A stunning time-lapse video captured from the International Space Station (ISS) shows the orbiting laboratory flying through a massive aurora, a rare sight made possible by a recent solar mass ejection. The footage was taken by European Space Agency astronaut Alexander Gerst and his Expedition 40 crewmates last week.
The video reveals the ISS orbiting Earth as green lights gradually come into view, eventually enveloping the station. Gerst commented: 'We flew right through a massive aurora after last week's solar mass ejection.' Auroras are typically seen near the poles, but increased solar activity can push them closer to the equator, allowing the ISS—which usually orbits near the equator—to pass through one.
Auroras are caused by electrically charged particles from the sun colliding with gas particles in Earth's atmosphere, emitting light. The most common greenish-yellow colour results from oxygen molecules about 60 miles (96km) above Earth, while rare red auroras are produced by oxygen higher up, at around 200 miles (320km).
The ISS completes an orbit every 92 minutes, but flying through an aurora is uncommon due to its typical equatorial path. This event followed a geomagnetic storm, which increased the solar wind hitting Earth, making the lights visible further south than usual.
