Lisa Varano, staff writer
June 13, 2010 — This is the time of year to spot mysterious, wispy clouds that glow white or electric blue. Click on the video to find out how.
When the sky is dark enough to see the stars, you may notice wispy clouds glowing white or electric blue.
These “elusive and mysterious” clouds are appearing in the northern hemisphere until August.
They're called “noctilucent clouds” - and that means “night-glowing.”
Astronomer Andrew Yee says that these clouds are higher than the ones we typically see. He says noctilucent clouds are 76 to 85 kms above earth's surface.
So how do you spot the mysterious clouds?
Look in the direction of the sunset, about half an hour after the sun has gone down. “You'll see these criss-crossing clouds hanging low above the horizon,” Yee says.
Noctilucent clouds are typically formed over Canada's polar region,but they have been seen as far south as Colorado. And that raises an interesting question.
“Atmospheric scientists are wondering if this in an indication that there's a long-term change in the conditions of the upper atmosphere,“ Yee says.
Photo courtesy NASA.