12301'The Youngness Paradox' --"Why SETI has Not Found Any Signals from Extraterrestr
- Jul 23, 2014URL to an interesting post from The Daily GalaxyWith all these pocket universes floating around in whatever they will occasionally collide. So, if you hear a sudden deep thump from the sky you know that someone has moved in next doorChris
Did you ever stop to think, and forget to start again?
First few paragraphs"
According to MIT's Alan Guth , originator of the inflationary universe theory, our Universe is a product of eternal inflation --eternal into the future, but not into the past. An eternally inflating Universe produces an infinite number of pocket universes , which in turn are producing more new universes. The old, mature universes are vastly outnumbered by universes that have just barely begun to evolve. Guth called it the "Youngness Paradox."Guth says that "the synchronous gauge probability distribution strongly implies that there is no civilization in the visible Universe more advanced than us. We would conclude, therefore, that it is extraordinarily improbable that there is a civilization in our pocket Universe that is at least one second more advanced than we are. Perhaps this argument explains why SETI has not found any signals from alien civilizations.”
In Guth's view, “nature gets a lot of tries -- the Universe is an experiment that’s repeated over and over again, each time with slightly different physical laws, or even vastly different physical laws,” says MIT physics professor Robert Jaffe.
Some of these universes would collapse instants after forming; in others, the forces between particles would be so weak they could not give rise to atoms or molecules. However, if conditions were suitable, matter would coalesce into galaxies and planets, and if the right elements were present in those worlds, intelligent life could evolve.
Some physicists have theorized that only universes in which the laws of physics are “just so” could support life, and that if things were even a little bit different from our world, intelligent life would be impossible. In that case, our physical laws might be explained “anthropically,” meaning that they are as they are because if they were otherwise, no one would be around to notice them.
MIT's Jaffe and his collaborators felt that this proposed anthropic explanation should be subjected to more careful scrutiny, and decided to explore whether universes with different physical laws could support life.
The MIT physicists have showed that universes quite different from ours still have elements similar to carbon, hydrogen, and oxygen, and could therefore evolve life forms quite similar to us, even when the masses of elementary particles called quarks are dramatically altered.