Astronomers have no idea what caused a mysterious burst of gravitational waves that hit the Earth on Jan. 14. The burst lasted only 14 milliseconds, but all three laser interferometer gravitational wave observatories on Earth identified it from their locations in Italy, Louisiana, and Washington state.
The collision of massive celestial objects such as black holes or neutron stars can produce gravitational waves. But those waves typically last longer and come in a series, rather than a burst. They also change frequency as the objects move closer to one another, Andy Howell, a staff scientist at Las Cumbres Observatory in Goleta, Calif., told Live Science.
Some astronomers speculate the supergiant star Betelgeuse, which mysteriously dimmed recently, may have sent the signal. Scientists think Betelgeuse might be headed for a supernova explosion, an event that takes place when a star dies. But that can’t explain the burst since the star hasn’t exploded at this point, Howell noted. Supernovas only occur about once a century in our galaxy, so it’s unlikely another one caused the burst. Supernovas also usually release neutrinos, and astronomers didn’t detect any in the gravitational waves.
A merger of medium-sized black holes could produce bursts or a series of waves, Howell said. The observatory detectors might also have experienced a meaningless blip, but that seems unlikely since all three picked up the signal.
“The universe always surprises us,” Howell said. “There could be totally new astronomical events out there that produce gravitational waves that we haven’t really thought about.” —J.B.