The ‘alien megastructure’ is acting weird again
For some people, the weird lights emanating from the ‘alien megastructure’ 1,280 light-years away from Earth are bursts of alien energy built by an advanced civilisation to harvest power. For the non-conspiratorial, it’s just a collection of cosmic dust passing in front of a star to produce a light show.
Whatever it is, the alien megastructure has just started acting up again and has dimmed by 5%, making it the faintest it’s ever been since observed by Kepler in 2013.
According to Tabetha Boyajian, the astrophysicist who discovered the star, the alien megastructure – known formally as KIC 8462852 or Tabby’s Star – had been dimming since 16 March, before brightening up then dimming right down to 5% of its usual brightness yesterday.
It’s not actually unusual for stars to dim. In fact, it is Kepler’s job to look for dimming stars since it’s what often signifies the existence of an exoplanet. The strange thing with Tabby’s Star, however, is that the dimming isn’t regularly occurring, something evidenced by the massive 22% brightening and dimming of the star back in 2013. Combine that with the erratic nature of the dimming, and scientists are faced with one unusual space phenomenon.
So what’s going on? Are the aliens heading off? While astrophysicists have no idea what’s leading to KIC 8462852’s light dim, they’re pretty certain we can rule out a bunch of nefarious aliens.
Back in January, Boyajian herself debunked the whole alien megastructure theory. With observatory time, Boyajian and her team were able analyse the star’s erratic light shifts and spectrum, and observe how the light was being blocked at differing intensities.
“Dust is most likely the reason why the star’s light appears to dim and brighten,” Boyajian explained. “New data shows that different colours of light are being blocked at different intensities. Therefore whatever is passing between us and the star is not opaque as would be expected from a planet or alien megastructure.”
That doesn’t mean the case is closed, however. We still don’t know where any of this cosmic dust is coming from, or in fact why it’s behaving in such a random way. Alien megastructure or not, Tabby’s Star just isn’t behaving as expected, and this sudden dim is only adding to its complete air of mystery.