“But it would have to be unlike anything else seen in our galaxy, by orders of magnitude,” Dr. Chatterjee said.
“So we can’t really rule out more exotic models, and theorists have a lot of those,” he added, and rattled off possibilities including the tubes of primordial energy called cosmic strings and the mysterious dark matter that makes up a quarter of the universe. “Because why not? It’s still a bit of a mystery.”
Snap, crack and pop indeed.
So it isn’t turning out to be a great year for E.T. — at least not so far.
Early in January, astronomers monitoring an enigmatic object known as “Boyajian’s Star,” after the astronomer Tabetha Boyajian, concluded that erratic and striking dips in its brightness were not caused by some gigantic alien construction project.
The dips — much greater than would be expected for a planet — were discovered by a group of citizen astronomers known as the “Planet Hunters,” who were following up on results from the Kepler spacecraft. The discovery had elicited suggestions that the dips could be caused by the construction of a Dyson-like sphere, a shell that an advanced civilization might build around its star in order to capture all its energy.
But new observations by Dr. Boyajian, of Louisiana State University, and other astronomers of a recent dimming showed that the amount of dimming depended on the wavelength, or color, of the light observed, a classic indication that the obscuring material is not solid but most likely dust.
Now another fantasy of extraterrestrial engineering is biting the dust. Sorry, E.T.
An earlier version of this article misstated the given name of an astronomer at Cornell University. He is Shami Chatterjee, not Simon.