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Barnard’s Star

June 6, 2016

Some of our nearest neighbors are a bit shy. Even though they’re practically on our doorstep, they’re so faint that you can’t see them without a telescope. That includes the second-closest star system of all, Barnard’s Star. It’s low in the east as night falls. Without a telescope and a star chart, though, you’d never know it’s there.

Indeed, just finding the closest stars is a lot harder than you might think.

If every star were equally powerful, the closest stars would look the brightest, and they’d be the easiest to spot. But that’s not the case. There’s a huge range in stellar brightness. And most stars are quite faint — just a fraction as bright as the Sun.

That’s certainly true for the star discovered by Edward Emerson Barnard in June of 1916. He was comparing photographic plates of the constellation Ophiuchus taken at different times when he noticed a faint star. It stood out because its position had changed from one plate to another — a sign that it was close by. It’s like driving down a highway — nearby road signs whiz by in a hurry, while the distant hills seem to hardly move.

It turns out that Barnard’s Star is just six light-years away. Only the three stars of Alpha Centauri are closer. But it’s extremely faint. In fact, the Sun emits more light in just one hour than Barnard’s Star will produce in the next three months — a testimony to Barnard’s skill in fishing this elusive neighbor out of the vast celestial sea.

Script by Ken Croswell, Copyright 2016

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