Distant star's strange behavior catches attention of astronomers

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Oct 14, 2015

A massive star has been providing such odd data that it's prompted some eyebrow-raising speculation among scientists.

Astronomer Phil Plait writes at his Bad Astronomy blog that the star, located 1,500 light-years from us and called KIC 8462852, has been observed by NASA's Kepler telescope to have drastic dips in its brightness. As Plait notes, such dips are one way in which we have been able to find thousands of exoplanets while looking at other stars: When a world orbits in front of the star as seen from Earth, it creates a tiny, regularly repeating dimming of that star's light and signals the existence of the planet.

Those dimmings, however, often amount to less than 1 percent of the star's total brightness, and what makes KIC 8462852 so bizarre is that not only are the dips in its light not following the kind of regular schedule that would indicate a planetary orbit, but they have dimmed the star's light by anywhere from 15 to 22 percent -- a massive dropoff.

Plait says that even a rock the size of Jupiter wouldn't cause that kind of blackout, so we're not talking about a giant planet here. Instead, the dips -- and there are many of them, happening at irregular intervals, in varying shapes and lasting all different lengths of time -- are being caused by something that could be half the width of the star itself.

Already ruled out as possible causes are things like mechanical error in the telescope or debris from a planetary collision. One potential cause is a group of comets orbiting the star, although it would apparently be difficult for even those to block nearly a quarter of the star's light. So while that's one possible answer, it's not a definitive one.

So, what else could it be? The lead author of a paper on the star, Tabetha Boyajian, working in conjunction with astronomer Jason Wright, has floated the idea that the dimming could be caused by an artificially constructed object such as a Dyson sphere, a titanic structure of millions of solar panels surrounding a star and capturing its energy for use by an advanced civilization.


The dips could theoretically be caused by the construction of such a mammoth object around KIC 8462852, although everyone involved remains highly skeptical. Nevertheless, Wright and Boyajian have submitted a request to use a radio telescope to look for signals from the star. Their request must be approved by a committee, since telescope time is at a premium, but if permission is granted the pair might be able to detect radio signals from the star that either suggest the presence of intelligent life or possibly provide a naturally occurring answer to the mystery.

Either way, as Plait says, it's "definitely worth investigating further." And while the solution is probably some natural phenomenon we haven't seen before, isn't it fun to wonder just a little if we're looking at the activity of an alien race?