Stargazers and lucky insomniacs were treated to a spectacular show of northern lights in Minnesota over the weekend.
The awe-inducing display was captured in a time-lapse video by storm chasers near St. Cloud, Minn. The footage, taken just after moonset and before sunrise, shows yellow-green lights dancing against central Minnesota's brilliant purple sky.
Astronomers say a powerful geomagnetic storm that occurred between 3 a.m. and 4 a.m. caused the stunning northern lights show.
The aurora borealis, commonly known as the northern lights, is a natural light display caused by the collision of gaseous particles in the Earth's atmosphere with electrically-charged particles released by the sun's atmosphere:
Variations in color are due to the type of gas particles that are colliding. The most common auroral color, a pale yellowish-green, is produced by oxygen molecules located about 60 miles above the earth. Rare, all-red auroras are produced by high-altitude oxygen, at heights of up to 200 miles. Nitrogen produces blue or purplish-red aurora.
Northern lights are visible year-round but are generally most vivid around the spring and fall equinoxes.
- Nature & Environment