Weather Stories

Northern lights possible again tonight; how and why they happen

INDIANAPOLIS (WISH) — For the second night in a row, the aurora borealis, perhaps better known as the northern lights, is expected to create streams of colors dancing across the sky as far south as Indiana.

Best viewing time is after 10 p.m. Thursday.

The beautiful site is caused by a cosmic collision of solar particles and the Earth’s magnetic field.

Astronaut Bob Hines took these photos from a time lapse aboard the International Space Station.

Courtesy Bob Hines – astronaut on the International Space Station
Courtesy Bob Hines – astronaut on the International Space Station

A coronal mass ejection, or CME, was detected earlier this week. A CME is a large expulsion of plasma from the sun. The expulsions can take anywhere from 15-18 hours or up to several days to reach Earth. The most recent one happened early Wednesday.

When the solar flare reaches Earth, the Earth’s magnetic field redirects the particles to the poles. The particles then interact with gases within our atmosphere creating different colors. The most common color created is green from oxygen.

The northern lights are hard to predict and may be around for a short period of time or last for hours at a time. It doesn’t look like this geomagnetic storm will be strong enough to cause any major problems or disruptions to satellites or GPS.