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

Thursday, October 24, 2013

C'mon, Get Happy!

And if you're not humming a Partridge Family song right're younger than I am.

Fall has finally arrived, and I am indeed happy.  I know the official start of Fall was over a month ago, but the weather hasn't really caught up with the fact here until today.  It is brisk and sunny outside, and now the season for good observing can truly get underway.

Apparently the Sun is happy about it as well, since it seems to have decided to put on a show celebrating the change of weather patterns.  Check it out:

The Sun on October 24, 2013.  Courtesy
Every 11 years, the Sun enters a period of maximum activity.  2013 is supposed to be a Solar Max year, but things on the Sun haven't exactly been popping.  In fact, this is one of the weaker solar maximums we've seen in recent history.  But some scientists are forecasting a tick up in activity as we approach the new year, and they may be right.  Those lovely dark areas you see on the face of the Sun are sunspots, and the more spots there are, the more active the solar surface is.  Sunspots are caused when the magnetic field of the Sun breaks through the surface and allows heat to be funneled away, cooling a small region of the surface.  "Cooling" is relative, by the way - the surface of a sunspot is still a toasty 7,000-8,000 degrees Fahrenheit.  But that is substantially cooler than the average 10,000 degrees of the bright solar surface! Oh, and when I say a "small region" of the surface...keep in mind, all those spots you can see on the Sun are bigger than the Earth in diameter.

Here we're seeing the Sun in white light, or the kind of light we normally see.  If we look in a different wavelength...say, ultraviolet...the sunspot regions show amazing amounts of activity.

Bright sunspot region AR1877 snaps off a solar flare.  Photo by the Solar Dynamics Observatory.  Courtesy
The inset image is a single frame from a movie taken by SDO of a solar flare that exploded out from one of the sunspot regions.  The Sun is an incredibly active body, and it is quite amazing to observe.  To safeguard your eyesight, however, always take proper precautions before viewing the Sun:

To safely view the Sun, use:
  • an ENDCAP solar filter on a telescope
  • Arc welder's glass #14
  • Solar Eclipse glasses
NEVER use the following:
  • Eyepiece solar filters (they can overheat and break)
  • Shades of arc welder's glass other than #14 (not enough protection!)
  • Regular or prescription sunglasses (even if they block UV, that is not enough protection!)
  • Exposed film
  • Viewing the Sun low to the horizon when it appears red (this is NEVER safe!)
As long as your eyes are properly protected, viewing the Sun can be a fabulous experience.  Depending on what kind of filter you use, you may be able to see sunspots, prominences, flares or other types of activity on the Sun's surface.  And these things may change or move right before your very eyes!  Our Sun is an active, exciting star, and it's worth taking a look at.

And right now, the Sun is giving us a whole lotta lovin'.  Enjoy!
Until next time...
Carpe Diem!  :D (and Noctem too!)

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