The sun is becoming more active as we head towards its peak in 2013. The boys and girls on the International Space Station are taking this opportunity to fly through the auroras and the geomagnetic storms. Here is as astronaut Don Pettit describes his filming and observing the auroras from the ISS.
Lately, the International Space Station has been flying through geomagnetic storms, giving astronauts an close-up view of the aurora borealis just outside their windows:
Auroras are caused by solar activity. Gusts of solar wind and coronal mass ejections strike Earth's magnetic field, rattling our planet's protective shell of magnetism. This causes charged particles to rain down over the poles, lighting up the atmosphere where they hit. The physics is akin to what happens in the picture tube of a color TV.
Incoming particles are guided by Earth's magnetic field to a pair of doughnut-shaped regions called "auroral ovals." There's one around the North Pole and one around the South. Sometimes, when solar activity is high, the ovals expand, and the space station orbits right through them.
Pettit is a skilled astrophotographer. He and other members of the crew video-recorded the displays, producing footage that officials say is some of the best-ever taken from Earth orbit.
Aurora colors can be red, green, and many shades of purple. These hues correspond to different quantum transitions in excited atoms of oxygen and nitrogen. The precise color at any altitude depends on the temperature and density of the local atmosphere.
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