Alpha Centauri, a system of three stars, one of whose membersProxima Centauriis the star nearest the sun. Proxima can be seen only with a telescope; the other two stars appear as a single, very bright star to the unaided eye. Alpha Centauri is slightly more than four light-years from the sun. It is in the constellation Centaurus.
It wasn't so long ago that astronomers thought the universe contained normal matter, or baryonic matter, the base unit of which is the atom. But when it comes to the cosmos, there's always more than meets the eye. What else is hanging out in space?
Some of the most interesting objects in our solar system are also the smallest or largest. In addition to the sun, planets, and moons, our solar system has a variety of small objects such as asteroids, comets, stars, meteors, and moons. These have affected what has happened on Earth in many ways.