Astronomy
The Lifecycle of Interstellar Gas Clouds
Quick fact
The typical density of an interstellar gas cloud is about 1,000 atoms per cubic centimeter — a billion times thinner than the air you breathe. A cloud spanning dozens of light-years may contain only a few thousand solar masses of material.
Why this is interesting
Every star in the night sky was born from a cold, dark cloud of gas and dust. But where do those clouds come from, and where do they go after a star dies?