This drawing shows how forming planets drew gas to themselves.
Click on image for full size
Image from: The New Solar System
How a proto-planet sweeps up nearby material
As shown in this picture, while they were forming in the solar nebula, the nucleii of the planets-to-be (called protoplanets) drew material to themselves from the cloud of gas and dust around them. The bigger protoplanets were able to attract even more gaseous material unto themselves. Because of it's position in the solar nebula, the proto-Jupiter, was able to draw an enormous amount of gas unto itself, and become the biggest of the planets.
You might also be interested in:

The position of the planets in the solar nebula greatly affected their 1. size and 2. composition. This is because of the effect of how cold it was in the nebula. 1. The nebula was a lot warmer close to
...more
The co-formation theory explains the origin of the moon as an object which formed out of the primitive solar nebula at the same time and roughly the same place as the Earth. As shown in this picture, while
...more
Scientists believe that the solar system was formed when a cloud of gas and dust in space was disturbed, maybe by the supernova of a nearby star. Shock waves from the explosion compressed the cloud of
...more
It may surprise you, but astronomers don't really have a good definition of a "planet". Because of this, Pluto is at the heart of a controversy about its status. Is Pluto a planet, or isn't it? Scientists
...more
Atmospheres of the giant planets have definetely evolved from their formation out of the primitive solar nebula. How much they have evolved remains to be seen, however. Because of their enormous gravity,
...more
The mesosphere of Jupiter is a region of balance between warming and cooling. That essentially means that nothing happens there. Except for diffusion, the atmosphere is still. Upper reaches of the atmosphere,
...more
As on Earth, the atmosphere of Jupiter consists of a troposphere, stratosphere, mesosphere, and thermosphere. The troposphere is the region where the visible clouds are to be found. The stratosphere, as
...more