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Astronomy

How Astronomers Detect and Study Exoplanets with Spectroscopy

Quick fact

The first detection of an exoplanet atmosphere was made in 2001 by analyzing starlight that passed through the planet's atmosphere during a transit, revealing sodium gas.

Why this is interesting

Imagine being able to know what gases are in the atmosphere of a world trillions of kilometers away—just by catching a few photons of its light. How is that possible?