It contains trace elements and compounds like carbon, oxygen, sulfur, neon, ammonia, water vapour, phosphine, hydrogen sulfide, and hydrocarbons.

Its internal structure is believed to consist of an outer mantle of fluid metallic hydrogen and a diffuse inner core of denser material.

Because of its rapid rate of rotation, one turn in ten hours, Jupiter is an oblate spheroid; it has a slight but noticeable bulge around the equator.

Jupiter's magnetic field is the strongest and second-largest contiguous structure in the Solar System, generated by eddy currents within the fluid, metallic hydrogen core.

[25] Current models of Solar System formation suggest that Jupiter formed at or beyond the snow line: a distance from the early Sun where the temperature was sufficiently cold for volatiles such as water to condense into solids.

[37][38] According to the Nice model, the infall of proto-Kuiper belt objects over the first 600 million years of Solar System history caused Jupiter and Saturn to migrate from their initial positions into a 1:2 resonance, which caused Saturn to shift into a higher orbit, disrupting the orbits of Uranus and Neptune, depleting the Kuiper belt, and triggering the Late Heavy Bombardment.

The dynamics of such an event would have dramatically altered the formation and configuration of the solar system, leaving behind only the four gas giants humans observe today.

[47] The atmosphere contains trace amounts of elemental carbon, oxygen, sulfur, and neon,[48] as well as ammonia, water vapour, phosphine, hydrogen sulfide, and hydrocarbons like methane, ethane and benzene.

[54] Jupiter's helium abundance is about 80% that of the Sun due to the precipitation of these elements as helium-rich droplets, a process that happens deep in the planet's interior.

[67] Although Jupiter would need to be about 75 times more massive to fuse hydrogen and become a star,[68] its diameter is sufficient as the smallest red dwarf may be slightly larger in radius than Saturn.

Data from the Juno mission showed that Jupiter has a diffuse core that mixes into its mantle, extending for 30–50% of the planet's radius, and comprising heavy elements with a combined mass 7–25 times the Earth.

[79] Alternatively, it could have been caused by an impact from a planet of about ten Earth masses a few million years after Jupiter's formation, which would have disrupted an originally compact Jovian core.

[102] Jupiter has a low axial tilt, thus ensuring that the poles always receive less solar radiation than the planet's equatorial region.

This feature may be formed by interactions between charged particles generated from Io and the strong magnetic field of Jupiter, resulting in a redistribution of heat flow.

[121] Jupiter's magnetic field is the strongest of any planet in the Solar System,[102] with a dipole moment of 4.170 gauss (0.4170 mT) that is tilted at an angle of 10.31° to the pole of rotation.

The solar wind interacts with these regions, elongating the magnetosphere on Jupiter's lee side and extending it outward until it nearly reaches the orbit of Saturn.

[124][125] As Io moves through this torus, the interaction generates Alfvén waves that carry ionized matter into the polar regions of Jupiter.

[70]: 65  The main ring is most likely made out of material ejected from the satellites Adrastea and Metis, which is drawn into Jupiter because of the planet's strong gravitational influence.

[138] Near opposition, Jupiter will appear to go into retrograde motion for a period of about 121 days, moving backward through an angle of 9.9° before returning to prograde movement.

A larger telescope with an aperture of 4–6 inches (10–15 cm) will show Jupiter's Great Red Spot when it faces Earth.

[143] The ancient Chinese knew Jupiter as the "Suì Star" (Suìxīng 歲星) and established their cycle of twelve earthly branches based on the approximate number of years it takes Jupiter to revolve around the Sun; the Chinese language still uses its name (simplified as 歲) when referring to years of age.

By the 4th century BC, these observations had developed into the Chinese zodiac,[144] and each year became associated with a Tai Sui star and god controlling the region of the heavens opposite Jupiter's position in the night sky.

[152] In the autumn of 1639, the Neapolitan optician Francesco Fontana tested a 22-palm telescope of his own making and discovered the characteristic bands of the planet's atmosphere.

[153] During the 1660s, Giovanni Cassini used a new telescope to discover spots in Jupiter's atmosphere, observe that the planet appeared oblate, and estimate its rotation period.

[202] This is seen most dramatically in the volcanic activity of Io (which is subject to the strongest tidal forces),[202] and to a lesser degree in the geological youth of Europa's surface, which indicates recent resurfacing of the moon's exterior.

The Kirkwood gaps in the asteroid belt are mostly caused by Jupiter,[212] and the planet may have been responsible for the Late Heavy Bombardment in the inner Solar System's history.

[213] In addition to its moons, Jupiter's gravitational field controls numerous asteroids that have settled around the Lagrangian points that precede and follow the planet in its orbit around the Sun.

[66] However, computer simulations in 2008 suggest that Jupiter does not cause a net decrease in the number of comets that pass through the inner Solar System, as its gravity perturbs their orbits inward roughly as often as it accretes or ejects them.

[234] The association between the planet and the Greek deity Zeus was drawn from Near Eastern influences and was fully established by the fourth century BC, as documented in the Epinomis of Plato and his contemporaries.

[238][239] In Central Asian Turkic myths, Jupiter is called Erendiz or Erentüz, from eren (of uncertain meaning) and yultuz ("star").