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Birthday · June 23, 2001

The Cygnus Loop

June 23, 2001

The Moon has changed phase thousands of times since the beginning of the cosmos, but only once did it shine on the night you arrived.

The Cygnus Loop

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APOD published June 23, 2001. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.

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The Cygnus Loop

Original APOD · June 23, 2001

The shockwave from a 20,000 year-old supernova explosion in the constellation of Cygnus is still expanding into interstellar space. The collision of this fast moving wall of gas with a stationary cloud has heated it causing it to glow in visible as well as high energy radiation, producing the nebula known as the Cygnus Loop (NGC 6960/95). The nebula is located a mere 1,400 light-years away. The colors used here indicate emission from different kinds of atoms excited by the shock: oxygen-blue, sulfur-red, and hydrogen-green. This picture was taken with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope.

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