This image of Jupiter's white oval, BC, taken by the Hubble Space Telescope, and a corresponding infrared image taken by the Galileo spacecraft. The infrared picture helps to show how what the temperature is like inside the oval.
The White Ovals of Jupiter
Among the cloud shapes in the atmosphere of Jupiter are white ovals
. White ovals are a collection of white clouds which are grouped together into an oval shape. They are found almost anywhere in the atmosphere of Jupiter. Even though the oval is made of clouds, the oval itself can be as long as 9000 km (that is, 3/4 the size of the entire Earth since the Earth is 12,000 km across).
White ovals can change their shape, migrate through the atmosphere, jostle each other for position, and even eventually merge with each other. Despite all of this, white ovals have been known to survive for 40 years or more in Jupiter's atmosphere. That means they are much younger than the Great Red Spot, which is at least 400 years old, but much older than any cloud feature found on the Earth.
The clouds circulate around the center of the oval, much the way a hurricane circulates around the eye. That is, ovals are known as anti-cyclonic systems the same way that a hurricane is considered to be cyclonic (circulating around). In the southern hemisphere, air in anti-cyclonic systems spins in the counter-clockwise direction. Air is also rising, just like inside a terrestrial thunderstorm.
Although there are other white ovals in Jupiter's atmosphere, in recent decades there have been 3 which are considered to be famous. They are famous because they have been around such a long time. They are named FA, DE, and BC, and they were born in 1939. You may ask, "where did the scientists get those awful names?". These three ovals have had a unique history which has lead to the names by which they are known today. After such a long time, two of the ovals, BC and DE, recently merged together (1998). What do you think scientists might name the newly merged oval: perhaps ABCDEF? Scientists have decided to call it BE.
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