Counting the Stars

Credit: European Space Agency/NASA;
Acknowledgment: E. Olszewski (Univ. of Arizona)

For my part I know nothing with any certainty, but the sight of the stars makes me dream. - Vincent van Gogh

In our consideration of the night sky so far, we've looked at the moon and the planets, as well as the aurora borealis. But the night sky is nothing without the stars, those tiny jewels of light hung on the blackness of space. (Unless, of course, you're up close to one, in which case it's an inferno of nuclear fusion, fusing hydrogen atoms into helium at temperatures in excess of 20 million degrees Fahrenheit. It's like a big, fiery twinkle factory.)

How many stars are there? It's an age-old question, but we may be gaining some insight into it. Astronomers routinely conduct star counts, usually in the Milky Way galaxy, then multiply that number by the estimated number of galaxies in the universe. As you might guess, it's hard to come up with a precise total. One estimate is that there are 400 billion stars in the Milky Way, but that may be off by as much as 50 percent.

Sometimes the public can get in on the star-counting action. Recently scientists asked "citizen-scientists" to help with a star count to determine the level of light pollution in different areas. The GLOBE at Night campaign collected data from around the world, hoping to find "dark sky oases" where night sky observations can be made more easily, away from city lights that obscure the stars.



But honestly, all this talk of star-counting is just a prelude (or really, an excuse) to post this wonderful video, a Russian animation called Hedgehog in the Fog. The hedgehog and his friend, the bear cub, spend their evenings counting the stars. But one night, on his way to his friend's place, the hedgehog encounters a white horse in a thick fog. I'll leave it to you to ponder the deeper meaning of his adventure.