Geminid Meteor Shower: Shooting Stars From Spectacular Celestial Event Set to Light up December Night Sky

The Geminid meteor shower has been active since December 4, but its activity will peak later this week in what is usually an annual highlight for skywatchers.

The Geminids are the "strongest shower of the year," according to the American Meteor Society (AMS), usually producing 100 visible meteors per hour or more during the peak nights (in 2019, these will be December 13 and 14).

However, this year the moon will be around 96 percent full on these nights, casting a glare that could make some of the meteors difficult to see.

"The full moon will greatly reduce the number of Geminid meteors visible this year," Robert Lunsford, from the AMS, told Newsweek. "The reason for this is that the intense moonlight will obscure all but the brighter meteors, just like it does the stars in the sky. Under ideal conditions upwards of 100 Geminids can be seen per hour from rural sites. This year I would expect that number to be reduced to around 20."

Meteor showers are celestial events during which numerous meteors appear in the night sky, originating from what seems like a single location. They occur when the Earth passes through streams of cosmic debris left behind by comets and, more rarely, asteroids.

Meteors, commonly known as "shooting stars," are the streaks of light we see when small pieces of debris from these objects enter the Earth's atmosphere and burn up at extremely high speeds.

These shooting stars appear to originate from a single point in the sky known as the radiant—which in the case of the Geminids lies in the Gemini constellation, hence the name.

The Geminids are usually very reliable and are one of the only meteor showers that provide good activity before midnight.

"Potential observers can optimize their chances for seeing Geminid activity this year by viewing during the short interval between dusk and moonrise," Lunsford said. "If the moon is above the horizon, view in the opposite direction where the moon has the least effect on the sky."

Geminid meteors tend to be bright and intensely-colored, although they don't usually have persistent trains—trails of vaporized material that can glow for several minutes.

The shower can be seen in both the Northern and Southern Hemispheres, although it is more clearly visible in the latter. For the best views, head to somewhere with dark, open skies away from light pollution.

The debris which produces the Geminids is thought to originate from the asteroid 3200 Phaethon. Every year between December 4 and 17, the Earth crosses Phaethon's orbital path around the sun, and some of the debris the asteroid leaves behind falls into our atmosphere and burns up as meteors.

"The earth reaches the core of the orbit on December 14, when the particle density is greatest and the most activity is observed," Lunsford said. "The display quickly subsides as the earth leaves the core area of the orbit."

Geminid meteor shower, Nevada
A Geminid meteor streaks between peaks of the Seven Sisters rock formation early on December 14, 2018 in the Valley of Fire State Park in Nevada. The meteor display, known as the Geminid meteor shower because it appears to radiate from the constellation Gemini, is thought to be the result of debris cast off from an asteroid-like object called 3200 Phaethon. The shower is visible every December. Ethan Miller/Getty Images

Because most meteor debris streams are associated with comets, some scientists have speculated that Phaethon could be an inactive comet nucleus.

In fact, 3200 Phaethon displays several characteristics that resemble those of comets—so much so that it has been described as a "rock comet." For example, its orbit is unusual for an asteroid, and some studies have even detected dust being ejected from the object—as is common with comets. Nevertheless, it is still classified as an asteroid.

Phaethon—which has a diameter of around 3 miles—was first discovered in 1983 by NASA's Infrared Astronomical Satellite. It is one of the largest near-Earth objects classified as "potentially hazardous" that scientists know about.

Any comet or asteroid whose orbit takes it within 121 million miles of the star and 30 million miles of our planet's orbit is described as a near-Earth object (NEO).

NEOs are defined as "potentially hazardous" if they are projected to come within 0.05 astronomical units (4,647,790 miles) of Earth at some point in the future and are estimated to measure more than 460 feet in diameter.

Phaethon is named after the son of the sun-god Helios in Greek mythology who lost control of his father's chariot one day and nearly set the Earth on fire.

This article was updated to amend a social headline.

Geminid Meteor Shower: Shooting Stars From Spectacular Celestial Event Set to Light up December Night Sky | Tech & Science