Last night I found myself at the Tatler Club, a posh lounge/restaurant in the Moscow Radisson, talking with Seth Lloyd, a professor at MIT and a brand-name guy in the world of quantum mechanics.
As a fun aside, Professor Lloyd shared an interesting theory on the existence of aliens. Instead of a scientific explanation, though, he offered up a sociological one.
It goes like this:
Given the size of the universe, it very unlikely that the humans on planet Earth are the only intelligent beings out there. There are simply too many opportunities for life to exist when you consider the number of stars with their own planetary systems around them.
Now, an overwhelming majority (about 85%) our universe is made of what's called dark matter, and science has yet to crack it open and make sense of it. The regular matter that makes up human beings, the planets, and everything with mass in the conventional sense only accounts for 4.9%. We are by far an inconsequential minority in the scope of astrophysics.
Professor Lloyd's "modest proposal" (as he outlined in a 2011 letter to the editor in the NYT) is that "cold" dark matter, which accounts for 23% of the energy in the universe, is the aliens. They use that which we can't understand as a means to hide from us.
As he wrote for the NYT:
While not actively hostile, the aliens would prefer not to live in our neighborhood. Whatever it is made of, the dark energy is their way of suggesting, politely but firmly, that we leave. Dark energy is simply the mechanism for 'alien flight' in the cosmic real estate market.
