A meteor shower takes place during the month of December every year generated by an asteroid named 3200 Phaethon wowing skywatchers around the world and is called the Geminid meteor shower. Defined as the "best and most reliable" meteor shower of the year by NASA, the spectacular sky show is generated because of 3200 Phaethon, which is thought to be a Palladian asteroid. The Geminids, along with the Quadrantids, is the only major meteor showers that don't originate from a comet.
Initially thought to be emerging from the constellation Gemini (from where it gets the name Geminid), scientists later discovered that the Geminids are fragments of 3200 Phaethon. “The asteroid has a debris trail in orbit around the sun. Once a year, Earth runs into this dusty path, which intersects our planet's path through space,” explains space.com.
These showers were first reported in the mid-1800s, where about 10-20 meteors would whiz past the earth's atmosphere per hour. But nowadays, nearly 120 meteors can be seen across the sky at the peak. Watch meteors showers observed in the skies over Daytona Beach, Florida, during the 2018 Geminid shower by NASA's Marshall Space Flight Center.
The meteors from this shower are slow in their pace and can be seen around December 13-14.
Phaethon’s nature is debated. It’s either a near-Earth asteroid or an extinct comet, sometimes called a rock comet. There is another object – an Apollo asteroid named 2005 UD – that is in a dynamically similar orbit to Phaethon, prompting speculation that the two were once part of a larger body that split apart or collided with another asteroid.
Most shower meteors are shed by comets when their orbits take them into the inner Solar System, but the Geminids may be the debris from this long-ago breakup or collision event. When you consider that the Geminid meteor stream has more mass than any other meteor shower, including the Perseids, whatever happened back then must have been pretty spectacular.
What's in store for the Geminid sky gazers this year?
It’s pretty simple, actually. The nearly First Quarter Moon sets around 10:30 p.m. local time, so wait until then to go out – the light from the Moon washes out the fainter meteors, which are more numerous. Find the darkest place you can, and give your eyes about 30 minutes to adapt to the dark. Avoid looking at your cell phone, as it will mess up your night vision. Lie flat on your back and look straight up, taking in as much sky as possible. You will soon start to see Geminid meteors. As the night progresses, the Geminid rate will increase, hitting a theoretical maximum of about 100 per hour around 2 a.m.
Bear in mind, this rate is for a perfect observer under perfect skies with Gemini straight overhead. The actual number for folks out in the dark countryside will be slightly more than 1 per minute. Folks in suburbs will see fewer, 30 to 40 per hour depending on the lighting conditions. And those downtown in major cities will see practically nothing – even though the Geminids are rich in beautiful green fireballs, the lights of New York, San Francisco, or Atlanta will blot even them out. Dark clear skies are the most important ingredient in observing meteor showers.
And while you’re scanning the sky for Geminids, you might notice a small, faint “ghostly” green patch in the constellation of Taurus – that’s Comet 46P/Wirtanen, which will be making its closest approach to Earth (7 million miles) for the next 20 years. We are actually going to have a comet visible to the unaided eye this holiday season!
Comets are notoriously unpredictable beasts, but if Wirtanen continues to follow its current brightening trend, it may reach a peak magnitude of around +3 (about as bright as a star in the handle of the Little Dipper) a couple of days past the Geminid peak, on December 16. Binoculars or a small telescope are good for taking a peak at Wirtanen, so bring them along for your night of Geminid watching. A green comet to compliment the green fireballs!
It’s a good time to bundle up, go outside and watch one of Mother Nature’s best sky shows!