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How to see anticrepuscular rays

View larger. | Anticrepuscular rays - seen in the east at sunset - in Nevada.  Shreenivasan Manievannan posted this photo on EarthSky Facebook in July 2014.  Visit Shreeniclix Photography.

Anticrepuscular rays – seen in the east at sunset – in Nevada. Shreenivasan Manievannan posted this photo on EarthSky Facebook in July 2014.

Next time you see crepuscular rays or sunrays extending from the horizon … turn around. You might catch a glimpse of elusive anticrepuscular rays.

Can sharks smile? Do they even feel happy?

The Discovery Channel’s Shark Week is coming up (starts August 10) and sharks are on our mind ….

Attributing emotions to animals is almost irresistible to most people, and some animals do seem to show happiness, anger, fear, and other feelings. Dogs, cats, dolphins, and monkeys can be especially expressive. So … how about sharks?

Will the Andromeda galaxy someday collide with our Milky Way?

Image Credit: NASA, ESA et al.

This image represents Earth’s night sky in 3.75 billion years. The Andromeda galaxy (left) will fill our field of view then, astronomers say, as it heads toward a collision with our Milky way galaxy. Image Credit: NASA, ESA et al.

It’s a question people ask us… Will our home galaxy someday collide with the next-nearest spiral galaxy, in the direction of the constellation Andromeda? And if so, when?

Does Earth have a second moon?

Image of Earth with two moons, generated in Celestia software, by Grebenkov in Wikimedia Commons.

Many planets in our solar system have more than one moon. Mars has two moons, Jupiter has 66, Saturn 62, Uranus 27, Neptune 13. But our planet Earth has just one moon. Doesn’t it?

What exactly is twilight?

Photo credit: joiseyshowaa

Photo credit: joiseyshowaa

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.

Does your dog pronk?

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.

What is a supermoon?

What most call a Blue Moon isn't blue in color. It's only Blue in name. This great moon photo from EarthSky Facebook friend Rebecca Lacey in Cambridge, Idaho.

What does a full supermoon look like? Astronomers say you can’t really detect any difference with your eye between a supermoon and any ordinary full moon. This great moon photo is from Rebecca Lacey in Cambridge, Idaho.

We in astronomy used to call them perigean new moons or perigean full moons, that is, new or full moons at their closest to Earth for that month. But, in accordance with the rapidly evolving skylore of the modern world, we now enjoy calling them supermoons. The name supermoon was coined by an astrologer, Richard Nolle, over 30 years ago. It was popularized and came to be the accepted term for most people only in the past few years. Are supermoons hype? In our opinion … gosh, no, just modern folklore. And they can cause real physical effects, such as larger-than-usual tides. The year 2014 has a total of five supermoons. They are the two new moons of January, and the full moons of July, August and September. Next supermoon: July 12. Follow the links inside to learn about the supermoons of 2014.

How can I see a green flash?

San Diego, California on October 25, 2012, taken by EarthSky Facebook friend Jim Grant.  Thanks Jim!

San Diego, California on October 25, 2012, taken by EarthSky Facebook friend Jim Grant. Thanks Jim!

It’s said that once you’ve seen a green flash, you’ll never go wrong in matters of the heart. Here’s all you need to know to see the legendary green flash, plus great pics.

Scared of thunder and lightning? You have astraphobia

Never let your pets watch scary movies. Never a good idea! Image Credit: John Veldboom via Flickr

Thunder and lightning can be scary to pets, too. Image via John Veldboom via Flickr

Bam! Yikes!

Do you – and your dog – have astraphobia?

Virga is rain that doesn’t reach the ground

Virga over west Texas by Deborah Byrd.

Virga over west Texas by Deborah Byrd.

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.