It has caused a media furore - but, the 'alien megastructure' star may be something a little more mundane, a new theory claims. It says that instead of a giant craft, dips in brightness were actually caused by a gigantic ringed planet that puts Saturn to shame and clouds of comets that contain more mass than Jupiter.
They say that in fact, the phenomenon could be 'entirely natural'
“KIC 8462852 stood out among more than 100,000 stars in the Kepler catalogue because of the strange features of its light curve: a wide and asymmetric dimming taking up to 15 per cent of the total light, together with a period of multiple, narrow dimmings happening approximately 700 days later.
Several models have been proposed to account for this abnormal behavior, most of which require either unlikely causes or a finely-tuned timing. We aim at offering a relatively natural solution, invoking only phenomena that have been previously observed, although perhaps in larger or more massive versions.” Fernando Ballesteros at the University of Valencia in Spain and his colleagues wrote in the journal Arxiv.
Several models have been proposed to account for this abnormal behavior, most of which require either unlikely causes or a finely-tuned timing. We aim at offering a relatively natural solution, invoking only phenomena that have been previously observed, although perhaps in larger or more massive versions.
The researchers created a simulation to test their theory using a large, ringed body whose transit produces the first dimming and a swarm of Trojan objects sharing its orbit that causes the second period of multiple dimmings. The team say a dip in 2011 which reduced the brightness of Tabby’s star by up to 15 per cent, can be explained by a massive ringed planet five times the size of Jupiter transiting in front of it.
“In this context the recent observation of a minor dimming can be explained as a secondary eclipse produced by the passage of the planet behind the star. Our model allows us to make two straightforward predictions: we expect the passage of a new swarm of Trojans in front of the star starting during the early months of 2021, and a new transit of the main object during the first half of 2023.”
The team also predicts another dimming that could prove their theory.
Earlier this month astronomers have issued an internet-wide ‘call to action’ after discovering this morning that ‘Tabby’s Star’ has once again begun to dim. The mysterious phenomenon was first detected in 2015, when a star in the constellation Cygnus was found to be ‘winking,’ with dramatic fluctuations in brightness – but, scientists aren’t quite sure what’s causing it.
Since it was first detected, scientists have been hard at work attempting to explain the fluctuations, which have seen brightness dip as much as 20 percent before reverting to normal. If an 'alien megastructure' really is to blame, one scientist has suggested that spotting it could be relatively easy – as long as experts focus on the right places.
He says that astronomers should turn their attention to 64 pulsar stars near our planet, which he believes offer the best chance of hosting an alien megastructure. In a paper published last year, Professor Zaza Osmanov said the alien megastructures are more likely to be shaped like thin discs rather than 'spherical shells.'
If his theory is correct, this would allow a Dyson's Sphere to exist in a star's 'habitable zone.' And in his new paper, Professor Osmanov argues that if the Dyson's Sphere does exist in a habitable zone, it should be easy to spot using infrared telescopes. Professor Osmanov is urging astronomers to focus their search on 64 pulsar stars.
In his paper, published on arXiv, Professor Osmanov said:
"We have argued that by monitoring the nearby zone of the solar system approximately 64 pulsars are expected to be located inside it."
But Professor Osmanov has warned that should we find the alien megastructure, it could be extremely powerful.
He said:
"Rapidly rotating pulsars are very powerful and harvesting their energy would be quite profitable, but a habitable zone would be much farther and mass of a material required for constructing the mega-ring would exceed the total mass of all planets, asteroids, comets, centaurs and interplanetary dust in a typical planetary system by several orders of magnitude."
This suggests that an alien civilization living on a megastructure could be strong enough to wipe out humanity.