Big Bang Expansion: 'Smoking Gun' for Universe's discovery - Video

Astronomers have found the first direct evidence of cosmic inflation, the theorised dramatic expansion of the universe that put the "bang" in the Big Bang 13.8 billion years ago, new research suggests.

If it holds up, the landmark discovery — which also confirms the existence of hypothesised ripples in space-time known as gravitational waves — would give researchers a much better understanding of the Big Bang and its immediate aftermath.

"If it is confirmed, then it would be the most important discovery since the discovery, I think, that the expansion of the universe is accelerating," Harvard CfA astronomer Avi Loeb, who is not a member of the study team, told reporters, comparing the finding to a 1998 observation that opened the window on mysterious dark energy and won three researchers the 2011 Nobel Prize in physics.