The finest meteor shower of 2018—and perhaps the best night sky sight this year—happens on Thursday, December 13. These are the Geminids, the sky’s “Old Faithful.” Their trustworthy one‑a‑minute frequency have created reliable December sparklers for the past century.
Geminid Facts and Oddities
- Geminids are much slower than either the famous summer Perseids or the hit‑or‑miss Leonids because they don’t strike us head‑on. They come at Earth sideways. At 20 miles per second, they lope along at half the speed of the other major showers, and it shows. It’s very appealing. Instead of sharp, brief zaps across the sky, we get leisurely streakers.
- These meteors are also the most mysterious in the known universe. All other showers are debris from comets, skimpy stuff less dense than ice. Strangely, Geminid meteors are twice as dense, yet nonetheless too lightweight to be bonafide, metal-stone asteroid material. So what could they be?
- There are other oddities too. All other major meteor showers have been observed for centuries or millennia. But the Geminids were unseen as recently as the mid‑1800s when it started as a modest shower that delivered only 20 meteors per hour. Over time, it’s grown increasingly rich; now it delivers one to two a minute.
- Despite decades of searching, the source of these strange fireworks was unknown until 1983, when NASA’s infrared‑detecting satellite IRAS found a small body moving in exactly the same path as the meteoroid swarm. Named Phaethon, it has a speedy orbit that carries it far within the orbit of Mercury and then out past Mars into the asteroid belt. Since Phaethon does not develop a cometlike tail nor shed material when approaching the sun, it was assumed to be an asteroid, a rocky body.
Fine. Except asteroids don’t disintegrate to produce meteor showers: Curioser and curioser. Maybe Phaethon is a true rocky asteroid that suffered enough collisions to fill its lopsided orbit with debris. Or else, maybe Phaethon is an odd has‑been comet, one that completely lost its icy outer covering and is presently just a comet‑core that has perhaps acquired a coating of interplanetary dust grains. Either way, the mystery material puts on quite a show.
How to See the Geminids: Viewing Tips
- Geminids are well seen all night long—bright in the sky from anywhere in the Northern Hemisphere. Take in as much sky as possible.
- They’re at their highest in the sky around 2 A.M. but any time of the night, you WILL see meteors if it’s clear. The later, the better.
- For best results, try to get away from city lights, to a place with an open expanse of sky, not just breaks between trees. Bring a folding chair to be comfortable or perhaps a sleeping bag. Dress warmly. You’ve got to be a little nuts to do this in the middle of December.
- It probably takes our eyes about 20 minutes to truly adapt to dark skies. The Geminid meteor showers tend to come fast and quick with very bright white lights.
Be patient and keep your eyes glued upward. You will be rewarded with the reliable Geminids!
Get more information on next year’s meteors on our 2019 Meteor Shower Calendar page.
And get ready for 2018’s brightest comet on December 15–16!