The Lagoon Nebula

About This Photograph

Deep in the heart of the Sagittarius constellation is a classic deep-sky object, the Lagoon Nebula. It is also known as "Messier 8," or "M8" for short, after French astronomer and comet hunter Charles Messier, who included it in his catalog of objects that are not comets. This patch of glowing gas is visible to the naked eye from a dark site, and probably appeared similar to a comet when first seen through a small telescope. The fact that it does not drift across the sky like comets do, however, was the first clue that it is something entirely different. In actuality, it is a vast cloud of glowing gas, some 140 light years (820 trillion miles) across. It is a stellar nursery, a birthplace of new stars, and it glows due to the close proximity of its bright, hot progeny newly hatched and gleaming brilliantly. The ultraviolet light from these newborn stars causes the gas to glow in colors characteristic of the elements making up the nebula.