Countless media outlets have been reporting that the Sun is gearing up for a massive solar storm that would disrupt communications, electronic devises and possibly power grids all over the world. What is the truth about the Sun’s future and is there anything that we can do to prepare for it?
Could the Sun Erupt in a Major Solar Storm in the Next Five Years?
The short answer to this question is ‘yes’. The Sun has left its solar minimum -- a period of inactivity -- and is gearing up for solar maximum -- its time of highest activity. During solar minimum the Sun lacks many of the features that make for good science fiction novels, things like sun spots, solar flares and prominences.
Conversely, during solar maximum these sorts of events occur in excess. Now, it is not only the frequency of these events that need to be worried about, but rather also the intensity of such events. And NASA believes that this particular solar maximum could be more intense than those of recent history. (More on that below.)
The fact of the matter is that this is all part of the natural cycle of the Sun. The solar cycle is a (roughly) eleven year cycle where the Sun alternates between periods of activity and inactivity. So, while a solar maximum is being predicted for 2013, it wasn’t that long ago that we experienced solar maximum and saw no adverse effects. But there cold be reason to suspect that this solar maximum could be different.
Why Does This Happen?
The Sun’s solar cycle is actually a complex beast. The simple explanation is that the Sun’s internal magnetic field gets twisted as the Sun rotates. As it becomes entangled, magnetic field lines will pierce the surface, prohibiting hot gas to rise to the surface. This creates points that are relatively cool compared to the rest of the surface (roughly 4500 kelvin, compared to the Sun’s normal surface temperature of about 6000 kelvin).
These cool points appear nearly black, surrounded by the yellow glow of the Sun, and are commonly called sun spots. Then as charged particles and heated gas stream from the sun spots they create the brilliant arcs of light known as prominences.
Of course the phenomenon that carries with it the most potential for destruction is the solar flare and the closely related coronal mass ejection. These incredibly powerful events result from these twisted magnetic field lines reconnect with other magnetic field lines in the atmosphere of the Sun.
During large flares, the reconnection can generate such energy that particles are accelerated to a nigh percentage of the speed of light. Causing an incredibly high flux of particles to stream toward the Earth from the Sun’s corona (upper atmosphere), where temperatures can reach into the millions of degrees. The resulting coronal mass ejection is the type of even that currently worries NASA scientists.
To get a sense of scale for how powerful these events are, the most powerful nuclear weapon ever detonated had a yield of about 58 megatons. The blast from this weapon vaporized the entire island on which it was detonated. In contrast, one of these solar events has the potential to release more energy than 300 million of those 58 megaton bombs at once.
What Makes This Solar Storm Different?
If the Sun reaches solar maximum every 11 years, shouldn’t we be used to such events by now? What makes this solar storm so different?
The reason has to do with trends. Specifically, the Sun has been at an incredibly high state of activity for the better half of the last century. But then, suddenly, during this last minimum it became very "quiet". And not only was the minimum more noticeable this time, but it was extended as well. In fact this cycle will likely be slightly longer than the normal 11 year period.
It is this "building up" that has scientists worried. The twisting of the Sun’s internal magnetic field is underway. As the energy builds within the Sun it will likely peak very quickly, releasing more energy at once than during a normal solar maximum.
This is probably as good a place as any to note that all of this is speculation. We have not been able to observe such events with the precision we now have today. This solar maximum could be no more energetic than previous solar maxima. In fact, looking at the geological record reveals that such flares happen about every 500 years (though the interval period can vary wildly). But we have to go with what the science is telling us, even if the results rely on incomplete data. So, all we can really say is that such a storm is "likely".
But while it may turn out that the solar output is no more harmful than during recent solar maxima, history has shown that such events have occurred. Therefore we would be justified in preparing for such a storm. Even if one does not come this decade, we are bound to see one eventually.
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