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Mares’ tails over the Pacific Northwest

Mares' tails - aka cirrus uncinus clouds - are found high above Earth's surface, where the air is very cold. They might mean rain is on the way.

Why and how fireflies light up

A firefly's familiar glow is caused by a chemical reaction. Why and how fireflies light up here, plus many wonderful firefly photos.

Thank you, Eleanor Imster

Say good-bye to Eleanor Imster, a fixture at EarthSky since 1995.

Love sea turtles? Here are 7 cool facts

Sea turtles are fascinating creatures. Learn some facts about these much loved marine reptiles.

Low-latitude noctilucent clouds in June 2021

Noctilucent cloud season has returned to Earth’s high latitudes. These "night-shining" clouds are beautiful ... photos here.

Happy World Oceans Day 2021

World Oceans Day has been celebrated every year on June 8 since 1992. It's a day to raise awareness about how we're connected to the oceans - no matter where we live on Earth - and what we can do to protect ocean habitats.

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.

What are the 2021 hurricane names?

The World Meteorological Organization chooses hurricane names several years in advance. Find hurricane names for 2021 here.

See it! May 26, 2021, lunar eclipse photos

Enjoy a few photos of the May 21, 2021 lunar eclipse from EarthSky friends around the world. Thanks so much to all who shared your photos with us!

Clouds that look like waves in the sky

Clouds in the sky can sometimes look like ocean waves. These photographic clouds are called Kelvin-Helmholtz clouds, and occasionally also go by the name billow clouds or shear-gravity clouds.