You can define twilight simply as the time of day between daylight and darkness, whether that’s after sunset, or before sunrise. Astronomers, surely the experts on nighttime, recognize three kinds of twilight, which are explained in this post.
Among wild animals, pronking may be a way of avoiding predators. But when you see an animal pronk, you can’t but think it’s leaping for joy. More videos inside.
Do you – and your dog – have astraphobia?
We’ve all seen virga, but maybe not known what it’s called. Virga is rain that evaporates before it hits the ground. It often appears in streaks or shafts extending from the bottoms of clouds. You often see virga over a desert, where low humidity and high temperatures can cause rain to evaporate shortly after being released by clouds. Or you might see virga at high altitudes; in fact, the precipitation often starts out in the form of ice crystals. Virga is commonly seen in the U.S. West and above the Canadian Prairies, in the Middle East, Australia and North Africa. At some northerly latitudes, too – as in the photos from Sweden on this page – virga sometimes paints the sky above.
July 8, 2013. On today’s date a year ago, a new record was set for the youngest moon ever photographed. Thierry Legault – shooting from in Elancourt, France (a suburb of Paris) – captured the July 2013 moon at the precise instant it was new, or most nearly between the Earth and sun for that lunar orbit. Legault’s image shows the thinnest of lunar crescents, in full daylight (naturally, since a new moon is always near the sun in the sky), at 0714 UTC on July 8, 2013.
This isn’t the Arctic. It isn’t Greenland. It’s Pakistan. At 63 kilometers (39 miles) in length, Baltoro Glacier in Pakistan is one of the longest glaciers outside the polar regions.
Happy Independence Day! If you’re celebrating the 4th of July by attending a fireworks display, maybe you’ll look up and wonder: What creates those red, orange, yellow, green, blue and purple colors exploding in the night sky?
Happy birthday to all you July babies! Your birthstone, the ruby, is among the most highly prized of gemstones. Large rubies are harder to find than large diamonds, emeralds and sapphires. As a result, rubies’ value increases with size more than any other gemstone.
Asteroids tend to be rockier or more metallic. Comets tend be icier. But some objects blur the distinction between asteroids and comets.
It is indeed possible to see the whole circle of a rainbow – but conditions have to be just right.