Meet: David Thompson

Physicist
NASA Goddard Space Flight Center
Greenbelt, MD

Who I Am

I got interested in physics in High School because this the science of how things work. I graduated from Johns Hopkins University with a degree in physics and went to Grad School at the University of Maryland, doing my thesis at Goddard's Laboratory for High Energy Astrophysics. Some of my interests include gamma-ray astrophysics and the Goddard Scientific Colloquium for which I maintain the website.

What I Do

Currently I am working with the GLAST team, a collaboration of particle physicists and astrophysicists that is building the next generation high-energy gamma ray telescope. I continue to work on data from NASA's Compton Gamma-ray Observatory, which was deorbited earlier this year.

Pulsars and Gamma Rays

In 1967, graduate student Jocelyn Bell discovered some mysterious radio stars that appeared to be pulsing ("blinking") with remarkable regularity. These stars are now known as pulsars, and are generally agreed to be rapidly rotating neutron stars, incredibly dense material left behind by stellar explosions (supernovae). Radio astronomers have now found more than 1000 pulsars, some of which are the most precise clocks known in the Universe. The pulses from some arrive about every 1/1000 of a second, while others only blink on every 10 seconds or so. Pulsars have turned out to be wonderful ways to explore the Universe. The best evidence for Einstein's predicted gravitational radiation comes from the study of a pulsar in a binary system, a result that won the Nobel Prize for Joseph Taylor and Russell Hulse. The first detection of planets outside our solar system came from seeing tiny "wiggles" in the arrival times of signals from one pulsar. Although pulsars are best known in radio astronomy, some have been seen with other types of telescopes, including optical, X-ray, and even gamma-ray telescopes. In fact, these pulsars are far more efficient in producing gamma rays than in making radio waves, so gamma-ray studies can tell us a lot about how pulsars work. Results from the Compton Gamma Ray Observatory gave us some of the answers, but pulsar mysteries remain that will be answered by NASA's Gamma ray Large Area Space Telescope (GLAST), scheduled for launch in 2005.