Michael Goldberg, age 11, of Garden Grove, California for his question:
How many light years away is the nearest star?
People have been star gazing for thousands of years and maybe dreaming all this time of visiting other worlds. Now the Space Age has dawned and all these dreams are much nearer. But to reach other worlds we need mountains of know how and our space knowledge would be impossible without countless small facts gathered by countless generations of patient star gazers.
Some smartie may tell you that the nearest star is about 92,300,000 miles away which is less that one sixty thousandth part of a light year. This smartie means to inform you that he knows that the sun is a star .. but Andy and most other people dislike smarties, even when they are correct: Naturally, you want to know the distance of the nearest star which appears in the night sky.
Sad to say, we who live north of the equator never get a chance to see our nearest star neighbor. It appears only in the skies of the Southern Hemisphere. Its name is Alpha. Centanri which means that it is the A number one star in the constellation Centaur. Our bright neighbor is actually a multiple star, a set of triplets.
The telescope shows that the bright speck Alpha Centaurs is two close stars orbiting around each other. The third member of the system is too dim to be seen by human eyes. It orbits at some distance from the bright twins. This invisible neighbor has bean named Proxima, meaning near, because it may sometimes be nearer to us than Alpha Centaurs.
A light year is equal to about six million, million miles which is the distance a beam of light travels in one earth year, Alpha Centaurs is 4.3 light years from our Solar System, which is about 26 million, million miles. Proxima may at times be a few million miles closer to us. Traveling at 186,000 miles a second a space ship could reach Alpha Centaurs in about four years and three months.
The brightest star seen from the earth appears 9.n the winter skies of tine Norrthern Hemisphere. It Ls Sirius the Dog Star. It is almost twice as far away as Alpha Centauri, but Sirius also rates as one of our star neighbors. When you look up as Sirius, you are seeing light which left the star more than eight and half years ago. Sirius is 3.6 light years away,
Many of the bright stars are hundreds of light years away. There are only about 5 stars within eleven and a half light years of our Solar System. Some of them, like Sirius, are big and bright. But more than half of these starry neighbors are too dim to be seen without the help of the telescope.