Meeting Information

Looking at the Sun and Seeing Comets

June 26, 2014
American Center for Physics
College Park, MD

Dr. William ThompsonDate: Thursday, June 26, 2014 (Please Note: Day and Date)

Speaker: Dr. William Thompson, NASA-­GSFC

Topic: Looking at the Sun and Seeing Comets

Time and Location: 1:00 pm, with Q&A to follow; in the AAPM conference room at the American Center for Physics (, 1 Physics Ellipse, College Park, MD — off River Rd., between Kenilworth Ave. and Paint Branch Parkway. Check at desk for AAPM room.

Abstract: Comets are often seen by NASA's fleet of spacecraft designed to study the Sun and its environment. The most commonly observed comets are those belonging to the family known as "sungrazers", whose orbits take them just above the solar surface. Only a few sungrazing comets were known about before the space age, but thousands have been discovered in the last twenty years by telescopes pointed toward the Sun. With the advent of "heliospheric imagers" looking at large distances from the Sun, comets that are not sungrazers are also now being seen and studied with images from solar missions. Besides being a lovely surprise whenever these comets appear, useful science can also be performed with these data. One of the great advantages of a solar observatory is constant steady pointing, usually with complete 24­-hour coverage. With most telescopes one has to compete for time with other targets, and ground­based telescopes can only observe during certain hours of the day, and are at the mercy of the weather. Solar telescopes can also see comets under conditions when they can't be seen by regular astronomical telescopes, close to the Sun. Not only are these data useful for studying the comets themselves, but some recent observations of comets in extreme­ — ultraviolet light ­ when they're deep down in the solar corona — is providing unique information about the structure of the solar magnetic field that the comet is passing through.

Biography: William Thompson was born and grew up in Syracuse, New York. He received a B.A. in Physics and Mathematics from New College of the University of South Florida in 1977, and a Ph.D. in Astronomy from the University of Massachusetts in 1982. Between 1982 and 1984 he was a lecturer in the Physics and Astronomy department of San Francisco State University. Since 1984, he has been employed as a contractor in the Solar Physics department at NASA's Goddard Space Flight Center, where has worked on the Solar Maximum Mission (SMM), Solar and Heliospheric Observatory (SOHO), and the Solar Terrestrial Relations Observatory (STEREO) missions. Most recently, he has been involved in building instrumentation for Solar Orbiter. He currently lives with his wife Linda in Lanham, Maryland.