All Eyes on Alpha Centauri

Takeaways from this week’s Breakthrough Discuss meeting.

Our stellar next-door neighbors, Alpha Centauri A (left) and B, shine brightly in this Hubble Space Telescope image. (ESA/NASA)
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Currently the premier organization dedicated to searching for advanced life in the universe is the Breakthrough Initiatives program funded by billionaire Yuri Milner in 2015. Each year the program holds a conference known as Breakthrough Discuss to talk about progress in the field, and this pandemic year was no exception. The fact that this week’s discussions were all virtual turned out to be an advantage for the public, who could watch the sessions live on YouTube. Alpha Centauri was the 2021 conference’s main theme, which makes sense considering that one of Breakthrough’s goals is to send a mission to our neighboring star system within the next generation.

The meeting started with an engaging keynote by John Grunsfeld, a former astronaut and head of NASA’s science program, who reviewed past space exploration efforts. Then the discussion turned to how to map the Alpha Centauri system. A highlight of this first session was film director James Cameron’s talk on how science informs his filmmaking (he also revealed that he is currently filming Avatar 2 and Avatar 3 in New Zealand).

The second session on “Prospects for Life at Alpha Centauri” began with Antígona Segura of the Universidad Nacional Autónoma de México talking about how light emitted by a star may affect plant photosynthesis on an exoplanet. In fact, plants on other worlds may not even be green—multiple colors are possible. Sarah Rugheimer of Oxford University followed, pointing out that biosignatures on exoplanets—signs indicating the presence of life—would change over time. Earth’s own history reveals how many different types of atmosphere a planet can have over time, which presumably would hold true in the Alpha Centauri triple star system as well.

The session then moved on to a discussion of technosignatures—evidence of alien technology—with theorist Brian Lacki asking some thought-provoking questions. Could it be that we are the first intelligent society in our cosmic neighborhood? Or could ancient intelligent beings from the Centauri system have terraformed other worlds, maybe even ours. This possibility of “directed panspermia” was suggested by famed molecular biologist Francis Crick and Leslie Orgel in a seminal 1973 paper.

For me, the most eyebrow-raising talk was by Sofia Sheikh of Penn State University, who walked the audience through the story of a radio signal called BLC1, which made the news last year as a possible signal originating from the Centauri system. The evidence was a narrow-band signal (near 982 MHz) detected in April and May 2019, which seemed to shift over time, had a non-zero drift rate, and persisted for a few hours with repeated observations. While these are all traits you might expect from an artificial object orbiting Alpha Centauri, unfortunately it turned out to be nothing quite so exciting. Careful analysis revealed that the it was, in her words, “a pathological example of [radio] interference,” emanating from our own planet or Earth orbit.

The afternoon session ended with a poll I found very interesting. Of course, polls don’t really matter in science, which is driven by facts and not majority vote. But it was intriguing that 69 percent of the meeting’s virtual attendees thought it would be between 5 and 25 years before we discover life beyond Earth. Most people (44 percent) thought it would be found within our own Solar System, even though most of the attendees seemed to be exoplanet researchers.

Even though it was 2 a.m. at my home in Germany, I couldn’t miss the Yuri’s Night panel discussion about possible life in the Venusian clouds. The controversy isn’t resolved by any means, but it’s encouraging that an atmospheric sample return mission to Venus is now seriously being considered. In fact, reported Janusz Petkowski of MIT, Breakthrough Initiatives is sponsoring an MIT-led study of a mission to Venus to search for signs of life, or even life itself.

The third and last session, held on Tuesday, focused on how we might actually someday get to Alpha Centauri. Artur Davoyan of UCLA emphasized that the system could in principle be reached by a lightsail mission in as little as 20 years. But to get a large payload (and perhaps humans in the far future) to Alpha Centauri, a nuclear fusion propulsion system may be required. Michael Paluszek of Princeton Satellite Systems outlined the current state of the art of that technology. It’s certainly a challenging task, but it felt good to hear people discussing such daring visions!

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