Autumn and the Active Sun
Credit:
Courtesy
TRACE Team,
NASA
As the Sun heads South, crossing the celestial equator today
at 1:37 a.m. Eastern Time,
Autumn begins for Earth's Northern Hemisphere.
This Autumnal Equinox
finds an increasingly active Sun steadily
approaching a solar cycle maximum expected
around the year 2003.
The solar activity cycle is driven by a periodic winding up of
the Sun's internal magnetic field.
This colorized picture is a mosaic of
recent ultraviolet images from the orbiting
TRACE satellite
sensitive to light emitted by
highly charged iron atoms.
Growing in
number,
the intricate structures visible are
the Sun's hot active regions
with temperatures over
a million
degrees Fahrenheit
and their associated magnetic loops.