Like a menacing apparition haunting the skies, this Very Large Telescope (VLT) image captures a cometary globule, known as CG4, in the Gum Nebula. With their dense, dark and dusty heads, as well as their sometimes long, faint tails, these globules have historically been described as comet-like objects. Indeed, with an opaque 'head' (1.5 light years in diameter) and a tail eight light years long (not visible in the main image), at first glance CG4 fits that description well. In reality, however, cometary globules are isolated and relatively small clouds of dust and gas where star formation can occur. In the case of CG4, this globule contains enough material to make several Sun-sized stars.
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