Clarification/Follow-up by Jim.McGinness on 11/13/05 8:30 am:
Oh, I don't doubt that you read it. When I did a Google search, I came up with plenty of hits. I just never heard this when I was young and I was expressing my ignorance as far as never having read it in a book. I guess I just haven't been reading the right sort of book lately.

Clarification/Follow-up by Geraldask on 12/28/05 4:39 pm:
Twinkle twinkle little star

There aren't many nursery rhymes about astronomy. But 'twinkle twinkle little star' makes a useful point. We can tell which lights in the night sky are stars because they appear to twinkle. Planets, on the other hand, don't, they shine steadily in the sky.

Stars twinkle because they are very far away, and so appear as tiny points of light in our night sky. Some of this light is absorbed by moving air in the Earth's atmosphere, making the star appear to sparkle.

Planets, like Saturn or Jupiter, don't sparkle. This is because they are a lot closer to the Earth and so they look bigger in our sky than stars.

Explore the planets with our travel guide

The brightest star in space - the Pistol Star



Rather than being points of light, planets are small discs. As their light is more spread out, even if some of it is absorbed by our atmosphere, some of the light still filters through, so the planet doesn't twinkle. This means that you can tell the difference between a planet and a star without even needing a telescope, just by seeing if it twinkles!

This is from google.