Wednesday, May 24, 2017

"Megastructure Star" is Dimming Again

KIC 8462852 sure is weird. The star is the subject of speculation as to whether or not some sort of "alien megastructure" might be constructed around it. This is because it shows a pattern of irregular dimming that has yet to be fully explained, despite several alternative hypotheses. Up until now, we have not been able to study the star as it undergoes the dimming process. But astronomers are seeing the star start to dim once more.

Star KIC 8462852, or Boyajian's star (also nicknamed "Tabby's star," for astronomer Tabetha Boyajian, who led the team that first detected the star's fluctuations), has demonstrated an irregular cycle of growing dimmer and then returning to its previous brightness. These changes were first spotted in September 2015 using NASA's Kepler Space Telescope, which was built to observe these kinds of dips in a star's brightness, because they can be caused by a planet moving in front of the star as seen from Earth.

But the brightness changes exhibited by Boyajian don't show the kind of regularity that is typical of a planet's orbit around its star, and scientists can't see how the changes could be explained by a system of planets.

Scientists have hypothesized that the changes could be due to a swarm of comets passing in front of the star, that they're the result of strong magnetic activity, or that it's some massive structure built by aliens. But no leading hypothesis has emerged, so scientists have been eager to capture a highly detailed picture of the light coming from the star during one of these dimming periods. This detailed view is what scientists typically call an object spectra. It can reveal, for example, the specific chemical elements that are in a gas. It can also tell scientists if an object is moving toward or away from the observer.

Observing the star as it dims allows us to make additional observations that may resolve the mystery. Spectroscopy can help identify characteristics of whatever is blocking the star's light. It should be able to establish whether the obstruction is a cloud of gas or dust. But if neither of those wind up matching the measurements, we could be back to the megastructure hypothesis. That would be supported by an observation that the light doesn't seem to be passing through anything - if we can assume that said megastructure is not transparent.

So I'm looking forward to whatever these new observations will detect. As usual, the paranormal explanation shouldn't be the default. But you never know - it just might be space aliens after all.

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