Astronomer Wants to Find Alien Life By Detecting Radiation from Light Sails

Harvard astronomer Avi Loeb is known for his unusual thought experiments regarding alien life; he has suggested a search for artificial light on Pluto, in the remote chance that aliens have built a civilization there, and detecting industrial pollution on exoplanets. Now, he has proposed his next radical idea: detecting radiation from light sails that aliens use to travel between planets. 

Solar sails, or light sails, as they’re frequently called, use ultra-thin mirrors to capture solar wind, using it to propel a spacecraft without the use of rockets. They don’t exist yet, but scientists agree that they are theoretically possible, and a prototype is currently in the works at the Planetary Society, with a test flight planned for next year.

Theoretically, a light sail would use most of the light it absorbed in order to generate power, but there would inevitably be some leakage. According to Loeb, if aliens are more technologically advanced than humans, and have discovered how to make light sails work, then we would be able to detect residual radiation from the sails. 

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“Because most travel within a planetary system would be conducted between the habitable worlds within that system, multiply-transiting exoplanetary systems offer the greatest chance of detection,” Loeb and his co-author wrote in their paper. “If interplanetary travel via beam-driven light sails is commonly employed in our galaxy, this activity could be revealed by radio follow-up of nearby transiting exoplanetary systems.”

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Since the light sails would require a beam of radiation with a tenth of Earth’s power output, it couldn’t be solar power. The aliens would need to use artificial radiation, most likely in the form of microwaves. From their calculations, the leaked microwaves could then be detected from Earth as radio signals, which would follow different patterns from natural microwave sources. 

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“It would be easily detectable out to hundreds of light-years away with existing antennas,” Loeb Scientific American.

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This is definitely out-of-the-box thinking, and could easily be more of a thought experiment than anything else. According to other experts, it’s not impossible, but there are too many unknowns about potential alien civilizations for it to be likely.

“I don’t think it’s nuts,” said Seth Shostak, senior astronomer at the SETI Institute. “It’s a clever idea.” But, he qualified, we have little to no reason to believe that aliens would use light sails specifically. They are not only likely to be more advanced than humans, they may have downloaded themselves into artificial intelligence, which would make it even more implausible that they would follow a similar trajectory to humans.

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“The aliens may well have gone beyond biological intelligence, and we really don’t know what machines would choose to do.”

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Source: Astronomer Wants to Find Alien Life By Detecting Radiation from Light Sails

Via: Google Alerts for AI

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