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Scientists probe cosmic visitor from deep space, come up empty in search for alien life

An image captured of the interstellar comet 3I/ATLAS.
An image captured by the Hubble Space Telescope shows the interstellar comet 3I/ATLAS on July 21, 2025, when the comet was 277 million miles from Earth.
(NASA / European Space Agency via Associated Press)
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Last summer, a NASA-funded asteroid impact warning system detected a mysterious object speeding through the solar system.

Scientists determined the object had entered the solar system from deep space, making it the third known object to have come from another star system.

NASA called it Comet 3I/ATLAS and said it didn’t pose a threat. But its discovery in July led to wild speculation that the object was a piece of extraterrestrial technology — maybe even an alien spacecraft.

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The SETI Institute, a nonprofit that explores the origins of life and searches for extraterrestrial intelligence, said this week that a team of scientists had used a radio telescope to try to detect signals that could indicate extraterrestrial life on the comet.

But they found none.

“While observations strongly indicate that 3I/ATLAS is a natural object, interstellar visitors are also compelling technosignature targets because an artificial object — however unlikely — could represent detectable extraterrestrial technology and potentially provide the first evidence of life beyond Earth,” the institute said in a news release.

SETI scientists said they used the Allen Telescope Array at the Hat Creek Radio Observatory in Northern California to scan the object for seven hours, covering a spectrum of 1 to 9 gigahertz.

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“This broad range allows scientists to search for narrowband radio signals, which are not produced in nature and would be evidence of technology,” the news release said.

The institute said the team identified nearly 74 million narrowband signals, but ultimately traced them back to technology on the Earth’s surface or orbiting satellites.

“The results from 3I/ATLAS show how realistic it is to detect a signal with the technology we have today,” said Valeria Garcia Lopez, one of scientists on the SETI team. “That is why it is important to keep searching for technosignatures, even from objects we might not expect to have signals.”

The institute said the researchers also can learn more about the natural properties of interstellar objects as they travel through our solar system.

“As more interstellar objects are discovered, each offers a new opportunity to probe the cosmos for technosignatures, advancing our understanding of both natural and possible technological phenomena beyond our Solar System,” the SETI statement said.

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