They seem to shoot from the constellation of the twins Gemini, but the bold, bright, white shards of light that crop up like clockwork in the night sky in the lead-up to Christmas really originate much closer to home. Seeming to radiate from Gemini’s bright star Castor as it rises in the early evening, just before 9 p.m. your local time, a darting spectacle of lights appears. It’s an intense meteor shower.
The Meteor Shower’s RadiantBright star Castor actually lies 51 light years away. And while these shooting stars seem to emanate from that faraway star, they don’t actually. Meteors are bits of cosmic debris littering space colliding with Earth’s upper atmosphere and burning up in our sky a mere 60 miles overhead. This particular shower is dubbed the Geminids, after the constellation Gemini where they seem to shoot from.
This is a faux convergence of stars and meteors, really. All that space debris actually travels in parallel, orbiting the sun, never converging. Akin to train tracks running parallel toward the horizon, the meteors seem to converge but never do. The point in our nighttime sky where their paths seemingly meet is called the “radiant”. The Geminids’ radiant aligns almost perfectly with the bright star Castor.
The Geminids’ tangible origin is closer to home. They are offshoots of a rocky space traveler in our solar system, as we shall see.
How Can I Enjoy the Geminids?You will have little time to wait to start spotting the Geminids—known as one of the best meteor showers on planet Earth. They’re here already, technically, running from Nov. 19 to Dec. 24. This time annually, Earth hits a patch of the solar system strewn with debris from a bouldery traveler. As we head into the countdown to Christmas, the light show in the sky produced by the thickest part of that cosmic debris field only intensifies.
The Geminids will reach their peak on Dec. 13 at exactly 2:27 p.m. EST. Yes, that’s the middle of the day in North America, so you‘ll have to wait until the radiant rises with Castor at around 9 p.m. And straight away there will be shots darting from that direction. One needn’t look directly at the radiant to find them; they’ll whip outward from it. Rather, after nightfall and into the wee hours of Dec. 14, you should kick back and relax. Take in as much sky as possible, for they could sputter up anywhere over the horizon.
As fortune would have it, the new moon falls on Dec. 12, meaning a slight, young sliver of crescent moon awaits us when the Geminids peak, presenting optimal dark conditions for meteor viewing. Ideally, find a vantage point far from city lights—a country cottage for a Christmas getaway perhaps? Grab a cup of hot chocolate, pull up a lawn chair, snuggle up with a blanket—or possibly a loved one—and gaze up at the stars. Weather permitting, without too much snow or cloud cover, you’re sure to spot a meteor or two!
Where Do They Really Come From?They burn brighter, scientists think, because they are rockier. Remember all that space debris we mentioned earlier? Most meteors are actually leftover bits of a comet that’s shed its matter across space—probably a lot of frozen gas that flashes out instantly. While comets are like amorphous, dirty snowballs of frozen gas traveling around the sun along gargantuan elliptical orbits, there is another, more robust type of space drifter that exists: asteroids.
Asteroids are basically hunks of space rock. In the past, scientists thought these could not produce meteors, but in 1985 the discovery of asteroid 3200 Phaethon by Simon Green and John Davies led to a new revelation. Its orbit was calculated, and Fred Whipple then announced it exactly matched the orbit of the Geminids’ debris trail. Was this a mere coincidence?
The Bottom LineThe countdown to Christmas has arrived—and with it, a meteor shower rivaling the best Earth has to offer. Soon the Geminids will swell to their peak, on Dec. 13, and swamp us with shooting stars. There’s no need to stay up late for these ones; they start dancing at 9 p.m., your local time, reaching their zenith at 2 a.m.
So, grab a friend or loved one. Be sure to let the other know when you spot one by yelling, “Meteor!”—the team approach is best for meteor seeking. And that spark of light you see shooting from the twins Gemini? That'll be your Christmas wishing star.