It’s been six years since Clowes Professor of Science and Master of Quincy House Robert Kirshner ’70 revolutionized astrophysics. Since then, he’s become something of a minor celebrity—his major paper has been cited 1,500 times in the last five years, and his conclusions have reached into the popular domain. Even Jerry Seinfeld tells jokes about the universe expanding.
But just six years ago, Kirshner too was flabbergasted by the conclusion. “At first it was quite a scare,” Kirshner says. “When you’ve got something that’s new you worry that it’s wrong. For theorists it is important to be interesting, but for us observers it is really important to be right.”
Tom Matheson ’89, a post-doctoral student on Kirshner’s team, was in awe of the transition from relative obscurity to popular acclaim. “All of a sudden we’re working on the stuff that everybody talks about,” he says.
The team made their ground-breaking discovery with a little luck and a giant telescope. Starting with a theory first postulated by Albert Einstein and then ignored for the last hundred years, they eventually concluded that a mere five percent of the universe’s matter is composed of the kind of atoms we know and love. The rest, they found, is an amorphous unknown they termed “dark energy.” This was the kind of discovery that raised questions rather than answering them.
But perhaps the most perplexing part of their discovery was the highly publicized conclusion that the universe is constantly expanding. And not only expanding, but accelerating.
Initially, the discovery stopped many physicists in their tracks. Yes, Einstein had thought of this concept of “dark energy” first, but could it really be true? Einstein’s “cosmological constant” had been deemed unnecessary by scientists for decades. Now Kirshner and his team were trying to bring it back.
“It’s such an absurd solution,” says Peter Challis, a project manager and technical specialist who works for Kirshner at the Center for Astrophysics. “It doesn’t sit well with a lot of our group.”
“I wouldn’t say it’s proven,” Kirshner says, “but signs are good that it’s really right.” There are countless theories about “dark energy” in the astrophysics world, but this discovery was a shock to the discipline.
The disbelief is part scientific process, but also perhaps part denial. When Copernicus turned geocentrism on its head, no one wanted to believe that. “People want to know what things are, what things are made of. We found out we’re in the minority in the universe,” says Challis.
As Matheson says, “It’s an entirely new view of the world.”
