When we humans look up at the night sky, we can see many stars and a few planets, but much of what goes on in the universe is invisible to us. Our eyes are sensitive to only the narrow range of energies or colors between blue and red.
Objects that are less energetic or cooler can be “seen” by infrared or radio telescopes, while hot, high-energy sources can be studied with ultraviolet and X-ray telescopes in space.
At the highest energy levels are gamma rays, which are emitted when supernovae, pulsars, and super-massive black holes interact with their surroundings. Gamma-ray astronomers are trying to learn more about those objects as well as about the characteristics of dark matter, fundamental particle physics and the origin of cosmic rays.
On Thursday (Oct. 9), Wystan Benbow, who is working at the frontier of gamma-ray astronomy, will give a free talk about VERITAS at
Arizona Senior Academy, starting at 3:30 p.m.
VERITAS is an acronym for the Very Energetic Radiation Imaging Telescope Array System. It consists of four large (12-meter diameter) telescopes located south of Tucson, halfway up the western slope of Mount Hopkins. It detects gamma rays by measuring the very short bursts of visible light they emit as they interact with the Earth’s atmosphere.
Stereoscopic imaging of these bursts with the four telescopes can reveal where the gamma rays came from. VERITAS can detect gamma rays with energy up to 30 trillion electron-volts, which is more than twice the energy reached by the Large Hadron Collider at CERN and about 100 trillion times more energetic than blue light.
Benbow, the director of VERITAS, works at the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA; he commutes frequently to Tucson where he formerly resided.
Written by Marcia Neugebauer, Academy Village Volunteer