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Posted by on Mar 26, 2016 in Tell Me Why |

How Many Stars Can We See at Night?

How Many Stars Can We See at Night?

Have you ever looked up at the night sky and tried to count the stars? The number of visible stars seems infinite. It may surprise you to know that even on the clearest night you can see fewer than three thousand stars with the naked eye.

We see only the brighter stars with the unaided eye. With a telescope, we can see millions of stars.

Nobody knows how many stars there are. The best estimate we can make is that there are two hundred and fifty billion stars in the Milky Way galaxy alone! And we think that there must be billions more beyond the reach of our most powerful telescopes.

Basically, the darker the sky, the more stars you can see. Moonlight brightens the night sky and reduces the number of stars you can see. A full Moon brightens the sky more than a crescent Moon or half Moon.

Artificial lights also reduce the number of stars you can see. In a large city, which has a lot of bright lights at night, you may only be able to see the brightest dozen stars. As the night sky gets brighter, the faintest stars disappear from view first.

A major problem for ground based astronomers is what we call “light pollution” – the increase in man-made light sources which affects observations of the night sky.

Content for this question contributed by Amy Miller, resident of Dover, York County, Pennsylvania, USA