Astronomers Spot Potentially Artificial Radio Signal From Nearby Star

large satellite dishes in silhouette at sunset, panoramic frame. Credit: sharply_done/Getty Images

(Credit: sharply_done/Getty Images) In 2015, Billionaire Yuri Milner launched the Breakthrough Listen project, an effort to scan the million closest stars for radio signals that could indicate intelligent life. Astronomers working on the project have announced the discovery of just such a signal from Proxima Centauri, which is just 4.2 light years away. We don’t yet know what this signal is, but there’s a (very) small chance it could have alien origins. 

Breakthrough Listen uses radio telescopes like the Parkes telescope in Australia or the Green Bank Observatory in West Virginia. These instruments regularly record what look like signals from space but are actually due to local interference from Earth. In April and May of 2019, the team caught something different — a narrow beam transmission around 980MHz that lasted 30 hours. The signal, dubbed BLC1, also appeared to shift in such a way that it could have been coming from a planet orbiting the star.

The team is still preparing a paper that the scientific community can scrutinize, but there are a few reasons to be excited here. Proxima Centauri is the closest star to our solar system, and in 2016, researchers announced the discovery of an Earth-like exoplanet orbiting in the habitable zone. Later, astronomers spotted a second, larger planet farther out in the solar system. So, it’s theoretically possible there’s life on one of those planets, particularly the one in the habitable zone. 

The Green Bank Telescope used by Breakthrough Listen.

However, it’s still far too early to start celebrating the discovery of alien life. BLC1 is a candidate signal that needs to be analyzed, and if we’re being realistic, it’s doubtful that intelligent aliens live in the next solar system over. The Milky Way galaxy has an estimated 300 million exoplanets and is almost 14 billion years old. To find another intelligent species existing at the same time as us just a few light years away would be exceedingly improbable. If said aliens are also using radio frequency technology at the same time as we are, that’s an even bigger coincidence. 

This is not the first signal that could be interpreted as having artificial origins. The famous “Wow” signal detected in 1977 by SETI researchers is another example. That one didn’t pan out, but BLC1 could be the first serious contender in decades. If this isn’t it, well, there are a lot more stars out there. The only way we’re going to find them is to keep looking. 

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