This nebula measures a whopping 250 light-years across, and it's close enough to Earth that its relative size in the sky is equivalent to that of four full Moons. But it's so faint in the wavelengths our eyes can actually see that it's generally been ignored until now. As this gorgeous new image from the European Southern Observatory reveals, that's been a mistake on our part.
Taken by the VLT Survey Telescope at Chile's Paranal Observatory, the ESO says this is likely the sharpest image ever taken of the nebula. In their announcement — which just happens to be their 1000th such release — the astronomers reveal the lowdown on the Prawn Nebula:
Located around 6000 light-years from Earth in the constellation of Scorpius (The Scorpion), the nebula formally known as IC 4628 is a huge region filled with gas and clumps of dark dust. These gas clouds are star-forming regions, producing brilliant hot young stars. In visible light, these stars appear as a blue-white colour, but they also emit intense radiation in other parts of the spectrum — most notably in the ultraviolet.
It is this ultraviolet light from the stars that causes the gas clouds to glow. This radiation strips electrons from hydrogen atoms, which then later recombine and release energy in the form of light. Each chemical element emits light at characteristic colours when this process occurs, and for hydrogen the predominant colour is red. IC 4628 is an example of an HII region.
For more information as well as some even higher-resolution images, check out the ESO website.