Our Solar System
Slightly more than 4.5 billion years old, the Sun is a large ball of hot plasma powered by nuclear fusion. CfA scientists study the Sun to learn about the day to day behavior of an ordinary star, which includes giant magnetic storms that eject high energy particles into the Solar System. The Solar System contains a motley collection of planets, moons, asteroids, comets, and other debris. The composition and orbits of these objects provide clues to the formation of the Solar System and the origin of life on Earth. CfA scientists use observations and theoretical models to try to understand these clues.