ON MONDAY we launched the Solar Orbiter, a spacecraft designed to tell us more about the Sun. Despite being the most massive object in our solar system, it makes up 99.8 per cent of the whole mass of the solar system.

The European Space Agency (ESA) in collaboration with Nasa has some fundamental questions about the sun that nobody knows the answer to, such as, what drives solar winds? How is the sun’s magnetic field generated and how does the sun affect space weather?

It comes as a surprise to people when you tell them that there is “weather” in space. But, this weather affects us here on Earth.

Getting a spacecraft close enough to the sun to be able to gather data is not easy, as you would imagine. Apart from the obvious problem of the intense heat, there’s also the issue of solar flares – ejections of hot plasma travelling at immense speeds and the basic problem of how to slow down a space craft enough that it will “fall” into the sun’s gravity.

The Earth, and all the other planets in the solar system, orbit the sun. The speed at which we move through space stops us from being pulled into the sun. We literally “fall” in an almost circular orbit around the sun. This makes travelling to other planets, and the sun itself, problematic. Everything moves in relation to the sun. After a spacecraft leaves the Earth, to get to say Mars it needs to speed up a little. We can use the Earth and sometimes the moon as a slingshot to help the spacecraft to speed it up.

To get to the sun, the opposite needs to happen. The spacecraft needs to slow down, then, it is pulled towards the sun by its massive gravitational pull.

To slow down, first the spacecraft needs to accelerate to match the speed at which the Earth is orbiting the sun, but it must go in the opposite direction to the Earth. You cannot just point a rocket at the sun and blast off. It requires some very complicated mathematics and a great deal of computing power.

Once you get close to the sun, there is the matter of the intense heat. Mercury, the closest planet to the sun, has surface temperatures up to 800 degrees Celsius on the side facing the sun. The opposite side can be as cold as minus 180 degrees Celsius. The solar orbiter needs to deal with these sort of extremes and more. The temperature at the core of the sun is about 15 million degrees Celsius, the photosphere (the actual disc of light we see) is about five to six thousand degrees Celsius.

The heat shield for the Solar Orbiter uses both ancient and modern technology to protect the delicate on-board instruments. A thin layer of the strong, corrosion resistant metal titanium is coated by powdered, charred animal bone. Together they make the best heat shield for the job.

One of the enduring mysteries of the sun is a phenomenon known as the solar wind. This wind is a plasma made up of radioactive particles blasted from the surface of the sun. This creates what we call solar wind. The particles in the wind can reach speeds of up to one million miles per hour, but it’s not constant, sometimes the wind travels much slower.

The mystery is how this plasma gets ejected from the sun and why it travels are such differing speeds. Our protection against these solar winds comes from the Earth’s magnetic field. This deflects the charged particles, though many of them will interact with our magnetic field. This interaction is responsible for the beautiful northern and southern lights.

Another phenomenon, known as a coronal mass ejection, is also a mysterious event. The corona is a region around the surface of the sun, like an atmosphere. During an eclipse, it is the bright ring of light we see around the dark disk of the moon. If a coronal mass ejection hits the earth it can cause radio blackouts and disrupt satellite communications. These solar storms have the potential to wreak havoc. If it were not for our own magnetic field, life would be impossible, as the ionising radiation given off from these particles would kill all living things.

Understanding the structure of the sun, and how the solar winds and coronal mass ejections work, will help us to predict them and protect ourselves against their potentially devastating effects.

Space exploration is expensive and many people criticise the huge sums of money spent. The more we know about our solar system and how the source of nearly all our energy works, the better we can protect ourselves and prepare for potential disastrous events.