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Editors of EarthSky

Solstices and equinoxes seen from space

See how sunlight falls on Earth's surface during the solstices and equinoxes, and get a better understanding of why Earth's tilt causes the seasons.

Interstellar object Comet 3I/ATLAS leaving the solar system

Interstellar object Comet 3I/ATLAS makes it closest pass by Earth today (December 19, 2025). How close will it come? And where will it go after this?

Year’s shortest season to start at December solstice

The year's shortest season - between the December solstice and March equinox - is about 89 days. It's 5 days shorter than the longest season.

What’s a green flash and how can I see one?

Have you ever seen the green flash from a setting sun? Learn how to see one here, plus how they appear, and enjoy some great photos and watch a video!

The Wright brothers succeeded 122 years ago

The Wright brothers made aviation history on December 17, 1903, taking humanity’s 1st powered flight into the skies at Kitty Hawk.

Schedar shines brightly at the Queen’s heart

Schedar is the brightest star in the distinctive W-shaped northern constellation Cassiopeia and is visible most of the year from northern latitudes.

The last full supermoon of 2025. Best pics here!

The full Cold Moon on December 4 was the last supermoon of 2025. See a gallery of photos of the last full supermoon from the EarthSky community here.

December birthstone: turquoise, zircon or tanzanite

The December birthstone is 1 of 3 gemstones, the exquisite blue-green turquoise, dazzling zircon, or the magnificent blue-violet tanzanite. Your choice!

December full moon is the Cold Moon and a supermoon

The 2025 December full moon will occur on December 4. It's also a supermoon, the last supermoon of 2025. It will look very bright. Don't miss it!

EarthSky’s lunar calendar: How to use this great gift!

Follow the moon! Here’s why you need an EarthSky lunar calendar, the top tips for using it and where you can order one.