NGC 6357: The Lobster Nebula

Explanation: Why is the Lobster Nebula forming some of the most massive stars known? No one is yet sure . Cataloged as NGC 6357, the Lobster Nebula houses the open star cluster Pismis 24 near its center -- a home to unusually bright and massive stars . The overall red glow near the inner star forming region results from the emission of ionized hydrogen gas. The surrounding nebula, featured here , holds a complex tapestry of gas, dark dust , stars still forming, and newly born stars . The intricate patterns are caused by complex interactions between interstellar winds , radiation pressures , magnetic field s, and gravity . The image was taken with DOE 's Dark Energy Camera on the 4-meter Blanco Telescope at the Cerro Tololo Inter-American Observatory in Chile . NGC 6357 spans about 400 light years and lies about 8,000 light years away toward the constellation of the Scorpion .