28 January 2015
Glowing menacingly in this new photograph, like the gaping mouth of a gigantic, cosmic creature, is an object called CG4 or the Hand of God. It is what we call a ‘cometary globule’.
Although these cloudy patches of sky are very different from the lumps of rock and ice we call comets – they do share a similar shape, with thick, dark, dusty heads and long, faint tails, although they are much, much bigger.
These comet-like objects were discovered for the first time in 1976 on pictures of a huge patch of glowing gas called the Gum Nebula. There were several of them, each with a thick, dark, dusty head and long, faint tail.
The part that we can see on this image is that head. The tail, which is not visible in the image, is about 5 times longer than the head. However, the head still contains enough gas to create several Sun-sized stars!
Why CG4 and other cometary globules are shaped this way is still a mystery to astronomers. However, two main theories have been developed.
Number one is that cometary globules begin as spherical clouds before the energy from a nearby supernova explosion knocks them into their comet-like shape.
Other astronomers believe that cometary globules are probably sculpted by the strong winds and radiation from hot, massive stars.
Although it looks very bright in this photograph, CG4 is actually very faint. In fact, it’s about the same brightness as Pluto.