After listening to radio waves from space for decades, astronomers have picked up "strange signals" at a frequency they haven't observed before. They still don't know what's causing the mystery transmission emanating from a nearby star, but they placed aliens in the bottom of the list as the possible source.
The "very peculiar signals" were picked up on May 12 by the Arecibo Observatory in Puerto Rico, and they lasted 10 minutes. The transmission appeared to have come from the vicinity of a red dwarf star known as Ross 128 about 11 light years away from Earth in the constellation Virgo.
Red dwarfs are the smallest and most common type of stars in the universe. They're far dimmer than stars like the sun and can't be seen with the naked eye. Stars can emit various wavelengths of electromagnetic radiation including radio waves, but the signals detected by Arecibo astronomers were unlike anything they had ever observed before.
They came up with possible explanations for the odd radio signals, all of which have weaknesses. Topping the list is intense eruptions of electromagnetic radiation similar to solar flares emitted by the sun. However, the bursts produced by red dwarfs generally occur at lower frequencies.
The next possible cause could be radio signals from another object in the telescope's field of view of Ross 128, but astronomers haven't observed many other celestial bodies there. Passing satellites were also ruled out as those are unable to emit intense bursts.
Another theory could be an interaction between a star and an orbiting planet, as the magnetic field produced by this interplay could produce tiny changes in radio emissions. The only problem with this angle is that there have been no planets discovered so far around Ross 128.
Scientists from Search for Extraterrestrial Intelligence (SETI) Institute have joined the study, and like their Arecibo counterparts, have concluded that aliens are unlikely to have caused the signals. But that doesn't mean they're dismissing the alien hypothesis. "[It]'s possible that Ross 128 will shed its anonymity and become the first star system to show good evidence of extraterrestrial intelligence," SETI senior astronomer Seth Shostak wrote.