In December, Mars is the planet to watch because it is very well positioned for observations. It is visible all night and is very high in the sky at midnight because it is at opposition, that is, on the opposite side of the sky from the Sun. Once every 26 months, Mars is very close to Earth, and depending on this event, research missions to the Red Planet are also launched.
Mars, seen by PerseveranceFoto: NASA /JPL-Caltech
Mars and Earth – between 53 and 401 million km
On December 8, the planet Mars will be at opposition, when the Sun, Earth and Mars will align. Unfortunately the weather forecast isn’t too great and it looks like a few cloudy nights too.
The year on Mars is two Earth years long, and the day is 24 hours long. Mars is much smaller than Earth (one tenth of Earth’s mass), and the average temperature is -65 degrees, compared to +15 degrees on Earth.
If the two planets had perfectly circular orbits the minimum distance between them would always be the same, but since the orbits are elliptical, the distance varies enormously. And the gravitational attraction changes the shape of the orbit a bit: for example Jupiter influences the Martian orbit.
The shortest distance between Mars and Earth, 54.6 million km, was reached in 2003, and the distance then was the smallest in the last 60,000 years, and the two planets in the Solar System will only be as close in the year 2287. In October 2020 Mars was 62 million km from Earth, in December 2022 it is 81 million km.
When Mars is this close, it becomes extremely bright in the night sky, being the second brightest celestial body after the Moon during this period.
The average distance between Mars and Earth is 225 million km, and the maximum: 401 million km.
Mars in December 2022 – When to see it and how to recognize it
In December, Mars is the planet to watch, because it is very well positioned for observations. It can be seen all night and is very high in the sky at midnight because it is at the opposition, i.e. on the opposite side of the sky to the Sun, writes the Bucharest Astronomical Observatory.
Oppositions occur every 2 years and a few months, and the next one will not come until 2025.
This is the time when Mars is even closer to Earth, so it is at its brightest and looks big through the telescope.
Opposition comes on December 8, but Mars is equally visible throughout the month. The apparent diameter of the planet during opposition will be 17 seconds of arc.
To see it in the sky, look at about 6 o’clock to the east, where a bright star can be seen. Or look at around 8pm higher up in the sky, still to the east, or, at midnight up in the sky, towards the south. Either way you should see an extremely bright, orange, non-flickering star. It’s Mars.
The moon passes by Mars on the evenings of December 7 and 8.
Saturn and Jupiter
Saturn is visible in the evening sky, just as it becomes evening until 9 p.m., when it sets.
It’s still easy to find Saturn: look to the southwest at about 8 o’clock and you’ll see, not far above the horizon, a star. This is Saturn. If it doesn’t twinkle, it’s probably Saturn, but the area it’s in doesn’t have as bright stars anyway.
Jupiter is still visible. At 7 p.m. it is high in the sky, towards the south. Look in that direction at that time and you will see a very bright star. It’s Jupiter. In the next few hours you can watch it head off into the sunset. The planet sets at midnight.
The night sky in December contains constellations that are part of the myth of Perseus. The constellations stretch from the western horizon to overhead, explain those from the Admiral Vasile Urseanu Astronomical Observatory.
The hero, Perseus, is high in the sky to the east, near the zenith (overhead). He reaches out to Andromeda, whom he saves. Not far from them is the constellation in the shape of the letter “W”, Cassiopeia, the mother of Andromeda.
The brightest star in Perseus is called Mirfak (alpha Persei) and is easily identified as the bright star below the W of Cassiopeia’s stars. The second brightest star in Perseus is called Algol (Devil’s Eye), a star whose brightness varies over time due to the mutual covering of two stars. The location of Algol represents the position of Medusa’s head, the monster beheaded by Perseus and used to destroy the sea monster that threatened Andromeda.
The monster is Cetus whose head is just to the south. Two of the constellation’s stars are brighter, lying southwest of the Pleiades and toward the southwest horizon. The star southwest of the Pleiades is Menkar. It represents the whale’s nostril and its name actually means “nostril”.
Between Cassiopeia and the star Mirfak is the “Perseus Binary Cluster”, a cluster of stars 7000 light-years away from the Sun. With the naked eye, a diffuse spot can be distinguished in this place, but through astronomical instruments tens and hundreds of stars become visible.
Another character in the story is Pegasus, the winged horse. It lies towards the west and can be identified as a large square.