The following article is definitely worth a read.

Harvard theorists: How sailing aliens could have caused fast radio bursts
https://www.washingtonpost.com/news/...-radio-bursts/
In 2007, a West Virginia University astrophysicist named Duncan Lorimer detected a brief yet intense signal while combing through archival data from the Parkes Observatory telescope in Australia. The signal was quick. The spurt of radio activity, originating from a source other than our galaxy, lasted fewer than 5 milliseconds. And it was furious. To generate such a burst would require 500 million times the power of our solar systemís sun. The unknown source of the signal prompted intense speculation.
One proposal, to be published in Astrophysical Journal Letters, may be the wildest yet: Sailing aliens.