New Meteor Shower May Grace Earth's Skies Next Week

We may be treated to a new cosmic sight next week, as the Earth gains a meteor shower.

The shower is forecast to appear in the night skies of the southern hemisphere on December 12, as the Earth passes through a cloud of debris left by a comet, according to a paper on the pre-print server arXiv.

While this comet—named Comet 46P/Wirtanen—has passed by the Earth before, no previous showers from this comet have been observed.

When is the meteor shower?

"We predict the birth of a new shower on Dec. 12, 2023, between 8:00 and 12:30 UT," the authors wrote in the paper. "The location of the radiant is close to the star λ-Sculptoris star, so a possible name for the shower is λ-Sculptorids."

What causes a meteor shower?

Comets are usually the driver behind the annual meteor showers we see, including the Orionids, Perseids and Taurids, among many others.

"Comets are best described as dirty snowballs. So, they are mainly composed of frozen gasses, enclosed in them are then some complex molecules but a substantial number of rocks, pebbles and sand grain sized other rocky debris," Daniel Brown, an associate professor in astronomy and science communication at Nottingham Trent University, told Newsweek. "As the comet moves along its orbit (which is usually extremely oval or stretched), it comes for a period of time quite close to the Sun that can then start heating it up. As a result, the ice turns into gas causing a beautiful halo around the comet and a long tail. But as the ice disappears, it releases the rocky debris along its orbit."

If a comet has left a trail of these tiny rocks that cross the orbit of the Earth, we will run into a thick patch of space debris around the same time each year, causing large numbers of meteors to be seen in the skies, marking a meteor shower.

Usually, the comets that cause meteor showers orbit the sun in large, oval-shaped ellipses, coming near to the sun and Earth in a regular pattern. Comet 46P/Wirtanen, however, doesn't follow this same orbit, which is why we haven't seen a meteor shower from it before.

"It's not quite so predictable (or put better, a regular annual occurrence you can count on) because its orbit passes quite close to Jupiter (called a 'near-Earth' comet, unlike Halley's Comet which goes out to Uranus in the outer solar system before turning around)," Brad Gibson, director of the E.A. Milne Centre for Astrophysics at the University of Hull in the U.K., told Newsweek. "Because Jupiter is so big and heavy, its gravity changes the orbit of the comet fairly commonly, which means any debris trail is not always in the same place each year or necessarily in path of the Earth as it goes around the Sun. The new work suggests things might just be aligned ideally next week to see the evidence of this debris in the form of meteor shower."

Will it be an impressive meteor shower?

However, the shower may not be visible at all, or if it is, it is expected to be very weak.

"[The comet's] material is released at a higher rate when it's closer to the Sun and then moves around in a similar orbit being distorted and bunched up by Jupiter's gravity once in a while. This means, to cause a meteor shower we not only need to 'cross' 46P's space debris path but also do that when an orbiting debris cloud is just moving through along that path. In the paper, [the authors] simulate the path and predict a possible clumping of material that we will be encountering in December. We missed it before, it was not bunched up that tightly, or might just not have been ejected from 46P yet," Brown said. "The possible debris encountered from 46P would consist of small particles and have a very low velocity. As a result, meteors would be very faint and difficult to spot."

"This shower will be rather unspectacular. It will be best observed in the southern hemisphere if at all. The predicted size and very low velocities relative to Earth ensure that only the very very largest of these particles would be able to be seen. Typically many will be just on visual detection limit or registered using radio waves. Also, the rates predicted are very low. So we really are not expecting anything like the Perseids at all," Brown said.

Gibson agrees: "I think though that even the most optimistic of us would urge caution in terms of not getting one's hopes up too, too much...if it does happen, it will likely not be particularly spectacular given the debris trail is likely quite minimal."

Will we see this meteor shower again?

There is a possibility that this meteor shower may become a regular occurrence.

"If the predictions are correct, then we would be encountering a somewhat regular new meteor shower. Not every year as the density of space rubble is not that high all along the orbital path so that it would be triggered every time we path that point in our orbit. The one we would encounter would just be seen as the usual random encounters," Brown said. "[The preprint] simulations indicate that we had most likely such a shower in 2007 and 2018 but they were not observed. Future work and monitoring of 46P activity will indicate when to expect this meteor shower."

Even if this year's shower isn't very spectacular, recurrences of the shower in the future may prove to be more impressive.

"There exists the possibility of a hidden pocket of dust from Comet 46P/Wirtanen colliding with Earth in the coming years," Minjae Kim, a research fellow in astronomy and astrophysics at the University of Warwick, told Newsweek. "However, the specifics of how, or even if, this event might manifest remain uncertain. This potential encounter could result in a one-time meteor shower, or, should the debris disperse over time, it might lead to an irregular series of showers."

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