Astronomers have detected 'strange signals' that may come from a star 11 light-years away
Astronomers say they've detected "strange signals" coming from the direction of a small, dim star located about 11 light-years from Earth.
Researchers picked up the mysterious signals on May 12 using the Arecibo Observatory, a huge radio telescope built inside of a Puerto Rican sinkhole.
The radio signals appear to be coming from Ross 128, a red dwarf star that's not yet known to have any planets and is about 2,800 times dimmer than the sun. Abel Méndez, an astrobiologist at the University of Puerto Rico at Arecibo, said the star was observed for 10 minutes, during which time the signal was picked up and observed to be "almost periodic".
Méndez said it's extremely unlikely that intelligent extraterrestrial life is responsible, but noted that the possibility can't yet be ruled out.
"The SETI [Search for Extraterrestrial Intelligence] groups are aware of the signals," Méndez wrote in an email to Business Insider.
Explanations for the 'very peculiar' signals
While Arecibo is known for its role in efforts to search for signals from aliens, it's also great for looking at distant galaxies and pinging near-Earth asteroids.
Méndez thinks the signal is more likely from something humans put in space, perhaps a satellite that passed thousands of miles overhead.
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"The field of view of [Arecibo] is wide enough, so there is the possibility that the signals were caused not by the star but another object in the line of sight," Méndez said, adding that "some communication satellites transmit in the frequencies we observed."
However, in a July 12 blog post about the mystery of Ross 128, he wrote that "we have never seen satellites emit bursts like that" and called the signals "very peculiar".
Another possible explanation is a stellar flare, or outburst of energy from the star's surface. Such bursts from the sun travel at light-speed, emit powerful radio signals, and can disrupt satellites and communications on Earth, as well as endanger astronauts.
Solar flares can also be chased by a slower-moving yet more energetic coronal mass ejections: a flood of solar particles that can distort our planet's magnetic field, generate geomagnetic storms, and cripple power grids and fry electronics.
Taking another look at Ross 128
To see if the signals are still there, Méndez said Arecibo is going to stare down Ross 128 and its surroundings many more times, starting July 16.
"Success will be to find the signal again" at the star's location but not in surrounding directions, he said. "If we don't get the signal again then the mystery deepens."
Strange Signals from the Nearby Red Dwarf Star Ross 128
posted Jul 12, 2017, 1:31 PM by Abel Mendez [ updated 9 hours ago ]
We are conducting a scientific campaign from the Arecibo Observatory to observe red dwarf star with planets. These observations might provide information about the radiation and magnetic environment around these stars or even hint the presence of new sub-stellar objects including planets. So far, we observed Gliese 436, Ross 128, Wolf 359, HD 95735, BD +202465, V* RY Sex, and K2-18. Only Gliese 436 and K2-18 are known to have planets. Observations were done between April and May 2017 in the C-band (4 to 5 GHz).
Two weeks after these observations, we realized that there were some very peculiar signals in the 10-minute dynamic spectrum that we obtained from Ross 128 (GJ 447), observed May 12 at 8:53 PM AST (2017/05/13 00:53:55 UTC). The signals consisted of broadband quasi-periodic non-polarized pulses with very strong dispersion-like features. We believe that the signals are not local radio frequency interferences (RFI) since they are unique to Ross 128 and observations of other stars immediately before and after did not show anything similar.
We do not know the origin of these signals but there are three main possible explanations: they could be (1) emissions from Ross 128 similar to Type II solar flares, (2) emissions from another object in the field of view of Ross 128, or just (3) burst from a high orbit satellite since low orbit satellites are quick to move out of the field of view. The signals are probably too dim for other radio telescopes in the world and FAST is currently under calibration.
Each of the possible explanations has their own problems. For example, Type II solar flares occur at much lower frequencies and the dispersion suggests a much farther source or a dense electron field (e.g. the stellar atmosphere?). Also, there are no many nearby objects in the field of view of Ross 128 and we have never seen satellites emit bursts like that, which were common in our other star observations. In case you are wondering, the recurrent aliens hypothesis is at the bottom of many other better explanations.
Therefore, we have a mystery here and the three main explanations are as good as any at this moment. Fortunately, we obtained more time to observe Ross 128 next Sunday, July 16, and we might clarify soon the nature of its radio emissions, but there are no guarantees. We will also observe Barnard’s star that day to collaborate with the Red Dots project. Results from our observations will be presented later that week. I have a Piña Colada ready to celebrate if the signals result to be astronomical in nature.
More updates via @ProfAbelMendez, @PlanetaryHabLab, and @NAICObservatory
UPDATE 2017/07/17: We successfully observed Ross 128 last night from the Arecibo Observatory. It was raining during the observations but this has a minimal effect on the C-band. SETI Berkeley with the Green Bank Telescope and SETI Institute's ATA joined our observations. We need to get all the data from the other partner observatories to put all things together for a conclusion. Probably by the end of this week.