If you enjoyed our Conversations with a Scientist video of astronomer Mike Brown, be sure to tune into the live Q&A chat with Mike on October 2 at 4pm ET, hosted by AAAS MemberCentral. Go to the chat page to submit your questions for Mike ahead of time, or type in your questions directly during the session.
As is described in the Conversations with a Scientist video, Mike Brown is the astronomer whose discovery of Eris, a celestial body orbiting our Sun farther away than Pluto, led to Pluto having its "planet" status stripped. As Eris is about the same size as Pluto, it was decided that only celestial bodies in our Solar System that are larger than Pluto would be considered planets. Pluto is now known as a dwarf planet as a result of Mike's discovery. Learn more about this discovery on AAAS MemberCentral.