the strip second from the bottom spins in the opposite direction of the others. That's Uranus, which is tilted nearly 90 degrees, meaning that it appears to spin on its side and backwards (relative to the other planets).

Venus also spins counterclockwise — it's the second strip from the top of O'Donoghue's globe. But the planet rotates so slowly that you can barely tell it's moving backwards. It takes 243 Earth days for Venus to rotate once.

In the last year, O'Donoghue has created a slew of scientific animations like this. His first were for a NASA news release about Saturn's vanishing rings. After that, he moved on to other difficult-to-grasp concepts, like the torturously slow speed of light.

"My animations were made to show as instantly as possible the whole context of what I'm trying to convey," O'Donoghue previously told Business Insider. "When I revised for my exams, I used to draw complex concepts out by hand just to truly understand, so that's what I'm doing here."

SEE ALSO: A stunning animation by a planetary scientist shows how huge our solar system is — and why that makes it so hard to depict

DON'T MISS: An incredible video shows what we would see if the planets replaced the moon. But that would turn Earth into a volcanic hellscape.

Join the conversation about this story »

NOW WATCH: The worst storms on Earth are nothing compared to the weather on other planets

Legendary mathematician and physicist Freeman Dyson has died at the age of 96


Freeman Dyson

Legendary mathematician and physicist Freeman Dyson has died at the age of 96, according to a press release issued by the Institute for Advanced Study. 

The British-born mathematician and physicist, best known for unifying the three versions of quantum electrodynamics invented by Richard Feynman, suffered a fall on his way to his office, his daughter Mia Dyson first told the Maine Public. He passed away on Friday. 

Dyson had a colorful career: He worked as a civilian scientist for the Royal Airforce in World War II, before attending Cambridge University to get his undergraduate degree in mathematics. He went on to do graduate work in Cornell University, and became a professor there despite never having formally gotten a PhD.

Dyson worked on a diverse range of physics and mathematical problems: nuclear reactors, solid-state physics, ferromagnetism, astrophysics, and biology (one of his ideas, the Dyson Sphere, was even featured in a "Star Trek" episode). He won the Max Planck Medal and the Templeton Prize, and wrote often-quoted books like "Disturbing the Universe" and "The Scientist as Rebel."

He also kept track of the politics that later surrounded his expertise. Notably, he was among 29 scientists who supported the Obama administration's 2015 nuclear deal with Iran. He also acted as a a military adviser regarding the use of nuclear weapons during the Vietnam War in 1967.

And in 2009, he was the subject of a lengthy profile in the New York Times Magazine after expressing his skepticism about the scientific predictions surrounding climate change. He stuck to that conviction, telling NPR in 2015 that, "I'm not saying the climate disasters aren't real, I'm merely saying we don't know how to prevent them."

Dyson is survived by his wife of 64 years and six children. 

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NOW WATCH: Jeff Bezos reportedly just spent $165 million on a Beverly Hills estate — here are all the ways the world's richest man makes and spends his money

Astronauts on the space station are helping to forge a bizarre 5th state of matter that disappears in seconds on Earth


NASA International Space Station

  • Researchers created a fifth state of matter in 1995, the Bose-Einstein condensate (BEC), by cooling atoms to temperatures lower than in interstellar space.
  • BECs don't exist naturally and have only seconds-long lifespans when subject to the force of gravity.
  • By creating BECs in space, researchers can study this form of matter for longer.
  • Astronauts on the International Space Station have helped scientists successfully and consistently create BECs in orbit, a new study reports. This could aid research into the mysteries surrounding gravity and the expansion of the universe.
  • Visit Business Insider's homepage for more stories.

NASA sent a dishwasher-sized box of lasers up to the International Space Station two years ago. The goal: create a bizarre, fifth form of matter that's not found in nature — the Bose-Einstein condensate.

This type of matter consists of clouds of a few million atoms that have been chilled with lasers inside a vacuum, to temperatures even lower than in interstellar space. At such super-low temperatures, atoms lose their individuality and blob together. This makes it easier for researchers to study the quantum world: a subatomic realm in which everything is smaller than a single atom.

The box of lasers, fittingly, is called the Cold Atom Laboratory

While Bose-Einstein condensates (BECs) have been made on Earth for 25 years, gravity makes them difficult to study; it yanks them to the ground, making them disappear within fractions of a second.

In space, however, it's a different story. A study published June 11 in the journal Nature reports that the Cold Atom Lab on the space station has successfully and consistently created BECs in microgravity. That gives researchers opportunities to examine the ultracool matter for longer periods of time than on Earth.

"It was recognized early on that microgravity would come in handy, and going to space would give us a lot of advantages in terms of measurement time," David Aveline, the lead author of the study and a scientist at NASA's Jet Propulsion Lab, told Business Insider. 

More time to measure BECs means more precise measurements — and that could help researchers study gravitational waves and dark energy.

An unprecedented space laboratory 

cold atom lab

Ever since the first Bose-Einstein condensate was created in 1995, researchers have been searching for ways to extend the matter's lifespan beyond a second or two. Some researchers have tried to create their own microgravity environments by throwing a BEC-creating apparatus off a 440-foot tower to achieve free-fall. Some weightless experiments have also been done inside a rocket.

"It takes a lot of effort to gather a few measurements," Aveline said.

