Questions people actually ask
Short answers, each with its source. Longer ones live on the topic pages.
How big is Jupiter?
Jupiter’s mean radius is 69,911 km, so it is 11 times wider than Earth. NASA Science: Jupiter facts If Earth were the size of a grape, Jupiter would be about as big as a basketball. NASA Science: Jupiter facts
How far away is Jupiter?
Jupiter orbits an average of 778 million km from the Sun: 5.2 astronomical units. NASA Science: Jupiter facts Jupiter comes as close as 588.5 million km to Earth, and gets as far as 968.5 million km away. NASA NSSDC: Jupiter fact sheet
How long is a day on Jupiter?
Jupiter has the shortest day in the solar system: it spins once in about 9.9 hours. NASA Science: Jupiter facts A day on Jupiter (sunrise to sunrise) lasts 9.9259 hours. Earth’s lasts 24 hours. NASA NSSDC: Jupiter fact sheet
How long is a year on Jupiter?
Jupiter takes 4,332.589 Earth days to orbit the Sun once: about 12 Earth years. NASA NSSDC: Jupiter fact sheet
Could you land on Jupiter?
Jupiter has no true surface. It is mostly swirling gases and liquids, so a spacecraft would have nowhere to land. NASA Science: Jupiter facts The pressures and temperatures deep inside Jupiter would crush, melt and vaporise a spacecraft trying to fly in. NASA Science: Jupiter facts
How much would I weigh on Jupiter?
Gravity at Jupiter’s 1-bar cloud level averages 25.92 m/s², 2.640 times Earth’s 9.82 m/s². NASA NSSDC: Jupiter fact sheet
Is Jupiter a failed star?
Jupiter has the same ingredients as a star, but it never grew massive enough to ignite. NASA Science: Jupiter facts
What is the Great Red Spot?
The Great Red Spot is a giant storm bigger than Earth. NASA Science: Jupiter facts Astronomers have watched the Great Red Spot shrink since the 1930s, and from 2012 it shrank faster, turning from an oval towards a circle. NASA Science: Jupiter’s Great Red Spot is shrinking (2014) · checked 27 Oct 2026
How many moons does Jupiter have?
Jupiter has 115 moons officially recognised by the International Astronomical Union. NASA Science: Jupiter facts · checked 27 Oct 2026 Some NASA pages still give an older count of 95, including the NSSDC satellite fact sheet. NASA NSSDC: Jovian satellite fact sheet · checked 27 Oct 2026
Which is Jupiter’s biggest moon?
Ganymede is the largest moon in the solar system, bigger than the planet Mercury and the dwarf planet Pluto. NASA Science: Ganymede facts
Does Jupiter have rings?
Jupiter has rings, discovered by Voyager 1 in 1979. They are dark and faint, and hard to see unless the Sun is behind them. NASA Science: Jupiter facts
Could there be life near Jupiter?
Jupiter itself is probably too extreme for life as we know it, but some of its moons may not be. NASA Science: Jupiter facts Europa may be one of the most promising places in our solar system to find environments suitable for life beyond Earth. NASA Science: Europa
Which spacecraft are at Jupiter, or on the way?
Juno was still at work in 2026: on 1 May 2026 it photographed Thebe, one of Jupiter’s small inner moons. NASA Science: Juno stories · checked 27 Oct 2026 NASA’s Europa Clipper launched on 14 October 2024 and is due to reach Jupiter in April 2030. NASA Science: Europa Clipper · checked 27 Oct 2026 ESA’s Juice launched on 14 April 2023 and is due to reach Jupiter in July 2031, to study Ganymede, Europa and Callisto. ESA: Juice factsheet · checked 27 Oct 2026
Can I see Jupiter without a telescope?
Jupiter has been known since ancient times: you can see it with just your eyes. NASA Space Place: All about Jupiter
Most Jupiter numbers here come straight from NASA’s Jupiter facts page and NASA’s Jupiter fact sheet. Sometimes NASA pages disagree, and when they do we show both rather than pick one quietly. Moons: NASA’s Jupiter facts page says 115 are officially recognised, while the older NASA satellite fact sheet still says 95. The Great Red Spot’s age: “more than 300 years” on one NASA page, “at least 150 years” on another. Counts and mission news change, so they carry the date we checked them.