Planet formation is dirty and inefficient, resulting in the ejection of large numbers of planetesimals to interstellar space. For the first time, we have detected interlopers in the solar system having an origin in the protoplanetary disks of other stars. I will summarize what we know about the first two interstellar interlopers, 1I/Oumuamua and 2I/Borisov, then discuss implications for the interloper population of the galaxy.
David Jewitt grew up in working class London and became interested in the sky at a young age. Through (gratefully received) state-subsidized education, he went to the University of London, then moved to the US to be close to large telescopes, becoming a professor first at MIT, then the University of Hawaii and more recently at UCLA. He is a member of the National Academy of Sciences and recipient of the Shaw Prize in Astronomy and the Kavli Prize in Astrophysics, for work done on the Kuiper belt.