A Solar Connection to the Aurora of November 7, 2004

Thursday, November 11 2004 @ 03:00 pm EST

Contributed by: bobmoody

The colorful aurora of Sunday, November 7, 2004, was widely seen in the Ft Smith/Van Buren area. Here are some current pictures of our Sun and the sunspot group responsible for this latest dance of "Fire in the Sky".

The colorful red and green aurora that lit up the skies over northwestern Arkansas last Sunday evening was caused by a huge blast of energized particles originating from the Sun a few days before. These high energy particles are produced by our Sun and exhaled in a sort of cosmic hiccup that sends the particles screaming away from the Sun in whatever direction the area that produced those particles happened to be facing when the exhalation occurred. This time, the area on the Sun which produced this aurora was pointed directly at Earth.

Aurorae are not uncommon. Energized particles from the Sun are streaming away from the solar surface all the time. The Earth's magnet field that protects us from harmful cosmic radiation, also acts to funnel the normal flow of solar material from our Sun and concentrate it into our atmosphere near the north and south polar regions. Hence the more widely known terms "Aurora Borealis", or Northern Lights, and "Aurora Australis", or Southern Lights. Thousands of people flock to areas of the world at high northerly or southerly latitudes on cruise ships or by air travel to places like Anchorage, Alaska, specifically to see these awesomely beautiful curtains of colorful light in the sky.

What was unusual about the local aurora last Sunday was the fact that we were able to see it from NW Arkansas. Where aurorae are common and easily seen virtually any given clear evening from the far southern or northern climes, we in middle America rarely get the opportunity to see these events. It does happen occasionally, however, and when the conditions are just right, we get our chance to see one here.

Aurorae are seen at our latitude of 35 degrees north generally 2 to 3 years after a sunspot maximum has occurred. The latest sunspot maximum occurred in 2001-2002 and so it may be possible to see another aurora from our location within the next year or so. Our area was also privy to another aurora just last year and again earlier this past winter. Arkansas astrophotographer, Mike Holloway from Van Buren, caught this earlier aurora on film as well as the event last Sunday. Here are some of Mike's pictures from the two dates.

In checking the current images of the Sun from the last few days, it is easy to see a sunspot group just past the center of the solar disk. Any sunspots seen from the web site these pictures originated from will be slowly moving from left to right across the sun over several days time.

The Sun makes one revolution in 26 days. That sunspot group is the area from where the material was ejected that caused the aurora we saw this week. It takes 2 to 3 days for the material ejected from the Sun to reach us at 93 million miles away, and if the images of the Sun are checked for November 4th or 5th, the sunspot group shown would have been centered on the solar disk. Anyone can check out what the Sun looks like every day by going to: http://sohowww.nascom.nasa.gov/. This is NASA's and ESA's site for the SOlar and Heliospheric Observatory, or SOHO for short.

A new article about the aurora has been posted by Astronomy magazine’s associate editor, Michael Bakich. The following link will take you directly to that article and near the bottom of the page you’ll even see a video of the aurora: http://www.astronomy.com/asy/default.aspx?c=a&id=2591

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