The European Southern Observatory's Cosmic Gems program exists solely to produce images of space that can entice and intrigue the public. In other words, it's an initiative dedicated to making pretty pictures of space for your viewing pleasure.
Above you can see Messier 17, a nebula some 5,500 light years away that measures about 15 light years across. But while Messier 17 is its official designation, this rose has many other names: the Omega Nebula, the Swan Nebula, the Checkmark Nebula, the Horseshoe Nebula and the Lobster Nebula, just to name a few.
Messier 17 has a mass about 800 times that of the sun. The interstellar gas cloud it sits in has the mass of 30,000 suns.
A nebula, lest you forget, is a cloud of dust and ionized gas. Messier 17 is a type of nebula known as an HII region. Unlike planetary nebulae -- the brilliant, round nebulae formed when dying stars cast off their gasses -- HII regions are more nurseries than deathbeds.
They form when giant clouds of molecular hydrogen -- stellar nurseries -- give birth to hot, massive young stars. These young stars ionize the local gas (hence the pretty colors) and send hot, supersonic speed gas out towards the surrounding cloud. When fast gas hits slow, the resulting shockwave compresses the gas, which leads to a jump in star formation.
Messier 17 contains hundreds, perhaps even thousands of stars. It gets its red and pink tones from glowing hydrogen gas, powered by the bright blue young stars throughout.