Some of the shooting stars will be so bright, they'll even be visible from city centers.

By Jamie Carter
December 13, 2018
A meteor streaks across the night sky during the Geminid meteor shower over Murat Mountains in Gediz district of Kutahya, Turkey on December 14, 2017.
Credit: Anadolu Agency/Getty Images

Have you ever seen a sky full of shooting stars? Despite the hype about meteor showers, there are, in truth, very few that live up to their billing. However, one of the "big three" of the year, the Geminids, peaks tonight. Expect fireballs!

What is the Geminids meteor shower?

It's an annual meteor shower that runs from around Dec. 7-16 each year, but it's the peak night of activity that's the one to go shooting star-gazing on. Even better, its shooting stars are distinctly yellow with long tails, truly a sight to behold in a clear sky.

Why is it called the Geminids meteor shower?

The shooting stars produced by the Geminids meteor shower appear to come from the constellation of Gemini, the Twins. It's not all that important for shooting star-gazers, because they can actually appear anywhere in the sky, but any shooting stars you do see will appear to shoot from the general direction of Gemini. Gemini's main bright stars are Castor and Pollux, named after the half-twin brothers in Greek and Roman mythology. The second-brightest star is Castor, about 50 light years from us, while brighter Pollux is 34 light years away.

When and where to see shooting stars

The midnight hour until about 2 a.m. is when to look for shooting stars. That's not because there are more at that time, but because by midnight you will be firmly on the night-side of Earth. So the sky is darker, and the shooting stars will be higher in the sky, and thus brighter. If you can stand the cold and the sky is clear, shooting stars from the Geminids meteor shower should be observable through until a few hours before dawn. The darker your sky, the better, though you don't have to leave the city to see the brighter ones. If light pollution is a problem where you observe from, at least make sure that no lights are in your field of view. Go stand in the shadows, perhaps behind a wall, building or shed, and you'll see more. Geminids are often very bright.

What causes shooting stars?

Dust. All that happens is that Earth is moving through a stream of dust and particles left over from the passing of a comet through the solar system. When the atmosphere hits them, the dust particles briefly energize and switch from what astronomers call meteoroids into meteors. However, the Geminids meteor shower is a little different from most because it's caused not by comet debris, but by a near-Earth object. 3200 Phaethon is a 5-kilometer-wide asteroid that's often in the solar system and came within 6.4 million miles of Earth in December 2017. It's an object that has long fascinated astronomers, and the Japanese Space Agency has plans to visit it in a mission called Destiny+, which will launch in 2022.

What is the Zenithal Hourly Rate?

The Geminids meteor shower has a Zenithal Hourly Rate (ZHR) of 120. ZHR is astro-talk for "the maximum you would see if you had perfect conditions ... and wide-angle eyes." Since you can't look at the whole sky, you'll miss some of those 120 per hour, but for comparison, most meteor showers have a ZHR of about 10. For the Geminids, you can expect to see around 40 to 50 per hour under a clear, dark sky.

When is the next meteor shower?

It may be the best meteor shower of 2018, but the Geminids is not the last. That title goes to the Ursids, which peak on Dec. 22. However, it’s one to ignore. As well as offering only about five or 10 shooting stars per hour, the Ursids occur this year during strong moonlight, which will dull them even more. However, coming up on Jan. 3 is the Quadrantids, which has a ZHY of 110. It all depends where you watch it from, but it promises to be a decent show in 2019 thanks to a lack of moonlight.

Go outside at night at midnight on Dec. 13-14 and look up, and keep looking, and if there's a clear, dark sky, you will be rewarded with some awesome festive fireballs.