The largest sunspot group ever recorded reached its maximum
on 8th April 1947. It covered an area of 18,130 million square
kilometres.
Sunspots are a feature of solar activity. The numbers visible on
the Sun at any time increase and decrease over a period of
approximately 11 years. Mid-1947 marked a strong maximum of
activity in the 11-year solar cycle. Sunspots form where the Sun's
magnetic field is particularly strong in the vertical direction. The
magnetic field inhibits the convection currents in the gas that
bring up hotter material from below. As a result, the sunspot is
at a lower temperature than its surroundings and glows less
brilliantly. Sunspots tend to form as nearby pairs in which the
two spots have opposite magnetic polarity. At times of high solar
activity it is not unusual for individual spots to become very
large and for spots to form in more extensive groups.
|
(1998).ISO/media/record_breakers/graphics/larsspgr.jpg)