Three US-born scientists have been awarded the Nobel Prize for Physics after discovering that the universe is expanding at an ever-increasing rate.
Saul Perlmutter of Berkeley National Laboratory, along with Brian Schmidt of Australian National University, and Adam Riess of Johns Hopkins University together share the $1.5m prize.
Their study of exploding stars revealed that after the Big Bang, the universe continued to expand for several billion years, but at a slower rate than today.
