Researchers Saul Perlmutter and Adam Riess of the United States and US-Australian Brian Schmidt won the 2011 Nobel Physics PrizeTuesday for their research on supernovae, the Nobel jury said.
"They have studied several dozen exploding stars, called supernovae, and discovered that the universe is expanding at an ever-accelerating rate," it said, adding that their discovery had changed mankind's understanding of the universe.
The award went to observations of ancient stars that flare in theirdeath throes into becoming supernovae.
By looking at a certain type of supernova, the astronomers discovered a benchmark for the movement of light.
Their work confirms a theory first proposed by Albert Einstein, which he dubbed the cosmological constant.
The prizewinning breakthrough came in 1998, when one research team headed by Perlmutter and another led by Schmidt and accompanied by Riess reached the same astounding conclusion that the expansion of the universe was rapidly accelerating.
"If the expansion continues to speed up, the universe will end in ice," the jury said.
When hearing the news, Schmidt, 44, said winning "sort of feels like when my children were born."
He told Swedish public broadcaster SVT by phone from Australia that he was "weak in the knees, really excited, and somewhat I guess amazed by the situation. It's been a pretty exciting last half-hour."
"I did not expect it... I guess it's one of these things you expect is probably not going to happen."
Perlmutter, born in 1959, won half of the 10 million Swedish kronor ($1.48 million, 1.08 million euros) Nobel prize, while Schmidt and Riess, born in 1969, were to share the other half, the Nobel jury said.
The trio will receive their prize at a formal ceremony in Stockholm on December 10, the anniversary of prize founder Alfred Nobel's death in 1896.