Portal:Astronomy/Picture/9 July 2005

This image shows the expansion over a period of three years of the planetary nebula NGC 6543, the Cat's Eye Nebula. All planetary nebulae are expanding, and will eventually disperse into the interstellar medium, enriching it with heavy elements such as carbon and oxygen. Only with the very high optical resolution available with the Hubble Space Telescope can the expansions of these distant objects be accurately measured.