Mysterious signal ​240 million light years away from Earth detected

ASTRONOMERS think an unidentfied X-ray signal found 240 million light years from Earth could be dark matter.

Mysterious ... NASA has detected an unknown signal 240 million light years away from Earth in the Perseus Cluster (not pictured). Picture: Supplied

A MYSTERIOUS X-ray signal 240 million light years from Earth has been detected.

Scientists say the unidentified signal is a "spike of intensity at a very specific wavelength of X-ray light" in the Perseus Cluster.

While the origin is not known, astrophysicist Esra Bulbul theorises the X-ray is produced by the decay of sterile neutrinos, a type of particle that has been proposed as a candidate for dark matter.

Astronomers think dark matter constitutes 85 per cent of the matter in the Universe, but does not emit or absorb light like matter that makes up planets, stars and galaxies.

"We know that the dark matter explanation is a long shot, but the pay-off would be huge if we're right," Bulbul, a postdoctoral fellow at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, said in a statement. 

"So we're going to keep testing this interpretation and see where it takes us.'

Bulbul's team found the signal after examining 17 days of observations taken over 10 years with NASA's Chandra X-ray Observatory and ESA's XMM-Newton.