How much oxygen comes from the ocean?

At least half of Earth’s oxygen comes from the ocean.

Hummingbird in flight.

Hummingbirds see colors we can only imagine

“Our experiments enabled us to get a sneak peek into what the world looks like to a hummingbird,” one scientist said.

A tree in the foreground, with the sun behind it, and, to its side, in the sky, a randomly colored cloud.

Iridescent cloud? Or circumhorizon arc?

It’s easy to confuse a circumhorizon arc with an iridescent cloud, and vice versa. Here’s how to tell these 2 elusive, colorful, beautiful daytime sky phenomena apart.

Huge dark storm cloud over flat yellow landscape.

What is a derecho? An atmospheric scientist explains these rare but dangerous storm systems

The derecho in the U.S. East on June 3, 2020, killed 4 people and left a million without power. A Colorado derecho on June 6 had winds in excess of 100 mph. Europe, Asia and South America also have derechos. Here’s what scientists know about them.

Photo of stars above the Sahara

Will large parts of Earth be too hot for people in 50 years?

Inhospitably hot regions on Earth occupy about 0.8% of the globe now. New research indicates that – if greenhouse gas emissions continue unabated – these regions may expand to something more like 19% by 2070.

Rippled, shining clouds above a waterway, in Arctic twilight.

The secrets of night-shining clouds

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

Close-up view of an egg resting on the feet of a male emperor penguin.

Emperor penguins are good dads

On this Father’s day, a special shout-out to one of the most exceptional dads in nature, emperor penguins. They endure the harshest winter conditions on Earth for their offspring.

Sun in blue sky between 3 buildings.

It’s summer. What’s noon to you?

What do you mean by noon? Do you define it by your clock or wristwatch? Or the gnawing in your stomach? Here’s how astronomers think about noontime.

Celebrate solstice sunrise at Stonehenge live online

This year, solstice celebrations at Stonehenge monument are canceled due to Covid-19. But for the 1st time, you can celebrate the 1st sunrise of summer from Stonehenge online.

All you need to know: June solstice 2020

The June solstice is June 20. Longest day for the Northern Hemisphere. Shortest day for the Southern Hemisphere. Details here.