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Deborah Byrd

What is a waning crescent moon?

A waning crescent moon is up in the east before sunrise. It’s waning toward new moon, when the moon will be between the Earth and sun.

How far could you travel and still see Earth?

You couldn’t see Earth from another star. From even the closest stars, the sun’s glare makes Earth impossible to see. And inside our own solar system? Spacecraft photos tell the tale.

Mars’ gala summer has ended

Mars – the world next-outward from Earth in orbit around the sun – has been brighter these past 2 months than since 2003. It’s still bright, but will soon fade. Here are a few recent images of Mars at its best.

Hazy light pyramid in east? False dawn

If you’re in the Northern Hemisphere, you can see the zodiacal light, or false dawn, at this time of year. If you’re in the Southern Hemisphere, look for it after sunset.

September guide to the bright planets

In September 2018, 4 planets continue to arc across the evening sky. From west to east as darkness falls, these bright worlds are Venus, Jupiter, Saturn and Mars.

Moonlight over Black Waterfall, Iceland

Svartifoss – the Black Waterfall – on Iceland’s south coast is a popular destination for hikers and tourists. It drops from a crescent-shaped cliff made of black basalt columns.

Saturn and its rings

Beautiful capture of Saturn and its major rings – and even the gap between the rings, known as Cassini’s Division – from Tom Wildoner.

New Horizons has Ultima Thule in view

The legendary craft that flew past Pluto in 2015 is still heading outward. New Horizons will sweep past its next target, nicknamed Ultima Thule, on New Year’s Day, 2019.

Hello, universe

A composite image of star trails with our Milky Way galaxy, and more, by Karthik Easvur.

What is a Dyson sphere?

Dyson spheres are back in the news. In case you’ve never heard of them – or want to brush up – here’s a primer.