Sunday Science: Jupiter

Artist concept of Juno Credits: NASA/JPL-Caltech

This week, NASA's Juno spacecraft flew past the largest planet in our solar system - Jupiter. The planet's 10,000-mile wide spinning storm, called the Great Red Spot, was the craft's primary target.

The images are just starting to come in, but the Juno spacecraft did not disappoint. While it could be months before we understand the full implications of the data and images captured, Jupiter's structure could help us understand more about how the planets in our Solar System* formed.

In the first of a special series on our Solar System, let's find out more about Jupiter.

* The term Solar System just refers to the planets and other bodies orbiting around the Sun.

Image of Jupiter's Great Red Spot, taken by NASA's Juno spacecraft. Credit: Joaquin Camarena / JUNO © PUBLIC DOMAIN

What is Jupiter?

Jupiter sits between Mars and Saturn in the Solar System, some 484 million miles from the Sun. It takes Jupiter 12 Earth years to orbit the Sun and a "day" is only 10 hours. Jupiter rotates faster than any other planet in our Solar System.

Jupiter is covered in thick red, yellow, brown and white clouds that give it a striped appearance. The planet is classified as a "gas giant". This simply means that it's a very big planet that's made up of gas. 

In fact, it's so big that you could fit more than 1,300 Earths inside Jupiter. Here's a quick Lego scale reference:

Trust me, I've done the maths. You could fit 1,300 Supermen in this giant Lego head. The volume of the head is 7,000cm^3 and Superman is just over 5cm^3.

But you couldn't stand on Jupiter. It is made up of predominately hydrogen and helium gas so there is no firm ground. 

If you parachuted into the planet then you'd first fall through its visible clouds containing ammonia and hydrogen.

As you approached the centre of the planet, you'd pass through increasingly thicker clouds and the pressure would build until the hydrogen gas assumes a state similar to a metal.

This liquid "metallic hydrogen" could be the source of the planet's incredibly strong magnetic field. 

Questions still remain unanswered around the planet's core so who knows what you'd find there. Some scientists believe the core is a hot molten ball of liquid, others think it could be a solid rock that's up to 18 times more massive than the Earth.

When will we know more about Jupiter?

The Juno spacecraft is destined for quite a dramatic finale. At the end of its mission, the craft will fly into Jupiter and burn up as it travels to the core of the planet, gathering plenty of data as it plummets to its death.

Juno's demise isn't planned until February 2018 and the next flyby will come on 1 September 2017, although the spacecraft will not be passing over the storm again soon.

​So, it could be some time before the inner workings of this mysterious planet are unrevealed.

Extra reading and watching

Did you know that if Jupiter was 80 times more massive, it would have formed into a star? And that it has 53 moons and three faint rings? NASA's Jupiter pages are full of fascinating facts about the gas giant.

​It's also hoped that Juno will help us understand planetary formation. Most solar system formation theories focus on giant clouds of gas and dust collapsing until distinct bodies like the Sun and the planets form. What is less clear is how this happens. For example, does a planet's core form first and then all the other layers evolve over time? Or is it a quicker process?

Unlike the Earth, Jupiter is so massive that it has held onto its original composition when the Solar System first came into being, so it gives us a way of tracing our Solar System's history.

The Juno spacecraft is not the first mission to Jupiter - here's a great summary of the nine of missions to the Solar System's largest planet.

And here's the most recent news from the Juno spacecraft, courtesy of the BBC. You can find out all about the mission on the NASA site too and here's a round-up of the craft and its recent images:

Another interesting fact about Jupiter is that it has no song, according to the Moon from comedy series the Mighty Boosh:

What is Sunday Science?

Hello. I’m the freelance writer who gets tech. I have two degrees in Physics and, during my studies, I became increasingly frustrated with the complicated language used to describe some outstanding scientific principles. Language should aid our understanding — in science, it often feels like a barrier.
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So, I want to simplify these science sayings and this blog series “Sunday Science” gives a quick, no-nonsense definition of the complex-sounding scientific terms you often hear, but may not completely understand. 

If there’s a scientific term or topic you’d like me to tackle in my next post, fire an email to [email protected] or leave a comment below. If you want to sign up to our weekly newsletter, click here.