- Astronomers have detected mysterious radio waves originating from the center of the galaxy which vary widely and appear to be extinguished at random.
- The origin of the waves is unknown, so they suggest the existence of a new type of celestial object.
- The signal does not resemble that of stars, planets, or even dead stars.
Mysterious radio waves emanate from the heart of our galaxy, and astronomers don’t know what makes them.
All celestial objects emit radio waves – planets, stars, dead stars, and even asteroids. But researchers at the University of Sydney recently detected radio signals that don’t match any known type. The waves, originating near the center of the Milky Way, do not appear to originate from any sort of star, planet, or space rock that scientists have seen before.
Even stranger, the strength of this signal has increased and decreased dramatically in just a few months. Most objects in the galaxy, on the other hand, don’t change much from year to year – and so neither do their radio waves.
“The signal turns on and off seemingly at random. We’ve never seen anything like it,” Ziteng Wang, lead author of the new study and a physics doctoral student at the University of Sydney, said in a statement. . Press release.
An article describing the discovery was published Tuesday in The Astrophysical Journals. In it, Wang and his co-authors concluded that the mysterious source of this radio signal “may represent part of a new class of objects.”
The radio signal disappeared for months, suddenly reappeared, then disappeared again
Whatever mysterious object responsible for this phenomenon was emitting strong radio waves for most of 2020. Researchers detected six signals over nine months, using the ASKAP radio telescope in Western Australia.
After that, the team tried to find the object in visible light, but they returned empty-handed. They also couldn’t find it in x-rays or infrared light.
So they went back to radio waves, first using the Australian Parkes radio telescope, but lost the source of the signal and couldn’t detect anything for a while. Then they turned to another radio telescope – the MeerKAT Observatory in South Africa – and observed the area for 15 minutes every few weeks.
Eventually, they captured the radio signal again, but it was gone in a single day. It was strange, since the six signals they had picked up with ASKAP had each lasted for weeks.
“This object was unique in that it became invisible, became shiny, faded, and then reappeared. This behavior was extraordinary,” said Tara Murphy, professor at the University of Sydney and thesis supervisor from Wang, in the press release.
Murphy and Wang don’t talk about visual brightness – a “bright” radio signal is just a strong signal.
“The object’s brightness also varies considerably, by a factor of 100,” Wang said in the statement.
In an email, Murphy told Insider “that’s part of what makes him unusual.”
âHot objects (eg stars) generally emit visible light, which is why we have ruled out a normal star as one of the possible interpretations for this object,â she wrote. “It could be a very, very cold star that is too faint to detect visible light but has bright radio flares.”
The mysterious radio signal shares some traits with signals from a class of objects called “galactic center radio transients” which were discovered in the 2000s. But researchers don’t know much about these objects either, except that they emit low frequency, highly polarized radio waves with no detectable x-rays. However, the new signal has properties that do not match those of radio transients.
“We don’t really understand these sources, anyway, so it adds to the mystery,” Wang co-director David Kaplan of the University of Wisconsin-Milwaukee said in the statement.