Astronomy
Spectroscopy for Stellar Chemical Composition
Quick fact
The Sun's spectrum contains thousands of dark lines, each caused by a specific element. In 1868, astronomers discovered helium first on the Sun (via spectroscopy) before it was found on Earth.
Why this is interesting
When you look at a star, you see a point of light—but hidden in that light is a detailed chemical fingerprint. How can astronomers tell what a star is made of without ever touching it?