21 April, 2018 by Nicholas O'Flaherty
The aurora australis displays are intensifying in Antarctica. In this view from Scott Base, a blue band appears above purple; both these colors are caused by electrically charged particles from the Sun colliding with nitrogen molecules, 300km above Earth.
The more common lower green band is caused by collisions with oxygen molecules at lower altitudes, approx 100km up. At lower left in the photo, the lights from Scott Base illuminate the sea ice.