The sky is filled with breathtaking pictures, many of which are available on the World Wide Web. Each day we feature a different picture of some part of our fascinating universe, along with a brief explanation written by a professional astronomer.
Explanation: In 1987 a star in one of the Milky Way's satellite galaxies exploded. In 1994 the Hubble Space Telescope, in orbit around the earth, took a very detailed picture of the remnants of this explosion. This picture, above, showed unusual and unexpected rings, and astronomers are not sure how they formed.
For more information see HST press release.