The Sun Changes
Our Sun changes every day.
This recent picture was taken in a very specific red color called
Hydrogen-Alpha.
Dark spots that might appear on the image are usually
sunspots,
dark magnetic depressions that are
slightly cooler than the rest of the Sun's surface.
Bright spots that might appear are usually
plages, active regions that are slightly hotter
than the rest of the Sun's surface.
Over the next few years the average number of
sunspots and plages will increase until "Solar Maximum"
occurs in 2001.
The Sun usually goes through a maximum and
minimum every 11 years. From
1645 to 1715, however,
almost no sunspots at all were recorded, for reasons unknown.
(An updated picture
can be found here.)