Astronomy
detectionandcharacterizationofexoplanetatmospheresthroughtransmissionspectroscopy
Quick fact
The first detection of an exoplanet atmosphere was made in 2001 when sodium was found in the atmosphere of HD 209458b, a hot Jupiter – using transmission spectroscopy.
Why this is interesting
Imagine knowing the recipe of a cake by looking at the shadow it casts. That's exactly how astronomers figure out what's in the atmosphere of a planet trillions of miles away.