Keep checking for clear skies this month, because there's plenty to see in the night sky throughout December!
Jupiter is exceptionally bright as it reaches Opposition. The Geminid meteor shower ramps up towards their annual peak, followed by the peak of the Ursid meteor shower about a week later. Look for the Full Cold Moon on the night of December 15. Plus, while spotting it will be challenging, for some night sky enthusiasts, a rare Black Moon will occur just before the new year.
Several planets are visible in the night sky throughout the month of December this year.
Venus can be spotted shining bright as the 'evening star' in the southwestern sky just after sunset, with dimmer Saturn found to the south, and Jupiter visible in the east. Meanwhile, Mars will rise a few hours after sunset, joining the lineup just as Venus sets.
A simulation of the night sky on December 15 shows the evening constellations, plus the locations of three of the major planets, along with the Full Cold Moon rising in the east. (Stellarium/Scott Sutherland)
Plus, as we transition from fall to winter weather, the skies also go through a transition of constellations visible throughout the night.
Facing south, Orion tends to be the most prominent constellation in the sky at this time of year, with two of the brightest stars and the famous "Belt of Orion".
A simulated view of the celestial objects and constellations in the southern sky at midnight on December 15, 2024. (Stellarium/Scott Sutherland)
Look 'past' the constellation lines and you can also see the "Winter Triangle". At the three points of this roughly equilateral triangle are Betelgeuse (the shoulder of Orion), Sirius (the brightest star of Canis Major), and Procyon (the brightest star of Canis Minor).
The Winter Triangle at midnight on December 15, 2024, with Jupiter, the Full Moon, and Mars. (Stellarium/Scott Sutherland)
Turning around to the north, perhaps the easiest constellations to recognize are Cassiopeia, Ursa Major ("The Big Dipper"), and Ursa Minor ("The Little Dipper").
A simulated view of the celestial objects and constellations in the northern sky at midnight on December 15, 2024. (Stellarium/Scott Sutherland)
DON'T MISS: Heads up! A total lunar eclipse will shine across Canada late this winter season
Watch for the planet Jupiter to be at its brightest on the nights of December 5 through December 8.
Very early in the morning on the 6th, at around 10 UTC (5 a.m. EST), the giant planet will be at its closest distance to Earth since November 2023. Furthermore, this will be the closest the two planets come to each other for the rest of this decade, at a distance of around 611,765,532 km. Thus, we won't see Jupiter this close and bright again until 2032.
On the night of December 7, just after we reach closest distance, the Sun, Earth, and giant Jupiter will line up in space, forming a syzygy. With Jupiter located on the exact opposite side of Earth from the Sun, this alignment is called Opposition.
The arrangement of the inner solar system, out to Jupiter, is shown here in this simulation for December 7, 2024. The Sun, Earth, and Jupiter are aligned in syzygy, with Jupiter in Opposition, on that night. (Celestia/Scott Sutherland)
Earth and Jupiter will be 611,768,524 km apart during Opposition, or a little over 3,000 km farther than they were at closest approach. While Opposition and closest approach for Jupiter do line up on the same date from time to time, it's just as likely that the gravitational influences of the Sun and the other planets will result in the two dates being off by a day or so.
One of the best annual meteor showers is going on right now. Each year, the Geminids begin on the night of December 2, as Earth plunges into the stream of gritty debris left behind by 'rock comet' 3200 Phaethon.
The shower starts off sparse, with maybe one or two meteors possible every hour, which streak out of the constellation Gemini. Activity is so light at this point that it may be difficult to notice. Dark skies and keen eyes can help.
Once we get past the first week of December, things start to ramp up. By the night of the 10th, we can maybe catch between 5 to 10 meteors every hour -- the equivalent of a minor meteor shower like the Draconids. Then, each night afterward, numbers typically double -- up to 20 per hour on the night of the 11th, 40-50 per hour on the 12th, and up to 100 or more on the night of the peak, on December 13-14.
The radiant of the Geminid meteor shower, located in the northeastern sky, on the night of December 13-14, 2024. (Stellarium/Scott Sutherland)
One limiting factor this year is the Moon. Since the Geminids reach their peak just two nights before the Full Moon, relatively bright moonlight will 'wash out' the sky, making it more difficult to see the dimmer meteors. This effect will be compounded by any urban light pollution present.
While it won't be as bad as during a Full Moon, we can still expect the number of visible meteors to be reduced, to maybe 50-60 per hour, under ideal conditions (clear, dark skies).
READ MORE: How to get the most out of auroras, meteor showers, and other night sky events
Eight days later, on the night of the Winter Solstice, December 21-22, the Ursid meteor shower will reach its peak.
The Ursids is a fairly short meteor shower, only lasting from December 16 through the 26th. It is also one of the weakest of the annual showers, only producing about 10 meteors per hour at its peak.
The Ursid meteor shower radiant, located near the Little Dipper in the northern sky, on the night of December 21-22, 2024. (Stellarium/Scott Sutherland)
The timing for the Moon will be a bit more favourable on this night. It will rise just before midnight, local time, leaving at least the first half of the night for meteor watching. For those dedicated spotters who stay up until the early hours of the 22nd, keeping the Moon out of your direct line of sight will help with spying meteors.
The cycle of the Moon is fairly well aligned with the calendar this December, which actually results in a rarity at the end of the month.
The New Moon occurs right on the 1st, followed by a waxing Crescent Moon for the first week, until the First Quarter Moon on the 8th. The Waxing Gibbous Moon will light our evening skies after that, rising later and later until the Full Cold Moon shines on the night of the 15th.
Past the Full Moon, the Waning Gibbous Moon will illuminate the skies until the Last Quarter Moon on the 22nd, and the Waning Crescent Moon will provide its faint moonlight through until the 30th.
Adapted from an image by NASA's Jet Propulsion Laboratory, this shows the FIVE phases of the Moon in December 2024, including the December 30 "Black Moon". (NASA/JPL/Scott Sutherland)
This is when a fairly rare event will occur, at least for some, known as a Black Moon.
Just as we periodically have a Blue Moon, when two Full Moons occur within the same calendar month, a Black Moon is when we have two New Moons in the same month.
A remarkable part of this is, due to the exact timing of the New Moons in December, not everyone in Canada will actually experience it. Why? Because the December 1 New Moon occurs at exactly 6:21 UTC.
In Canada, our time zones range from UTC-3h30m (NST) to UTC-8h (PST). So, those of us east of the Mountain Standard time zone will see this New Moon happen in the early hours of December 1, and there will be two New Moons this month.
However, for those observing MST or PST, this New Moon will actually occur before midnight, in the late hours of November 30, making the December 30 New Moon the only one for this month.