SOUTHERN LIGHTS: When an interplanetary shock wave hit Earth’s magnetic field on April 19th, northern skies lit up with electric blue auroras. Southern skies lit up, too, but the palette was different. Peter Sayers sends this photo of red, yellow and green lights over Wilmot, Tasmania:
“Overlooking Wilmot and the iconic Mt Roland, we saw bright naked eye auroras lasting an hour or two,” says Sayers. “They were stunning. I used Lightroom to clean up some noise, but the color saturation in this image was not altered from the camera.”
What’s the difference? Northern Lights stimulated by the shock wave were dominated by ionized nitrogen molecules, which produce a blue glow at the upper limits of Earth’s atmosphere. Southern Lights, on the other hand, were dominated by oxygen. Oxygen atoms glow red and green when excited by incoming particles from space. Oxygen and nitrogen are abundant in both hemispheres–so why they dominated in different places is anyone’s guess. Consider it a beautiful mystery.