Final answer:
Jupiter is the largest and most massive planet in our solar system, far exceeding the mass and size of Saturn, Uranus, and Neptune. It can contain more than 1,300 Earths due to its size and has a massive magnetic field.
Step-by-step explanation:
The biggest planet in terms of mass and size within our solar system is Jupiter. Jupiter is 318 times more massive than Earth and has a colossal size that allows for over 1,300 Earths to fit inside it. None of the other giant planets, Saturn, Uranus, or Neptune comes close to Jupiter in mass; Saturn is only about 25% as massive, whereas Uranus and Neptune are merely 5% as massive as Jupiter.
In addition to being the largest, Jupiter has a very strong magnetic field and a significant internal heat source, unlike Uranus which has no internal heat source. All giant planets possess a core of 'ice' and 'rock' with approximately 10 Earth masses and have atmospheres primarily composed of hydrogen and helium, with Jupiter and Saturn having mantles of liquid hydrogen, unlike the higher density Neptune and Uranus which have different compositions.