Behold: a spectacular view from the International Space Station of an aurora generously slathered like salsa verde onto the Earth’s thermosphere just before midsummer 2017. To wit:
About 400 kilometres (250 miles) above Earth, the orbiting station is itself within the upper realm of the auroral displays. Aurorae have the signature colours of excited molecules and atoms at the low densities found at extreme altitudes. Emission from atomic oxygen dominates this view. The tantalizing glow is green at lower altitudes, but rarer reddish bands extend above the space station’s horizon. The orbital scene was captured while passing over a point south and east of Australia, with stars above the horizon at the right belonging to the constellation Canis Major, Orion’s big dog. Sirius, alpha star of Canis Major, is the brightest star near the Earth’s limb.