Spacecraft to seek the secrets of the Sun

Fiery: The temperature on the surface of the Sun is estimated to be 5,500°C.

Will the source of life on Earth also be its end? This weekend, a new space probe will blast off towards the Sun to investigate one of the biggest threats to our planet – the solar wind.

As the reindeer herders of Lapland settle down for the night in the snowy landscape of the Arctic Circle, they often witness one of the most extraordinary sights known to man. The Northern Lights fill the sky with colours like those of a celestial firework display. But they also show that the Earth’s magnetic field is carrying out a vital task – protecting us from the solar wind.

The “wind” is a stream of radioactive particles sent out by the Sun. These usually travel at around 300 mph, and the magnetic field deflects most – but not all – of them. And sometimes, the Sun emits such enormous blasts of them, travelling at such great speed, that they can disrupt the workings of satellites and the internet, and even electricity supplies on Earth.

In a world that relies so much on technology, scientists are worried that increased activity by the solar wind could be devastating for humans. Indeed, it has been identified as one of six cosmic catastrophes that could wipe us out. So in the next few days, a European Space Agency (Esa) probe, the Solar Orbiter, will be launched to find out more about how it works.

The probe’s equipment includes cameras, telescopes, and sensors to measure X-rays and radio waves. Its three-and-a-half-year journey will carry it 67 million miles from Earth, and to within 26 million miles of the Sun. Protected by a heat shield designed to withstand temperatures of 500°C, it will take the first-ever photographs of the Sun’s poles.

“This is epic,” says one member of the Esa team, Professor Lucie Green. “Solar Orbiter gives us this ability to get up and close and personal with our star. It’s going to have a big impact on science.”

If we can forecast the solar wind’s activity, we should be able to take protective measures.

But the wind does not only threaten us through its effect on technology.

Scientists believe that as the Sun grows older and nears the end of its life, it will expand enormously, engulfing the nearest planets to it, Mercury and Venus. The solar wind will become so strong that it will cause the Earth to slow down and eventually – in about 7.59 billion years from now – fall into the Sun.

Will the source of life on Earth also be its end?

Danger from the skies

Some say that the fate of Earth ultimately depends on the Sun. Humans have become so dependent on electronics – whether to keep us warm or cool, or preserve our food and medicine – that a blast of solar wind which knocked out power supplies would leave us unable to survive. And though other forms of life might do better, they too would be wiped out when the Earth finally falls into the Sun.

Others believe that humans are likely to destroy themselves – and the rest of the planet – before the Sun does. The climate crisis is the most immediate threat, with the possible reduction of habitable places and food supplies. Nuclear war is another worry, as is disease. We could also be destroyed by a different cosmic catastrophe, such as collision with an asteroid or a supernova explosion.

You Decide

  1. Would you rather stay on Earth or move to a planet further away from the Sun?
  2. Is it better to spend money on trying to avoid a cosmic catastrophe, or on solving the problems Earth already has?


  1. Make a chart showing the Earth, the Sun, Mercury and Venus, and the distance between them when they are closest to each other.
  2. Make a list of the six electronic devices you depend on most. Imagine that you’ve had to spend a week without them, and write a one-page diary entry about how you coped.

Some People Say...

“Even if I knew that tomorrow the world would go to pieces, I would still plant my apple tree.”

Martin Luther (1483-1546), German theologian

What do you think?

Q & A

What do we know?
It is generally agreed that the Sun burns through 600 million tonnes of hydrogen every second. And for every billion years the Sun spends burning hydrogen, it gets about 10% brighter. Eventually, the Sun will bleed Earth dry of water. Approximately 3.5 billion years from today, the Sun will boil Earth’s oceans, melt its ice caps, and strip all of the moisture from its atmosphere. Our planet, once bursting with life, will become unbearably hot, dry, and barren – like Venus.
What do we not know?
Whether it will ever come to that! There are plenty of ways Earth could go. It could smash into another planet, be swallowed by a black hole, or get pummelled to death by asteroids. There’s really no way to tell which doomsday scenario will be the cause of our planet’s demise. And there are almost as many theories about this as there are astronomers.

Word Watch

An area of northern Europe stretching across Norway, Sweden and Finland to the edge of Russia.
Arctic Circle
The region closest to the North Pole. In the middle of winter there, the Sun never comes up; in the middle of summer, it never goes down.
Relating to the sky.
Causes (something) to change direction; turn aside from a straight course.
Sends out.
To do with the Universe or cosmos. Using the word cosmos (rather than Universe) views it as a complex and orderly system – the opposite of chaos.
European Space Agency
An organisation founded in 1975 to explore space. It is based in Paris and has a membership of 22 countries, including Britain.
An unmanned spacecraft designed to explore the solar system and send data back to Earth.
Overwhelming or swamping.
A large rock that travels around the Sun.
An explosion caused by the collapse of a star.

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