Written by Kelly Herbst, Astronomy Curator for the Virginia Living Museum. Updated every two weeks, more or less.

Wednesday, October 24, 2012

The Ultimate in Star-Power

Did you have trouble with the radio in your car this past Monday?  Did the GPS in your phone suddenly go on the fritz?  If so, then you've experienced the power of the Sun.

The Sun cracked off a wicked little flare which impacted us this past Monday, disrupting some radio and GPS signals.  Many people don't realize just how much the Sun impacts us.  Sure, we all know it gives us light and heat, but did you know it can cause power outages, disrupt communications, and is responsible for the auroras?  There's an entire industry devoted to predicting what the Sun is going to be's called space weather.

The area of the Sun which unleashed Monday's solar flare in several different types of light.  The bright spot on each of the pictures is where the flare originated, except on the magnetogram (there the spot appears dark).  Courtesy NASA.

The Sun is a massive ball of plasma - a highly electrically charged state of matter that has similarities to both gases and liquids.  Material comes streaming out of the Sun almost all the time.  But sometimes, the Sun gets pretty stirred up, and it can unleash an extra burst of material on out into space.  If that material happens to be headed in the direction of Earth, we may experience a variety of effects, from the merely beautiful to the highly dangerous.

The most common effect of solar activity is the Northern Lights, or the Aurora Borealis.  These shimmering colored lights are most easily seen in the extreme north (or, if you're living down under, you can see the Aurora Australis in the extreme south), and occur when charged particles from the Sun strike particles in our atmosphere and excite them.  Eventually the particles give up the extra energy they've received from the Sun and produce a variety of colored lights that seem to dance through the sky.  Auroras are amazingly beautiful, and completely harmless.

Red and green auroras over White Dome Geyser in Yellowstone National Park this month.  Picture by Robert Howell.  Courtesy Astronomy Picture of the Day.

Sometimes, when the Sun is really agitated, those particles come in towards the Earth at speeds sufficient enough to allow them to punch down into the lower atmosphere and affect high-voltage power lines.  Since the particles from the Sun are themselves charged...well...this can do very nasty things to equipment designed to send charged particles in only one direction.  We've been able to trace the causes of several wide-scale blackouts back to the impact of solar material.

The flare that disrupted radio and GPS on Monday was not all that intensive.  Scientists track what happens on the Sun so companies with satellites in orbit and power companies can be made aware of when solar material might be on the way.  We expect an uptick in solar events over the next year, as the Sun reaches the peak of its 11-year activity cycle in 2013.  Want to stay up to date on space weather happenings?  Check out for the latest on solar events.

Until next time, enjoy the sunshine...
Carpe noctem!

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