We on Earth get to take in the wonder of a meteor shower typically when our planet passes through the trail of a comet. The bits of rock and debris burn up when they hit Earth’s dense atmosphere, and streak across the sky.
But the Geminid meteor show — which will reach its peak Wednesday night and early Thursday morning — is not typical.
If you go outside Wednesday night and watch, you’ll be seeing bits of debris from an asteroid named 3200 Phaethon burn up in the night sky.
The asteroid is small — just 3 miles wide — and rocky. It also behaves much more like a comet than an asteroid.
While asteroid orbits tend to be more round, 3200 Phaethon has a highly elliptical orbit like a comet. But more importantly for the meteor shower, 3200 Phaethon is a rare asteroid that forms a tail.
This is likely due to its orbit, which brings it very close to the sun (in Greek mythology, Phaethon is the son of Helios, the sun god). The heat of the sun fractures the rock and creates the trail of debris that the Earth is about to barrel through. For this reason, 3200 Phaethon is sometimes referred to as a “rock comet.”
What’s more, those asteroid bits are denser than typical meteor kindling, which means they move more slowly across the sky as they burn. They also tend to be a bit brighter than the typical meteor. “The brightest often break up into numerous luminous fragments that follow similar paths across the sky,” the Royal Observatory Greenwich explains in its guide to the night sky.
All of this makes the Geminids “the best and most reliable of the annual meteor showers,” usually producing around 120 meteors an hour at peak, NASA notes.
And Wednesday night should be especially good for viewing: The moon will be a thin, waning crescent that won’t rise until 3:30 am and will only give off off dim light that shouldn’t obscure the meteors.
The constellation Gemini — out of which the Geminids appear to radiate — will rise in the Northeast in the early evening, and then by midnight, will be nearly directly overhead in the Southwestern sky, before setting in the West around daybreak. When Gemini is nearly overhead all you have to do to spot these meteors is look up (a star-spotting app like SkyGuide is helpful for knowing exactly where to look and when where you live). You should be able to see some meteors in the early evening hours after dark, but the most meteors will be visible from midnight to 4 am, NASA explains.
“The Geminids will be the best shower this year,” Bill Cooke, a NASA meteor scientist, said in a press release.
It should be a great show. Don’t miss it!