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Are they aliens using a quirk of SunWhat is the gravity to transmit information through an interstellar communication network? For the first time ever, astronomers explored this intriguing possibility and searched for signals from occult non-human probes orbiting the sun.
So far, the method has revealed no signs of aliens in space, but it represents a promising new avenue for hunting aliens as part of the search for extraterrestrial intelligence (SETI).
The new search strategy is based on the findings of Albert Einstein, who demonstrated in 1915 that gravity deforms the fabric of space-time. This means that massive objects, such as stars and galaxies, bend light around them. This effect, known as gravitational lensing, allows scientists to see extremely distant objects whose light has been distorted by huge foreground galaxies and galaxy clusters.
“It’s a lot like a magnifying glass,” Nicholas Tusaya graduate student at Penn State, told Live Science.
With gravitational lensing and a magnifying glass, magnification works best when a person or detector is placed in a specific location known as a focal point, he said.
The sun’s gravitational focal point starts at about 550 astronomical units (AU), or 550 times the distance between Earth and the sun, Tusay said. A telescope placed in this location would have mind-boggling capabilities: It could resolve continents and mountains on a planet orbiting another star, he added.
“The light goes both ways,” Tusay said. “If you can magnify the light that reaches you, you can also magnify the light that leaves.”
This means that gravitational lensing can also be used to efficiently send signals across interstellar distances, so scientists have speculated about tech-savvy aliens placing probes at the focal points of stars, effectively turning them into a gigantic peer-to-peer communication network.
To test this idea, Tusay and his colleagues used the Green Bank Telescope in West Virginia to perform six five-minute scans looking for radio signals coming from the sun’s gravitational focal point. And what did they find?
“Nothing,” he said. “To put it precisely: at the frequencies that we observed, during the time that we observed, we did not find convincing signals that were of extraterrestrial origin.”
The results were published last summer in the astronomical journal and were presented last week by Tusay at the 241st meeting of the American Astronomical Society in Seattle.
While the findings are not yet evidence of aliens, Tusay said it’s possible that alien probes positioned at the sun’s gravitational focal point turn on only from time to time. And other stars have properties that make them better nodes in a gigantic space internet, so they could be additional search targets, he added. He sees the method more as a proof of concept that could lead to something interesting if carried out over time and with more resources.
“We’re always talking about new ways to search the SETI field,” julia demarines, an astrobiologist at the University of California, Berkeley, who was not involved in the work, told Live Science. “This is the first time I’ve seen a search dedicated to this specific ability to intercept messages.”
When nothing is seen in a SETI search, it could mean a number of things, he added, including that no one is communicating, or simply that no one is communicating in this way. Any new search methods are always welcome, DeMarines said. “If you don’t look,” he added, “then you’ll never know.”
