Mercury is the smallest planet in our Solar System. And it’s the fastest planet! Learn how Mercury is like Earth’s Moon. Then discover the history of exploring Mercury, what we have found on the planet’s surface, and other fun facts! Dr. Bruce Betts is Chief Scientist and LightSail Program Manager for The Planetary Society, the world's largest space interest group. Dr. Betts is a planetary scientist who earned a B.S. in physics and math and an M.S. in Applied Physics from Stanford and a Ph.D. in Planetary Science with a minor in Geology from Caltech. He spent several years with San Juan Institute/Planetary Science Institute as a Research Scientist, and later Senior Research Scientist. Dr. Betts is the author of Astronomy for Kids: How to Explore Outer Space with Binoculars, a Telescope, or Just Your Eyes! He regularly writes for The Planetary Society member magazine The Planetary Report , and on his blog on planetary.org.