A common question that we get here at Universe Today is: what is the biggest planet in the Solar System? Jupiter is the biggest planet in our Solar System. It is the largest by mass, volume, and surface area among other statistics. Here are the critical measurements of Jupiter as well as a few other interesting facts about the planet and other bodies in the Jovian system.
Starting with mass, here are Jupiter’s measurements: mass 1.8981 x 1027 kg, volume 1.43128 x 1015 km3, surface area 6.1419 x 1010 km2, and a mean circumference of 4.39264 x 105 km. Despite its size, it only has a density of 1.326 g/cm3, which is less than one fourth of Earth’s density. The low density is one way scientists are able to determine that it is made mostly of gases and probably does not have a solid core.
Jupiter is not the largest possible planet in the Universe. TrES-4 is about 1.4 times the size of Jupiter. Scientist theorize that a gas gain could get 15 times the size of Jupiter before it began deuterium fusion, making it a brown dwarf star.
On Earth, we are fascinated by the auroras near the north and south poles. On Jupiter, the aurora activity is much more intense and rarely ever stops. The intense radiation, Jupiter’s magnetic field, and the abundance of material from the moon Io’s volcanoes in Jupiter’s ionosphere create a light show that is spectacular yet would become commonplace if you lived there.
The Jovian system includes 63 acknowledged moons along with a few other theorized satellites. The four largest are called the Galilean satellites after their discoverer, Galileo Galilei. They include: Ganymede, the largest moon in our Solar System, Io, the most volcanically active body in our Solar System, Europa, which is suspected of having a massive subsurface ocean, and Callisto. Callisto is also thought to have a subsurface ocean and features some of the oldest surface material in the Solar System.
Jupiter has a violent atmosphere. Winds in the clouds can reach as high as 620 kph. Storms form within hours and can become thousands of km in diameter overnight. One storm, the Great Red Spot, has been raging since at least the late 1600s. The storm shrinks and expands, but has never gotten smaller than 20,000 km in diameter and can be seen from Earth with a medium-sized telescope.
We have recorded a whole series of podcasts about the Solar System at Astronomy Cast. Check them out here.