Solar Radiation - the Good, the Bad, and the Beautiful

As spring arrives in the northern hemisphere, people look forward to more sun; longer daylight hours, plant growth, and the chance of getting a tan.  This year, however, the media has been casting the sun in a whole different light.  The affects of powerful solar events during the last few months have caused some to wonder if the sun has a dark side.

NASA

The cycles of the earth are very familiar to us – seasons, calendars, tides.  The sun also has a cyclical nature, but many of these events still stump scientists.  The sun undergoes a solar cycle (or solar magnetic activity cycle) every 11 years.  This cycle is evidenced by the number of sunspots (small dark areas on the surface of the sun) that appear near the equator of the sun.  Sunspots are an indication of solar activity – scientists believe that they are caused by the electromagnetic fields knotting up as they move around the sun.  Since the solar maximum is predicted for next year, solar activity is nearly at its peak.

The solar cycle also causes changes closer to home.  Frequent solar flares and coronal mass ejections (CMEs) unleash huge waves of solar radiation during the peak of the cycle.  In fact, just last month a huge solar flare bombarded the earth with charged particles.  This event measured in as the largest solar radiation storm since 2003.  The effects of this storm and others like it have been widespread and occasionally serious – they can cause spacecraft electronics to malfunction, disrupt power grids, and even cause increased corrosion on fuel pipelines.

The good news about solar radiation storms is they cause very little increase in background radiation levels.  The earth’s atmosphere does a good job of blocking solar radiation, even in increased amounts.  Unless you are doing a good deal of flying (at higher altitudes the atmosphere is less effective at blocking radiation) or are visiting regions near the Antarctic, you won’t have any measureable exposure over the normal amount.  If you’d like more information on the threats solar storms can cause, check out this paper by James Marusek.

National Geographic

Even if they can cause damage, solar radiation storms have a silver lining – these events create some of the most striking auroras ever seen.  The Northern Lights (as well as those in the southern hemisphere) are caused charged particles colliding with the upper atmosphere.  For some great National Geographic images of auroras caused by a solar storm, visit this link.

As the sun strengthens this spring, remember that the news you hear about solar events may not all be bad after all.

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