This article originally appeared in The Skeptic, Volume 22, Issue 1, from 2011.
The Sun is our constant companion; it supplies heat and light to us and keeps our small blue-green world from freezing. However, as serene as the Sun seems on a lazy summer’s day, a close look at its surface tells a very different story.
The surface of the Sun is a roiling, turbulent, ever-changing environment. Pockets of superheated gas larger than the Earth rise to the surface and sink again within a matter of hours. The colossal magnetic field of the Sun can even physically lift some of the superheated gas right off the surface, wrap it into coils and fling it off into space at hundreds, if not thousands of miles per hour. If this ejecta is flung at the Earth, things down here on the surface can get very interesting indeed. Space weather is now a full time area of study for astronomers – trying to predict when the next major solar flare will happen and what we could possibly do to mitigate its effects.
New Scientist magazine ran an article entitled Space storm alert: 90 seconds from catastrophe in their 21 March 2009 issue. It was full of dire predictions of death, disaster and the collapse of society if such an event were to occur today. But how true is this scenario? For example, if the next solar cycle, due to reach maximum in 2012, were to produce such a space storm, what would happen to our everyday lives?
A truly massive solar event would swamp out radio emissions, as the Sun increased its output of radio frequencies, followed shortly by satellites’ circuitry shorting out due to induced current because of the increase in electromagnetic radiation. The Earth’s magnetic field would warp, bend and reconfigure, causing showers of highly energetic particles to rain down into the upper atmosphere, and causing brilliant aurorae that could be seen as far south as the tropics. Induced currents along high-voltage power lines would flood transformer stations, causing the breakers and transformers to melt, creating blackouts across entire cities. Any humans in space would, if inadequately shielded, be exposed to radiation that could kill them very quickly.
Following on from this, if we couldn’t get the grid back online, there would be no power, no heating; without the ability to pump gas, water or petrol, essential services would vanish within a couple of days, hospitals would run dry of essential medicines and starvation and disease would ramp up, as food and medical supplies couldn’t be transported.
Sounds like a pretty doomsday scenario, and it is something that we should be concerned about; after all, the Sun is well known as a troublemaker. In both 1972 and 1989, telecommunications, electricity grids and other services were severely disrupted. Should we really be worried?
The worst solar storm on record, now known as the Carrington Event after the man who witnessed it, was an unprecedented eruption from the surface of the Sun. It happened without warning and it was only because Richard Carrington was studying the Sun that morning that we even knew what was to unfold was caused by the Sun. On the morning of 1st September, 1859, Carrington was observing the Sun. He was an amateur astronomer, widely regarded as one of the finest solar astronomers alive. Using the projection method of viewing the Sun, he was tracing the outlines of sunspots; in particular, a large group near the equator of the Sun. As he was doing so, he saw a brilliant white flash of light, quickly followed by another bright flash that lingered for almost five minutes.
Within 24 hours, the Earth was subjected to a geomagnetic storm the likes of which haven’t been seen since. Skies all over Earth erupted in auroras that were seen as far south as the equator. Such solar outbursts normally take between 3 to 4 days to reach Earth; this one managed the 93-million-mile journey in less than 24 hours. Even more worrying, telegraph systems worldwide went berserk. Electrical discharges sparked along the wires and caused fires. In some cases, the telegraph wires melted from the increased current.
In the 150 years since the Carrington Event, there has been nothing even close to it. It’s now possible to look back in time by examining arctic ice as energetic particles leave a nitrate record in arctic ice cores. The Carrington Event was the biggest event in 500 years and nearly twice as big as the next largest. Are we in danger? Potentially. The current solar cycle appears to be fairly quiet compared with the past few cycles, so the Sun may be entering a ‘quiet phase’. Ice cores show these events seem to have a half-millennium cycle, so we could be safe for another 350 years, but it’s always wise to be prepared.
