In June 2024, Australian astronomers had detected a powerful radio signal, capable of dazzling the sensors and overshadowing the sky for a few nanoseconds. The reason for this phenomenon has just been presented in the review The Astrophysical Journal Letters.
A year ago, in June 2024, excitement won Australian astronomers. They had just detected ASKAP radiotelescope a strange radio signal so powerful that has, for a few nanoseconds, dazzled the sensors and overshadowed the sky. “”We were all very excited, thinking of having discovered an unknown object near the earth“Said CNN Clancy James, associate professor at the Institute of Curtin Radioastronomy in Australia-Western.
The scientists originally believed that it could be a rapid radio start, a phenomenon still not elucidated and potentially linked to magnetars – neutron stars with an extremely intense magnetic field. But the real explanation of this radio signal is quite different, as revealed by a study published on Monday June 30 in the journal The Astrophysical Journal Letters .
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«We were able to determine that it came from around 4,500 kilometers (2800 miles). And we have obtained a fairly precise correspondence with this old satellite called Relay 2. There are databases to determine where a given satellite is, and there was no other satellite nearby“Said James, still for CNN. “”We were all a little disappointed, but we said to ourselves: “Wait a second. What could have produced this?“»
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“2000 to 3000 times more powerful than all other radio data”
Launched by NASA in 1964, the Relay 2 satellite was used to broadcast the 1964 Tokyo Olympic Games in the United States and Europe. He ceased to operate in 1967, becoming with Relay 1 one of the many debris that orbit around the earth … before he returned to the radar of astronomers.
“The signal was 2000 to 3000 times more powerful than all the other radio data that our instruments have detected. It was by far the most brilliant thing in the sky ”describes James. To explain the return to the life of Relay 2 almost 60 years after being out of service, like a “zombie” satellite, scientists advance two hypotheses. The first, first, would be that of an accumulation of static electricity on the metal shell of the satellite.
She would have provoked a short circuit which would in turn have trained the spark responsible for the signal. The second, less likely, would be a collision with a microMéteorite. It would have transformed the debris into plasma, releasing a large amount of energy. In one case as in the other, these results recall the need not to draw hasty conclusions on unknown radio signals, as powerful as they are.
