Alpha Centauri A and B

Is Alpha Centauri safe enough for us to possibly live there someday?

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Jun 11, 2018, 9:49 AM EDT

Humans are already thinking of living on the moon, Mars and even living in a futuristic floating colony in the atmosphere of Venus, but we still want to make sure Alpha Centauri is safe — because we might end up landing there too.

Alpha Centuari, the triple star system of Alpha Centuari A, Alpha Centuari B and Proxima Centauri, is the closest system to our own at just 4.367 light years (about 25 trillion miles) away. Until now, scientists remained optimistic about the habitable zones around Alpha Centauri A and B, even though no Earth-like planets have been discovered there yet. A new study recently presented at the recent meeting of the American Astronomical society just proved that we really could live there if we find a suitable planet.

"Because it is relatively close, the Alpha Centauri system is seen by many as the best candidate to explore for signs of life," said Tom Ayres of the University of Colorado Boulder. "The question is, will we find planets in an environment conducive to life as we know it?"

When the rocky planet Proxima b was discovered in the Proxima Centauri’s habitable zone back in 2016, scientists were excited about its potential habitability until they found out the space weather forecast. The new study is based on data collected after fixing the telescopic eye of NASA's Chandra X-Ray Observatory on Alpha Centauri for a decade. There are indications from this data that planets orbiting Alpha Centauri A and B and not being blasted with the same intense X-ray radiation that scientists believe has Proxima b under attack.


Closeup of Alpha Centauri. Credit: NASA

For a radiation-ravaged planet closer to home, look no further than Mars. Its atmosphere has been just about completely obliterated.

Alpha Centauri A and B are not so threatened by stellar radiation. Just about every aspect of Alpha Cen A, even its age, is a mirror of our sun, while Alpha Cen B may be smaller and dimmer than our star but still similar. Proxima is a much smaller red dwarf that orbits the other two. While it is the nearest star to Earth, but is constantly shooting flares of radiation into space. At least Chandra has revealed that prospects for life (and future colonies) are actually pretty high around Alpha Cen A and B. If hypothetical aliens were seeking out a planet to live on based solely on X-ray radiation, they would actually choose Alpha Cen A over the sun.

"This is very good news for Alpha Cen AB in terms of the ability of possible life on any of their planets to survive radiation bouts from the stars," said Ayres. "Chandra shows us that life should have a fighting chance on planets around either of these stars."

Now all astronomers need to find is a planet that could be crawling with alien organisms, conducive to a human colony, or both. The only known Earth-like planet in Alpha Centauri is the inhospitable Proxima B. That could change.

Just in case Mars, Venus or the moon don’t appeal to future space travelers, there could soon be another option for off-Earth living and, you know, generally taking over the universe.

(via Chandra X-Ray Observatory)