Let’s move on to the largest planet in our solar system, the great gas giant Jupiter.
- Jupiter is over twice as heavy as all the other planets in the Solar system put together.
Jupiter is a gas giant planet, the largest in the solar system, made up of swirling gases (mostly Hydrogen, with some Helium) on its surface. It has no solid surface – if you were to try and land on Jupiter you would simply sink into its gassy outer layers! However, it is believed to have a rocky or liquid core, right in the centre of the planet. Because of its size, the gravity on Jupiter is very strong, and would crush you if you were to get too close. It is about eleven times the diameter of the Earth and over three hundred times as heavy, but it is only one-thousandth the mass of the sun. That might seem small, but consider the size of the Sun – to put it in perspective, Jupiter is still 2.5 times heavier than all the rest of the planets put together! It could also fit all the other planets in the solar system inside it, it has such a huge diameter.
- The Great Red Spot is shrinking, but storms still rage.
Jupiter is a very beautiful planet, with many brown, red and orange (and even blueish) colours on the surface that swirl around the Planet. One of its most famous features is of course the Great Red Spot. This is a giant storm that has been raging for at least two hundred years. It was discovered definitively in 1831, but there is anecdotal evidence of it being there since 1665. It may look small from our perspective, but this storm could fit Earth inside it three times over. It has recently been getting smaller though, so does this mean that it is disappearing? Well, mathematical modelling would suggest that it isn’t. it seems to be a very stable feature of the planet and may even be permanent. Back to the lines on Jupiter’s surface though, and these are made of clouds of ammonia circulating around the planet. This is the reason for the storms and weather systems. The fast spin of Jupiter means that the clouds of its atmosphere are left trailing behind the core, and the bands of clouds travel in opposite directions, causing storms where they meet or overlap. Lightning can be seen sometimes in Jupiter’s cloud layer, which suggests that there might be water clouds in a lower layer of the Jovian atmosphere. Just like everything else on Jupiter, these lightning storms are big. They have been measured to be up to a thousand times more powerful than the lightning we get on Earth (and even that can be pretty scary).
- There are Aurorae on Jupiter
Just like on Earth, at the poles of Jupiter there is a spectacular light show, but this one happens every day. Jupiter’s Aurorae (or Northern and Southern lights) happen constantly, rather than just occasionally like on Earth. Aurorae are caused when charged particles from the sun enter the planet’s atmosphere and glow when they hit the atmosphere’s particles. The many moons of Jupiter affect the aurorae as well, with distinct spots of brighter light where solar particles are affected by the four largest moons. These moons are Io, Europa, Ganymede, and Callisto and you can see their contributions to the Northern Aurora in this picture!
- Spins so fast it bulges
Jupiter has the fastest rotation in the solar system; it spins around once every ten hours, giving it a day length of less than half of Earth’s. Because of this mega fast spin, the equator of Jupiter bulges out like your arms do when you spin around fast on the spot. This means Jupiter isn’t spherical – it is an ‘oblate spheroid’ which basically means a 3D oval.
- A comet hit Jupiter in the 1990s
Comet Shoemaker-Levy 9 was the comet that collided with Jupiter in 1994. It left behind large impact marks on the visible surface of the planet in the form of brown spots, which lasted for months. The comet impact taught us a lot about comets in space, as it was the first collision outside Earth that we were able to watch as it happened. The comet travelling towards Jupiter and hitting it became a sensation in the media, and loads of astronomers were watching closely as it fell towards the planet. In fact, Jupiter gets hit by small objects as much as 8000 times as frequently as Earth. This fact and the Shoemaker-Levy event inspired the idea that Jupiter acts as a ‘cosmic vacuum cleaner’, hoovering up some comets and asteroids with its gravity before they can reach the inner solar system and pose us harm!