The days are gradually getting shorter now even as the nights are getting longer and colder. That natural cycle will reverse itself again right after the winter solstice, which happens at 6:03 p.m. on Sunday the 21st. That minute marks the lowest point that the sun will reach in the sky in the northern hemisphere. The word solstice means “sun stands still.” If you could photograph the sun every few days exactly at noon for a whole year from a fixed location on Earth, you would see that it traces a figure eight in the sky. That is called the analemma. The sun will soon be at its lowest point on this figure eight.

There are several interesting highlights this month that will be well worth braving the cold to see and experience, and understand the causes of these events. Venus returns to our evening sky in the middle of the month after a three-month absence from our visibility, Saturn returns to our morning sky, Jupiter becomes an evening planet and the plane of its four large moons tilts edge-on to Earth now, an asteroid sojourns between two star clusters in Taurus, a comet glides past a bright galaxy and there will be not one but two meteor showers this month.

Brilliant Venus will join Mars low in our southwestern evening sky by the middle of the month. Mercury will join the pair on the last night of this year.

Saturn returns to our morning sky before dawn after the first week of this month. It will rise higher each morning, and by the end of the month it will be 20 degrees high in the southeast one hour before sunrise. You can find the ringed planet near Antares in Scorpius, near where Mars was three months ago, but Saturn will be a little brighter than Mars or Antares.

Jupiter is rising four minutes earlier each day and is slowly getting brighter and larger as it approaches its opposition on Feb. 6 of next year. The king of the planets will end its normal, direct, eastward motion on Dec. 9 and begin its retrograde motion. The midpoint of a superior planet’s retrograde loop in the sky always marks its opposition, when it is at its best and brightest because it is closest to the earth on that day.

Jupiter is now going through a fairly rare event, which only happens about every six years. The orbital plane of its four bright Galilean moons is tilted exactly edge-on from our perspective on Earth. That allows us to see occultations and eclipses of these moons through a telescope. More than a dozen of these rare events will happen this month. Callisto will occult Europa by passing directly in front of it on Dec. 6 at 2 a.m. Then Europa will occult Io and their shadows will merge on the Jovian disk on the morning of the 23rd.

An asteroid named Thalia, discovered by John Hind in 1852, will be visible at 9th magnitude with a good pair of binoculars or a telescope in Taurus all this month.

Comet Panstarrs will pass close to the 8th magnitude spiral galaxy named NGC 55 in the constellation of Sculptor on Dec. 17-19. The comet itself will be about 21/2 times fainter than the galaxy, which would be 9th magnitude. Comet Siding Spring passed very close to Mars last month and is still visible at 10th magnitude close to the globular star cluster M14 in Ophiuchus. You will need an average telescope to spot these two comets.

The Geminid meteor shower peaks on Saturday night the 13th into Sunday morning the 14th. This is a unique shower because it is one of only two of the major 10 or 12 showers every year caused by an asteroid instead of a comet. The Geminids are caused by the debris of an asteroid named 3200 Phaethon. This is a bit of a hybrid because it is believed that its now extinct nucleus used to be an active comet a long time ago. This asteroid, three miles across, has an orbit that goes out a little past Mars and only takes 1.4 years.

Tiny pieces of the asteroid will slam into our upper atmosphere at 80,000 mph, or about 13,000 mph faster than we are orbiting the sun. You could see up to 100 meteors per hour from this excellent and consistent shower. They tend to be brighter than most meteors because the tiny particles of this asteroid are denser than the comet dust that creates most of the meteor showers.

The last-quarter moon will rise around midnight, but you could keep watching after that time by looking in other parts of the sky.

All the Geminids will appear to originate in the constellation of Gemini in the winter hexagon, but they will be visible everywhere in the sky.

Just bundle up, get to a dark sky site, and bring binoculars to enjoy any slowly twisting dust trails created by the brighter meteors.

The bonus meteor shower this month will be the Ursids. Caused by Comet 8P/Tuttle, you can expect only about a tenth of the meteors that the Geminids will produce, but the conditions will be perfect with no moon to interfere with the show. They will originate from Ursa Minor, which is also the Little Dipper, close to Polaris, our current North Star.

They will peak on the 22nd, the day after the winter solstice.

They experienced some problems on Comet 67P/Churyumov-Gerasimenko when the Philae lander bounced a couple of times after not being able to anchor itself to its icy surface.

Its solar panels can no longer collect any sunlight, but its 10 instruments did get about two days’ worth of data before they ran out of power.

They may have found evidence of complex carbon molecules in the dust kicked up by the landing. They are also hoping to discover some rare isotopes of hydrogen, oxygen and nitrogen, which could not occur on Earth.

Correctly interpreted, the ratios of those elements to their isotopes will reveal many important mysteries about the nature of this comet and whether or not comets could have been a source of the water on Earth.

This is only the seventh time we have landed anything on another object in our solar system other than the moon and it was the first time we performed a controlled landing on a comet, so there were many risks and unknowns involved, but the mission was still well worth it.

I toured the night sky through my telescope recently on a cold and clear night from our Starfield Observatory in Kennebunk.

I started with orange Mars, then moved on to the Pleiades, the double cluster in Perseus, a brilliant gold and blue double star in Cygnus named Albireo, the ring nebula, M 57 in Lyra, a beautiful and ghostly smoke ring suspended in the heavens, which is a planetary nebula similar to what our sun will turn into when it runs out of fuel in about 5 billion years, and we ended with the Andromeda Galaxy. At about 2.5 million light years away, that is considered our sister galaxy in our local group of 30 galaxies with around 400 billion stars and about 150,000 light years in diameter, which is about one and a half times larger than our own Milky Way. It was nice to find and appreciate these familiar objects again and realize what they are really telling us about the deeper nature of the sky all around us.

DECEMBER HIGHLIGHTS

Dec. 2: Pioneer 11 flew by Jupiter on this day in 1974. The asteroid Thalia is at opposition tonight in Taurus.

Dec. 3: On this day in 1973 Pioneer 10 flew by Jupiter.

Dec. 6: Full moon is at 7:27 a.m. This is also known as the cold moon or the moon-before-Yule.

Dec. 9: Jupiter appears stationary as it starts its retrograde motion.

Dec. 11: Annie Jump Canon, who was instrumental in developing the spectral classification system of stars, was born on this day in 1863. The moon will be 5 degrees south of Jupiter.

Dec. 13: The Geminid meteor shower peaks tonight.

Dec. 14: Last quarter moon is at 7:51 a.m. Tycho Brahe was born on this day in 1546.

Dec. 17: On this day in 1903, the first powered flight occurred on Earth. It would take less than 66 years to get all the way to the moon.

Dec. 21: The winter solstice is at 6:03 p.m. New moon is at 8:36 p.m.

Dec. 22: The Ursid meteor shower peaks.

Dec. 25: Isaac Newton was born on this day in 1642.

Dec. 27: Johannes Kepler was born on this day in 1571.

Dec. 28: First-quarter moon is at 1:31 p.m. Arthur Eddington was born on this day in 1882.

Bernie Reim of Wells is co-director of the Astronomical Society of Northern New England.