That weird ‘alien megastructure’ star is dimming again right now

Astronomers are scrambling to take measurements.
Illustration of the star KIC 8462852
Although scientists have suggested the weird light dips from this star might come from a family of mega-sized comets, there isn't yet a scientific explanation that fits. NASA/JPL-Caltech

In late 2015, astronomers noticed something absurd happening around a distant star. Something massive seemed to be blocking as much as 20 percent of the star’s light.

That’s way too much to be a planet. It might be comets, or maybe an alien-made Dyson swarm. The problem is that none of the hypotheses that scientists have come up with (including the one about aliens) really fits with the data. That leads them to think that some as-yet-undiscovered phenomena is happening around this star.

For years, astronomer Tabetha Boyajian and her colleagues have been waiting for the mysterious light dips to happen again, so that they could collect more data and try to get to the bottom of the mystery. And now it seems the star is finally dimming again:

The researchers suspected another dip was happening yesterday, but this morning the Fairborn Observatory in Arizona confirmed that the star has dimmed by three percent. (By comparison, a Jupiter-sized planet would block one percent of a star’s light, at most.) The team has put out a call for amateur astronomers and large observatories to point their scopes at the star and try to collect data. The Swift, Keck, Fairborn, and Lick telescopes are among the observatories who’ll helping the effort.

In particular, the astronomers want to see how the star looks in different wavelengths. That’s because different materials will block some wavelengths but not others, offering clues to the identify of any circumstellar material that may be blocking the light.

kic dips
The light from ‘Tabby’s Star’ has dipped by three percent so far. Astronomers aren’t sure if the light will continue to plummet, or if so, for how long. Livestream

If it’s dust that’s blocking the light, the spectra should show big dips in the blue and ultraviolet wavelengths. If it’s other stuff orbiting the star, like a family of huge comets, then the observations should show extra heat being radiated off of this stuff. So far, that excess infrared has remained elusive, but Jason Wright, an astronomer from Penn State, said that the observations that will start tonight could provide the first evidence of that.

If it’s an alien megastructure, or some kind of internal process, all of the wavelengths should get dimmer equally. A bizarre signature, such as Tritium or artificial elements would be a pretty strong hint for aliens, although it would take an extraordinary amount of evidence to prove such an extraordinary claim.

Wright said they might have some preliminary results back as soon as tomorrow night, but other data will take longer to analyze.

“I don’t think we’re going to solve the puzzle this weekend,” says Wright, but he added that this weekend may be when they collect the data that eventually solves the puzzle.

This post was updated to include information from a livestream starting at 2pm Eastern on 5/19/2017.