By contrast, the Cold Atom Laboratory (CAL) has endless microgravity, so it can collect data for years. 

"We're getting to make BECs on a daily basis, for many hours a day," Aveline said. "CAL is completely remote-controlled. We're running it from computers on the ground, literally inside our living rooms."

Christina Koch working on cold atom lab

Originally, NASA's goal was to have CAL function for one year before it would need replacement parts, Aveline said. But thanks to astronauts like Christina Koch who check up on it and occasionally update its hardware, the floating laboratory just passed its two-year mark in space.

Bose-Einstein condensates teach us about the quantum world

CAL uses lasers and magnets to chill atoms to within 1 10-billionth of a degree above absolute zero (minus 459.67 degrees Fahrenheit, or minus 273.15 degrees Celsius). 

Typically, atoms are arranged in a particular order to create matter like solids, liquids, and gases. But Albert Einstein and physicist Satyendra Nath Bose predicted in 1924 that if atoms could be cooled enough, they'd lose their individuality. That would lead them to form a lump of mass about 1 millimeter across that behaves as one entity. This is a BEC, sometimes known as a superfluid.

albert einstein office

The reason scientists care about BECs is because they bridge the gap between the world we can see — which is governed by classical physics — and the subatomic world, in which quantum physics reigns.

"They're like the holy grail" of quantum physics, Aveline said.

Quantum physics describes the behavior of the smallest things in the universe. According to its laws, tiny particles like electrons could be in many places at the same time. So physicists describe those electrons using probabilities that show how likely it is an electron is positioned in a certain configuration at a given time.  

The atoms in BECs follow quantum laws, but because they've blobbed together, they're large enough to be observed with a microscope — which enables scientists to measure them and observe their behavior.




bose einstein condensate

What CAL's experiments can teach us 

One piece of new hardware that Koch installed into CAL is an atom interferometer, an instrument that uses BECs to measure changes in gravity across a planet's surface.

"Analyzing the gravitational field of our planet can tell us a lot about its structure (is water or stone or oil below?), and analyzing its variation can teach us about processes going on (how much does the water level of the oceans rise?)," Maike Lachmann, a physicist at Leibniz University, told Business Insider in an email.

The applications for this type of measurement are huge, according to Lachmann and Aveline — it can help scientists understand what's happening under Earth's surface and also map moons and other planets.

apollo 13 mission moon surface craters nasa projectapolloarchive flickr 21412012804_8365886a58_o

Additionally, physicists are looking into using atom interferometry to measure gravitational waves or other potential sources of energy in the universe, like dark energy.

Dark energy is the force that's making space expand; it accounts for 70% of the universe. (The remaining chunk is 25% dark matter — an unseen particle that exudes a large gravitational force — and 5% normal matter, which makes up everything we see.)

Some researchers suspect that dark energy and dark matter are derived from not-yet-seen particles called axions and solitons. A study last month suggested that BECs could be used to detect those axions.

Other research from 2015 and 2016 used BECs to probe for different possible sources of dark energy.

Measuring dark energy is critical, since scientists think it could be responsible for accelerating the universe's expansion — pushing galaxies apart at an ever-faster rate.

A study published last year found that the universe is expanding 9% faster than scientists predicted it should be — a finding one Nobel-prize winner said"may be the most exciting development in cosmology in decades."

David Mosher contributed reporting to this story.

SEE ALSO: Researchers have succeeded in creating a fifth state of matter in space

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NOW WATCH: This mind-melting thought experiment of Einstein's reveals how to manipulate time

An underground dark-matter experiment may have stumbled on the 'holy grail': a new particle that could upend the laws of physics


xenon dark matter experiment

  • A dark-matter experiment in an underground Italian lab may have discovered a new particle called the solar axion.
  • If that's indeed what was detected, it would be the first direct evidence of a particle that shouldn't exist according to the known laws of physics.
  • Alternatively, the data could also reveal new and surprising qualities of mysterious particles called neutrinos.
  • Larger, more sensitive experiments in the next year will help scientists figure out whether they have indeed discovered a new particle.
  • Visit Business Insider's homepage for more stories.

An underground vat of liquid xenon in Italy may have just detected a new particle, born in the heart of the sun.

If that's indeed what happened, it could upend laws of physics that have held fast for roughly 50 years.

Researchers created the underground vat to search for dark matter, the elusive stuff that makes up 85% of all matter in the universe. Scientists know dark matter exists because they can measure the way its gravity affects faraway galaxies, but they've never detected it directly before.

That's why an international group of researchers built the experiment at Italy's Gran Sasso National Laboratory. The vat is filled with 3.2 metric tons of liquid xenon, and those atoms interact with tiny particles when they collide. Each interaction, or "event," produces a flash of light and sheds electrons.

In theory, this experiment is sensitive enough to detect interactions with particles of dark matter.


In the latest version of the experiment, researchers expected the machine to detect 232 events within a year, based on known particles. But instead, it detected 285 events — 53 more than predicted.

What's more, the amount of energy released in those extra events corresponded with the predicted energies of a yet-undiscovered particle called the solar axion: a type of particle that physicists have hypothesized exists but never observed.

"The hypothetical particle that could potentially explain the XENON data is one that is much too heavy to be dark matter, but could be created by the sun," Sean Carroll, a physicist at the California Institute of Technology who is not affiliated with XENON, told Business Insider. "If that were true, it would be hugely important — it would be a Nobel Prize-winning finding."

