The Geminids radiant point is actually very near to the bright star of Castor in Gemini.  It’s a chance alignment, of course, as castor lies some 52 light-years from Earth, whilst the meteors actually burn up in Earths upper atmosphere, just 60 miles (100KM) above the Earths surface.  Castor is noticeably near another bright star, the golden star Pollux of Gemini. It’s fun to spot them, but you don’t need to find a meteor shower’s radiant point in order see the meteors. In actual fact, meteors in annual showers appear in all parts of the sky you just need to look up. It’s even possible to have your back to the constellation Gemini and see a Geminid meteor fly by.

That’s why, when you’re meteor-watching, it’s good to bring along a friend. Then two of you can watch in different directions. When someone sees one, they can call out “meteor!” This technique will let you see more meteors than one person watching alone will see.  Be sure to give yourself at least an hour of observing time. It takes about 20 minutes for your eyes to adapt to the dark.  Be aware that meteors often come in spurts, interspersed with lulls.

Earthgrazers possible at early evening.  Although I said you’ll likely see the most meteors at a time of night centered around 2 a.m. You won’t see as many Geminid meteors in early evening, when the constellation Gemini sits close to the eastern horizon.  But the evening hours are the best time to try to catch an earthgrazer.  An Earth-grazing fireball (or Earth-grazer) is a fireball, a very bright meteor that enters Earths Atmosphere and then leaves again. Some fragments may impact Earth as meteorites, if the meteor starts to break up or explodes in mid-air. These phenomena are then called Earth-grazing meteor processions. Famous examples of Earth-grazers are the 1972 Great Daylight Fireball and the Meteor Procession of July 20, 1860.

Geminid’s parent – 3200 Phaethon – is a “rock comet” Every year, in December, our planet Earth crosses the orbital path of an object called 3200 Phaethon, a mysterious body that is sometimes referred to as a rock comet. The debris shed by 3200 Phaethon crashes into Earth’s upper atmosphere at some 80,000 miles (130,000 km) per hour, to vaporize as colorful Geminid meteors.

In periods of 1.43 years, this small 5-kilometer (3-mile) wide asteroid-type object swings extremely close to the sun (to within one-third of Mercury’s distance), at which juncture intense thermal fracturing causes it to shed yet more rubble into its orbital stream.

In 2017, 3200 Phaethon was exceedingly nearby around nights of the Geminid meteor shower’s peak. This object swept to within 0.069 astronomical units (6.4 million miles, 10.3 million km, 26 lunar-distances) on December 16, 2017.

Bottom line: Meteor showers are part of nature and so inherently unpredictable. But the reliable Geminid shower counts as one of the year’s best, peppering the nighttime sky with 50 or more meteors per hour at its peak.