South of
Antares, in the tail of the nebula-rich constellation
Scorpius, lies
emission nebula IC 4628. Nearby hot,
massive stars, millions of years young,
irradiate the nebula with invisible
ultraviolet light, stripping electrons from atoms. The electrons eventually recombine with the atoms to produce the
visible nebular glow, dominated by the red emission of hydrogen. At an estimated distance of 6,000 light-years, the
region shown is about 250
light-years across, spanning over three full moons
on the sky. The nebula is also
cataloged as Gum 56 for Australian astronomer
Colin Stanley Gum, but seafood-loving deep sky-enthusiasts might know this cosmic cloud as the
Prawn Nebula. (NASA)