A few hours ago, NASA's Swift spacecraft detected a huge explosion in M31, better known as the Andromeda Galaxy.
And astronomers suspect it could have been one of the most violent events in the Universe - a gamma ray-burst that, in just a few seconds, could have released as much energy as our Sun in its entire lifetime.
If confirmed, this will be the closest gamma-ray burst we’ve ever detected, and will help scientists find out more about these mysterious pulses of energy.
Gamma-ray pulses are so powerful, that if one occurred within our galaxy, they could potentially trigger mass extinctions on Earth, explains Dr Alan Duffy, an astronomer at Swinburne University of Technology in Melbourne.
But fortunately this explosion was far enough away to not do damage - the actual event would have happened around two and a half million years ago, with the energy just flying past Earth this morning.
While nothing is confirmed as yet, if the reaction of some of the world's leading astrophysicists on the Twitter hashtag #GRBM31 is anything to go by, this could be HUGE:
And the whole world is now watching to see what happens next, says Duffy. “Telescopes around the world are currently trained on the Andromeda galaxy looking in all wavelengths of light to learn more about this once-in-a-lifetime event.”
The majority of gamma-ray bursts appear to be caused by the collapse of huge stars. But this extremely short gamma-ray burst may have been caused by a rare event - the collision of two neutron stars, which are the remnants of supernovae.
This NASA image shows how that would work:
“The explosion seen in light will also potentially be visible in gravitational waves, a key prediction of Einstein, ending a long quest to detect these ripples in space time,” he explains.
“Unfortunately the world-wide facility for detecting these events, LIGO, is currently shut down for an upgrade and missed out on the explosion - and a potential Nobel Prize winning discovery.”
Until more data is analysed, it's unclear exactly what exactly this explosion was, and what caused it. But whatever happens, this is definitely an exciting time to be following astrophysics.
In fact, one of the most fascinating things about the event is how quickly the world has responded to it.
“The most astounding aspect of today is that these potential gamma rays have travelled undisturbed for 2.5 million years until hitting NASA’s Swift satellite, and within minutes telescopes across the globe were tracking it and an hour later people around the world were following it on Twitter,” says Duffy. “It’s been hectic.”