Here's why:
* Outer Solar Nebula: The outer solar nebula was much colder than the inner regions. This coldness allowed lighter elements like hydrogen and helium to condense and form massive gas giants.
* Jupiter's Composition: Jupiter is primarily composed of hydrogen and helium, making it a gas giant. It has a small, rocky core but is mostly a swirling mass of gas.
While Saturn is also a gas giant, it's important to note that both Jupiter and Saturn formed in the outer solar nebula. Jupiter, being the largest planet in our solar system, likely accumulated more of these light gases.