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| Distance from earth | ||
| 2,500 lightyears |
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| Cygnus Loop is the aftermath of the cataclysmic explosion of a supernova. | |
| It released a billion billion billion times | |
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| as much energy as the largest nuclear bomb ever detonated on the earth. Supernovae release so much energy they can totally destroy a star, turn it into a neutron star, or even into a black hole. | |
| The colorful gas in the picture is not the remains of the star that exploded, but the signature left behind when the blast wave shocked the interstellar medium. The blast wave, traveling at over 10,000 miles per hour, smashed into the gas, heating and compressing it enough to make it glow. The supernova itself occurred about 15,000 years ago, and it took over 10,000 years for the blast wave to reach the gas that we see in this picture. We are actually seeing the gas as it was about 1000 years after the shock wave hit it | The interstellar medium is the gas between stars in a galaxy. |
| The various colors of the gas are due to the radiation from different elements at different places in the aftermath of the blast wave. The green emission is from hydrogen atoms right behind the shock front. The blue light is from twice ionized oxygen, farther behind the shock wave. And the red gas is ionized sulphur, so far behind the shock front that it has cooled | ionized atoms have had one or more electrons removed, causing them to become ions. |
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| In some places, the shock wave was reflected into already shocked
gas causing the gas to get so hot that it produced very high energy X-rays
(not shown in this HST picture, but confirmed by the ROSAT satellite).
By studying this supernova remnant astronomers can learn about the gas between stars and how shock waves interact with this gas, giving rise to the filamentary structures seen in this and other Hubble pictures. After decades of having to rely only on theoretical calculations about shock waves, Hubble is finally giving astronomers a chance to see their inner workings firsthand. |
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Additional Resources |
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Official Images at STScI |
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| Text © 1997 Andy Howell All Rights Reserved
Hubble Space Telescope images are the intellectual property of the Space Telescope Science Institute, operated by the Association of Universities for Research in Astronomy, Inc., from NASA contract NAS5-26555, and are reproduced with permission from AURA/STScI. | ||
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Cygnus Loop
