Solar storm threat as Sun does magnetic backflip
The Sun’s magnetic field is about to reverse – a cosmic event that happens every 11 years and sends waves of energy through the solar system. What will the effects be here on Earth?
When people think of space, they think of emptiness. Space is a vacuum, empty of air, sound, heat and life. To stare into space is to stare into an infinite void.
That, at least, is how space looks to human eyes. But the right sort of aliens – creatures with more finely developed senses than ours – might see things rather differently. These imaginary aliens would look at our Solar System and see not a great expanse of emptiness but a great rippling bubble of energy and light. At the heart of this ball, which astronomers call the heliosphere, sits the source of all this beaming radiation: the Sun.
The Sun works, essentially, like an enormous fusion reactor, smashing hydrogen atoms together to produce the bigger helium atoms and releasing vast quantities of energy in the process. Fusion heats the centre of the Sun to over 15 million ºC and is the source of the heat and light that sustains life on Earth.
At the same time, the Sun’s dense layers of superheated hydrogen plasma produce an extremely strong magnetic field that reaches for billions of kilometres into space. This vast magnetic bubble is swept by ‘solar winds’ of charged particles hurled from the Sun’s surface at a million kilometres per hour.
Most dramatic of all, if we could see it, would be what astronomers call the ‘current sheet,’ an invisible charged surface that spreads out from the Sun’s equator. As the Sun rotates, the current sheet swirls in waves like the skirt on a spinning ballerina.
Normally, those waves are fairly gentle. Within the next few weeks, however, the complex magnetic web that runs through the heart of the Sun will be literally turned on its head. Every eleven years, the magnetic poles of the Sun swap places.
This swap is due any minute now, and it will have effects that are felt across the solar system. The Sun will erupt to produce more frequent solar flares. The solar wind will intensify, battering the Earth’s atmosphere with charged particles. At the same time, the waves in the current sheet will get deeper and more frequent. For the next few weeks, Earth will swim through space like a ship on a stormy sea.
Scientists are remarkably calm about the incoming solar tempest. Solar storms could be dangerous for astronauts and satellites, or briefly knock out an electrical power grid, but there is no known scientific mechanism that would cause solar weather to have much effect on us directly.
But there are many on the fringes of the scientific world who are alarmed. Surely such disruption to the Sun, which sustains all life, must have a profound effect on humans too. There are forces out there that science still does not understand.
- How scared do you think we should be of bad solar weather?
- Do you trust what scientists say? Why / why not?
- What do you think is the greatest wonder of nature? Choose your wonder and write no more than 100 words justifying why you have chosen it. Compare notes with the class. Whose case is most convincing?
- Write a science fiction story set in a world where the Sun has mysteriously stopped shining. How would the planet change? How would humans survive, if at all?
Some People Say...
“Science will never solve the mysteries of the Universe.”
What do you think?
Q & A
- Solar storms sound dangerous!
- There really is no reason to think they pose much danger to us directly. We are lucky enough to be shielded by Earth’s magnetic field. In periods of intense solar activity, charged particles from the Sun collide with our protective field to produce auroras – the Northern and Southern Lights.
- So I don’t need to worry about the Sun then?
- On the contrary! The Sun kills 1,500 people a year in England and Wales alone – not through solar storms but through ultraviolet radiation which causes sunburn and skin cancer.
- Okay – wear sunscreen. Got it. Anything else?
- Try not to live to the grand old age of five billion years. If you do, you’ll see the Sun begin to die, expanding into its ‘red giant’ form and scouring all life from the face of the planet.
- Sound waves are vibrations. Essentially, when you hear a loud noise your ears are detecting tiny shockwaves spreading through the surrounding air. In space there is no air, or any other kind of matter, so there is nothing for the shockwaves to spread through, and therefore no sound.
- The heliosphere stretches over 18 billion kilometres from the Sun, far beyond even the orbit of Pluto. Last year, the Voyager space probe crossed out of the heliosphere and into interstellar space. It is the only man-made object to have done so, and has been travelling for more than three decades.
- Fusion reactor
- Nuclear reactors on Earth are driven by nuclear fission, in which heavy atoms are split to form lighter atoms, releasing energy as the atomic bonds break. In fusion, light atoms are combined to form heavier atoms, a process which also releases energy. Scientists attempting to produce fusion reactions on Earth have to recreate conditions that naturally only occur inside the Sun.