A few days ago Centauri Dreams, a popular website for space professionals and enthusiasts run by Paul Gilster, broke the news that astronomers using the RATAN-600 radio telescope in Zelenchukskaya, Russia, had detected a strong signal from a star known as HD 164595.
The characteristics of the signal have ignited the imagination of SETI (Search for Extraterrestrial Intelligence) enthusiasts all over the internet, and some radio-astronomy facilities, including the Allen Telescope Array, are now watching HD 164595.
Is this the long expected call from an alien civilization? “No one is claiming that this is the work of an extraterrestrial civilization, but it is certainly worth further study,” says Gilster. Seth Shostak, Senior Astronomer at the SETI Institute, adds that a message sent from aliens is a possibility, but warns that there are other plausible explanations for the signal, including terrestrial interference. “Without a confirmation of this signal, we can only say that it’s ‘interesting’,” concludes Shostak.
The findings are reported in a paper titled “SETI observations on the RATAN-600 telescope in 2015 and detection of a strong signal in the direction of HD 164595,” authored by a team of Russian and international scientists including Claudio Maccone, chair of the International Academy of Astronautics SETI Permanent Committee, who forwarded the paper to Gilster. The work will be officially presented and discussed at a Committee meeting during the forthcoming International Astronautical Congress (IAC) in Guadalajara, Mexico, on September 27.
A Message from a Super Advanced Alien Civilization?
HD 164595 is a star of 0.99 solar masses, similar to the Sun, at a distance of about 95 light years in the constellation Hercules. There is a known planet orbiting the star, about 15 times heavier than the Earth, but there could be other planets that haven’t be detected so far.
The distance of 95 light years makes it highly unlikely that hypothetical aliens could have detected our civilization and beamed a signal to us. Therefore, the signal could be an all-directional spherical beacon. But, in this case, the required power would be 100 billion billion watts. Shostak says:
“That’s hundreds of times more energy than all the sunlight falling on Earth, and would obviously require power sources far beyond any we have.”
Glister notes that such power would be available only to a super-advanced “Kardashev Type II” civilization, able to harness the entire energy output of its star. It’s worth noting that, with an estimated age of 6.3 billion years, HD 164595 is much older than the Sun, and therefore civilizations much older than ours could have evolved there.
In October 2015, Hacked reported the detection of what could be a “megastructure” built by an alien Kardashev Tyle II super-civilization around the star KIC 8462852, located in the constellation Cygnus at approximately 1,481 light years from the Earth. The jury is still out on that one.
Most candidate SETI signals are eventually found to be bogus, or of natural or terrestrial origin, and a few remain a mystery. To date, no clear evidence of messages from alien civilization has been confirmed. But one thing is certain: the discovery of a message from the stars would have a momentous positive impact on our own civilization, and therefore the time, effort, and money spent on SETI are well spent.
Silence from Russia
RATAN-600 is a radio telescope in Zelenchukskaya, Russia. It is a circular array of independently steerable radio reflectors that, combined, form a partially steerable antenna with the resolving power of a 600 m diameter dish, making RATAN-600 the world’s largest diameter individual radio telescope.
The “2015” in the title of the paper is not a typo. In fact, the signal was received on May 15, 2015, but there have been no leaks until now. Of course, this is exciting the imagination of conspiracy theorists, and a recent disclaimer from Russia could make things worse.
“There have been no scientific results within the framework of this research so far. Some time ago, in the spring of this year, an unusual signal was received but its analysis showed that it was most likely a terrestrial disturbance,” said researcher Yulia Sotnikova to the Russian news agency TASS. The researcher added that the observatory was preparing the text of an official disclaimer.
Images from ESO and Shutterstock.