Jupiter is a gas giant, meaning it doesn't have a solid surface like Earth. It's mostly composed of hydrogen and helium, with trace amounts of other elements like methane, ammonia, and water. Here's a breakdown:

Size:

* Diameter: 142,984 kilometers (88,846 miles) - about 11 times wider than Earth.

* Mass: 1.898 × 10²⁷ kg - about 317.8 times more massive than Earth.

* Volume: 1.431 × 10¹⁵ km³ - about 1,321 times larger than Earth.

Composition:

* Hydrogen: About 89.8% by mass.

* Helium: About 10.2% by mass.

* Trace elements: Methane, ammonia, water, and others.

Internal Structure:

Jupiter's internal structure is believed to be layered:

* Gaseous Outer Layer: Composed mostly of hydrogen and helium, this layer extends to depths of about 1,000 kilometers.

* Metallic Hydrogen Layer: Under immense pressure, the hydrogen gas becomes a liquid metal. This layer is believed to be responsible for Jupiter's powerful magnetic field.

* Rocky Core: Scientists believe that a small, dense core of rock and ice exists at the center of Jupiter. This core is likely only about 10 times the mass of Earth.

Note: It's important to remember that these are estimates based on our current understanding of Jupiter. Future research may reveal more detailed information about its composition and internal structure.