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What makes a halo around the sun or moon?

Halo around the sun, seen from Sweden on April 24, 2014 and captured by Fotograf Goran Strand.

Halo around the sun, seen from Sweden on April 24, 2014 and captured by Fotograf Goran Strand.

A ring or circle of light around the sun or moon is called a halo by scientists. We get many messages throughout each year from people who’ve just spotted a ring around the sun or moon.

People want to know: what causes a halo around the sun or moon?

What is lake-effect snow?

Podcast and interview with Tom Niziol, a longtime meteorologist-in-charge of the National Weather Service in Buffalo, New York, about lake-effect snow.

What is the Zodiac?

The changing location of the vernal equinox.

Image credit: Kevin Heagen (via Wikipedia)

Today’s FAQ!

The Zodiac, the 12 signs listed in a horoscope, is closely tied to how the Earth moves through the heavens.

Which bird migrates the farthest?

Arctic Tern in flight via Wikimedia Commons

Arctic Tern in flight via Wikimedia Commons

Over its lifetime of about 25 years, an Arctic Tern can fly a million kilometers – nearly three times the distance from the Earth to the moon.

What’s the birthstone for November?

Photo credit:  Orbital Joe/Flickr

Photo credit: Orbital Joe/Flickr

Happy birthday to all you November babies! Your birthstone is the topaz.

The word “topaz” comes from a Sanskrit word meaning “fire.” And in ancient lore, the topaz could be used to control heat. It was said to have the power to cool boiling water, as well as excessive anger.

Why do we scream?

Despite our fascination with screams, science knows relatively little about them.

Harold Gouzoules is one of the few scientists researching human screams. He collects them and analyzes their tone, pitch, and frequency to try and uncover the hidden patterns and complexities carried in one of the most intense human sounds.

When is the next 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.

Moon photo is from Rebecca Lacey in Cambridge, Idaho.

According to the definition of supermoon coined by Richard Nolle 30 years ago, the year 2015 has a total of six supermoons. They are the new moons of January, February and March and the full moons of August, September and October. The September 28, 2015 full moon will be the closest supermoon of 2015. It’ll also undergo a total lunar eclipse! Follow the links inside to learn about the supermoons of 2015.

When can you see Earth’s shadow?

Night falls when the part of Earth you’re standing on enters Earth’s shadow. Click here to expand this image. Image via NASA

At yesterday’s solar eclipse, the moon’s shadow brushed Earth. But what about Earth’s shadow? You can see it any clear evening. Just like you or me, Earth casts a shadow. Earth’s shadow extends millions of miles into space, in the direction opposite the sun.

Why do trees shed their leaves in the fall?


Autumn leaves. Image Credit: Tracy Ducasse.

Something to think about while raking …

Why does the sun look red at sunset?

Image courtesy Tim Haynes

Image courtesy Tim Haynes

Imagine standing on a beach, a mountaintop or any open area, watching a beautiful sunset. As the sun sets, it appears redder and redder as it gets closer to the horizon. Sometimes you can see a gradation of color a across the surface of the sun. Why does this happen?