Exoplanets are planets that are outside our solar system. They are usually detected through observations of the changes they cause in starlight or the gravitational fields of a star.
What is astronomy
One of the most important areas of astronomy is planetary science. It studies the planets, their satellites, asteroids, and other objects in our solar system.
Light years help us understand the scale of the universe
Light years is a unit of distance measurement in space that is based on the speed of light. A light-year is the distance that light travels in one Earth year.