Stellar Nurseries

Stars form inside vast clouds of hydrogen gas and dust called molecular clouds or nebulae. These clouds can span hundreds of light-years and contain enough material to birth thousands of stars. The most famous is the Eagle Nebula, whose "Pillars of Creation" are columns of gas actively forming new stars at their tips.

A molecular cloud is incredibly cold, around 10 to 20 Kelvin (-263 to -253°C). At these temperatures, gas molecules move slowly enough for gravity to start pulling them together. Once a region of the cloud begins collapsing, gravity accelerates the process.