"...The cosmos was assumed to be expanding at a decreasing rate. This was based on the premise that the initial outward force of the big bang, and subsequent period of inflation, was counteracted by gravity, which acted as a kind of cosmic brake on galaxies in their headlong rush away from one another.
Then along came two teams of scientists, one led by Brian Schmidt of the Australian National University's Mount Stromlo Observatory near Canberra and the other by Saul Perlmutter of the Lawrence Berkeley National Laboratory in the US.
After scrutinising supernovas, or exploding stars, in relatively nearby and distant deep space, the teams reached an astounding conclusion: the universe's expansion was accelerating. The discovery rocked the cosmology world and earned its pioneers the 2011 Nobel prize for physics..."