A worldwide call has been put out for astronomers to turn their telescopes towards a mysterious star some believe is proof of extra-terrestrial intelligence.
KIC 8462852, also known as Tabby's star or Boyajian's star, over the past two years has been blinking erratically, its light dimming and brightening in a way scientists haven't been able to explain.
Some astronomers have suggested it could be a sign the star is surrounded by an alien megastructure known as a Dyson swarm or shell - solar panels in orbit around the star, collecting energy.
Others have posited it could be a comet swarm or something else less fantastical.
"At about 4am this morning I got a phone call... that Fairborn [Observatory] in Arizona had confirmed that the star was 3 percent dimmer than it normally is," Jason Wright, an astronomer at Pennsylvania State University, said during a webcast, reports space.com.
"That is enough that we are absolutely confident that this is no statistical fluke. We've now got it confirmed at multiple observatories, I think."
He took to Twitter to tell the world to point their telescopes at Boyajian's star for the next 48 hours.
Boyajian's star first came to astronomers' attention in 2015, when NASA's Kepler telescope monitored wild fluctuations in its brightness.
Prof Wright's call for "spectra" in his tweet refers to measurements that can show what elements are present in or around the star, and what direction things are moving in.
"If there is a lot of dust between us and the star... it will block more blue light than red light. If there is gas in that dust, that gas should absorb very specific wavelengths and we should be able to see that."
Dips in brightness have been so far unpredictable, and last between two days and a week. At most, its brightness dips about 22 percent.
Boyajian's star is named after Tabetha Boyajian, the leader of the Yale University team which first spotted the star's unusual behaviour in NASA's data.
"We'd never seen anything like this star," Dr Boyajian said at the time. "It was really weird."
It's located about 1500 light years away in the constellation Cygnus.