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A crewmember aboard the International Space Station caught this view of the aurora australis (the Southern Lights) during a geomagnetic storm last month.

Aurora from orbit

The Southern Lights from orbit

Auroras happen when electrically charged particles from the Sun smack into Earth’s atmosphere and ionize the oxygen and nitrogen there. Since the high speed particles follow the Earth’s magnetic field, they primarily end up over the magnetic poles. B ut, when the Sun is especially active (or when it burps out a solar flare, as it did on May 24), the auroral displays can be seen at lower latitudes.

Ionized gases emit light of particular frequencies — colors. Neon, for example, glows a bright red color. Oxygen in the atmosphere typically emits green light, as we can see in the photo.