Physicists will make their big gravitational wave announcement this Thursday!

It's been 100 years since Einstein first predicted the existence of gravitational waves - ripples in spacetime caused by the most explosive events in the Universe - and scientists have been desperately searching for direct evidence of them ever since.

But the wait might finally be over, with a big announcement scheduled for this Thursday, 11 February at 10.30am EST (2.30am on Friday AEDT). If the educated rumours are anything to go by, we're about to see the first clear evidence of gravitational waves' existence - a discovery that'll be a front-runner for a Nobel Prize. Yep, we're quietly freaking out over here.

So why are gravitational waves such a big deal? The light-speed waves are a crucial part of our understanding of how the Universe functions, and they're the last major prediction of the general theory of relativity that has to be discovered. As we reported last month:

"According to Einstein's general theory of relativity, gravitational waves explain how mass in the Universe influences the shape of space. Thanks to gravitational waves, the fabric of spacetime around anything that’s particularly massive can become curved, and this curviness can then ripple out elsewhere in space, like how seismic waves propagate in Earth's crust."

But regardless of how important these waves are to our understanding of the Universe, until now, no one's ever been able to directly observe one.

That's because they're incredibly difficult to detect. Picture our Universe as a grid of spacetime, weighed down in certain points by giant stars and planets. When something cataclysmic occurs, such as two black holes smashing into each other, or the big bang, these events cause ripples to spread through the grid, just like if you dropped a stone into a pond.

That sounds simple enough, but by the time these ripples get to us from across the other side of the Universe, they're tiny. And we mean tiny - around a billionth the diameter of an atom.

In order to try to detect them, physicists built LIGO, the Advanced Laser Interferometer Gravitational-Wave Observatory. The observatory has detectors in Washington and Louisiana that aim to spot any passing gravitational waves by measuring incredibly small changes they produce in two 4-km-long pipes.

On Thursday it's predicted that LIGO scientists will announce the first clear evidence of gravitational waves, rumoured to have come from the merging of two huge black holes. And if the number of press conferences are anything to go by, we're in for something exciting, with simultaneous announcements scheduled in Washington DC, Livingston, London, and Paris, as well as an online broadcast.

"People are hugely excited. The rumour is that it’s a whopping big signal, in other words, it’s unambiguous, and that is fantastic," Pedro Ferreira, professor of astrophysics at Oxford University, told Ian Sample over at The Guardian.

The press conferences on Thursday are for media only, so unfortunately we can't share the live stream with you, but we'll be covering the announcement live on the site so you'll know everything as soon as it happens. 

We seriously can't wait.