On Cool Science Radio, Joining the show is Avi Loeb, Chair of Harvard's Department of Astronomy.
In late 2017, scientists at a Hawaiian observatory glimpsed an object soaring through our inner solar system, moving so quickly that it could only have come from another star.
Loeb contends it was not an asteroid; it was moving too fast along a strange orbit and left no trail of gas or debris in its wake. He says there is only one conceivable explanation: the object was a piece of advanced technology created by a distant alien civilization.