Eta Carinae nebula, Cassini image. This nebula is a huge cloud of glowing gas and dark dust that surrounds the star Eta Carinae (centre). Eta Carinae is one of the brightest stars known, and is wildly variable. It was the second brightest star in the sky in the mid-1800s, then faded to below naked eye visibility, and is currently (2006) just visible. It is a massive star of some 120 solar masses, and is likely to explode as a supernova in the next few million years. At its distance of around 7500 light years, this should not adversely affect life on Earth, although satellites and spacecraft may be damaged. Image taken by the Cassini spacecraft in orbit around Saturn, on 14th May 2005.