The science of
other worlds.

When a planet passes in front of its star, it dims the starlight by a tiny but measurable fraction. This essay explores the mathematics behind transit photometry and how Kepler and TESS turned it into the most prolific planet-finding technique in history.

Long before we could see exoplanet shadows, astronomers noticed stars moving. Not through space — but toward and away from us, in tiny rhythmic pulses. This is the story of the Doppler technique and the discovery of 51 Pegasi b.

Not too hot, not too cold. The habitable zone is the orbital band around a star where surface liquid water is theoretically possible. But the concept is more nuanced — and more contested — than it first appears.

When starlight filters through a planet's atmosphere during transit, different molecules absorb different wavelengths. The result is a fingerprint. JWST is now reading those fingerprints on worlds dozens of light-years away.