Imagine the Universe!

Gamma Rays in Your Eyes

night time sky with gamma-ray eyes
What if you had gamma-ray eyes?

Click on image to view QuickTime video. (4.6 MB)


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.

gamma rays passing through traditional lens.
How can gamma rays be produced?

Click on image to view QuickTime video. (3.5 MB)


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.

gamma rays being blocked by Earth's atmosphere
How are gamma rays detected?

Click on image to view QuickTime video. (5.8 MB)


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.

These clips were taken from the GLAST Video (2001, MZCS, Inc.), produced by Mike Zeko

Imagine the Universe is a service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA's Goddard Space Flight Center.

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Acting Project Leader: Dr. Barbara Mattson
All material on this site has been created and updated between 1997-2012.

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