Scientists found a short burst of gravitational waves, which are distortions of space and time. But scientists don’t know where this explosion came from.
The gravitational wave signal was picked up by the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo interferometer. It only lasted 14 milliseconds, and scientists still don’t know where it came from or if it was just a blip in the detectors.
Gravitational waves can be made when two big things, like two black holes or two neutron stars, hit each other. Astronomers found these waves in 2017 and April 2019 when two neutron stars collided, according to research presented at a conference of the American Astronomical Society.
Andy Howell, a staff scientist at the Los Cumbres Observatory Global Telescope Network and an adjunct professor of physics at the University of California, Santa Barbara, says that gravitational waves from collisions of such massive objects tend to last longer and show up in the data as a series of waves whose frequency changes over time as the two orbiting objects move closer to each other. He didn’t work on the LIGO project.
Howell said that the new signal was not a series of waves but rather a burst. One more likely explanation is that this short burst of gravitational waves is caused by a temporary event, like a supernova explosion, which is the violent end of a star’s life.
Some astronomers think this could be a message from the star Betelgeuse, which has recently gotten dimmer and is likely to explode as a supernova. But the Betelgeuse star is still there, so Howell said it’s not that case. He also doesn’t think it’s a supernova because they only happen about once every 100 years in our galaxy.
He also said that the burst “seems a little too short for what we would expect from the collapse of a massive star.” “On the other hand, we’ve never seen a star explode in gravitational waves before, so we don’t really know what it would look like.” Also, the astronomers didn’t find any neutrinos. Supernovas are known to make neutrinos, which are small subatomic particles with no charge.
Howell says that another possibility is that the signal was made when two black holes of intermediate mass merged. Waves from merging neutron stars last longer (about 30 seconds) than this new signal, while waves from merging black holes may be more like bursts (that last around a couple of seconds). But when two black holes merge in the middle, they might also send out a series of waves with different frequencies.
LIGO found this signal when it was looking for other bursts like it. But, Howell told Live Science, “that doesn’t mean that what they found is a merger of two black holes with intermediate masses.” “We don’t know what they found,” he said, especially since LIGO hasn’t said what the signal looks like exactly yet.
Howell also said that it was possible that this signal was just random noise in the data from the detector. On the other hand, all three LIGO detectors picked up this burst of gravitational waves: one in Washington state, one in Louisiana, and one in Italy. So, the LIGO detectors would only find this signal by accident once every 25.84 years, which “gives us some indication that this is a pretty good signal,” said Howell.
There could be other reasons for this increase that no one knows about. Howell says that a supernova may have collapsed directly into a black hole without making neutrinos, but this is a very unlikely event. Astronomers now point their telescopes in that direction to try to figure out where the waves are coming from.
He also said, “The universe always shocks us.” “There could be completely new astronomical events out there that make gravitational waves that we haven’t really thought about.”