Could Mysterious Cosmic Light Flashes Be Powering Alien Spacecraft?

[Warren DeMontague]

3. Fascinating, if a bit far fetched, speculation

it's interesting that we imagine extraterrestrial civilizations to coincidentally be pursuing interstellar travel or communication at the precise apex of the technological level we ourselves, are at- namely, we've had a lot of talk in the past year or so about using lasers to propel ultra-light micro probes to, say, Alpha Centauri.

This, from the article, jumped out at me, though:

indeed, a transmitter capable of generating FRB-like signals could drive an interstellar spacecraft weighing 1 million tons or so, Lingam and Loeb calculated.

"That's big enough to carry living passengers across interstellar or even intergalactic distances," Lingam said in the same statement.

...great. But how do those guys stop?