On March 10, 1989, there was an explosion on the sun, catapulting a large mass of hot solar plasma off into space at thousands of kilometres a second.
In the early hours of the 13th, this cloud, properly called a “coronal mass ejection,” hit us. The Earth’s magnetic field convulsed, triggering a major magnetic storm that caused power outages, disruptions of communications and somewhere around $2-billion worth of damage. In 1859 there was a far bigger solar storm. Back then, the only hi-tech communications system was the telegraph. Operators got electric shocks off their equipment, which, in some cases, caught fire.
If we had another event like that today, the consequences would be enormous. We are now tied together by complex communication, power and transportation infrastructure in a way that affects almost all aspects of our lives. Solar activity can black out radio communications and disable communication satellites. Solar-induced currents can cause failures in electrical power systems and enhanced corrosion in pipelines. Enhanced high-altitude radiation due to solar activity can be a hazard to air travel on polar routes. Navigation systems can be disrupted, and on the ground, railway signalling systems may be affected.
Imagine losing the Internet for a week, or, having put all your data in the cloud, finding you cannot connect to it. Until recently we had no information as to how big a solar storm could be other than the 1859 event. Now we know the sun can do far “better” than that.
Although our medieval ancestors would not have noticed solar activity and solar storms much, apart from occasional displays of aurorae, those storms left some environmental signatures. Solar activity changes the intensity of high-energy particles hitting the upper atmosphere. When these particles hit atoms of oxygen or nitrogen, they create new elements, some of them radioactive. These new elements get carried down in rain and snow to the Earth’s surface. In most places, they just diffuse off into the soil.
However, when these atoms fall on permanent ice caps, they end up being trapped in a layer of surface ice. Then, the following year another layer forms on top, and so on, so that the icecap contains a historical record of solar activity. Scientists have extracted ice cores yielding solar activity records dating back to remote historical times.
When we look at these ice cores, we can see the annual layering quite easily, so we can scan along the core looking for particular elements, counting the layers as we go. Doing this we can track solar activity back in time thousands of years. It has been found that although our hi-tech free ancestors never noticed, there have been solar storms far larger than anything of which we had prior knowledge. One hit the Earth in 660 BCE. Others occurred in 775 and 994 CE.
Our vulnerability to bad solar behaviour is now at an all-time high, so the big question is when will the next supersized solar storm happen? Can it be predicted? How much warning will we get?
In Canada, we are monitoring the sun every day and have an extensive set of instruments monitoring the Earth’s ionosphere and magnetic field. We are trying to get a better understanding of the connection between what the sun gets up to and what the consequences would be here on Earth. Working with international partners, our aim is to minimize what the sun can do to our modern, technology-dependent way of life.
This involves predictions of dangerous solar activity, assessment of its potential impacts, and developing means to mitigate them, and where there is damage, making the recovery as rapid as possible. We will solve these problems because we have to.
Mars lies in the southwest after dark. Jupiter rises around 2 a.m., Saturn at 3 a.m. and Venus lies low in the dawn glow. The moon will new on April 5.
Ken Tapping is an astronomer with the National Research Council’s Dominion Radio Astrophysical Observatory near Penticton. E-mail: ken.tapping@nrc-cnrc.gc.ca
