It’s not every day that you see something completely new in the night sky. But that’s what Australian and US researchers have announced this week. They uncovered a mysterious burst of radio energy that came from outside our galaxy. It was incredibly bright, emanating from a tiny object, and lasted for only 5 milliseconds. Blink and you would have missed it (actually, don’t bother blinking, you’d still miss it). So, the big question is: what was that?!
Astronomers from Swinburne University and West Virginia University announced their unexpected discovery this week, with an article in the journal Science.
Their discovery was made by chance. The researchers were analyzing radio observations of rotating pulsars – the corpses of massive stars – when they noticed a brief, bright flash of radio waves in their images. They were looking at the Small Magellanic Cloud, a nearby dwarf galaxy, and were fortunate to have the flash occur in their field of view; off to the side away from the galaxy.
Based on their further analysis, whatever made the flash of radio waves is millions of light-years away, well outside the galaxy, and tiny; probably less than 1,500 km across. Objects at this distance should be very faint, but what they found overwhelmed the radio telescope’s detectors.
So what was it?
There are two theories on the table right now. One is a collision between a binary pair of neutron stars. These exotic objects were once stars much larger than our own Sun. After both detonated as supernovae, they spiraled inward towards one another, eventually merging. Astronomers think this event can also cause a certain kind of gamma ray burst, but a flash of radio waves has never been seen before.
Another, even more exotic explanation is the death of black hole. Famed astrophysicist Stephen Hawking proposed that black holes can actually evaporate, losing mass over long periods of time. As the black hole loses mass, the evaporation speeds up, and the last few moments of a black hole could actually go quite quickly, perhaps with a flash of radio waves like this.
Based on the fact that the discovery was a total coincidence, the astronomers are hopeful that this kind of event is happening all over the sky, all the time. Astronomers have just never thought to look for them. It’s possible that this discovery could even open up a whole new field of astronomy, just like when gamma ray bursts were first discovered 30 years ago when the military orbited satellites designed to see nuclear explosions on the Earth.
Original Source: Swinburne University News Release