Gravitational waves are caused by catastrophic events in the universe. Neutron stars that end up merging after long rotation with each other can create them, as can two black holes that collide with each other. But sometimes there are bursts of gravitational waves that have no clear cause.
One such explosion was detected by LIGO / VIRGO on January 14 and originated from the same region of the sky as the star Betelgeuse. Yes, Betelgeuse, aka Alpha Orionis. A star that has shown some darkening lately and is expected to go supernova in the future.
Betelgeuse is a red supergiant star in the constellation Orion. It left the main sequence about a million years ago and has been a red supergiant for about 40,000 years. Eventually, Betelgeuse will burn up enough hydrogen for its core to collapse and it will explode like a supernova.
Betelgeuse has recently faded. This has sparked speculation that she may be preparing to go supernova. There is no exact date, but it is assumed that Betelgeuse will not go supernova for another 100,000 years. But when the star dims, something is clearly happening.
Is this new burst of gravitational waves related to the recent darkening of Betelgeuse?
Astronomers understand that Betelgeuse is a variable star, and its brightness can fluctuate. Stars like Betelgeuse are not just static objects. It is a semi-permanent variable star that exhibits both periodic and non-periodic variations in its brightness.
The kind of gravitational waves that LIGO discovered are called blast waves. It is possible that a supernova could have produced them, but Betelgeuse did not go supernova.
Some believe that the detection of gravitational waves from the direction of Betelgeuse is not related to the star itself. In fact, detecting blast waves may not even have been real.
Christopher Berry is an astrophysicist studying gravitational waves at the Center for Interdisciplinary Research and Research in Astrophysics at Northwestern University. On Twitter, he talked about the bursts of gravitational waves.
https://twitter.com/cplberry/status/1216917328841117696?ref_src=twsrc%5Etfw
Andy Howell of the Las Cumbres Observatory studies supernova and dark energy. He, too, had something to say on Twitter and seemed to be in awe of it all. He even went outside to check on Betelgeuse after discovering the explosion of gravitational waves.
For the record, I do know that it can take hours for the shock to reach the surface. I didn't point that out initially because I didn't want people staying up all night to watch Betelgeuse. I was mostly joking (but I did walk outside because I couldn't resist).
– Andy Howell (@d_a_howell) January 14, 2020
It isn't Betelgeuse blowing up because:
– It is outside the GW localization region.
– The burst might not even be real.
– The burst was probably too short.
– No neutrinos were detected
– Betelgeuse's dimming is well explained.
Me walking outside to check = buying a lottery ticket– Andy Howell (@d_a_howell) January 14, 2020
In any case, there is no supernova yet. Explosive gravitational waves may just be a mistake, and the blackout of Betelgeuse poses no threat.
One day, Betelgeuse will explode and our night sky will change forever. But for us here on Earth, this supernova is not a problem.
An exploding star is a tremendous event. And it produces a cataclysm of deadly radiation. X-rays, ultraviolet radiation and even stellar material are ejected with incredible force.
But in any case, we are about 700 light-years from Betelgeuse, and this is too far away to worry.
The biggest consequence is that the constellation of Orion will change forever. And a new object will appear in the sky to study: a supernova remnant.
Sources: Photo: Rogelio Bernal Andreo / Wikimedia Commons / CC BY-SA 3.0)