It's also possible, however, that the interactions were anomalies, which pop up all the time in highly sensitive physics experiments like XENON.

A new particle forged in the heart of the sun

sun solar eruption

Particle physicists study the smallest, most fundamental components of the universe: elementary particles like quarks and gluons, along with forces like gravity and electromagnetism.

"Particle physics is an important part of modern physics, but it's also been stuck for a long while," Carroll said. "The last truly surprising discovery in particle physics was in the 1970s."

That's when what's known as the Standard Model was established — a set of all the rules known to particle physics, which describe all the particles scientists have detected and how they interact with one another.

"With it we can essentially explain every single thing we see in a particle-physics laboratory," Aaron Manalaysay, a dark-matter physicist at Lawrence Berkeley National Laboratory who is unaffiliated with XENON, told Business Insider. "It's probably the most accurate scientific model in history. But we also have good reason to think that it's not the most fundamental model of nature that exists."

Engineers assembled the Xenon experiment's electric field cage.

Physicists have hints that the model doesn't fully capture the way our universe behaves — their indirect observations of dark matter are among those hints. But they have yet to directly detect a particle that lies beyond the Standard Model.

That's why it would be a big deal if XENON really has found a solar axion.

"That would be the first concrete discovery of something beyond the Standard Model," Manalaysay said. "That's kind of the holy grail right now of particle physics."

Carroll agreed — but he added that the unprecedented nature of the potential discovery "is one of the reasons we think it's probably not there."

In other words, without further evidence, nobody is celebrating yet.

For now, several other theories could also explain the extra events XENON researchers saw.

Misbehaving neutrinos could point to a 'new physics'

xenon dark matter experiment photomultiplier tubes array

Another possible explanation for XENON's 53 extra events is that neutrinos — a subatomic particle with no electrical charge — could have driven the interactions.

That would also defy the known laws of physics, though, since it would mean that neutrinos have a magnetic field much larger than what the Standard Model predicts.

"That could point potentially to new physics beyond the Standard Model," Manalaysay said.

xenon dark matter experiment tank

It wouldn't be the first time neutrinos have broken the rules. According to the Standard Model, neutrinos shouldn't have mass — yet they do. The discovery that they have a sizable magnetic field would be yet another clue that something is missing from the model.

"Neutrinos are really strange beasts, and we don't really understand them," Manalaysay said.

Larger, more sensitive dark-matter experiments are coming

xenon dark matter experiment computer daq data

It's also possible that XENON's extra events didn't happen at all — though that's unlikely. The researchers calculated a chance of two in 10,000 that the detected events were due to random fluctuation.

The signals may have come from other mundane particle interactions, however, making their explanation far less interesting than axions or neutrinos. The extra events could have come from tiny amounts of tridium, a radioactive isotope of hydrogen, decaying inside the vat. Argon isotopes would produce a similar effect, according to Manalaysay.

"It wouldn't take much. It would just take a few atoms," he said, adding that a number of other things unknown to the researchers could also be responsible for the excess interactions.

"We've gone down this road before, where there's a little bit of an anomaly that you aren't expecting ... and then it goes away," Carroll said. "So this is clearly a place where you need to do a better experiment, and they're planning to do exactly that."


A new generation of XENON-like experiments, currently in the works in the US and Europe, should help researchers study these extra events and determine which particles are causing them. That's because the new experiments will be larger and significantly more sensitive.

"If this is real, we will absolutely see it in our next generation of experiments," Manalaysay said. He has worked with one such effort, called the Large Underground Xenon dark-matter experiment. "It's like you're going into a quieter and quieter room ... You start hearing new things you couldn't hear in a louder room."

Whereas XENON picked up 53 unexplained events, the successor to LUX — called LUX-ZEPLIN — could detect 800, according to Manalaysay. Despite delays caused by the coronavirus, he added, new experiments will likely be running and returning results "within the next year."

"It's like a teaser," he said. "The season's finale ends on a cliff-hanger, and you've got to wait until the next season."

SEE ALSO: A 'spooky' effect of physics that Einstein couldn't believe has been photographed for the first time

DON'T MISS: The US is building its first new particle collider in decades on Long Island. Stephen Hawking called the technology a 'time machine.'

Join the conversation about this story »

NOW WATCH: The most powerful physics machine on Earth may have found something that breaks the laws of physics as we know them

The Beirut explosion created a huge mushroom cloud and visible blast wave, but nuclear-weapons experts say it wasn't an atomic bomb. Here's why.


A picture shows the scene of an explosion in Beirut on August 4, 2020

  • An explosion at a port rocked the Lebanese capital city of Beirut on Tuesday, killing at least dozens of people.
  • As videos of the explosion spread across social-media sites, some observers likened the appearance of a mushroom cloud to that of an atomic bomb.
  • The Lebanese prime minister has said the blast came from a stockpile of ammonium nitrate in a warehouse.
  • Nuclear-weapons experts say the detonation was definitely not triggered by an atomic bomb.
  • Atomic explosions are characterized by a blinding flash of light, a pulse of searing heat, and radioactive fallout, none of which were detected.
  • Visit Business Insider's homepage for more stories.

