Alien megastructure theory just suffered another major blow

3 Jan 2018

Planetary debris has been theorised as causing the irregular dips seen around Tabby’s Star. Image: Dotted Yet/Shutterstock

A crowdfunding campaign to determine once and for all whether there is an ‘alien megastructure’ around Tabby’s Star has found an answer.

Few points of space have drawn as much interest from space enthusiasts than KIC 8462852, otherwise known as Tabby’s Star, after a group of scientists proposed that it might be the first sign of an ‘alien megastructure’ in deep space.

The star first came to astronomers’ attention when they noticed it had unusual dips in brightness, by as much as 20pc over a matter of days.

Not only that but, unlike most stars, this particular one has shown much subtler but longer-term, enigmatic dimming trends, with the suggestion that it is being caused by a Dyson sphere, a theoretical megastructure that would surround a star to harvest its enormous quantities of energy.

So, while varying opinions as to what is causing the peculiar dips have been proposed over the past few years, a team of astrophysicists has now published what it believes to be the most likely answer – and it is sad news for those hopeful of extraterrestrial life being the cause.

In a paper to be published in The Astrophysical Journal Letters, a team of 200 researchers led by the scientist for which the star is named – Tabetha Boyajian – has come to the conclusion that the culprit is nothing more than space dust.

Mysterious, but plausible

The project began after a crowdfunding campaign raised more than $100,000 to find an answer, allowing a dedicated ground-based telescope time to observe and gather more data on the star through a network of telescopes around the world.

Between March 2016 and December 2017, the team observed four distinct episodes where the star’s light dipped, referring to them as Elsie, Celeste, Skara Brae and Angkor.

The paper’s authors described the dips as “mysterious”, despite them being caused by something considered normal in the cosmos.

The purpose of the study was to analyse the dips at all wavelengths because if they were all of near-equal measure, they would be caused by a physical structure, which includes the possibility of an alien megastructure. However, the fact that the star got much dimmer at some wavelengths than at others extinguishes that idea.

Speaking of the findings, Boyajian said: “Dust is most likely the reason why the star’s light appears to dim and brighten. The 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.”

Colm Gorey was a senior journalist with Silicon Republic