A Great Year for the Geminids

By: The Editors of Sky & Telescope December 6, 2023 0

Note to Editors/Producers: This release is accompanied by high-quality graphics; see the end of this release for the images and links to download.

On Wednesday night, December 13th, and continuing into the early hours of Thursday, December 14th, be sure to head outside and look up — you may very well see brief streaks of light crossing the sky from the annual Geminid meteor shower.

It’s worth venturing forth into the cold for this meteor shower. “Although the Perseids, which arrive every August, are better known, the Geminids usually put on a better show,” says Diana Hannikainen, observing editor at Sky & Telescope. “Just make sure to bundle up!”

The Geminid meteor shower should peak around 2 p.m. EST (11 a.m. PST) on December 14th, which means that observers in North America have the best chance of catching a flurry of meteors in the pre-dawn hours on Thursday, December 14th.

It is, however, worth looking for meteors on both evenings bracketing the peak, on Wednesday evening, December 13th, and Thursday evening, December 14th. This way, families can enjoy the event together, since kids won’t have to miss their bedtimes by too much. Due to the timing of the maximum this year, the evening of December 14th should also provide a good show (so long as skies are clear, of course). The Moon will be new on December 12th, so it won’t hamper viewing opportunities.

The shower’s radiant — the spot in the sky from which all Geminid meteors appear to emanate — is near the relatively bright star Castor in the constellation Gemini. For viewers at mid-northern latitudes, the radiant is well above the eastern horizon by around 9 p.m. local time on December 13th. The radiant will stand highest at 2 a.m. local time on December 14th, which is ideal viewing time for those who can stay out late.

The number of meteors you see will depend very much on the darkness of your location, and what time you’re out looking. If you’ve got a clear, dark sky with no light pollution, you might see a meteor streak across the sky every minute or two from 10 p.m. until dawn on the night of the peak.

The shower’s maximum is broad, with lower counts on the nights preceding and following the peak. Fainter meteors are more abundant ahead of the peak, brighter ones after the peak. So should the night of December 13–14 be cloudy, it’s worth casting your gaze skyward several nights before and after, especially this year when the evening of December 14th could prove favorable for meteor-viewing.

How to Watch for Geminids

Meteor-watching is easy — you need no equipment other than your eyes. But you'll see more of them if you allow at least 20 minutes after going outside for your eyes to adapt to the darkness. Find a dark spot with an open view of the sky and no glaring lights nearby. Lie back in a reclining lawn chair, and gaze up into the stars. Bundle up as warmly as you can in many layers. “But, as always, be patient as your eyes adapt to the darkness and don’t give up too soon,” advises Hannikainen.

Geminids can appear anywhere in the sky, so the best direction to watch is wherever your sky is darkest, probably straight up. Small particles create tiny, quick streaks. The occasional bright one might leave a brief train of glowing smoke. The few that you may see early in the evening will make longer, dramatic trails, continuing for a few seconds as they graze sideways through Earth's uppermost atmosphere.

The Source of the Geminid Meteors

The last major meteor shower of the year is brought to us courtesy of 3200 Phaethon (FAY-uh-thon), a unique asteroid referred to as a rock comet since it shares characteristics with both asteroids and comets. The Geminids were first reported in 1862 and have been recognized as an annual phenomenon since then, but the source of the shower was unknown until Phaethon was discovered in 1983.

Phaethon is small, only about 3 miles (5 kilometers) across, and it loops around the Sun every 1.4 years in an orbit that approaches the Sun closer than any other named asteroid. It sheds rocky dust, rather than the ice-related vapors typical of comets, every time it nears the Sun, which heats its surface to roughly 1300°F (700°C). The dusty debris is about the size of sand grains to peas.

Over the centuries, these bits of Phaethon have spread all along the asteroid’s orbit to form a sparse, moving “river of rubble” that Earth passes through in mid-December every year. When we encounter these particles, they are traveling 22 miles per second (79,000 mph) with respect to Earth. So every time one of them dives into our planet’s upper atmosphere, about 50 to 80 miles up, air friction vaporizes it in a quick, white-hot streak.

Read more on this year’s Geminids in the December 2023 issue of Sky & Telescope and on S&T's website.

Contact Us

Diana Hannikainen, Observing Editor, Sky & Telescope
+1 617-500-6793 ×22100, [email protected]

Susanna Kohler, Communications Manager and Press Officer, American Astronomical Society
+1 202-328-2010 ×127, [email protected]

Gary Seronik, Consulting Editor, Sky & Telescope
[email protected]

Illustrations

Sky & Telescope is making the illustrations below available to editors and producers. Permission is granted for nonexclusive use in print and broadcast media, as long as appropriate credits (as noted) are included. Web publication must include a link to skyandtelescope.org.

Geminid meteor shower radiant — Geminid meteors can flash into view anywhere in the late-night sky. But if you follow their paths back far enough, they all appear to diverge from a point in the constellation Gemini. The meteors' perspective point of origin is called the shower's radiant. Don't expect to see several meteors at once! This diagram is meant only to show their divergence from the radiant point. Click on the image or here for a version of the radiant diagram in HD format.
*Sky & Telescope diagram*

Orbit of 3200 Phaethon — The asteroid 3200 Phaethon completes an orbit around the Sun every 1.4 years. Its path is highly elongated, much like a comet's. Perhaps it is an extinct comet, or maybe it's a true asteroid that is cracking and shedding rocky bits when closest to the Sun. In fact, it's most commonly called a "rock comet." Click on the image or here for a version of the orbit diagram in HD format..
*Sky & Telescope diagram*

Meteors hitting Earth — Meteor showers often appear strongest in the pre-dawn hours, when Earth is rotating into the direction of the oncoming particles as at left in the diagram. On the "sunset" side (at right), the particles strike Earth's atmosphere at slower speeds.
*Sky & Telescope*

*Sky & Telescope* Associate Editor Sean Walker created this composite image of Geminid meteors.
*Sean Walker*

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