December is proving to be a busy month for stargazers. The Geminid meteor shower- a highlight of the meteor year- is expected to peak from the evening of Sunday, Dec. 13 until dawn on Monday, Dec. 14.
According to NASA, the Geminids, which are visible from Dec. 4 to Dec. 17 this year, are considered to be “one of the best and most reliable annual meteor showers.”
The first of the Geminid meteor showers started appearing in the mid-1800s but were considered insignificant as the showers only produced 10 to 20 visible meteors per hour.
Today, the Geminid meteors showers have become one of the most popular showers of the year, producing more than 100 meteors per hour during its mid-December peak.
Unlike most meteor showers, which originate from comets- a celestial object consisting of a nucleus of ice and dust and, when near the sun, a “tail” of gas and dust particles pointing away from the sun, the Geminids originate from an asteroid known as 3200 Phaethon.
3200 Phaethon was discovered nearly 40 years ago by Simon Green and John Davies with the help of the Infrared Astronomical Satellite, the first-ever space telescope to perform a survey of the entire night sky at infrared wavelengths.
Following Green and Davies’ discovery of Phaethon, Fred Lawrence Whipple, an American astronomer who worked at the Harvard College Observatory for over 70 years, was the one who discovered that the asteroid and the Geminids have the same orbit. This was the first time an asteroid had been linked to a meteor shower.
Phaethon, named after the character of Greek myth who drove the sun-god Helios’ chariot, is a small asteroid with a diameter of only 3.17 miles. Phaethon’s diameter is much smaller than the largest known asteroid, Ceres, which measures 587.82 miles in diameter. The asteroid takes approximately 1.4 years to orbit the sun.
Scientists are still not sure how to describe the object because it does not develop a cometary tail as it passes by the sun. This, and other strange characteristics, lead scientists to refer to Phaethon as a “dead” or “dormant comet,” but it is scientifically categorized as an asteroid.
As 3200 Phaethon passes by Earth during its pilgrimage around the sun, bits and pieces break off and burn up in the Earth’s upper atmosphere. These are the Geminid meteors, which appear 60 miles above Earth’s surface.
The constellation Gemini, “The Twins,” is the Geminids’ radiant- the point in the sky from which the meteors appear to come. This constellation is where the Geminids get their name; however, the constellation for which a meteor shower is named only serves to help stargazers determine which shower they are viewing. The constellation is not the source of the meteors and NASA tells stargazers that the meteors will be visible all across the night sky, not just near the constellation of Gemini.
The Geminids will be the most visible during the night and predawn hours of Dec. 13 and Dec. 14. The best time to see the meteors will be around 2 a.m. on Dec. 14 because that is when the shower’s radiant point- the constellation Gemini- is highest in the sky.
Nasa also says that “this shower is considered one of the best opportunities for young viewers since this shower starts around 9 or 10 p.m.”
On a dark night, stargazers could see anywhere from 50 to 150 meteors per hour. Experts are saying this year’s shower should be especially visible, given the moon free skies.
The 2020 moon phase calendar indicates that a new moon falls on Dec. 14. On the mornings before the shower’s peak, stargazers will see a waning crescent moon. After the meteor shower, the sky will welcome a slender lunar crescent and the planet Venus will rise into the eastern sky.
Telescopes and other special equipment are not needed to view the spectacle, but astronomers say to arrive early because it takes at least 20 minutes for human eyes to adjust to the darkness.
All prospective stargazers should also understand that meteors often come in spurts, followed by lulls. When the meteors do fianlly pass into view, they will be traveling at 79,000 mph (22 miles per second.)
For more information, visit solarsystem.nasa.gov.
