These next two nights – December 12 and 13, 2017 – are expected to be the best nights for watching the annual Geminid meteor. The peak night will probably be the night of December 13 – but tonight should be fine, too. Just know that the best viewing hours are typically in the wee hours after midnight (around 2 a.m.), no matter where you are on Earth. In the Northern Hemisphere, this meteor shower often rates as one of the best – if not the best – shower of the year. You can often see as many as 50 or more meteors per hour. This year, in 2017, the waning crescent moon in the wee morning hours should not be a hindrance. Once again, the optimal viewing should be the night of December 13-14. Follow the links below to learn more:
For the Southern Hemisphere. At temperate latitudes in the Southern Hemisphere, the number of meteors tend to be lower. The Geminids do favor the Northern Hemisphere, where the radiant is higher in the sky. However, this shower is also visible from the tropical and subtropical parts of the Southern Hemisphere. Watch for it anyway!
If you’re not one to stay up late, watch during the evening hours. Although the meteors are few and far between at early-to-mid evening, you might – if you’re really lucky – catch an earthgrazer – a slow-moving and long-lasting meteor that shoots horizontally across the sky.
At northerly latitudes, the shower radiant point – near the bright star Castor in the constellation Gemini – stays out from early evening until dawn. When the radiant point is near the horizon, the number of meteors that you see are few. The radiant climbs highest up around 2 a.m. and that’s why you see the highest numbers of Geminid meteors around that time.
How many meteors will I see? The Geminids are a consistent and prolific shower. You’ll see the most meteors in a dark sky, unspoiled by light pollution. Meteors often come in spurts and are interspersed by lulls, so give yourself at least an hour of observing time. Simply sprawl out on a reclining lawn chair, look upward and enjoy the show. Often, in the wee hours after midnight, you can see 50 or more meteors per hour. But the Geminids tend to be bright, so we expect some Geminid meteors to blaze even if your sky is somewhat beset by light pollution.
Why are they called the Geminids? The Geminid meteors are named for the constellation Gemini the Twins, because the radiant point of this shower lies in front Gemini, closely aligning with the bright star Castor. If you trace all the Geminid meteors backward, they all appear to originated from this constellation.
But you don’t need to know the constellation Gemini to see the meteor shower. The Geminid meteors will streak across all parts of the heavens from late night until dawn.
Where do the meteors come from? Although meteors are sometimes called ‘shooting stars,’ they have nothing to do with stars. Instead, they are strictly a solar system phenomenon. Around this time every year, our planet Earth crosses the orbital path of a mysterious object called 3200 Phaethon, which might be an asteroid or a burnt-out comet orbiting our sun. Debris from this object burns up in the Earth’s upper atmosphere to give us the annual Geminid meteor shower. The moderately fast Geminids slice through the Earth’s atmosphere at some 35 kilometers – or 22 miles – per second.
What else should I look for? Look for the waning crescent moon near the planets Mars and Jupiter in the wee hours before dawn. Look for these worlds (and also the star Spica) to light up the eastern predawn sky on the peak nights of the Geminid meteor shower.
Bottom line: Find a dark sky to watch a seasonal attraction, the Geminid shower. It peaks on the night of December 13, 2017 (morning of December 14), but the nights before and after will feature some Geminid meteors as well. Watch the Geminid meteors add to this year’s holiday lighting!