Look up in the sky tonight! See that streak? Is it Santa and his eight little reindeer? Nope. It’s the Geminid meteor shower – the most sensational celestial show of the year. If the clouds cooperate, you should be able to see up to 100 meteor showers per hour. The show starts at about 5 p.m., but will be most visible after 9 p.m. as it peaks after midnight and in the early morning hours of December 14. The waning crescent moon plans to do its part in keeping the sky dark. It doesn’t rise until about 4:30 a.m.
The Geminid meteor shower makes for exciting action because the meteors travel at slower speeds, which means the streaks last longer. Moving through our atmosphere at around 20 miles a second, they produce beautiful long arcs that stay visible for up to two seconds. And the colors can be dazzling depending on what kind of gases the meteors pass through, how large they are, and how fast they’re moving. In general, the red-hued meteors tend to be slower, and the blue meteors are faster.
Meteor showers occur when the Earth crashes through a cloud of debris. Most meteor showers are created by passing comets, which shed dust and debris as they get close to the sun and their ice vaporizes. These bits of dust get incinerated as they enter our planet’s upper atmosphere, creating blazing streaks of light. Most of the light you see from meteors, though, is not from combustion but from from the temporary destabilization of the column of air they plow though. That’s why you see meteors as streaks, and some of the sparks remain visible as the atoms and molecules reorganize and restabilize.
The Geminids are unusual because the debris trail was left behind, not by a comet, but by the asteroid 3200 Phaethon discovered by astronomers in 1983. Scientists believe it has a diameter of about three miles and an elliptical orbit that facilitates it stopping by our neighborhood in the solar system every year and a half. Each time it passes, it unloads new interplanetary debris. Much like a giant astral dump truck!
This shower is called the Geminid meteor shower because all of the meteors appear to be originating from the constellation Gemini the Twins. The Twins start the evening in the eastern sky, and by dawn are stretched across the low western heavens. Living in a rural area away from any light pollution is a definite advantage, and Earthlings above the equator will have the best seats in the house (uh backyard), because Gemini will rise highest in the northern hemisphere. But that also means cold temperatures. Luckily, everyone already knows how to dress in layers. If you plan to stay out a while, why not grab some cozy blankets, a mug of hot cocoa, and lie back on a reclining lawn chair?
This is one show you won’t want to fall asleep during, though. And if you’re still stargazing – say at 5 a.m.- that super bright object in the low eastern sky is Jupiter, and it’s about 577 million miles from Earth now. The next brightest star just visible above Jupiter – the one with a reddish glow – that’s Mars, and it’s about 195 million miles away. (Even farther than the North Pole.) By next July, Mars and Earth will journey to within 36 million miles of each other, the closest they’ve been since 2003.
If tonight’s extravaganza piques your intergalactic interest, you’ll be happy to know the fun isn’t over yet. The orbit of 3200 Phaethon takes it closer to the sun than any other known asteroid. On December 16, star-gazers with backyard telescopes will get another stellar treat -a rare glimpse of 3200 Phaethon. Responsible for creating tonight’s shower as it zips and trips across the sky, it makes an historically close flyby of Earth, coming within 6.4 million miles of the planet. (Now doesn’t your holiday trip seem a lot shorter?) 3200 Phaethon hasn’t gotten this close since 1974; it won’t get this close again until 2093. Better catch it this time around! While the asteroid regularly crosses Earth’s orbital path, astronomers predict that it poses no threat for at least a thousand years.
Regardless, if it’s naughty or nice, Santa says you won’t want to miss it. If clouds get in the way, or the temperatures dip too low, you can still see the show online at the Virtual Telescope Project. They host live webcasts for the Geminid meteor shower on December 13 and 14 and for 3200 Phaethon on December 15 and 16.