Images of Jupiter show that the planet is veiled by clouds. But these clouds could not be penetrated even with the high resolution instruments on board the Voyager spacecraft. Scientists think that Jupiter 's visible clouds consist of ammonia, but this composition is not entirely certain. A problem with ammonia is that it is white whereas the Jovian clouds are colorful. These colors are a mystery also.
Scientists think that the colors are due to sulfur compounds or organic materials in the atmosphere.
Solar abundances of elements would suggest that beneath the clouds there are probably various cloud decks of different compositions. But this would depend onabundances of materials in the original solar nebula at Jupiter 's distance from the Sun. Scientists also speculate that Jupiter might have water clouds like Earth. Several years of observations with the Voyager spacecraft and the Hubble Space Telescope have shown that the jet streams have maintained the same strength and location for at least ten years. In contrast with Earth 's jet streams the Jovian streams are very stable.