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For the second time, astronomers caught a mysterious sign of repetition coming from an unknown source in space. They are called Fast Radio Bursts (FRBs), or fast radio bursts. And in less than a blink of an eye, they penetrate the radio telescopes with as much energy as a hundred million suns. Most of them are detected only once.

Only one of those indescribable signals already detected was repeated, and allowed astronomers to locate their origin for the first time. Now they found a second.

"Until now, there was only one repeated FRB known," said astrophysicist Ingrid Stairs of the University of British Columbia in Canada. "Knowing there is another suggests there might be more out there. And with more of them available for study, we may be able to understand this cosmic puzzle - where they come from and what causes them, "he concluded.

This signal is called FRB 180814.J0422 + 73, and in the period of three weeks, beginning in August 2018, the repetition was detected by the CHIME radio telescope (Canadian Hydrogen Intensity Mapping Experiment). And more explosions were detected in the following weeks. In total, CHIME detected 13 new explosions, including repeated signals.

What makes this even cooler is that these were just test observations for the telescope - it was not operating at full capacity.

The previous repeated signal, FRB 121102, is famous for its peculiar repeats. It explodes with pause periods, enabling astronomers to trace it back to its source, a galaxy about 3 billion light-years away. And as the signal has been polarized or twisted, we know that it has undergone an intense magnetic field.

But that's more or less the limit of our knowledge of FRB 121102. We still do not know what it causes, or because any of the rapid radio bursts do not repeat themselves.

However, the FRB 180814.J0422 + 73, which comes from a galaxy 1.5 billion light-years away, already provides some new clues about this great cosmic mystery. The first is that several of the 13 radio bursts detected by CHIME appeared at a much lower frequency than other fast radio bursts - 400 MHz, compared to the previous 700 MHz record. These are the lowest frequency peaks recorded by the moment.

This means that, since 400 MHz, is the lower limit of the capacity of the telescope, the signals may be occurring at lower frequencies still. The other great clue is that the 13 signs show evidence of scatter or drift from their original path. From this, astrophysicists are able to make inferences about the environment in which the radio explosions originated.

"We now know that sources can produce low frequency radio waves and these low frequency waves can escape from their environment and are not too scattered to be detected when they reach Earth," said physicist Tom Landecker of the National Institute of Technology. "It tells us something about environments and sources. We did not solve the problem, but there are several other pieces in the puzzle, "he concluded. [ ScienceAlert ]

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