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Jupiter

Jupiter is the fifth planet from the Sun and the largest planet in the Solar System.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 27, 2026|2 min read| Fact-checked

Jupiter is the fifth planet from the Sun and the largest planet in the Solar System. It is a gas giant made mostly of hydrogen and helium, and it has a large system of moons and faint rings. Jupiter is also bright enough to be seen from Earth without a telescope.

Physical characteristics

Jupiter is an immense gas giant with a diameter of roughly 143,000 km and a mass about 318 times that of Earth. It is the largest planet in the Solar System and is more than twice as massive as all the other planets combined. Jupiter has no solid surface in the usual sense; its visible clouds are part of a deep atmosphere.

Atmosphere and composition

Jupiter's atmosphere is composed mainly of hydrogen and helium, with small amounts of other gases and aerosols. The atmosphere transitions into denser material deeper down, rather than ending at a solid surface.

Moons and rings

Jupiter has 95 officially recognized moons, led by the four Galilean moons discovered by Galileo in 1610: Io, Europa, Ganymede, and Callisto. It also has a faint ring system made of dust.

Visibility from Earth

Jupiter is visible to the naked eye from Earth and is commonly one of the brightest objects in the night sky. Its distance from Earth changes with the positions of the two planets in their orbits, so the exact distance varies.

Astronomical importance

Jupiter is the Solar System's dominant planet by mass and size and has a powerful magnetic field and large magnetosphere. It formed early in Solar System history, about 4.6 billion years ago.

Key facts

  • Jupiter is the largest planet in the Solar System.
  • It is a gas giant with no solid surface; its visible clouds are part of a deep atmosphere.
  • Jupiter’s atmosphere is composed mainly of hydrogen and helium.
  • It has 95 officially recognized moons, including the four Galilean moons: Io, Europa, Ganymede, and Callisto.
  • Jupiter has faint rings and a strong magnetic field.
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Canadian context

Jupiter is visible from Canada’s night sky and is a common target for amateur astronomy across the country.

Frequently asked questions

How big is Jupiter?
Jupiter’s diameter is about 143,000 km, or about 11 times Earth’s diameter.
How many moons does Jupiter have?
Jupiter has 95 officially recognized moons.
What is Jupiter made of?
Jupiter is made mostly of hydrogen and helium, with smaller amounts of other gases and aerosols.
How far is Jupiter from Earth?
The distance from Earth to Jupiter changes constantly because both planets orbit the Sun. A precise current distance depends on their positions in orbit.
Can you see Jupiter from Earth?
Yes. Jupiter can be seen with the naked eye and is one of the brightest objects in the night sky.
What are some Jupiter facts?
Jupiter is the fifth planet from the Sun, the largest planet in the Solar System, and it has a very short day of about 9.9 hours, faint rings, and a large system of moons.

References

  1. NASA — https://www.nasa.gov/jupiter/
    Supports: Largest planet, composition, day length, moons, and general Jupiter facts.
  2. NASA — https://science.nasa.gov/jupiter/jupiter-facts/
    Supports: Diameter, composition, orbital distance, and official moon count.
  3. Encyclopaedia Britannica — https://www.britannica.com/place/Jupiter-planet/Basic-astronomical-data
    Supports: Diameter and mean distance from the Sun.
  4. Universe Today — https://www.universetoday.com/articles/jupiter
    Supports: Gas giant composition and atmospheric structure.
  5. European Space Agency — https://www.esa.int/Science_Exploration/Space_Science/Juice/Facts_about_Jupiter
    Supports: Diameter, mass, atmosphere, moons, rings, and day length.
  6. Las Cumbres Observatory — https://www.lco.global/spacebook/solar-system/jupiter/
    Supports: Visibility from Earth and basic planetary facts.