Our solar system is roughly 4.6 billion years old and weighs 1.0014 solar masses (a solar mass is the mass of the Sun: about two nonillion kilograms – that’s 2×1030 kg, or ridiculously heavy). Over 99% of all the material in our solar system can be found in the sun, and most of what remains makes up Jupiter.
Size and Composition
At roughly 11 times bigger than Earth (in size, not weight) Jupiter is the largest of the planets in our solar system and if you look up at the sky tonight you’ll see that it looks very big and very bright, out-shined only by Venus (and the moon if it’s up whilst you’re star gazing, or planet gazing). Jupiter always looks pretty big but at the moment is the closet it’s been to Earth for 13 months due to how the two planets orbit the sun, which gives it that extra wow factor. maybe that’s why the planet is named after the king of the gods and the god of the sky and thunder.
Like our Sun, Jupiter is made up of hydrogen and helium. In fact, if it was a bit bigger (well, about 75 times bigger) it could start nuclear fusion reactions and turn into a tiny star! Even at its current size Jupiter radiates more heat than it receives, a process which sees it shrink by about 2 cm every year.
Moons and Magnets
To go with its impressive size there are 67 moons that we’ve discovered orbiting Jupiter so far and four of those moons: Io, Europa, Ganymede and Callisto are big enough to see through a telescope. The Great Red Spot in Jupiter’s southern hemisphere is also visible with a half-decent telescope and is very well known. It is an anticyclone bigger than the Earth, and with no sign of slowing down. Scientists think that this storm is stable enough to be a permanent feature on Jupiter and we know that it has been raging since at least 1831.
Jupiter has a magnetic field that is four thousand times stronger than Earth’s and causes magnetic particles to vibrate. Even though the vacuum in space makes noise impossible these vibrations can be detected and turned into sound. Check out this recording of Jupiter’s sounds by NASA’s Voyager.