Geminids Meteor Shower to Light Up Bay Area Sky With 120 Meteors Per Hour

The dazzling finale of a season of meteor showers is at hand!

Late Wednesday night on Dec. 13 and into Thursday morning on Dec. 14, the Geminids meteor shower will reach its peak activity. Considered one of the year’s most spectacular and reliable showers, the Geminids produce as many as 120 meteors every hour.

The December Geminids are a bit like the fireworks finale, except for a season of meteor showers that started with the August Perseids and moved along through the Orionids in October and the Lyrids in November.

How and when to see Geminids

To see the Geminids, plan a late-night trip to a viewing location as far from city lights as you can get, and dress warmly. Bring something to sit or lay down on — a chair or a picnic blanket — and get comfortable. Plan to spend at least 30 minutes, preferably more, since it can take that long for your eyes to become dark adapted.

By midnight, the region of the sky the meteors will appear to fly from — the constellation Gemini, this shower’s “radiant” — will be high in the eastern sky, almost directly overhead. The twin stars Castor and Pollux mark the spot to center your gaze on.

Relax, taking the entire sky into your gaze. Meteors can appear anywhere in the sky at any moment. Each fiery streak of light you see can be a thrill, and with a shower like the Geminids, there will be plenty to see.

Geminids meteors are bright and move fast, and tend to be yellow in color. And this year, the moon will be absent from the night sky, only slightly past its new phase, so there will be no moonlight to interfere with viewing.

What causes the Geminids shower?

The Geminids, like all meteor showers, are the result of Earth passing through a cloud of dust in space. The bits of dust, most no larger than a pebble, are incinerated by friction when they hit our atmosphere at speeds of tens of miles per second.

The source of dust for most meteor showers is comets, so-called “dirty snowballs” that pass close to the sun and spew out gas when some of their frozen materials evaporate, leaving a trail of debris in their wake. If the comet’s path happens to cross Earth’s orbit, we can see a meteor shower.

We see meteor showers in the morning hours, when we’re located on the side of the Earth leading into the dust cloud.

The Geminids shower is special. Its dust particles were not left behind by a comet but by a sun-grazing asteroid named 3200 Phaethon. Phaethon’s behavior of shedding dust like a comet has astronomers thinking it could be the rocky remnant core of a dead comet, one whose volatile ice has mostly been lost over time. More recent observations have highlighted the possibility that 3200 Phaethon may not shed dust at all, as a typical comet does, but may have ejected the Geminids material long ago in a cataclysmic event.

3200 Phaethon orbits the sun every 1.4 years and is little more than three miles in diameter. Like most comets Phaethon’s orbit is highly elliptical, and carries it within 13 million miles of the sun — three times closer than the planet Mercury!

Meteor showers through the year

Meteor showers occur throughout the year, and there are no fewer than 40 recognized annual showers, each supplied by a different sun-grazing comet — not all of which have even been discovered. Most of these showers produce few meteors, some as low as two or three meteors per hour. 

The Geminids, however, top the charts with the highest rates and brighter-than-average meteors, so if you can only manage to get up for one or two meteor showers each year, this one should be first on your list.