When humans were less dependent on technology, it didn’t really matter that the sun was spitting out lumps of plasma four times the size of Mount Everest. But nowadays, with satellites, cellphones and planes, and pylons marching across the land, the behaviour of the sun is inextricably tied up with our way of life as our electronics respond to its eccentricity.
Last week, Elon Musk announced that his SpaceX company had successfully launched a $350-million space weather satellite to monitor what is happening outside our atmosphere.
If the sun coughs, it is felt throughout the solar system. This is not entirely surprising since the giant ongoing nuclear explosion, whose heat allows for life on Earth, accounts for about 99.86% of our solar system. While meteorology refers to the behaviour of weather on Earth, space weather is the measurement, analysis, interpretation and modelling of the environment between the sun and the Earth.
In the sleepy whale-watching town of Hermanus in the Western Cape, two people sit in a glass-and-wood-panelled room at the entrance to the South African National Space Agency’s (Sansa) space science directorate in Hermanus.
This is the heart of Africa’s regional space weather warning centre, part of Sansa’s space science directorate, which is located in a white building surrounded by green lawns and the salty tang of sea air. The warning centre operates as part of the International Space Environment Service.
Large television screens cover one wall, each showing a different-coloured mottled circle. These red, green and blue circles are images of the sun at different frequencies.
‘One big nuclear explosion’
Kobus Olckers, a former space weather officer at the centre (when it was the Hermanus Magnetic Observatory, before it became part of Sansa in 2010), once told me that in the past, “we used to think the sun was something static that just gave off rays but it is, in fact, “one big nuclear explosion that happens all the time – like a million fusion bombs going off constantly’.
A gigantic molten nuclear reaction with its own magnetic field is not static: from solar winds – filled with atoms, electrons, photons and radiation of every frequency – to big lumps of plasma, which are like huge magnets, the behaviour of the sun wreaks havoc with the Earth’s own finely tuned system, not to mention our technology and satellites.
Satellites are outside our protective atmosphere and often catch the brunt of belligerent solar behaviour. The official reason for the death in 2011 of South Africa’s SumbandilaSat, a micro Earth observation satellite, was it got caught in a solar storm. The particles in these solar winds travel through space in their billions at nearly the speed of light and can slice into satellites like a knife through cheese.
This may be an inconvenience for you and me at home – a snowy picture on the satellite-fed television or perhaps a greater danger if you are driving using GPS – but for the military, the aviation industry and maritime services, an unpredicted solar storm could be catastrophic.
Aside from the chaos that could ensue if a pilot thought the GPS was working, whereas they were kilometres away from where they were meant to land, many of these operators still rely on high-frequency communications, which are affected by solar storms. High-frequency communication includes short-wave radio, often a lifeline for rural communities and emergency services.
‘We made a decision in 2010 to focus on and become good at one aspect of space weather first – the prediction and impact of space weather on high-frequency communications,’ says Sansa space science managing director Dr Lee-Anne McKinnell. “In developed countries, they’re using satellites, but in Africa many people are still using that form of communication.’
High-frequency radio involves “bouncing” radio signals off the charged upper layer of the Earth’s atmosphere – known as the ionosphere – allowing people to transmit these signals to the other side of the Earth, rather than transmitting it into space for it to be relayed back.
But, because the ionosphere is charged, it responds to the whims of the magnetised emissions from the sun. Although this ionosphere protects us from most radiation and charged particles – because they cannot traverse our magnetic field – it can be distorted by magnetised emissions.
Sitting in the surprisingly snug space weather centre, it is peculiar to think that variations in a celestial body 150-million kilometres away will have a direct effect on my life.
But then Mpho Tshisaphungo, a space weather practitioner at the centre, starts telling me about the kinds of things that the sun is throwing at us. “We have three different kinds of events,’ she says.
A solar flare looks like a deformed arm rising out of the sun, with a gesture sending a wind of energy and particles at close to the speed of light. It takes about eight minutes to reach the Earth. But not all solar flares are equal – there are A-, B-, C-, M- and X-class flares, classified according to their power per square metre, with A-class flares being the weakest and X-class the strongest.
A proton storm seldom makes it to Earth because these positively charged particles are absorbed by the atmosphere before they make it to us. Satellites, however, do not have this protective shield; nor do astronauts. “This is of concern for us now that we have re-entered the satellite space, joining the countries that have satellites,’ says Pierre Cilliers, a senior researcher in the space physics division.
Spectacular solar event
The most spectacular solar event, a coronal mass ejection, is the final event on Tshisaphungo’s list: a large lump of plasma is jettisoned off the surface of the sun, taking about two to three days to reach Earth. “It causes disturbances to the Earth’s magnetic field, introducing a large influx of energy into the upper atmosphere,’ says Cilliers.
This is where the space warning centre comes in. Space weather scientist Teboho Nxele says that if they see that an event is coming “that could potentially have an effect or we know it could affect some system, we send warning to the defence force, mainly the guys using high-frequency communications’ for occurrences such as a M-class flare and upwards, or a solar wind speed of more than 600km/h.
Cilliers, who has worked in space science for more than a decade, says they are working on including commercial operators, such cellular providers, power utilities and aviation companies, in their client portfolio.
The images on the screen, and satellite images the centre receives, are courtesy of Nasa, but “for us here, we have ground-based instruments to monitor the impact the sun has on Earth’, says Tshisaphungo.
Sansa has bases all over the country, collecting data on space. Perhaps one of its most important ground stations is the one in Antarctica, supported by the departments of environmental affairs and science and technology.
McKinnell says: “The reason we do science in Antarctica [at the South African National Antarctic Expedition (Sanae) base] is because it’s the most amazing place to get info on the space environment … If there is a storm coming, we’ll see it at Sanae first. The base is vital in terms of South African science.’
Sarah Wild’s trip to Hermanus forms part of her research for a book project that will be published in 2015 by the Gordon Institute of Business Science and Pan Macmillan South Africa.