Astronomy Picture of the Day

Discover the cosmos! Each day we feature a different image or photograph of our fascinating universe, along with a brief explanation written by a professional astronomer.

August 11, 1995
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The Compton Gamma Ray Observatory
Credit: NASA, Compton Gamma Ray Observatory Science Support Center

Explanation: The Compton Gamma Ray Observatory (CGRO) was the most massive instrument ever launched by a NASA Space Shuttle and continues to revolutionize gamma-ray astronomy. This orbiting observatory sees the sky in gamma-ray photons - light so blue humans can't see it. These photons are blocked by the Earth's atmosphere from reaching the Earth's surface. Results from CGRO have shown the entire universe to be a violent and rapidly changing place - when viewed in gamma-rays. Astronomers using CGRO data continue to make monumental discoveries, including showing that mysterious flashes of gamma-rays are much more powerful than previously imagined, discovery of a whole new class of QSO, and discovery of objects so strange that astronomers can't yet figure out what they are.

Tomorrow's picture: Atlantis Landing

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Astronomy Picture of the Day (TM) is created by Robert Nemiroff and Jerry Bonnell who are solely responsible for its content. Text copyright 1995 by Robert Nemiroff and Jerry Bonnell.