Portal:Astronomy/Picture/Week 33 2006
From Wikipedia, the free encyclopedia
The Helix Nebula is one of the closest planetary nebulae, but is not easy to see in small telescopes due to its very low surface brightness. Hubble Space Telescope images reveal a large number of comet-like knots with 'tails' hundreds of millions of miles long, swept out by a stellar wind from the dying star at the centre of the nebula.
