M42, the Orion Nebula, is probably the best-known nebula of all, since it is visible to the naked eye. It is a prominent part of the “sword of Orion”, beneath (south of) the 3 stars of the belt, and the whole sword is shown in this image. It is a star factory, or star nursery, with new stars forming from the gas and dust. At about 1,350 light years away it is the closest such star-forming to the Earth. It is estimated to be about 24 light years across.