Astronomy Picture of the Day

Explanation: Normally faint and elusive, the Jellyfish Nebula is caught in this alluring scene. In the telescopic field of view two bright yellowish stars, Mu and Eta Geminorum, stand just below and above the Jellyfish Nebula at the left. Cool red giants, they lie at the foot of the celestial twin. The Jellyfish Nebula itself floats below and left of center, a bright arcing ridge of emission with dangling tentacles. In fact, the cosmic jellyfish is part of bubble-shaped supernova remnant IC 443, the expanding debris cloud from a massive star that exploded. Light from that explosion first reached planet Earth over 30,000 years ago. Like its cousin in astrophysical waters the Crab Nebula supernova remnant, the Jellyfish Nebula is known to harbor a neutron star, the remnant of the collapsed stellar core. Composed on April 30, this telescopic snapshot also captures Mars. Now wandering through early evening skies, the Red Planet also shines with a yellowish glow on the right hand side of the field of view. Of course, the Jellyfish Nebula is about 5,000 light-years away, while Mars is currently almost 18 light-minutes from Earth.