Alpha Centauri(a triple-star system)․

Alpha Centauri is a triple-star system. It consists of Alpha Centauri A, Alpha Cetauri B and Proxima Cetauri. One of the three stars in Alpha 2. Centauri is Proxima Centauri, which is the nearest star to the Earth, except, of 3. course, for the Sun. The name “Proxima” comes from a Latin word which 4. means “close”. 5. Even though Proxima Centauri is the closest star to the Earth outside of our 6. solar system, it is not really close. Interstellar distances are so large that 7. they are almost impossible to imagine. A person traveling in a modern 8. spacecraft would not arrive at Proxima Centauri within this lifetime, or the 9. next, or even ten lifetimes because the distance is so great. Light travels at a 10. speed of 186000 miles per second, and it still takes light more than four 11. years to travel from Proxima Centauri to the Earth. 12. Alpha Centauri can be easily seen in the night sky without a telescope 13. from certain parts of the Earth. It is the third brightest star in the sky, out of 14. approximately 6000 visible stars. It cannot be seen from most parts of the 15. United States because most of the United States is too far north; however, it 16. can be seen from the southern parts of the southernmost states.