Space weather

Just a tiny fraction of the matter and energy hurled out into space by the Sun is intercepted by the Earth, but that fraction is all we need. And sometimes it’s almost too much. Earth’s magnetic field (‘magnetosphere’) protects us against highly energetic particles from the Sun that could harm us by smashing into DNA molecules and disrupting the chemistry of life. ‘Space weather’ in the uppermost reaches of our atmosphere (the ‘ionosphere’) can be just as significant as the weather we experience on the ground. Solar storms and violent surges in the stream of solar particles (the ‘solar wind’) can knock out expensive space satellites, distort GPS navigation signals, and even black out our electricity supplies.

In March 1989 the restless Sun hurled a massive pulse of charged particles in our direction, and the world witnessed a spectacular ‘Northern Lights’ (‘Aurora Borealis’) display which could be seen as far south as Florida and Cuba. Suddenly, the entire electricity output from Hydro-Quebec's La Grande Hydroelectric Complex went haywire, and Quebec’s power grid collapsed. Six million people were left without heat and light on a cold winter’s night. People were trapped in darkened buildings and elevators, and all the traffic lights stopped working.

Engineers in the US also experienced problems. New York, Washington, and other major East Coast cities only narrowly avoided total shut-down. No wonder scientists are keen to discover more about how these space weather storms are triggered, and how we can protect ourselves against them.