NASA astronomers recently made a surprising discovery: a mysterious signal coming from beyond our galaxy. This discovery emerged during the analysis of 13 years of data collected by the Fermi Gamma-ray Space Telescope, a powerful instrument capable of detecting gamma rays.
The signal, described as “unexpected and still inexplicable“, was spotted while scientists were looking for something completely different. The discovery, called “completely fortuitous” by Alexander Kashlinsky, cosmologist at the University of Maryland and NASA’s Goddard Space Flight Center, was presented to the American Astronomical Society.
Initially, scientists were looking for one of the oldest gamma-ray features linked to the formation of the first atoms, known as cosmic microwave background or CMB. However, they detected a signal coming from a similar direction and with an almost identical magnitude to another unexplained feature, which had some of the same most energetic cosmic particles ever detected.
This discovery may be linked to a gamma-ray phenomenon observed by the Pierre Auger Observatory in Argentina in 2017. Astronomers believe that the two phenomena could originate from a single, unidentified sourcegiven their similar structure (it is true that the signals that reach us from space are becoming increasingly strange).
“A disagreement with the size and direction of the CMB dipole could provide us with insight into the physical processes operating in the early universe, potentially dating back to when it was less than a trillionth of a second old“, said Fernando Atrio-Barandela, co-author of the research. This is not the first time we have witnessed a similar phenomenon, as we find hundreds of them.