THREE PHYSICISTS who discovered why we have a very cold, very dark future ahead of us have won the 2011 Nobel Prize for physics. Their realisation that the universe is expanding at a faster and faster rate has transformed our understanding of how the cosmos works.
Saul Perlmutter of the Lawrence Berkeley National Laboratory at the University of California, Berkeley, Brian Schmidt of the Australian National University and Adam Riess from Johns Hopkins University and the Space Telescope Science Institute share the coveted $1.5 million (€1.14 million) prize.
Working in two separate research teams, they astounded the world’s science community in 1998 with the news that our universe was expanding at a faster and faster rate.
They achieved this by using exploding stars – supernovas – as a kind of measuring tape to gauge distances for billions of light years across space. Their ability to use these “standard candles” as an extremely accurate measuring system proved conclusively that the expansion of spacetime was speeding up.
The assumption for decades had been that the universe was expanding but at a slowing rate as gravity gradually put the brakes on. The discovery shook cosmological theory to the core however and helped spawn the idea that some kind of “anti-gravity” was pushing everything apart.
This force, dubbed dark energy, is now estimated to make up about 75 per cent of the mass/energy of the universe and remains one of the most profound mysteries of astrophysics. It is expected in time to deliver a cold, dark universe as galaxies are carried further and further apart and as stars age and grow dim.
Schmidt and Riess took measurements using their supernova metre sticks at the Harvard Smithsonian Centre for Astrophysics. They will share half the cash award, while competitor Perlmutter of the Supernova Cosmology Project claims the other half for his research efforts.
“It seemed too crazy to be right and I think we were a little scared,” Schmidt said yesterday, while Perlmutter said the finding was a “huge surprise”.
Riess used an effective analogy to describe it all. “If you tossed a ball into the air and it kept right on going up instead of falling to the ground, you’d be pretty surprised. Well that’s about how surprised we were.”
The results show the universe is expanding but “all bets [were] off” about whether the expansion would actually continue forever, Riess declared. “The universe could still recollapse,” he warned yesterday.
The discovery “revolutionised our understanding of the universe”, said University College Cork professor of physics Paul Callanan. “It was completely unexpected, as some of the best discoveries are,” said emeritus professor Mike Redfern of NUI Galway’s Centre for Astronomy.
“It is the most striking discovery to have been made since I became involved in physics,” said Prof Edward Witten, professor of physics at the Institute for Advanced Study in Princeton, New Jersey. “It changes our understanding of the universe.”
Additional reporting: Reuters