The Alien Observatory –Searching for ET Signals in the Milky Way: “May Be Too Advanced For Us to Detect”

 

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"Every single one of those stars could have a New York City, a Paris, a London, and we would have no idea,” said Nate Tellis of the University of California, Berkeley about the 5,600 stars analyzed in a study released by the Keck Observatory in Hawaii — one of the world’s most powerful telescopes –this past spring, 2017. Tellis, who searches for laser light, powerful pulses of photons that could be as short as a nanosecond, wondered if somewhere buried in that data, could there be a signal from an intelligent civilization trying to reach Earth?


As astronomers analyze data from Keck and NASA's Kepler Mission, and they are discovering more and more Earth-like planets orbiting other stars, the odds are growing that that one of them may harbor something of interest.
Imagine another life-form on a distant world conducting the same kind of search for laser light, said Tellis. “If we had pointed our telescope at Earth at sort of the distance that we’ve been doing here, we wouldn’t have seen us,” he said, "because Earth is not firing a laser beam into the universe as a beacon of its existence. Other worlds may not be, either."

 

Keck astronomers spent hours staring at the night sky in search of exoplanets and accumulating huge amounts of data about potential new worlds elsewhere in the Milky Way. Tellis, along with astronomer Geoff Marcy, dug into the Keck archives for data from 67,000 spectra studied, observed between 2004 and 2016 using a laser-detecting computer algorithm to comb through all that recorded starlight using the Keck 10-meter telescope and spectroscopy with high resolution. Laser emission lines coming from non-natural sources are distinguished from natural astrophysical sources by being monochromatic and coming from an unresolved point in space. Their algorithm identified around 5,000 that warranted further investigation. Tellis and Marcy then analyzed these by hand, ruling out all but 12 signals, which warranted more detailed study.

 

The data from Kepler CK01474, which is a candidate exoplanet host. The narrow emissions in the top and middle panels suggest laser activity. But the bottom panel shows two tracks in the original CCD image, revealing that one or more cosmic ray events caused this signal.

Seti-particles (1)

 

Tellis and Marcy were able to rule out signs of laser signals in all the spectra they studied. “We found no compelling evidence for extraterrestrial laser emission among any of our 5,600 stars at power levels of 3 kW to 13 MW," which helps place limits on how prevalent intelligent civilizations might be.

Based on the rate at which astronomers have found Earth-like planets orbiting other stars, Tellis and Marcy estimated the number of Earth-like planets their survey required: “As [these star systems] contain roughly 2000 lukewarm, Earth-size planets, we rule out models of the Milky Way in which over 0.1% of warm, Earth-size planets harbor technological civilizations that, intentionally or not, are beaming optical lasers toward us.”

In short, if technological civilizations emerge on just 1 percent of such Earth-size planets, then Tellis and Marcy’s survey must have sampled roughly 20 such civilizations.

There's also the possibility that technological civilizations out there, but are many millions of years more advanced than we are, with technology that's beyond our current ability to detect or, perhaps a decision not to contact civilizations as primitive as our own.

“I think when you’re doing a SETI project, it’s very important not to get discouraged by a null detection,” Tellis said. “SETI has been in process for about 60 years, and it’s been non-detection after non-detection after non-detection.

“If you proposed to do a laser SETI study on Keck with thousands of hours, there’s nobody that will let you do it,” Penn State astronomer Jason Wright said. Meanwhile, there’s plenty of astronomical datasets sitting around, waiting for a second look. One man’s trash is another man’s treasure, even in the search for life in the universe. Tellis, Wright said, “was digging through all the trash in case someone threw out a diamond."

The Daily Galaxy via ARVIX , MIT Technology Review, and The Atlantic

Image credit: Keck Observatory

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