The Sun's impact on our solar system is important

In February 2022, a burst of high solar activity caused the loss of a set of Starlink satellites that were in the process of deployment.

The solar activity heated the upper atmosphere, causing it to expand outwards. The satellites found themselves having to push their way through a far denser atmosphere than was expected. The drag brought them down, leading to them burning up in the upper atmosphere.

The loss was an example of how our increasingly interconnected world is leading to our living in a more vulnerable one. Unavoidably, our normal way of life is becoming more and more dependent on having high connectivity with others.

Our vulnerability comes mainly from three things. First, we depend a lot on complex systems in potentially hazardous places, like communication and broadcasting satellites. These are vulnerable to damage by high-energy radiation from the Sun, and if in low orbits, vulnerable to increased drag in a solar-heated upper atmosphere.

Second, because air transportation is more efficient when the planes operate at high altitudes, they do not enjoy the protection from solar high-energy radiation we enjoy on the ground. The hazard is far higher in the polar regions, where the Earth's magnetic field traps incoming high-energy particles and funnels them down around the magnetic poles.

The third vulnerability is due to our dependence on metal structures on the ground that can be hundreds or even thousands of kilometres long, such as power lines, railway lines, pipelines, communication wires and cables. These are vulnerable to magnetic storms, periods where the Earth's magnetic field fluctuates wildly in response to being hit by a cloud of hot, ionized and magnetized material ejected by the Sun at up to thousands of kilometres a second, a coronal mass ejection or CME.

When a long wire or piece of metal finds itself in a varying magnetic field, electric currents are set up. These can fry transformers and other components, causing power outages. They can damage electronics by pushing higher voltages and currents into them than they were designed to handle. They can cause more rapid corrosion in pipelines and mess with railway signalling systems.

This knowledge of our vulnerability to the Sun's bad behaviour is not new. In 1859 there was a huge solar flare. The resulting CME caused a huge magnetic storm, bigger than anything we have experienced since. At the time the cutting edge technology was the telegraph, connecting the world by wires running long distances over land and sea. The electric currents induced in the wires by the magnetic storm were so high the equipment was catching fire and the operators were getting electric shocks as they tried to work.

In 1989 a smaller event caused large-scale power outages in Quebec and elsewhere, and an assortment of communication system disruptions.

Dealing with these threats requires monitoring and understanding solar activity, Canada has been telling the world the daily levels of solar activity since 1947. The programme is based at our observatory. Other countries have solar monitoring programmes too, and there are several satellites continuously watching the Sun.

One big problem is we can see CME's leaving the Sun. Then they become invisible. Since we have only a rough idea as to how fast they are moving we don't know their arrival time until they pass the monitoring satellites, about fifteen minutes before impact. It is not long, but does give us some time to prepare.

However, in the longer term, we will have to make our systems as immune as possible to solar damage or disruption, or at least make them suffer the minimum damage and to quickly recover. This is the focus of a serious international effort.

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Mercury, the closest planet to the Sun lies low in the sunset glow. Venus, planet two, shines brightly above it, and Mars, planet four, is high in the south. The Moon will reach its last quarter on the 13.

Ken Tapping is an astronomer with the National Research Council's Dominion Radio Astrophysical Observatory, near Penticton.

This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.