Dragons may be make-believe, but a dragon-shaped aurora borealis that flickered in the sky over Iceland this month was breathtakingly real — just have a look at this dramatic photograph.
The photo, taken by Jingyi Zhang on Feb. 6, became NASA's astronomy photo of the day on Feb. 18 and has been widely viewed online since. It shows a swirling green aurora over a dark, snowy landscape where a solitary figure — the photographer's mother — stares up at the sky as if awestruck.
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Zhang said in an email that she didn't see the dragon shape initially — only later, when she examined the photos she had taken that night. "The aurora that night was chaotic," she said.
An aurora borealis forms when fast-moving charged particles from the sun strike Earth's magnetic field, colliding with oxygen and nitrogen atoms and molecules in Earth's upper atmosphere, exciting them and causing them to release particles of light known as photons.
Because these collisions are focused by Earth's magnetic field at the North and South poles, they're most commonly seen in high northern and southern latitudes. In the Northern Hemisphere, they're known as aurora borealis or the northern lights; in the Southern Hemisphere, they're called aurora australis or the southern lights.
Auroras tend to be green, like the dragon-shaped one, but they can also be shades of red, blue, violet, pink and white. They're too faint to be seen in daylight. At night, some are quite dim but others are bright enough to read by.
And while auroras can be beautiful, the so-called solar storms that trigger them can disrupt radio transmissions on Earth and satellite operations in space. "So the solar storms can benefit the auroras ... but hurt some kinds of long-distance communications," Jay Pasachoff, an astronomer at Williams College in Williamstown, Massachusetts, said in an email.
Auroras have also been observed on other planets, including Jupiter and Saturn.