A team of scientists, physicists and people with titles filled with impressive letters have announced that for the first time in history gravitational waves have been detected - and it changes everything.
About 100 years ago, Albert Einstein (the chap with the hair) put forward a theory that upset a lot of physicists.
This theory of General Relativity attempted to explain how gravity works - why something that goes up must come down. It was beautiful, incredible, and also totally impossible to prove. Until now.
Researchers at laboratories around the world have been monitoring similar versions of the same experiment, that see lasers fired down long tunnels in an effort to detect tiny vibrations caused by gravitational waves. One such experiment has now picked up waves emitted by two black holes colliding a billion light-years from Earth.
Their collective findings, now published in the journal Physical Review Letters, indicate that gravitational waves are indeed real - and could help redefine our understanding of the Big Bang, black holes and how the whole Universe works.
"Gravitational waves provide a completely new way at looking at the Universe," Professor Stephen Hawking (the chap with the chair) told the BBC. "The ability to detect them has the potential to revolutionise astronomy. This discovery is the first detection of a black hole binary system and the first observation of black holes merging.
"Apart from testing (Albert Einstein's theory of) General Relativity, we could hope to see black holes through the history of the Universe. We may even see relics of the very early Universe during the Big Bang at some of the most extreme energies possible."
At present, we've only been able to theorise about the Big Bang through physical properties we have a solid understanding of - such as light and radiation. However, these are both affected by any body they come into contact with, leaving a weak impression of any hint of the Big Bang they may carry. Gravitational waves behave in an entirely different way, meaning that we (well, clever physicists) have a much better chance of interpreting them and the echoes left over from the start of the Universe.
For now, the discovery will result in a lot of backslapping and handing out of Nobel prizes - but long term, it will change our understand of how we came to be. Which is a pretty big deal.