Harvard astronomer's book argues that alien vessel paid us a visit

An artist's impression of the first interstellar asteroid: Oumuamua. This unique object was discovered on Oct 19,2017 by the Pan-STARRS 1 telescope in Hawaii. Subsequent observations from ESO's Very Large Telescope in Chile and other observatories around the world show that it was travelling through space for millions of years before its chance encounter with our star system. Photo: AFP

Discovering there's intelligent life beyond our planet could be the most transformative event in human history - but what if scientists decided to collectively ignore evidence suggesting it already happened?

That's the premise of a new book by a top astronomer, who argues that the simplest and best explanation for the highly unusual characteristics of an interstellar object that sped through our solar system in 2017 is that it was alien technology.