Every now and then the Sun ejects material into space – and it can play havoc with technology

WORDS ANDREW MAY

Fortunately for life on Earth, the Sun is remarkably constant in the heat and light it radiates. In more subtle ways, however, our star is much more capricious. It can blast matter out into space in a way that for most of human history people have been blissfully unaware of. Today, though, such phenomena, known as space weather, can have drastic effects on the satellites and electronic technology we rely on. The origins of space weather can be traced to contortions in the Sun’s magnetic field, leading to dark blotches, or ‘sunspots’, on its surface. It’s from these spots that solar flares, coronal mass ejections (CMEs) and other electromagnetic phenomena can emerge – with potentially hazardous consequences for our technological way of life. Sunspot activity rises and falls on an 11-year cycle, and we’re currently approaching the next solar maximum in 2025. Now is a good time to look at the worst space weather that the Sun can throw at us, in the form of solar storms.

While space weather ultimately originates on the Sun, the term ‘solar storm’ refers to occurrences on or near our planet, when material thrown out by the Sun reaches us. There are two distinct types of solar storms: geomagnetic storms and solar radiation storms. The first – and most important – of these occurs when a clump of solar material, called a coronal mass ejection, disrupts the Earth’s magnetic environment. The second refers to a stream of much faster moving particles ejected by the Sun. As dangerous as the latter sounds, we’re largely protected from the effects by the geomagnetic field, as are the majority of satellites in Earth orbit.