How do you tell a star from a planet in the night sky?
Well, one good way to tell stars from planets is that looking at them with the naked eye, stars twinkle and planets don’t. Stars are so far away that they are essentially just a single point. Movement in the Earth’s atmosphere causes them to look li ke they are twinkling. Since the twinkling effect is caused by the atmosphere, stars do not twinkle when viewed from outer space. We receive more rays of light from planets, which balances out the effects of the atmosphere and makes them look like steady lights, even though they can appear no larger than stars.
