Scientists have suggested that aliens may be waiting until the space version of “high noon” to send us their signals.
In a new study, scientists have been looking for technological signs of ETs at the times when exoplanets pass directly in front of their suns, from an Earthly point of view. These very moments may be the perfect opportunity for the alien world to send a signal to Earthlings to make contact.
“Exoplanetary transits are unique in that they can be computed both by us on Earth as observers and by any potential tech species in the exoplanet system itself as transmitters,” said the study leader. Sofia Sheikh (opens in a new tab), researcher with a PhD in radio astronomy at the Institute for the Search for Extraterrestrial Intelligence (SETI). These transits are therefore a predictable and repeatable time when aliens might think of sending messages, and earthlings might want to receive them.
“This strategy helps us narrow down the huge question of where and when to look for news in the vast expanses of space,” Sheikh told Live Science in an email.
The new study, published Dec. 9 on the preprint site arXiv (opens in a new tab) and scheduled for peer-reviewed publication in The Astronomical Journal, found no evidence of talkative aliens. But the study only searched a dozen distant planets. In the future, they plan to search further with various telescopes.
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Since radio technology was invented in the late 19th century, Earth he transmitted transmissions into space – and occasionally, as in the case of the famous Message from Arecibo, 1974sent them on purpose in hopes of contacting an intelligent extraterrestrial who might be listening to them. Hoping that intelligent alien civilizations can also emit tech signals or technosignals, researchers are also scanning the galaxy radio waves that may have come from alien technology.
But galaxy it’s a big place so the key question is where to look. Sheikh and her team decided to eavesdrop on distant exoplanets as they pass in front of their suns, the so-called “Schelling point” – a solution to a problem two people usually face if they don’t communicate with each other. In other words, the timing of a planetary transit seems like a logical timing to connect from both the transmitter and receiver point of view.
Sheikh and her colleagues used the Robert C. Byrd Green Bank Telescope in West Virginia to look for radio signals from 12 exoplanets that could be seen transiting during a short window in March 2018. They detected many radio signals – nearly 34,000 in fact – but 99, 6% of these can be immediately dismissed as interference caused by terrestrial communications. A group of trained citizen scientists did the work of studying the signals.
It was eventually determined that all but two of the signals were caused by interference. The other two, a few short outbursts from Kepler-1332b and Kepler-842b – both potentially rocky planets larger than Earth – were considered worthy of further study. However, the Sheikh said that these two are almost certainly caused by disruptions and are not real news.
Nevertheless, she said, the study was proof that the search method could work. The scientists plan to make more observations at the Allen Telescope Array in California in the future.