Sometimes it's not that hard to predict the future -- everyone paying attention (including me) knew that one of the most Nobel-worthy discoveries out there was the 1998 announcement that our universe is accelerating. Now the achievement has been officially honored, with this year's Physics Prize going to Saul Perlmutter, Adam Riess, and Brian Schmidt. (Great quotes and coverage at the Guardian.) Congrats to three extremely deserving scientists!
Like regular people with major historical events, most physicists can remember where they were when they first heard that the universe is accelerating. That's how big this discovery was. It was just the right combination of "startling" -- very few people really thought the universe was accelerating, and if they did they certainly weren't proclaiming that belief very loudly -- and "believable" -- we all knew it was possible, and as soon as the data came in people realized that it solved a bunch of problems at once. There was a healthy amount of skepticism, but in a very short period of time it became difficult to get a Ph.D. as a cosmologist without working on this problem in one way or another -- either verifying the result observationally, or trying to come up with a theoretical explanation. The leading explanation by far, of course, is the existence of a smooth and persistent source of energy known as dark energy, of which Einstein's cosmological constant is the simplest and most compelling example. If that's the right answer, we're talking about 73% or so of the universe. Something to tell your grandkids that you helped discover, eh? A small sampling of what this discovery has wrought, just taken from this here blog:
Not a bad result, I would say. You don't think I'm going to leave this without mentioning that Brian Schmidt was my office mate in grad school, do you? Taught the young man all he knows (about inflation and field theory). Adam Riess was a fellow classmate of ours, both of them studying under Bob Kirshner. I even got to collaborate on a follow-up paper with these upstanding gentlemen. Saul Perlmutter was already at Lawrence Berkeley Labs thinking about supernovae and the expansion of the universe, so I can't claim to have influenced him, but we did chat on the phone several times about what different observational outcomes would imply for theory. This is the first Nobel Prize where I was friends with all the winners before they won. In this day and age, of course, much good science is done by teams, not by individuals. This is certainly an example; Brian has already said that he'll be bringing his team to Stockholm. Congratulations again to everyone involved in this discovery, truly one of the historic events in science.
