The Sun is the closest star to Earth, about 93 million miles away. The Sun’s nearest neighbor, Alpha Centauri, is actually a triple-star system — three stars bound together by gravity. Alpha Centauri A and B are two bright, closely orbiting stars with a distant, dim companion, Proxima Centauri. The inner binary appears to the unaided eye as a single star, the third brightest in the night sky, but it lies 4.37 light years from the Sun. Proxima Centauri alone claims the honor of being our true nearest stellar neighbor at only 4.24 light years away.
It’s difficult to conceptualize such vast distances, but a popular analogy sets the Sun at the size of a grapefruit. If you wanted to get from your grapefruit-sized Sun to a grapefruit-sized Alpha Centauri system, you would have to travel about 2,500 miles, which is about the distance from coast to coast on the continental United States. And that’s just to the Sun’s closest neighbor!
But Proxima Centauri is only currently the closest star. The Sun, the Alpha Centauri system, and other nearby stars all move around the Milky Way over time, and they approach and pass each other as they travel. In another 10,000 or so, the closest star will be something else.
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