When an enormous explosion created a mushroom cloud over Beirut on Tuesday, killing at least dozens of people and injuring thousands more, online observers and conspiracy theorists quickly jumped to a frightening conclusion: A nuclear bomb had gone off in Lebanon's capital city. But as state officials say, and contrary to those fast-spreading rumors, the explosion was almost certainly not caused by a nuclear weapon.

Even before Lebanese officials said the explosion was caused by a large stockpile of ammonium nitrate stored in a warehouse at the port, according to The Guardian, experts who study nuclear weapons quickly and unequivocally rejected the idea that Beirut had been hit with a nuclear bomb.

Key to those rejections are the videos that Beirut residents managed to record of the huge detonation.

People had trained cameras on the Beirut port at the time of the blast because a worrisome cloud of smoke rose beforehand. Some of those videos show small flashes of light and reports (or sounds) that are distinctive to fireworks. Moments later, the huge explosion — which came with a visible blast wave and mushroom-like cloud of smoke — rocked the area, destroying nearby buildings and shattering distant windows.

In a tweet that accumulated thousands of likes and reshares before it was deleted, one user wrote: "Good Lord. Lebanese media says it was a fireworks factory. Nope. That's a mushroom cloud. That's atomic."

Vipin Narang, who studies nuclear proliferation and strategy at the Massachusetts Institute of Technology, immediately spiked the claim. "I study nuclear weapons. It is not," Narang tweeted on Tuesday.

Martin Pfeiffer, a doctoral candidate at the University of New Mexico who researches the human history of nuclear weapons, also rejected assertions on social media that a "nuke" caused the blast. "Obviously not a nuke," Pfeiffer tweeted, saying later: "That's a fire setting off explosives or chemicals."

Pfeiffer indicated that the explosion lacked two hallmarks of a nuclear detonation: a "blinding white flash" and a thermal pulse, or surge of heat, which would otherwise start fires all over the area and severely burn people's skin.

The explosion did trigger a powerful blast wave that apparently shattered windows across Beirut, and it was briefly visible as an expanding, shell-like cloud — something often seen in historical footage of nuclear detonations. But Pfeiffer noted such blast-wave clouds, known to weapons researchers as Wilson clouds, are made when humid air gets compressed and causes the water in it to condense. In other words: They aren't unique to nuclear bombs.

A back-of-the-envelope calculation reshared on Twitter by Narang estimates the blast was equivalent to about 240 tons of TNT, or about 10 times what the US military's "mother of all bombs" is capable of unleashing. By contrast, the Little Boy atomic bomb that the US dropped on the Japanese city of Hiroshima in 1945 was about 1,000 times as powerful.

As a counterpoint to suggestions the Beirut explosion was caused by a nuclear weapon, Pfeiffer offered a video showing the detonation of a rocket-propelled "Davy Crockett" nuclear weapon, which exploded with a force equivalent to about 20 tons of TNT.

The Davy Crockett was one-tenth as strong as the estimated strength of the Beirut explosion but still had a distinctive flash that's missing from Tuesday's blast. No reports suggest there was radioactive fallout after the Beirut blast, which would have been quickly detected.

It's perhaps unsurprising that some might speculate such a large blast in a major city might be an act of nuclear terrorism. In fact, it's one of 15 disaster scenarios the US government has simulated and planned for (to the point at which it created scripts for local authorities to use after such an attack).

But in this case, Beirut's tragedy was not in any way nuclear.

SEE ALSO: I just nuked Manhattan in a realistic new VR simulation, and the experience changed how I understand the bomb

DON'T MISS: If a nuclear weapon is about to explode, here's what a safety expert says you can do to survive

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NOW WATCH: Here's how easy it is for the US president to launch a nuclear weapon

NASA patented a faster, cheaper route to the moon. The first spacecraft to use it could make Nobel Prize-winning discoveries about the universe.


dapper Dark Ages Polarimeter Pathfinder spacecraft mission concept moon farside university colorado boulder nasa

Summary List Placement

The moon is both seductively close to Earth and cosmically far away: Decades after the end of the space race, it remains extraordinarily expensive and difficult to actually get there.

The journey just got a bit easier, however, thanks to a freshly published NASA invention. The agency's patent doesn't cover a new piece of equipment or lines of code, but a trajectory — a route designed to save a lunar-bound mission time, fuel, and money and boost its scientific value.

On June 30, the US Patent and Trademark Office granted and published NASA's patent for a series of orbital maneuvers, which Business Insider first learned about via a tweet by a lawyer named Jeff Steck.

The technique isn't meant for large spaceships that carry astronauts or rovers, but for smaller, more tightly budgeted missions tasked with doing meaningful science. And the first spacecraft to take advantage of this new orbital path could deliver unprecedented discoveries from the far side of the moon.

Called the Dark Ages Polarimeter Pathfinder, or Dapper, the upcoming mission aims to record, for the first time, low-frequency radio waves emitted during the earliest epochs of the universe — when atoms, stars, black holes, and galaxies were just beginning to form, and where scientists may detect the first signals of as-yet-unseen dark matter.

Charting a new budget-friendly path to the moon

dare dark ages radio explorer spacecraft mission gto geosynchronous transfer orbit patent graphics earth moon nasa

When NASA launched three astronauts to the moon in 1968, it took the crew just a few days to get there. Such direct shots are expensive, though, requiring an enormous rocket to climb out of Earth's deep gravity well.

