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Editors of EarthSky

Orion the Hunter and the Milky Way on December evenings

The constellation Orion the Hunter is very easy to find. If you have a dark sky, you can also see the luminous band of the Milky Way running behind it.

The Wright brothers succeeded 120 years ago

Check out one of the world's most famous photos. It shows the Wright brothers and the 1st true airplane flight on December 17, 1903.

Meteor shower guide: Up next the Ursids and the Quadrantids

We've got several more meteor showers this year. Next up are the December Geminds followed by the Ursids. Your 2023-2024 meteor shower guide here.

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!

Kelvin-Helmholtz clouds look like ocean waves

Kelvin-Helmholtz clouds - aka billow clouds or shear-gravity clouds - can sometimes look like ocean waves. Check out these photos of them!

Look for Mercury after sunset, early December 2023

Mercury is visible in the evening sky. Look in the west as the sky is darkening. The planet will reach its greatest elongation overnight on December 4, 2023.

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.

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!

Achernar is the End of the River of Eridanus constellation

Achernar is the 9th brightest star and flattest star known. It marks the end of Eridanus the River. Here's why much of Earth never sees it ... and how you can.

Meet Hamal, an ancient equinox star

Meet Hamal, the brightest star in Aries, and learn why people sometimes refer to the March equinox point as the First Point in Aries.