Astronomy
Spectroscopy of Transiting Exoplanet Atmospheres
Quick fact
During a transit, the planet's atmosphere blocks tiny amounts of starlight at specific colors, creating a 'fingerprint' of its chemicals—much like a barcode for the sky.
Why this is interesting
We can't visit distant exoplanets, yet we know they have water vapor, sodium, and even clouds. How? It isn't a direct photo—it's hidden in the starlight.