Letters and Science C70V, 001 - Spring 2015 Descriptive Introduction to Physics - Steven W. Stahler All rights reserved

Recent evidence suggests that a massive body is lurking at the outskirts of our solar system, far beyond the orbits of the known giant planets. This object, at a distance approximately 20 times further than Neptune and with a mass approximately 5000 times larger than Pluto, is the real ninth planet of the solar system. In his lecture, Mike Brown talks about the observation that led his team to the evidence for this Planet Nine and discusses how so massive an object could have been hiding in the outer solar system for so long. He also discusses the international effort to pinpoint this newest member of our planetary family. Mike Brown is the Richard and Barbara Rosenberg Professor of Planetary Astronomy at the California Institute of Technology, specializing in the discovery and study of bodies at the edge of the solar system. He is best known for his discovery of Eris, the most massive object found in the solar system in 150 years, which led to the debate and eventual demotion of Pluto from a real planet to a dwarf planet. In 2006 he was named one of Time Magazine's 100 Most Influential People and was inducted into the National Academy of Sciences in 2014.