"And the third possibility is that it is aliens." Only the *third* possibility, mind. That s the assessment of Dr Seth Shostak, a senior astronomer at the SETI Institute (the Search for ExtraTerrestrial Life) in California. So what s all this speculation about aliens sending us signals from a faint star in our "neighborhood"?
"On the basis of history, I would say the chances are not very great that it s aliens," Shostak told Deutsche Welle on Tuesday. "We go through this fairly frequently whenever anybody picks up an interesting signal - or anything unusual in the sky - and if you don t know what it is, one possibility is that it s aliens. Right? Well, look at history …"
In the 1960s, recalls Shostak, the British found a pulsing source of radio signals in the sky, and for a while they called them "LGMs," Little Green Men. But it turned out they were pulsars, a rapidly spinning neutron star, the remains of a more massive star. They look like a light blinking, not an alien winking.
"It s totally natural," says Shostak.
So what could explain the radio signals that appear to be coming from the red dwarf star, Ross 128? Are they natural events like pulsars? Here s what we know so far.
Astronomers at the Arecibo Observatory say they picked up "peculiar signals" from Ross 128, a star just 11 light years from Earth, on May 13 of this year. In a blog post, Professor Abel Mendez, the director of the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo, describes the signals in more detail: "[They] consisted of broadband quasi-periodic non-polarized pulses with very strong dispersion-like features."
If you could hear them, which you can t really, they might sound a bit like sweeping, whistling sound, a modulating up and down. It s not the kind of signal alien hunters like Shostak look for as a rule.
"We generally look for narrow-band signals," says Shostak. "They are at one spot on the radio dial, like Norddeutsche Rundfunk - it s one spot you know where to tune to, because those are the kind of signals that are made by transmitters."
The SETI Institute has been helping the scientists at Arecibo collect data, with colleagues at the Berkeley SETI Research Center and SETI s Allen Telescope Array at Hat Creek, California. They hope to come to some conclusion by the end of this week.
Seti-Astronom Seth Shostak in seinem Buero (Picture alliance/Karsten Lemm)
Shostak: If there s extra terrestrial life as close as Ross 128, are there "intelligent critters" everywhere?
The signals from Ross 128, continues Shostak, "cover megahertz of spectrum, and the most interesting thing is that they seem to shift in frequency with time …" Then he makes that whistling sound, "going down the dial."
"Each of the possible explanations has their own problems," writes Mendez in his blog, including the "recurrent aliens hypothesis." Yet speculation abounds.
Help! My world is on fire!
There s something we should bare in mind here. Ross 128 is a star. It is not a planet.
"There is probably no habitable life on that star. It is very hot," writes David M. Jacobs of the International Center for Abduction Research in an email to DW. "But I am not an astronomer, so be careful with what I say."
Thanks for the heads up.
Well, Jacobs may not be an astronomer (he s a retired professor of history from Temple University), but he s probably right, at least by my earthly logic, that stars are very hot places. Some red dwarf stars are known to have planets orbiting them - and those planets could hold life, perhaps a kind that s as sensitive to heat as humans, and if so, you d hope for their sake their world was far enough away from their star.
