Aurora and Milky Way
Centered
on the apex of the sky above Lake Storsjön in Jämtland, Sweden,
this "little
planet",
or little sky photo, captures the milky way during the northern
hemisphere's autumn equinox. The bright green and yellow bursts of
light that can be seen in the upper left hand corner of this photo is
an aurora, which increase in frequency the closer to the equinox they
get. Auroras are caused by solar activity; where gusts of solar
wind,
often called solar flares or CMEs, hit the Earth’s magnetic field,
messing up the planet's protective magnetic shell. This then causes
charged particles to rain down over the south and north poles, which
are where the doughnut-shaped regions called “auroral ovals"
are located,
lighting
up the atmosphere where they hit. This is why auroras are only seen
at high altitudes, except for certain times of the year when solar
activity is high and the ovals expand.
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