Final answer:
Jupiter, Saturn, and Neptune emit more heat than they receive from the Sun due to internal heat sources, while Uranus does not. Jupiter has the largest internal heat source among these planets, which originates from primordial heat and slow contraction.
Step-by-step explanation:
Three of the four giant planets, Jupiter, Saturn, and Neptune, emit significantly more heat than they receive from the Sun due to major internal heat sources. These planets obtain as much, or more, energy from their interiors as by radiation from the Sun.
In fact, Jupiter's largest internal energy source amounts to approximately 4 × 10¹⁷ watts, which is about equivalent to the total solar energy it absorbs. This excess internal heat is derived from a combination of primordial heat left over from the planets' formation and, in the case of giant planets, from heat generated by ongoing slow contraction.
These internal energy sources cause the temperatures of these planets' atmospheres to be higher than would be predicted from solar heating alone. By contrast, Uranus lacks a measurable internal heat source, hence, it does not emit more heat than it receives from the Sun.
These internal processes, along with factors such as the greenhouse effect, contribute to the planets' overall radiation budgets and can influence the potential for maintaining liquid water under certain conditions, though liquid water is unlikely on the gas giants due to their extreme temperatures and pressures.