Formation of Jupiter
Written by Fraser Cain
Just like the rest of the gas giants in the Solar System, the formation of Jupiter began with the build up of ice covered dust in the outer, cold solar nebula. Small particles of ice and dust came together, forming larger and larger objects. When the nascent planet had gathered together enough mass, its gravity attracted more dust, as well as hydrogen and helium. The heaviest elements sunk into the core of the planet, surrounded by the lighter hydrogen and helium in its atmosphere.
Jupiter is 2.5 times more massive than all the other planets in the Solar System combined. In fact, if the planet had any more mass than it currently does, it would probably shrink down. Some astronomers call Jupiter a failed star, but only it would only have enough mass to ignite stellar fusion if it gathered another 50 times its current mass.
When Jupiter first formed, it was much hotter. This heat would have expanded it to twice its current diameter. As it cooled, it began to steadily shrink down; even now, Jupiter is shrinking by about 2 cm a year.
One final implication of Jupiter's formation is its gravity. Astronomers think that Jupiter really threw its weight around in the early Solar System, perturbing orbits of other planetoids, and stopping some from forming entirely. Scientists think that Jupiter might have been vital to the evolution of life on Earth, clearing out he Solar System of potentially destructive asteroids.
Here's an article on Universe Today discussing how the gas giants needed to form quickly, and how gas giants probably consumed most of their moons early on.
This page has some graphics that illustrate how particles clumped together to form Jupiter. And here's the Galileo project's information on Jupiter.
We've also recorded an entire show just on Jupiter for Astronomy Cast. Listen to it here, Episode 56: Jupiter, and Episode 57: Jupiter's Moons.
Filed under: Astronomy
