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EarthSky

The secrets of night-shining clouds

They’re back! People at high latitudes are seeing noctilucent or “night-shining” clouds, which always return to the skies around this time of year. Don’t miss the gorgeous photos in this post!

What makes a halo around the sun or moon?

A large ring or circle of light around the sun or moon is called a 22-degree halo by scientists.

Deneb, tail of Cygnus the Swan

Deneb marks the Tail of Cynus the Swan … and the head of a crosslike pattern known as the Northern Cross.

What’s a safe distance between us and a supernova?

And how many potentially exploding stars are located within the unsafe distance?

How Pluto got its name

Eleven-year-old Venetia Burney suggested Pluto, a classical mythological god of the underworld. The name also honored Percival Lowell, whose early efforts led to Pluto’s discovery.

Traveling by air? Watch for a glory

People traveling in airplanes often see glories. The sun has to be behind your head. You’ll see the plane’s shadow cast on a cloud, surrounded by a halo of light.

Why rainbows are curved

A rainbow isn’t a flat 2-dimensional image on the dome of sky. It’s more like a mosaic, composed of many separate bits … in 3 dimensions.

Follow the arc to Arcturus, and drive a spike to Spica

If you only ever learn one star mnemonic, make it this one!

Top 10 things about brown recluse spiders

It’s their active season. Here are some things you might not know.

Use the Big Dipper to find the Little Dipper

Polaris – aka the North Star – marks the end of the Little Dipper’s handle. The 2 outer stars in the bowl of the Big Dipper always point to Polaris.