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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?