Since astronomers discovered the first planet orbiting a star other than the Sun, we have found many worlds that are very unlike the ones in our own Solar System. A large number of these “exoplanets” are large, gaseous planets roughly the size of Jupiter, orbiting close to their parent stars once every few days.
Although we can’t directly see these “hot Jupiters”, because they are hidden in the glow from their parent stars, they are the easiest planets to detect using the transit method. This works by inferring their presence indirectly when they pass in front of their parent star, blocking some of the starlight.
