Physicists Andrei Linde and Alan Guth “distorted by gravitational waves.” (HuffPost image.)
Cosmic background radiation has long been considered by physicists to be the smoking gun evidence for the big bang, but what about the recent discovery of bent gravity waves? Of what is that the smoking gun evidence for?
That would be cosmic inflation–the idea that, in the first moments of the big bang, space expanded faster than the speed of light (something that Einstein’s relativity permits in this limited instance only; space itself does not have to abide by the cosmic speed limit, but objects in relation to one another do).
Physicists Alan Guth and Andrei Linde, in the 1980s, predicted that if cosmic inflation is true, you’ll find that the gravity waves that pervade the cosmos as remnants of the big bang are bent or warped in a very particular way. Nothing else could likely bend gravity waves (a quantum phenomenon) except breaking the speed of light in the manner of cosmic inflation. When a team of Harvard and Stanford physicists went in search of those gravity waves, they found them curved in the robust manner that Guth and Linde predicted.
If confirmed by additional experiment later this year, cosmic inflation will be considered a discovery of science and Nobel Prizes will be in order. One implication of cosmic inflation being true (again, if confirmed) is that the cosmos is probably much, much larger than we previously thought; that our 13.7 billion-year old inflationary bubble is just one of many, many such bubbles–which may well be infinite. In other words, in the cosmic cooking pot, we took our bubble to be the whole stew, but if cosmic inflation is correct, there have likely been numerous expansions of space. It’s highly unlikely that ours is the first or the last. Indeed, if the physics is correct, cosmic inflation is the product of a vast cosmos behaving in unstable ways.
So in answer to the question, who or what banged the big bang universe that we know, cosmic inflation suggests that another inflationary universe alongside of our own did it (and our own does the same thing as well, we just can’t detect it because cosmic inflation rushes beyond light speed away from us). Physicists like Lee Smolin have speculated that these inflationary events take place on the expulsion end of black holes.
Put another way, space may keep opening up new bubble spaces, and so space may be an engine that reproduces itself. God, if God exists, may have gotten the whole process started, but our local universe–the one we know–is an inflationary bubble from another inflationary bubble.
To really learn about this, Google “Linde and Guth” (the two physicists associated with cosmic inflation). MIT physicist Max Tegmark’s brief essay for The Huffington Post (“Good Morning Inflation! Hello, Multiverse!”) is also a good place to start. Here’s a taste from Tegmark’s article (which was written on the day of the official announcement of warped gravitational waves having been detected–March 17, 2014):
I’m writing this from the Harvard press conference announcing what I consider to be one of the most important scientific discoveries of all time. Within the hour, it will be all over the web, and before long, it will lead to at least one Nobel Prize. But what precisely is it that the BICEP2 experiment has discovered during years of sky-gazing from the South Pole?
About 13.8 billion years ago, merely 400,000 years after our Big Bang, everything in our observable universe was a hot plasma not too different from the surface of the Sun. Photos of this plasma, baby pictures of our universe around its 400,000th birthday, have already revolutionized modern cosmology and triggered two Nobel prizes. Now a team of astronomers has spent three years zooming in on about 1% of the sky, taking [an] even sharper photo of this plasma, including its polarization (a property of light that bees can see and use to navigate), discovering that it’s distorted in a tantalizing way. […]
Andrei Linde looks particularly happy today, perhaps because two numbers have now been measured that act as a sort of fingerprint of inflation, and they both agree beautifully with the specific predictions of his own favorite brand of inflation known as “quadratic”, where these numbers are 0.96 and 0.15, respectively.
Today is a great day for most scientists except multiverse skeptics — at least in this particular universe. Alex Vilenkin, Andrei Linde, Alan Guth and others have shown that inflation generically predicts a space that is not merely large but infinite, teeming with duplicate copies of our civilization living out countless variations of our lives far far away. Now it’s harder for skeptics to dismiss this by saying “inflation is just a theory”: first they need to come up with another compelling explanation for BICEP2’s gravitational waves. Today is also disappointing for the ekpyrotic/cyclic models that had emerged as the most popular alternative to inflation: they are ruled out by BICEP2’s gravitational wave detection.
So did our big bang cosmos come most immediately from God or the multiverse? At this point, at least for our local 13.7 billion-year old bubble of space, the answer appears to be the multiverse. Our cosmos, it seems, is the contingent product of an evolutionary history, not a rabbit-out-of-the-hat magician’s trick. If there was ever a free lunch–something out of nothing–it came at the very, very beginning–and our big bang cosmos was not, apparently, that beginning.