Aurora Crown the Earth
			
		
		
		
			What do aurora look like from space?  The 
POLAR 
spacecraft answered this by
photographing an auroral oval surrounding the north pole of the Earth,
causing displays on both the night and day side.  The auroral sub-storm,
pictured in false-color above, developed within 15 minutes and may have
lasted as long as on hour.  
Aurora are caused by charged particles
streaming away from the 
Sun and towards the 
Earth.  As the particles fall
to Earth, they spiral along magnetic field lines and cause
colorful radiation. The 
UVI experiment 
onboard the POLAR spacecraft is
equipped with special filters that allow it to see 
aurora in a band of
ultraviolet light 
where sunlight is relatively dim.   The more red the
emission depicted in the above photo, the more intense the radiation.
Earth's continents have been drawn in for clarity