Have you ever seen a complete auroral oval? You can't see one from the ground because it makes too
large a circle around one of
Earth's magnetic poles. But spacecraft high above
the Earth can see them. The
featured video from
ESA and
CAS's robotic
SMILE spacecraft shows not only a
full auroral oval, but using
ultraviolet light, one that occurred during the day. The time-lapse covers about an hour in late July and shows visually how
variable and turbulent
auroras really are. The points of light on the sides are
distant stars that appear to move only because
SMILE's camera view shifts as the spacecraft
orbits the Earth. A goal of SMILE is to
better understand how the Sun's wind interacts with the
Earth's magnetosphere -- and so better understand how to protect astronauts, spacecraft, and ground-based
electrical grids from
solar storms.