08 February 2016

Starts With A Bang: “Have Astronomers Found Alien Megastructures After All? (No, Probably Not)”

Late last year, one of the stars that NASA’s Kepler mission was observing made headlines for having a very unusual signal around it. Rather than a standard planet-like signal, it saw something we couldn’t explain: huge quantities of blocked light in varying amounts. Immediately, the speculation ran rampant, including from Penn State astronomy professor Jason Wright, who noted that the five separate large dips in the light, which did not occur at regular intervals, might be something far better than planets, comets, dust or even an ultra-massive ringed system.

It might be evidence of aliens building gigantic structures around their own star to harness its energy, and we might be seeing evidence of a work-in-progress.

We’ve often found that — when it comes to unexpected astronomical signals — our imaginations run away with us, leading us to immediately jump to conclusions about our greatest hopes and/or fears, like the existence of sentient aliens accessible to us. But the real Universe, every time thus far, has shown itself to be more diverse, complex, and rich in phenomena than we had previously realized, including the existence of quasars, pulsars, exoplanets and more. We haven’t yet ruled out the possibility of alien megastructures, but what we’re most likely seeing is a new type of natural phenomena whose origin is yet unknown. Follow-up observations, particularly those scheduled for 2017, when another major “transit” event is scheduled to occur, should teach us a whole lot more.

Until then, keep an open mind, but don’t let your imagination run away with you!

Ethan Siegel

Over the past two decades, the detection of extrasolar planets has become almost routine, but every once in a while something really strange turns up among the large data sets. This particular star, KIC 8462852, shows irregular dips in brightness that can be poorly explained by known astronomical phenomena. Another recent study analyzing archival photographic plates at Harvard found evidence that the star dimmed over a much longer timeframe, more than a century, making the previous preferred explanation (a random swarm of mega-comets) rather unlikely. So, does this mean it’s an alien-built Dyson swarm?

NASA Possible Comet Swarm around KIC8462852 artist concept
Image credit: NASA/JPL-Caltech, of the now-disfavored “shattered comet” scenario. But a destroyed planet scenario is a real possibility.

No, not really. There are natural mechanisms that can account for a steady reduction in brightness over a long period. And the study showing steady dimming has already been disproven by another, proving the dimming is most likely a data artefact affecting several stars and not a real phenomenon. Still, I am looking forward to more results – and hopefully a valid explanation – to this fascinating mystery.

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