The Northern Lights and technology's vulnerability to space weather

Skies across the UK have been lit up this week by the spectacular Aurora Borealis (Northern Lights). The Lights are a beautiful sight, and photos of them have appeared throughout the media – there was even a live ‘Can you spot the Northern Lights across the UK?’ page on the BBC website running until 2am. As majestic as they are, they also serve as a reminder of the considerable impact that our Sun can play on modern technological systems.

Sitting at the centre of the Solar System is the Sun, a giant ball of ionized plasma - a state of matter made up of positively and negatively charged particles. Some of this plasma is constantly streaming out into space, which we call the solar wind.

Thankfully the Earth has a Star Trek-esque shield, the magnetosphere, protecting our atmosphere from being blown away. However some of the high-energy electrons in the solar wind make it through the shield and can hit molecules in our atmosphere. During these collisions some of the electrons energy is transferred to the molecules and, if the conditions are just right, cause them to vibrate and emit a tiny amount of light. The colour of this light depends on the amount of energy involved and the altitude of the interaction. Enough vibrating molecules, enough emitted light and voilà, we get the aurorae (Borealis or Australis), which typically form in the high latitudes above 65 degrees north or south, but this can vary significantly.

‘Space Weather’ is a term which describes variations in the near-Earth space environment and the influence that has on technology and human life and health. Just like terrestrial weather, space weather is impacted by storms. Minor storms, like we have experienced this week, are relatively common, a major storm may occur once or twice per decade and solar ‘superstorms’ occur once every 100 to 200 years. During these storms the aurora can be seen at lower latitudes which is why they have been visible over the UK recently. In the most severe storms, famously during the “Carrington Event” in 1859, the aurora were observed in the Caribbean and Hawaiian Islands! But the aurora are not the only consequence of space weather.

Aside from pictures of the aurora, space weather does not feature in the everyday news and goes largely unrecognised by the public. However, space weather must be accommodated in the design and operation of an increasing number of modern technological systems. For example, high energy particles associated with space weather can cause satellite failures and can render satellite-based navigation systems, such as GPS - a now ubiquitous technology - useless for several days. Other impacts are experienced on the electricity grid, satellite and cellular communications systems, avionics and the radiation doses experienced by air passengers and crew. Even communications with aeroplanes are impacted, and can be completely disrupted, forcing airlines to change their routes and rely on backup systems. Looking to the future, space weather will be a major hazard on any crewed mission to Mars.

The impact of space weather on all these systems will be much more significant during a solar superstorm with serious consequences for the national infrastructure, UK industry and the wider public. As a result, in 2011 space weather was added to the Government National Risk Register of Civil Emergencies, with its likelihood currently judged as comparable to that of an emerging infectious disease. Only by providing sufficient advance warning and having robust plans in place for reacting to an extreme event, can we be confident of minimising the consequences.

The Space Environment and Radio Engineering (SERENE) research group at the University of Birmingham investigate innovative mathematical methods, and develop novel small scale, and non-linear physics, to create the next generation of space weather forecast models. These models can be used to provide accurate, and actionable, forecasts to improve airline route planning to avoid communications losses, predict outages of GPS, warn satellite operators of potential collisions, and even tell you when and where you are most likely going to be able to take your own photo of the aurora.