Jupiter doesn't work well as a model for what's going on in the rest of the solar system, particularly for the terrestrial planets like Earth. A gas giant can be considered a sort of "proto-star," or a potential star that didn't make it because it just didn't manage to accumulate enough mass for sufficiently powerful nuclear reactions to ignite in its core.   But it's interesting to note that, unlike terrestrial planets that absorb energy from the sun and reflect a small percentage of it, Jupiter is actually emitting more energy than it absorbs. This indicates that it may have nuclear reactions taking place in its core, nowhere near enough for it to be even remotely considered a star, but enough to effect the temperature of the planet in general.

So one can't point at Jupiter and say, "See? Global warming is happening all through the solar system" (sorry—not the case!) "so it can't be caused by human activity. Go right ahead, buy that gas-guzzling SUV and pollute the atmosphere all you want."

Don Firth