Does the big spot you always see in the pictures of Jupiter have a name?
Yes. That oval spot is called the "Great Red Spot."
Believe it or not, that "spot" is actually a giant storm that rotates counter-clockwise and is big enough to hold two Earths. Scientists think the red color is caused by impurities in the planet's atmosphere constantly absorbing ultraviolet and violet light, such as sulfur or phosphorus.
The Great Red Spot is quite a mystery. Nobody is sure how long the storm has been going on. All we know is that the spot has been visible since the day we first built a telescope strong enough to see Jupiter in the 17th century.
—The Fact Monster