Anyone looking towards the southwest after sunset cannot miss Venus – the brightest object in the sky, apart from the sun and the moon.
It continues to rise higher and higher as the days go by, during the evening hours.
Venus has been called the Earth’s sister planet, but the resemblance stops after considering only their near-identical sizes. This is because temperatures on Venus rise to a high of around 460°C, barely varying due to its slow rotation. In contrast, the highest and lowest temperatures recorded on the Earth are 57°C in Death Valley in the US and -89°C in Antarctica.
In addition to Venus, the first two weeks of December bring Mercury back in the evening sky as well, far to the lower right of Venus, as seen from Malta.
This evening the crescent moon joins Venus and Mercury in the evening sky and tomorrow it will move further upwards in its monthly trek around the Earth.
Further up and to the left, reddish Mars can be glimpsed. If you have been following Mars throughout the past months you will now notice that it is much fainter than it was, say, last summer. Keep a watch on how the distance between Venus and Mars will shrink over the next few months.
The only other bright planet visible this month is Jupiter, but we will have to wait until well after midnight to see it. Jupiter rises at around 2.30am and is located in the constellation of Virgo. Jupiter is also easy to spot due to its brightness – it will be the brightest object in that part of the sky. As the Earth races in its orbit we will see how Jupiter continues to rise earlier and earlier, and by the end of the year it will rise around 1am.
Unfortunately the moon will reach its full phase during the maximum night of the Geminid meteor shower. But it is still worth looking out for the usual proportion of bright Geminid shooting stars, which will appear, sooner or later, between December 13 and 14 – so look high towards the south.
Geminid meteors are, like all meteors, just small rocky fragments which ionise the gases as they disintegrate upon entering the Earth’s atmosphere and burn up. Under ideal conditions, that is no moonlight, no light pollution, with perfect weather and with Gemini constellation overhead, we would have been expecting 100 meteors or more each hour. This month’s full moon will be another ‘supermoon’, though not as close to the Earth as the one of last month.
December 21 marks the winter solstice at 11.44am. This is when the sun reaches its lowest point in the sky (in the northern hemisphere) and when we will receive the fewest hours of daylight. Winter begins, and from this day onwards the daylight hours will become longer.
However, in the coming weeks, make good use of the long December nights to try and identify the large constellation Orion. Orion looms high in the south as the night progresses. It is quite easy to identify – the unmistakeable three stars in a row create Orion’s ‘belt’, with the M42 (Orion nebula) below it. This is the place where new stars are being formed right now.
Two further stars above and below the belt of Orion form a large celestial rectangle to complete the constellation. In reality it contains a much higher number of stars, but identifying the seven ones I mentioned above is a nice achievement for a beginner stargazer.
Astronomical events occuring this month
Tomorrow evening: The moon close to Mars
December 7: First quarter moon
December 10: Saturn in conjunction with sun (not visible)
December 11: Mercury furthest east of sun
December 13: Peak of Geminids meteor shower
December 14: Full moon
December 21: Last quarter moon; 11.44am winter solstice
December 22: Moon close to Jupiter
December 29: New moon