Exoplanets: worlds around other stars
An exoplanet is a planet outside our Solar System. Many travel around other stars, and some look very different from our neighbors.
Scientists can notice a star dim slightly when a planet passes in front of it. Repeated measurements help test the idea.
Wonder about this
Does one tiny dip in starlight prove there is a planet?
A science clue
No. Scientists check repeated signals and alternative explanations.