A unique event from outer space might have slightly squeezed and stretched our planet last week. On January 14, astronomers observed a burst of gravitational waves for a split-second, which provoked distortions in space-time. At the moment, researchers are working on discovering and understanding where the blast came from and why.
Detection of the phenomenon
The signal was detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo interferometer. It lasted for a mere 14 milliseconds. Astronomers are still wondering whether it was just a blip in the detectors or an actual burst.
How could this have happened?
Gravitational waves are the result of collisions between massive objects, such as neutron stars or black holes. Astronomers detected such bursts in the past, once in 2019 and once in 2017.
However, gravitational waves produced by collisions of massive cosmical objects usually last longer. They manifest themselves as a series of waves that alternate in frequency over time, according to Andy Howell, a staff scientist from the Los Cumbres Observatory Global Telescope Network.
It’s less likely that this newly detected signal is a series of waves because it was observed in a particular spot in the sky, Howell stated.
There is a chance that the brief burst of gravitational waves was provoked by a more transient event, like a supernova, which is a catastrophic way of ending the life of a star.
Some astronomers believe that this could have been a signal originating from the Betelgeuse star, which suspiciously dimmed recently, and will likely suffer a supernova explosion.
However, Howell debunked this hypothesis by saying that Betelgeuse is still there, and it’s far from going supernova.
Also, supernovas happen about once every 100 years, which means that the probability of a supernova generating the detected gravitational waves is low.
Howell believes that the burst seemed too short for what usually results from the collapse of a massive star. “On the other hand, we’ve never seen a star blowing up in gravitational waves before, so we don’t really know what it would look like,” he added.
Additionally, astronomers didn’t detect any trace of neutrinos, which are tiny subatomic particles that carry no charge, telltale signs of supernovas.
Howell also believes that the newly discovered gravitational bursts were provoked by a phenomenon that is yet unknown to astronomers: “There could be totally new astronomical events out there that produce gravitational waves that we haven’t really thought about.”
The final possibility is that the merging of two intermediate-mass black holes provoked the signal. The merging process of neutron stars results in waves that last longer (about half a minute). However, merging black holes better resembles bursts because it lasts for a couple of seconds. Also, intermediate black hole mergers seem to release a series of waves with variable frequency.
Discovery of the signal
LIGO observed the signal while explicitly searching for short bursts. Astronomers and scientists alike are still not sure about what they found, especially since LIGO hasn’t yet released the precise structure of the signal, Howell said.