This blog is written by Gemma Richardson, a geomagnetic hazard specialist at the British Geological Survey. In her spare time Gemma likes to make crafty things very slowly and walk up the occasional hill. You can find her on Twitter @geomaggem
I know what you’re thinking – “what does space have to do with a Geoscience website, surely that’s all about Earth science?” Well, bear with me and I’ll explain why I, a geophysicist, study space weather.
What is space weather?
For a start, “space weather” is nothing like the standard weather we love to spend so much time talking about. There’s no rain, snow or fog, and space ‘wind’ and ‘storms’ are very different to the ones that like to leave you looking like you’ve been dragged through a hedge backwards on the one day you left home without a waterproof.
In a nutshell, space weather is anything that happens in near-Earth space that can affect us, or our technology, either in space or on the ground.
There is a flow of charged particles, called the ‘solar wind‘, flowing continuously from our Sun out into the solar system. This solar wind blows onto the Earth’s magnetic field, squashing it on the side nearest the Sun and stretching it out into a long tail on the other (if you could see it, it would look a bit like a teardrop on its side). Every so often, something happens on the Sun to interrupt this flow of solar wind, creating faster or denser patches. When these patches reach the Earth they interact with the magnetic field and cause disruption to technology.
The solar wind blowing towards the Earth and becoming deflected by the Earth’s magnetic field (credit Victoria Taylor, BGS/UKRI)
Space weather is a relative newcomer in terms of geological hazards, not because it hasn’t been around as long as other geological hazards, but because its impacts largely affect our technology, rather than us directly. A whole range of technology is at risk, from the obvious things like satellites (they are in space after all), to GPS and long distance radio signals, aircraft, power transmission systems, pipelines and navigation (both above and below ground). One of the biggest concerns is that a severe space weather event could affect many technologies simultaneously and have global reach.
There are lots of wonderful multi-disciplinary people working on space weather, from solar physicists studying the Sun itself, to engineers designing sturdy satellites and infrastructure, to risk analysts and economists assessing the potential costs of a severe space weather event, to forecasters, aurora chasers, and even airline pilots who check the space weather conditions before taking polar flights. And, of course, geophysicists (like me) who study the Earth’s magnetic field and how space weather affects technology on the ground.
Solar Storms
The really big space weather events (which I’m most interested in, because they cause the most damage) are usually associated with ‘Coronal Mass Ejections’, sometimes called solar storms. These are a huge release of plasma (superheated gas) and solar magnetic field from near the surface of the Sun, which travels in a bubble out into space at speeds between 250 and 3000 kilometres per second (for comparison, the speed limit on Britain’s motorways of 70 miles per hour is equivalent to 0.031 kilometres per second!) Once a solar storm hits the Earth’s magnetic field, it introduces a lot of extra energy and solar particles into the system. This causes the Earth’s magnetic field to start varying rapidly, which in turn causes electric currents to flow through the ground.
Don’t worry- these currents aren’t strong enough to shock you, but if they happen across something like a power transformer (which normally provides a low resistance route for electricity to flow into the ground) they can get into the power network and cause a lot of problems. The currents push the transformers to operate outside their standard operating range, causing parts of the system to shut down for protection. In the absolute worst case scenario, they can heat up the transformer core, which can lead to sparking and cause the transformer to fail.
A SOHO satellite image looking towards the Sun. The Sun itself is blocked out by an opaque disk so we can see the ‘corona’ (Sun’s atmosphere)- much like what happens during an eclipse. The big bright bubble on the right is a coronal mass ejection leaving the Sun and heading out into space (credit ESA/NASA).
The biggest storm ever recorded happened in 1859, the so-called “Carrington event”. An astronomer named Richard Carrington was making his daily observations of sunspots (regions of the Sun which appear dark due to complex magnetic fields) when “two patches of intensely bright and white light broke out”. He had just witnessed what we would now call a solar flare (an intense flash when the Sun releases a burst of radiation). It must have been also been accompanied by a solar storm, because 14 hours or so later a geomagnetic storm began on Earth. Telegraph systems around the world experienced large currents along the cables, making them unusable for the duration of the storm; some even began causing electric shocks to the operators, sparking and starting fires.
More recently, a storm in March 1989 caused a collapse of the power system in Quebec, leaving many without power for at least 9 hours, and leading to communications blackouts. Another storm in October 2003 led to a power blackout in Malmo in Sweden, as well as causing damage to some transformers in the UK.
A different kind of weather forecast…
Nowadays, all the fabulous research happening around the world is helping to mitigate the risk of space weather. If we were to see another storm on the scale of the one in March 1989, we shouldn’t see the same level of damage as we did then. However, we can’t rule out the possibility that a much bigger storm could be on the way, which could affect regions that have previously never had to consider space weather risk. The real challenge is forecasting these events; particularly as the largest, most damaging solar storms also tend travel the fastest, reaching Earth relatively quickly and giving the least warning.
Forecasting capability has improved greatly in recent years, with satellites and forecast centres keeping a constant watch on the Sun and its explosive outbursts; but we still have a long way to go to be able to match the forecasting capabilities of terrestrial weather (and even they don’t get it right all the time). At the British Geological Survey we provide daily forecasts of space weather and put out weather warnings when a storm is due. These forecasts help power grids plan for the effects of space weather on their system, for example, by making sure that all the lines and transformers are connected to the system so that these extra currents get spread out rather than being focussed on a single transformer, which could overload it.
Amazing Aurora
But it’s not all about the hazard. The side effect of space weather is that we get to see the beautiful phenomenon of the northern (and southern) lights. The lights are visible in a region called the ‘auroral oval’ which is normally confined to a narrow band at high latitudes (e.g. covering Iceland and northern Canada), but during a storm this oval expands and moves towards the equator, at times extending far enough to be seen in the UK, and the lights become much brighter and more dynamic. During the “Carrington event” there were reports of sightings as close to the equator as Cuba. Descriptions of the sky filling with light came from all over the world, including France, Australia, the UK, USA and India.
The aurora, or Northern Lights, as seen from the International Space Station (credit NASA)
So if you hear that a solar or geomagnetic storm is in progress, you might see some short term disruption to communications and possibly power networks, and your compass will definitely get a little confused- but as soon as its dark, if you head outside you might just catch a glimpse of the northern lights.
In the next few years, as we enter a new solar cycle, we expect to see an increase in the number and intensity of space weather events. As our reliance on technology continues to grow, and new technologies are developed (such as driverless cars) understanding space weather and its impacts will become more important than ever.