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A. Satellite Reveals Surprising Features of Earth's Gamma-Ray Flashes

Narrator:  This is Science Today. Terrestrial gamma-ray flashes, or TGFs, are very short blasts of gamma rays emitted into space from the Earths upper atmosphere. David Smith, a professor of physics at the University of California, Santa Cruz led a recent observation of flashes of gamma rays that appear over thunderstorms, which revealed surprising features.
Smith:             The x-rays and gamma-rays that come from these flashes extend in energy all the way up to about three hundred times the energy of one of the x-rays that a dentist or a doctor would use. So, these are extremely high energy photons and I was very surprised to find that the Earth is capable of making gamma-rays at those very high energies.
Narrator:           Usually, energies this high are emitted from black holes and neutron stars.
Smith:             Of course, here on Earth, one of these flashes is a miniscule total number of photons. I mean, the black hole is so bright we could see it across the galaxy. So, the total amount of energy is not comparable, but the energy per gamma-ray is which to me, is fascinating.
Narrator:            For Science Today, Im Larissa Branin.