There are far more efficient paths to the moon that can use smaller rockets — if you have time to spare, which robots do. By taking time to swing around the Earth, for instance, a spacecraft can steal some of the planet's momentum and slingshot out to the moon in a series of long orbits that cost it little to no fuel.

Fuel remains necessary to correct orbits and maneuver through space, but every ounce a spacecraft carries is mass that an engineer can't dedicate toward other components, including scientific instruments.

The calculus is especially tricky for compact spacecraft like Dapper, which would be about the size of a microwave, since there is (quite literally) less margin for error. Faced with the extra challenge of trying to fly Dapper on a relatively thin $150 million budget from NASA's Explorers program, the team behind the mission concept realized they couldn't buy their own rocket ride all the way to lunar orbit.

"This trajectory to the moon arose out of necessity, as these things often do,"Jack Burns, an astrophysicist at the University of Colorado Boulder and leader of the Dapper mission, told Business Insider. "We needed to keep the launch costs low and find a cheap way to get to the moon."

They started with a flight they knew they could afford: one to geosynchronous or high-Earth orbit, a region about 22,236 miles from Earth's equator (about one-tenth of the way to the moon). It's a common destination for telecommunications and other satellites built to hover above one spot on the planet. Dapper is small enough to piggyback on such missions.

"If we could just get a launch into high-Earth orbit, geosynchronous orbit, then we could get the rest of the way there with only a modest tank of fuel," Burns said.

After crunching the numbers, the team found a new low-energy trajectory to the moon, which their patent describes as a "method for transferring a spacecraft from geosynchronous transfer orbit to lunar orbit." It enlists the help of Earth and the moon's gravity to speed up and slow down Dapper at the right moments, cutting down on the amount of propellant required. NASA says this new spin on the gravity assist keeps the flight time to about 2 1/2 months, whereas similar options can take six months.

The trajectory also comes with numerous options to slip a spacecraft into an orbit of any angle around the moon, at practically any time. And it avoids a zone of radiation around Earth called the Van Allen belts, which can damage sensitive electronics.

Why NASA is patenting and licensing ways to reach the moon

earthrise earth from moon apollo 8 nasa

It may seem odd to patent lunar travel, but Burns said it is really no different from any other invention. "It's a creation that was the result of doing numerical modeling of planetary trajectories, he said. "So it is intellectual property."

NASA patents and licenses inventions to achieve the "widest distribution" of a technology, Dan Lockney, a NASA executive, told IPWatchdog in 2018.

"Securing patents and licensing the technologies is a method NASA and other government agencies use to ensure access to government-funded innovations," Clare Skelly, a NASA representative, told Business Insider in an email.

The agency charges as much as $50,000 to license its patents but typically asks for $5,000 to $10,000, plus royalties. "It is through the upfront fees that NASA seeks to recover some of its investment in the patent filing and maintenance costs," the agency's licensing website says.

In other words: Doing the grunt work of patenting and then charging a minimum for that work is a formal and industry-compatible practice of disseminating the fruits of NASA's labors.

Unofficially, NASA's scheme also keeps private companies and foreign nations from stockpiling important space technologies for exorbitant sums, and that helps foster American missions and international collaborations. (The agency does occasionally release patents into the public domain.)

Burns said he didn't believe that NASA will "ever make any money" off the new trajectory patent, since it's often a matter of historical record-keeping.

"It just is a marker that lays down that this was your intellectual property — you did this, and you were the creator of it — so that at least when people use it, they give credit," he said.

2 Nobel Prizes may await in the lunar 'cone of silence'

dapper Dark Ages Polarimeter Pathfinder spacecraft mission moon radio cone silence map apj

Dapper's goal is to study the universe from a "cone of silence" on the far side of the moon. In that solitary region, humanity's cacophony of wireless emissions can't interfere with antennas trying to pick up weak, low-frequency emissions from more than 13 billion years ago.

"This is the only truly radio-quiet region in the inner solar system," Burns said. Humanity's pollution of radio waves — which leak out of almost every electronic device — can easily bend around corners and over horizons (so erecting barriers to block them is fruitless). "In order to get the same amount of quiet, you'd have to go out past the orbit of Jupiter, and go that far out in order for the noise just from Earth."

Specifically, the mission seeks to detect radio emissions of the "neutral hydrogen" that dominated the very early universe. The cosmos produced the nuclei, or cores, of these first-ever atoms within a microsecond of the Big Bang; the event's dense, hot soup of energy had expanded and cooled off, permitting protons, neutrons, and electrons to form. About 380,000 years later, that particle soup had cooled off further, allowing the positively charged protons to capture negatively charged electrons and become neutrally charged hydrogen atoms.

The phase is often called the "Dark Ages" because, in visible wavelengths of light, a human wouldn't have seen anything.

"There's no stars. There's no galaxies. There's no other source of radiation. So how do you probe that part of the universe?" Burns said. "You use the one thing that you've got a lot of, which is neutral hydrogen."

The problem is that those radio signals, which reach Earth in the 10-to-100-megahertz range, not only are scrambled by our planet's atmosphere, but match the emissions of countless power supplies, garage-door openers, radio transmitters, space satellites, digital TV signals, and more.

