First Contact? Mysterious Radio Signal From Deep Space Baffles Astronomers

A mysterious radio signal detected by the Arecibo telescope has excited and baffled astronomers, who have been able to determine that it originated from a source in deep space, beyond the borders of the Milky Way.

The signal detected at Arecibo serves as conformation that similar signals recorded by the Parkes Radio Telescope last year do indeed originate from a source beyond Earth. Called “fast radio bursts,” they last less than a millisecond. When astronomers detected four of the signals last year with the Parkes telescope, there was no time to have them checked by other observers. As IFLScience reports, this led to some speculation that the signals were the result of an unknown source of terrestrial interference working on the telescope.

Arecibo’s fast radio burst has refuted that speculation, however, as astronomers have been able to prove that it originated from a source outside of the Milky Way. Radio pulses that travel through deep space are differentiated from those with an origin on Earth by an effect known as “plasma dispersion.” According to the Mail Online, this effect is the result of “interstellar electrons,” which cause low-frequency radio waves to slow down as they travel between the stars. When the dispersion rate of the Arecibo signal was measured, it proved to be three times higher than what would be expected for a signal originating within our own galaxy.

“Our result is important because it eliminates any doubt that these radio bursts are truly of cosmic origin,” said Victoria Kaspi, who is the Principal Investigator for the project that detected the radio signal. An astrophysics professor at McGill University in Montreal, she added, “The radio waves show every sign of having come from far outside our galaxy — a really exciting prospect.”

The Arecibo signal was recorded on Nov 2nd, 2012, but just recently revealed. While fast radio burst signals have only rarely been detected, the international team reporting on the signals say that they could occur as many as 10,000 times a day. That number was deduced by comparing how many times the signals have been detected with how much of the sky was observed, and for how long. A targeted study by SETI in 2012 found little evidence of similar signals within the Milky Way, as The Inquisitr reported, although those efforts analyzed a narrow frequency band.

There are a myriad of possibilities that could explain the signal’s source. Evaporating black holes, mergers of neutron stars, or flares from a unique kind of neutron star called a magnetar could all be responsible. Efforts are now underway to observe wider areas of the sky with radio telescopes in hopes of detecting and identifying more fast radio bursts. Scientists say that new facilities under construction in Australia and South Africa may have the capability to detect similar deep space radio signals.

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