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[Music throughout](Announcer): Liftoff of the Delta rocket carrying a gamma-ray telescope

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searching for unseen....[fades out] (Narrator): I'm Julie Mcenery, Fermi project

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scientist. Since its launch in 2008, the Fermi Gamma-ray

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Space Telescope has revolutionized our understanding of the cosmos.

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Fermi has mapped the entire sky in gamma rays, the highest-energy form of light,

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and detected thousands of sources so far.

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In celebration of its 10th anniversary in space, here are five of its

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transformative discoveries. In 2017, Fermi saw

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a gamma-ray burst coming from the constellation Hydra. The burst

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was tied to ripples in space-time detected by the Laser Interferometer

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Gravitational Wave Observatory, operated by the National Science Foundation.

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This was the first time light and gravitational waves were detected from the same source.

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Scientists believe the event formed when two neutron stars merged. The merger

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created the gravitational signal and a jet of particles traveling at nearly the speed

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of light that gave off gamma rays. In 2009,

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Fermi used a short-duration gamma-ray burst to confirm that all light

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travels at the same speed, no matter its energy. This proved Einstein's theory

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that space-time is smooth and continuous.

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Early in Fermi's mission, scientists noted odd structures emerging from

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above and below the Milky Way. These bubbles, spanning

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50.000 light-years. were produced by our galaxy's supermassive black hole and are

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only a few million years old. In 2013,

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Fermi studied the remains of two supernovas to learn more about cosmic rays,

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particles traveling at nearly the speed of light. It was hard to find the source

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of cosmic rays because they veer off course as they travel and encounter magnetic fields.

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Fermi showed that gamma rays from these supernova remnants

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came from cosmic rays that were accelerated by the explosions' blast waves.

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Fermi has seen 5,000 terrestrial gamma-ray flashes

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in the last 10 years. These flashes are associated with lightning

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and thunderstorms in Earth's atmosphere.

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From Earth, to the farthest reaches of the cosmos, Fermi's first ten years

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have fundamentally altered how we look at the universe. Who knows what mysteries

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remain to be solved?

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[Beeping]

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[Beeping]