"The radio spectrum down at these frequencies? It's just absolutely filled with garbage," Burns said. Even in space, there's so much interference from humanity and the sun that the radio-equivalent temperature around Earth is "nearly a million degrees," Burns said.

By slipping behind the moon at a moment when the sun is blocked as well as the Earth, Dapper is expected to make the first clear recordings of neutral hydrogen signal. The spacecraft might also gather evidence of the first stars, and possibly the first black holes and galaxies that formed about 500 million years after the Big Bang, during an epoch called "Cosmic Dawn."

And maybe — just maybe — the spacecraft could turn up the first direct detection of dark matter, which makes up about 80% of the mass in the universe but has yet to be identified.

For the researchers that successfully pull off such a mission, two Nobel Prizes in science could await.

"One is you're detecting when the first stars and galaxies form and what they are. And No. 2, you're detecting dark matter," said Burns, who pooh-poohed the idea of winning any such prize himself.

The race to the early-universe radio emissions is on

big bang

Burns and others came up with the Dark Ages Radio Explorer lunar mission about 10 years ago, which is why that mission and not Dapper is described in the patent, which NASA filed in 2015. (The USPTO is a notoriously slow-moving federal organ.)

Burns said that while NASA was excited about DARE — no one had ever done something like it before — the agency was bound by rules that favored established science and hardware over newer approaches.

"There is no history of low-frequency experiments in space. So, on the one side, people are excited: 'Wow, you're opening up an entire new field of cosmology. This is great. This is fantastic. You need to do it,'" Burns said. "The other side is, 'Well, you've never done it before, so it must be risky.' And so you get marked down for the risks."

After years of being passed up, Burns and his colleagues decided to shrink the car-size spacecraft, ditch novel hardware for proven "heritage" technologies, and try again.

The gambit appears to be working. NASA has awarded Dapper a few million dollars to prove out the concept and mature its hardware design to a flight-ready state over the next two years. When that work concludes, Dapper would have a good chance of getting NASA's full funding to build the spacecraft and book a rocket ride, possibly from SpaceX, United Launch Alliance, Blue Origin, or some other provider. (Burns said the mission is estimated to cost about $70 million, plus the price of a launch.)

Burns isn't sure the mission will require the new patent to reach lunar orbit anymore. In the years since his team came up with it, commercial rocket providers have started planning launches to the moon. NASA is also working toward the launch of its massive Space Launch System rocket, which could easily carry Dapper on a flight in the mid-2020s.

"The possible ways to get there have widened considerably since this orbital trajectory was first designed," Burns said.

But time is growing short. There's a push to land humans (and their noisy electronics) at the moon's poles, including an effort by China. That nation's space agency has also landed spacecraft on the lunar far side, where its robots are exploring the surface for the first time.

"Given how simple we have made the Dapper instrument now, a lot of people could build it. A lot of countries, even individual companies, could build this," Burns said. "Every so often I see a paper coming out of China with my figures in it, and they're talking about their own mission."

This story has been updated with new information.

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A collision in space revealed a black hole that physicists thought could never exist. The observatory that detected it cracked a 100-year-old mystery posed by Einstein.


gravitational wave detector laser mirror ligo virgo worker suit

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Seven billion years ago, two black holes crashed into each other and merged into one enormous black hole with the mass of 142 suns.

The collision reverberated through space and time, and these ripples — a phenomenon called gravitational waves first predicted by Albert Einstein — traveled 16.5 billion light-years through the universe, reaching Earth in May 2019.

For one-tenth of a second, the waves stretched the mile-long arms of two enormous physics observatories: the Laser Interferometer Gravitational-Wave Observatory in the US and its Italian companion, Virgo.

The scientists behind these observatories immediately knew they'd detected something unique.

"This doesn't look much like a chirp, which is what we typically detect," Nelson Christensen, a Virgo scientist and a researcher at the French National Center for Scientific Research, said in a press release. "This is more like something that goes 'bang,' and it's the most massive signal LIGO and Virgo have seen."

gravitational waves

The black-hole merger the observatories detected is the most massive and distant they've ever picked up. But more strikingly, it defies the known laws of physics.

The scientists' calculations showed that the heavier black hole of the two that crashed was 85 times the mass of the sun — falling within a range that many physicists thought impossible.

"This is exactly what I predicted wasn't there," Stan Woosley, an astrophysicist who models the deaths of massive stars (the process that creates black holes), told Business Insider. "A big black hole smack-dab in the middle of the forbidden zone."

LIGO and Virgo scientists described the new findings in two papers published Wednesday.

"This event opens more questions than it provides answers," Alan Weinstein, a LIGO scientist and a professor of physics at the California Institute of Technology, said in the release. "From the perspective of discovery and physics, it's a very exciting thing."

'Some of us will owe bottles of wine to others'

Black holes form when heavy stars die and collapse; their gravitational pulls are so strong that not even light can escape.

There are two main types of black hole: stellar-mass (which are tens of solar masses) and supermassive (which have the mass of millions or even billions of suns).

black hole

The 142-solar-mass black hole that formed as a result of this 7-billion-year-old collision is the first detected that's between 100 and 1,000 solar masses. This "intermediate mass" object could reveal a missing link between the two types of black holes. It may also help scientists understand where supermassive black holes come from.

