The Eagle Nebula (or M 16), an Emission nebula which is 7,000 light year distant, is well known for containing the famous Hubble photo of the Pillars of Creation. Nebulae are the places where huge clouds of gas and dust contract under their own gravity and form stars and planets, just like our own Sun, together with all the planets, was born this way 4.6 billion years ago. The centre of this nebula already contains a cavity, a region which has lost almost all its gas and dust. The stars that have formed in that region - or to be precise their star winds - and the Supernovae have blown away most of the material in the cavity, but not yet everything. Some gas and dust that remains has formed the clouds that seem to resemble an eagle. In this central region, stars are still forming as well as in the other dark clouds of the cavity and in the nebula outside the cavity.
By the way, this is a false colour image of the nebula showing us the different elements, concentrating on hydrogen (green), oxygen (blue) and sulphur (red). Here is a true colour image of the Eagle Nebula.
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Molecular Clouds and Dark Nebulae