Uranus and Neptune are less massive than Jupiter and Saturn, probably because they formed earlier than Jupiter or Saturn.

Question

Quizplus · Accepted Answer

Uranus and Neptune are less massive than Jupiter and Saturn because they are located farther from the Sun, where there is less gas and dust to form planets. Additionally, Jupiter and Saturn are believed to have undergone a process called runaway gas accretion, where they rapidly gathered large amounts of gas from the protoplanetary disk, while Uranus and Neptune did not have enough time to undergo this process.

Uranus and Neptune Are Less Massive Than Jupiter and Saturn