Why does Jupiter so big?

Question

The Planet Jupiter is the biggest planet is'nt it...

Answer 1

The first answer is a good one, but doesn't really address the actual question very well. That question being (I think) "Why IS Jupiter so big?"....

That has to do with how much gas/solid material was present in the early solar system, and the solar wind. The solar wind pushed lighter substances out into the outer solar system (lighter substances = gasses) where they were captured by a small planetesimal's gravity (icy/rocky body, probably about the size of Mercury). This planetesimal was fed with more and more gas (mostly hydrogen and helium) until it became what we now call Jupiter. The fact that there was a lot more light/gaseous material in the early solar system explains why the outer planets are so much more massive than the inner planets (which are composed of the heavier material that wasn't blown away by the solar wind).

Jupiter is the largest of the gas giant planets because it is the closest to the sun - so it gets the first shot at picking up the material blown its way by the sun. The more massive Jupiter became, the more material its gravity was able to pull in.

This is a fairly simplified explanation, so I'll put a link to the Wikipedea section on the Milky Way's solar nebula if you'd like more detailed information.
http://en.wikipedia.org/wiki/Planet_formation#Jovian_planetesimals

Answer 2

Because current technology is not sufficiently sensitive to detect solar systems like ours around other stars, however, there is no way to determine at present whether our solar system is common or rare.

If planets form only through core accretion, then our solar system's protoplanetary disk must have been long-lived. And if long-lived disks are rare, then planets in general must also be rare. If, however, planets can form by another, quicker means like disk instability, then planets could be more common.

So far, over 60 extrasolar planets have been discovered. These planets are all large, gaseous planets, most of which (because of the limitations of current observing techniques) are several times larger than Jupiter. Boss views the discovery of these super-Juptiters as strong evidence that disk instability is at work.

"The rate of discovery of extrasolar gas-giant planets seems to show that gas-giant planets are common," says Boss. "This implies that there must an efficient mechanism for forming gas-giant planets. That seems to point to disk instability. If long-lived disks exist, they are a rarity, whereas disk instability may occur very frequently. A high frequency of extrasolar planets orbiting nearby stars would imply that disk instability must occur."

Answer 3

yeah so it needs trim spa, stop picking on fat planets or scientists will kick uranus.