Anything weird has been spotted by scientists hunting for evidence of existence outside Earth. An unidentified radio pulse seems to originate from the direction of the star nearest to the earth, named Proxima Centauri, a tiny red star about 4.2 light-years distant. Adding to the intrigue, this star is orbited by at least two planets, one of which may be temperate and rugged like Earth.
Breakthrough Listen, a decade-long quest for alien signals from the nearest million stars, used Australia's Parkes Observatory to examine Proxima Centauri. The squad found the conspicuous signal they called BLC-1. In observations made between April and May 2019, the radio waves were picked up.
Sofia Sheikh, a graduate student at Pennsylvania State University and a part of the Breakthrough team heading the signal study, noted that experts had been seeing something strange every now and then. The new breakthrough, though, Sheikh said is fascinating because it's something weird that they have to ask about the next move.
Although Sheikh and others strongly believe that the signal is really human in nature, BLC-1 is Breakthrough's most tantalizing discovery in its quest for extraterrestrial intelligence, or SETI, thus far. The team is writing two reports, which are not yet complete, explaining the signal and a follow-up review.
Though researchers continue to study the signal, experts warn that there is almost definitely a standard, earthly explanation despite having a distant glimpse of existence outside Earth.
Strange Signal
In 2015, a decade-long quest sponsored by Silicon Valley founder Yuri Milner kicked off Breakthrough Listen. So far, the team has not discovered something conclusive in their sky scans.
Breakthrough targeted the Parkes telescope at Proxima Centauri from April 2019 because experts wanted to better grasp the giant flares often produced by tiny red dwarf stars like Proxima. Shane Smith, an undergraduate from Hillsdale College in Michigan collaborating with Breakthrough, spotted BLC-1 seemingly radiating from the star when processing certain observations this summer.
While the signal is faint, BLC-1 passed all the experiments used by the Breakthrough team to strip out the millions of human-generated signals: it was small in bandwidth, seemed to shift in wavelength, and vanished as the telescope switched its focus to another object from Proxima. Four identical signals emerged within the next two days, but these have been ruled out as radio interference.
If BLC-1 is, despite all odds, a Christmas card from the galaxy next door, then the Milky Way must be completely stuffed with talking civilizations, says Seth Shostak of the SETI Institute. In this situation, Shostak said that in our own universe, there will be over half a billion civilizations out there. That seems to be a lot.
Follow-Up
The team has analyzed Proxima Centauri again after the discovery and has not noticed anything. Scientists are focusing on designing new experiments that might determine the sources of the signal, including trying to target Proxima with the Parkes telescope.
Jill Tarter of the SETI Institute said earlier this year that the method of generating new experiments and working tirelessly to validate the origin of a signal is a normal part of the SETI endeavor and one that anyone will learn and gain from.
Proxima Centauri's follow-up observations would be useful for learning how certain stars work, as well as for completing a detailed SETI quest for a nearby star system with identified planets, even though it is not inhabited by technically inclined aliens.
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