It is the search for and study of planets orbiting stars other than our Sun. These distant worlds are called exoplanets.

The most common method is called the transit method, where we watch for a star's light to dip slightly. This dimming tells us a planet may have passed in front of it.

Yes. When an exoplanet transits its star, we can study the starlight that filters through its atmosphere. This light tells us what gases, like oxygen or methane, might be present.

A primary goal is to find planets that exist in the "habitable zone"—the right distance from a star where liquid water could exist on the surface, which is a key ingredient for life as we know it.