The sun is our nearest star. It is 149.6 million km (92.9 million miles) away from Earth. Stars are massive nuclear reactors, generating energy in their cores. It is the heat and light from the Sun that makes life on Earth possible. The huge gravity pull of the Sun keeps the planets of our Solar System orbiting around it.
The closest stars to Earth are three stars in the Alpha Centauri system. The two main stars are Alpha Centauri A and Alpha Centauri B, which form a binary pair. They are an average of 4.3 light-years from Earth. The third star is Proxima Centauri. It is about 4.22 light-years from Earth and is the closest star other than the sun.
Alpha Centauri A and B orbit a common center of gravity every 80 years. The average distance between them is about 23 astronomical units (AU) — a little more than the distance between the sun and Uranus. Proxima Centauri is about one-fifth of a light-year or 13,000 AUs from the two other stars, a distance that makes some astronomers question whether it should be considered part of the same system.
Proxima Centauri may be passing through the system and will leave the vicinity in several million years, or it may be gravitationally bound to the binary pair. If it’s bound, it has an orbital period around the other two of about 500,000 years.
Picture Credit : Google
