Stars are born in nebulas.
A nebula appears like a cloud, only in space. It's comprised of dust, helium, hydrogen, and ionized gases.
At one time any astronomical object that looked blurred or diffuse was labeled a nebula. For example, galaxies were once called nebula. Now we know galaxies are collections of stars, planets, and other interstellar matter held together by a strong gravitational force. There are many nebula within most galaxies.
The incredible picture above is what you might call a "stellar nursery".
Some of the most massive stars ever discovered are forming in this nebula known as NGC6357 or the War and Peace Nebula, also known as the Lobster Nebula (look closely for the lobster)
One massive star is nestled in the center of what looks like a cocoon. The opening is 10 light years across (light year = distance light travels in a year or about 6 trillion miles). The nebula is about 8,000 light years away from earth and is located near the constellation Scorpius.
The matter within this cloud of interstellar dust is collapsing upon itself to form a star. Inside, a hot core develops and gradually gets denser as it attracts more stellar dust. This inner core is called a protostar. Sometimes the globs of spinning gas and clouds breaks apart creating multiple stars, also called a star cluster.
Some of the stars in the nebula appear to be wrapped in a cocoon while other stars are hidden by dark clouds of gas.
The overall glow of the nebula is caused by light emitting from ionized hydrogen gas. The complex patterns are caused by interactions of stellar winds, radiation, magnetic fields, and gravity.
The nebula was labeled War and Peace because scientists from the Midcourse Space Experiment thought the bright portion resembles a dove and the other part appears to be a skull.
Astronomer John Herschel discovered the nebula in 1837 making observations from the Cape of Good Hope, South Africa.