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'Alien' signal likely isn't, but if it is, they're way smarter than us

There's something strange coming from a distant star once again. It's probably nothing, unless it's something...something really big.

Artist's representation of a crumbling Dyson sphere.
Artist's representation of a crumbling Dyson sphere.
Danielle Futselaar/METI International

Another weird signal from the cosmos has scientists checking for E.T. attempting to make an interstellar call. So far, it's looking like nobody's home and something natural or some sort of human interference is the real source. But if intelligent aliens did indeed turn out to be behind this latest blip, their tech would be the stuff of far-fetched science fiction.

The latest SETI (search for extraterrestrial intelligence) stir started when author Paul Gilster revealed he's seen documents from a presentation set for late September that lay out the detection of a "strong signal" coming from a star system 95 light years away. Russian scientists discovered the signal over a year ago, by way of a powerful radio telescope.

The signal reportedly came from the direction of the star HD 164595 in the constellation Hercules, which has at least one confirmed planet, a Neptune-size world in close orbit that would seem unlikely to support life as we know it.

There's lots of reasons to be skeptical that anything intelligent is behind this signal. For starters, the scientists waited more than a year to contact anyone else in the SETI community to conduct additional observations and attempt to confirm their detection, as is protocol among astronomers. Also, the Russians reportedly picked up the signal only once in 39 tries. Both these factors would suggest the scientists didn't seem to think the signal was a very big deal at the time.

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SETI Institute senior astronomer Seth Shostak also notes that the Russian RATAN-600 radio telescope "is of an unusual design" and it can't even be said for sure that the signal originated from HD 164595.

"The most likely explanation for the signal from the direction of HD 164595 is that it's *not* a sign of extraterrestrial intelligence," METI (for Messaging Extra-Terrestrial Intelligence) International President Doug Vakoch told me via email. "It could be due to a satellite flying overhead at just the right time, or it could be radio interference caused by an Earth-based transmitter. But there could also be a natural explanation that we haven't yet figured out."

This latest excitement over weird things happening beyond our solar system comes less than a year after talk started about possible alien megastructures around the star KIC 8462852 and with talk still swirling about Proxima b, a potentially habitable planet orbiting the closest star to the sun.

Regardless of how low the odds are that the mysterious signal will turn out to be aliens, both organizations have already gone to work to take a closer look and listen to HD 164595.

When I last checked with Shostak, on Monday, the SETI Institute had already pointed the Allen Telescope Array in northern California at the star and picked up nothing in its early observations. The ATA has yet to cover the full range of frequencies in which the signal could be detected, though, something Shostak says will continue over the next day or two.

The Panama-based telescope that METI International uses for such searches has been plagued by bad weather hampering its ability to check things out, but Vakoch is hopeful the weather will clear up Tuesday night.

Probability aside, what if the signal were to be confirmed as alien? If an advanced civilization really is sending signals into space, what might that society be like?

In a word, it would probably be pretty impressive to our eyes.

If a civilization in the vicinity of HD 164595 were sending such a strong signal every which way in space, it would have to be what's classified as a Type II civilization on the Kardashev scale, which means the society would have the technical capability to turn a star into its personal power plant.

"If the signal from HD 164595 is from a civilization that is radiating out electromagnetic signals in all directions, that takes tremendous energy -- the energy of an entire star, represented by a Type II civilization," Vakoch told me.

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To be clear, this doesn't mean being able to harness all the energy of a star that hits a single planet by, say, blanketing the atmosphere with transparent solar panels -- that capability would constitute a Type I civilization. Instead it means harnessing all of a star's power that radiates in all directions, perhaps by building a hollow shell called a Dyson sphere around the star itself.

A society with that capability seems like one we wouldn't want to upset.

Another possibility is that a distant civilization could be narrowly targeting a signal only in our direction, which would take less power, but still more than humans would be able to muster right now. Vakoch estimates that a Type I civilization might be able to send out such a transmission.

"Humanity is currently somewhere between Type 0 and Type I," he explains. "So if E.T. is merely 'pinging' us periodically from 95 light-years away, with a targeted beacon, they might be only a few hundred years more advanced than we are."

That's still a lot of catching up to do. But there's more reason to doubt that Herculean aliens are attempting a conversation that requires nearly a century between messages. The earliest radio signals sent out by humans would just now be reaching HD 164595, so if broadcasters there picked up our radio shows from the 1920s and decided to target a message right back at us immediately, that signal wouldn't arrive at Earth until about 2109 or later.

Unless the aliens have achieved some mind-bending science fiction conceits like sending signals through a hypothetical wormhole, it's more likely that the signal picked up last year is better explained by a microwave oven than an E.T.