But the 85-solar-mass black hole involved in the collision wasn't supposed to exist at all.

Though black-hole sizes can range "from microscopic to the size of the universe," Woosley said, his models suggest that when it comes to pairs of stars orbiting a shared center of gravity, "it would be very hard to form a black hole with a mass between about 50 and 130 solar masses."

Instead, physics models suggest that stars in that mass range should die in a unique type of supernova explosion that annihilates the star, leaving behind no material to collapse into a dense black hole.

supernova explosion

"But nature finds a way," Woosley said. "In our defense, they had to scrounge around in a substantial fraction of the visible universe to find one. It's very far away."

He added that physicists like him who predicted this mass gap would need to rethink their models. "We and a lot of other people will go back and look hard at our assumptions," Woosley said.

That may also mean paying up on a lost bet against the gravitational-wave researchers.

"The observers will look for more — just one of anything is not nearly so nice as two. And some of us will owe bottles of wine to others," Woosley said. "I'm not 100% convinced that they saw an 85 [solar-mass black hole] but am convinced enough to pay out."

The black hole could have grown from a previous collision

ZTF BH Merger

It's unlikely that this impossible black hole was created directly from a collapsing star, so some researchers think it could have come from a previous merger.

"There are many ideas about how to get around this — merging two stars together, embedding the black hole in a thick disc of material it can swallow, or primordial black holes created in the aftermath of the Big Bang," Christopher Berry, a gravitational-wave astronomer and LIGO researcher, said in the release. "The idea I really like is a hierarchical merger where we have a black hole formed from the previous merger of two smaller black holes."

Woosley, too, said the black hole probably got so big because of something that happened after it formed.

"We really just predict the masses of black holes when they are born," he said.

Another possibility is that the event LIGO and Virgo detected may not have been a black-hole merger at all. A collision, however, is the best fit for the data.

Einstein's predictions led scientists to violent space collisions and a new realm of physics

neutron star collision

Einstein predicted that collisions of massive objects, like black holes and neutron stars, would produce gravitational waves. But he didn't think anyone would ever detect these ripples in space-time — they seemed too weak to pick up on Earth amid all the noise and vibrations here.

For 100 years, it seemed Einstein was right.

But in the late 1990s, LIGO's machines in Washington and Louisiana were built in an attempt to pick up the signals. For the first 13 years, they waited in silence.

Finally, in September 2015, LIGO detected its first gravitational waves: signals from the merger of two black holes some 1.3 billion light-years away. The discovery opened a new field of astronomy, and three researchers who helped conceive of the experiment earned a Nobel Prize in physics.

ligo nsf laser interferometer gravitational wave observatory

Since then, LIGO and Virgo have identified two other types of collisions. The observatories registered gravitational waves from two neutron stars merging for the first time in October 2017. In August 2019, LIGO and Virgo detected what scientists believe was a black hole swallowing a neutron star.

"After so many gravitational-wave observations since the first detection in 2015, it's exciting that the universe is still throwing new things at us, and this 85-solar-mass black hole is quite the curveball," Chase Kimball, an astronomy doctoral student at Northwestern University who works with the LIGO team, said in the release.

Researchers expect to learn more as they delve further into this field of physics. Planned upgrades and new observatories may enable scientists to detect new space collisions every day by the mid-2020s.

"Gravitational-wave observations are revolutionary," Berry said. "Each new detection refines our understanding of how black holes form. With these gravitational-wave breakthroughs, it won't be long until we have enough data to uncover the secrets of how black holes are born and how they grow."

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Time travel is theoretically possible, new calculations show. But that doesn't mean you could change the past.


Back to the Future

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Imagine you could hop into a time machine, press a button, and journey back to 2019, before the new coronavirus made the leap from animals to humans.  

What if you could find and isolate patient zero? Theoretically, the pandemic wouldn't happen, right? 

Not quite, because then future-you wouldn't have decided to time travel in the first place.

For decades, physicists have been studying and debating versions of this paradox: If we could travel back in time and change the past, what would happen to the future?

A new study offers a potential answer: Nothing.

"Events readjust around anything that could cause a paradox, so the paradox does not happen," Germain Tobar, the study's author and a student at the University of Queensland, told IFLScience.

His work, published in the journal Classical and Quantum Gravity last week, suggests that according to the rules of theoretical physics, anything you tried to change in the past would be corrected by subsequent events.

Put simply: It's theoretically possible to go back in time, but you couldn't change history.

china wuhan travel silence

The grandfather paradox

Physicists have considered time travel to be theoretically possible since Einstein came up with his theory of relativity. Einstein's calculations suggest it's possible for an object in our universe to travel through space and time in a circular direction, eventually ending up at a point on its journey where it's been before – a path called a closed time-like curve.

Still, physicists continue to struggle with scenarios like the coronavirus example above, in which time-travelers alter events that already happened. The most famous example is known as the grandfather paradox: Say a time-traveler goes back to the past and kills a younger version of his or her grandfather. The grandfather then wouldn't have any children, erasing the time-traveler's parents and, of course, the time-traveler, too. But then who would kill Grandpa?

A take on this paradox appears in the movie "Back to the Future," when Marty McFly almost stops his parents from meeting in the past – potentially causing himself to disappear. 

time travel dog

To address the paradox, Tobar and his supervisor, Dr. Fabio Costa, used the "billiard-ball model," which imagines cause and effect as a series of colliding billiard balls, and a circular pool table as a closed time-like curve.

