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What if you had gamma-ray eyes?
Click on image to view QuickTime video. (4.6 MB)
Description
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Gamma rays are the most energetic form of light, with billions of
times more energy than visible light. This set of videos explores
what the night sky would look like if we had gamma ray eyes, how
nature creates gamma rays, and one example of how gamma rays are
detected. These clips are taken from a video about the
Gamma-ray Large Area Space Telescope (GLAST), which NASA launched on June 11, 2008.
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How can gamma rays be produced?
Click on image to view QuickTime video. (3.5 MB)
Description
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Imagine looking at the night time sky with gamma-ray eyes. The
familiar look of the stars would give way to the exotic and the
mysterious: steady emission of gamma rays from pulsars, supernova
remnants, active galaxies. There would also be flashes of gamma
rays from gamma ray bursts, the most powerful explosions in the
universe.
One way of producing gamma rays is when photons of lower energy light smash into fast moving electrons. This steals energy from the electron and boosts the light's energy, producing gamma rays.
Conventional telescopes can't focus gamma rays for detection, since
gamma rays pass through optical lenses and mirrors. Astronomers have
adopted techniques from high energy physics to detect gamma rays.
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How are gamma rays detected?
Click on image to view QuickTime video. (5.8 MB)
Description
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When gamma-ray photons interact with matter, they create pairs of
oppositely charged particles. Light turns into matter and
anti-matter, such as an electron and positron. This conversion of
light energy into matter is described by Einstein's equation,
E=mc2.
This pair conversion process is the scientific basis for one type of instrument used to detect gamma rays. The charged particle pairs are tracked and can point back to the source of the incoming gamma ray.
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