2024-01-16 06:50:10
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Discovering an “unexpected” signal coming from outside our galaxy
NASA astronomers have discovered an unexpected ‘signal’ coming from outside our galaxy, and they can’t explain it.
Scientists indicated that they found the mysterious feature following analyzing regarding 13 years of data from NASA’s Fermi Gamma-ray Space Telescope while searching for something else entirely.
The powerful telescope can detect gamma rays, which are huge bursts of energetic light thousands to hundreds of billions of times as powerful as our eyes can see. They are often created when stars explode or a nuclear explosion occurs.
Scientists were searching for one of the oldest features of gamma rays to create the first atoms, known as the cosmic microwave background (or CMB), which is leftover radiation from the beginning of the universe.
Congratulations to @JAXA_en on XRISM’s first images and spectrum! They are the first glimpse of XRISM’s capabilities and the exciting science to come. Here, the telescope’s Resolve and Xtend instruments captured N132D:
— NASA (@NASA) January 5, 2024
The cosmic microwave background radiation has a dipole structure, with one end, towards the constellation Leo, being hotter and more energetic than the opposite end.
Astronomers generally believe that the motion of our solar system creates this structure.
Instead, the team detected a signal coming from a similar direction and of almost identical size with another unexplained feature, produced by some of the most energetic cosmic particles ever discovered.
“We found a much stronger signal, and in a different part of the sky, than the one we were looking for,” said Alexander Kashlinsky, a cosmologist at the University of Maryland and NASA’s Goddard Space Flight Center.
Scientists have suggested that the signal might be linked to these highly energetic particles, known as ‘ultra-energy cosmic rays’ (UHECR).
Read also: Signals from space… Is anyone talking to us?!
According to NASA, the origins of ultra-high-energy cosmic rays, which carry more than a billion times the energy of gamma rays, remain one of the biggest mysteries in astrophysics.
On the other hand, scientists explained that this new property of gamma rays might resemble the cosmic microwave background (CMB), which is the oldest light in the universe.
“We found a gamma-ray dipole signal, but its peak is in the southern sky, far from where the cosmic microwave background is, and its size is 10 times larger than we expect,” said Chris Schrader, an astrophysicist at Goddard.
Scientists believe that this discovery can be linked to a feature of cosmic gamma rays observed by the Pierre Auger Observatory in Argentina in 2017.
Astronomers believe that the two phenomena (gamma rays and ultra-high-energy cosmic rays) might originate from one unknown source, due to the similarity of their structure. They hope to identify the mysterious source or come up with alternative explanations for both features.
NASA’s unexpected discovery might help astronomers confirm or challenge ideas regarding how the dipole structure is created.
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