Imagine a bunch of billiard balls laid out across that circular table. If you push one ball from position X, it bangs around the table, hitting others in a particular pattern. 

The researchers calculated that even if you mess with the ball's pattern at some point in its journey, future interactions with other balls can correct its path, leading it to come back to the same position and speed that it would have had you not interfered.

"Regardless of the choice, the ball will fall into the same place," Dr Yasunori Nomura, a theoretical physicist at UC Berkeley, told Business Insider.

scientists time travel

Tobar's model, in other words, says you could travel back in time, but you couldn't change how events unfolded significantly enough to alter the future, Nomura said. Applied to the grandfather paradox, then, this would mean that something would always get in the way of your attempt to kill your grandfather. Or at least by the time he did die, your grandmother would already be pregnant with your mother. 

Back to the coronavirus example. Let's say you were to travel back to 2019 and intervene in patient zero's life. According to Tobar's line of thinking, the pandemic would still happen somehow.

"You might try and stop patient zero from becoming infected, but in doing so you would catch the virus and become patient zero, or someone else would," Tobar told the University of Queensland.

Nomura said that although the model is too simple to represent the full range of cause and effect in our universe, it's a good starting point for future physicists.  

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Physicists made a superconductor that works at room temperature. It could one day give rise to high-speed floating trains.


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Superconductors – materials that transport electricity with no energy lost – have until now only worked at extremely cold temperatures, from about -100 degrees Fahrenheit to the near-absolute zero of space. But this month, that changed.

In a study published October 14, a team of researchers described a superconductor they engineered, which works at 59 degrees Fahrenheit. The material is composed of carbon, sulfur, and hydrogen, so is appropriately called carbonaceous sulfur hydride.

Physicists had previously found that a combination of hydrogen and sulfur worked as a superconductor under intense pressure and at -94 degrees Fahrenheit. With the addition of carbon, the team was able to create a material that worked at a higher temperature.

Ranga Dias, a professor of mechanical engineering at the University of Rochester, told Business Insider that they did so by "chemically compressing instead of mechanically compressing" the material. In other words, they made a denser material by adding carbon and sulfur atoms into a pre-existing network of hydrogen atoms.


So far, Dias said, his team has only been able to create tiny specks of the superconductor material, about the size of ink-jet particles. The specks are made under almost 40 million pounds per square inch of pressure, almost the pressure in Earth's inner core. They only function as superconductors under that level of pressure, too. 

"Somebody can argue that, 'so you went from one extreme to another extreme,'" Dias said.

However, he added, now that it's clear a superconductor can function at room temperature, the researchers can start tinkering with their material to make it work at ordinary pressure levels. 

If they succeed, superconductors could become widespread – potentially causing dramatic advances in technology by making electricity faster, cheaper, and more powerful.

What a superconducting society would look like 

Electrical currents are flows of electrons that move through materials. Electrons move through certain types of materials easily, including most metals. Materials that convey electricity more easily are called conductors. But electrons have a harder time moving through materials like rubber and wood, so currents that try to pass through those materials tend to weaken. These materials are called insulators.

Most electricity in the US is transported through conductors and semiconductors, which can convey electricity, but not perfectly, so some energy always gets lost. A superconductor, on the other hand, has zero resistance; electrons move freely through the material. An electric current traveling through a superconducting material doesn't weaken or dissipate. 

If superconductors could function at the range of temperatures and pressures seen above ground on Earth, they could change society as we know it, Dias said.

Magnetic lavitation

A world with widespread superconductors, he said, could save society billions of dollars on electricity per year. It could also have high-speed trains that would float above magnetic tracks. 

This is because the movement of electrons creates a magnetic field. In a superconductor, some freely moving electrons move toward the surface, pushing the material's magnetic field outward. That repels other magnetic fields, so when a superconductor meets a magnet, the two objects will push against each other. 

In the case of a train, a superconducting material on the car's underside could repel magnetic tracks below it. 

Superconductors that function at normal temperatures and pressures could also give rise to computers so powerful that they'd make our most compact, advanced machines today look like the room-sized IBM computers of the 1950s and 60s. 

ibm 1401 computer

But first, Dias and his colleagues are trying to figure out whether the hydrogen compounds they studied could be made "meta-stable"– that is, whether they could stay in solid form after they're created under pressure, even once that pressure is removed.

Diamonds, the form carbon takes after being subjected to extreme pressure, are examples of meta-stable materials on Earth. Even after they are brought to ambient pressure levels, diamonds last for millions or billions of years (before eventually reverting to graphite). Researchers have figured out how to grow diamonds in a lab; Dias hopes they could do the same with a meta-stable version of the superconductor they created. 

To work towards that goal, Dias and his study co-author, Ashkan Salamat, formed a startup called Unearthly Materials. The company is currently raising funds for further superconductivity research. 

"Hopefully the next two, three years are going to be exciting," Dias said.

Even if the team's material doesn't work without added pressure, their findings could catalyze a flood of new developments in relation to superconductors, according to Russell Hemley, a professor of chemistry and physics at the University of Illinois at Chicago.

"This may be just a tip of the iceberg of a broader set of discoveries," Hemley told The New York Times.

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