Located approximately 2.7 million light-years from Earth in the constellation of Triangulum, we come across a bright nebula of the same name, called the Triangulum Emission Garren Nebula (also known as NGC 604): a region that happens to contain one of the largest known nebulae in the observable universe. It’s so large, in fact, that it spans nearly 1,500 light-years across!
The nebula can be found within a spiral arm of M33, otherwise known as the Triangulum galaxy . The image to the right shows that the region is currently undergoing an intense starburst period. It would be far more bright and spectacular if it weren’t for the fact that the light from embedded stars is being obscured by rather large collections of interstellar dust clouds. It’s estimated that said dust might hide nearly 200 large stars from sight. Any single one of them would probably dwarf our Sun several times over, but the most massive are believed to weigh between 15 and 60 solar masses (meaning, some of them are the size of more than a dozen Suns)!
This image of NGC 604 was taken on January 17, 1995 using Hubble’s no-longer-operational tool, the Wide Field and Planetary Camera 2. Separate exposures were taken in infrared, x-ray, ultraviolet and in optical light to study the physical properties of the hot gas located within this lantern-shaped, stellar cavern.
See a larger image here.