Starwatch: moon makes passing encounter with Jupiter | Science

The moon is rapidly approaching fullness, and this week it will make a passing encounter with Jupiter on 21 and 22 December.

The chart shows the view looking due south from London at 9pm GMT on 22 December. The moon will be waxing gibbous (getting bigger) with 82% of its visible surface illuminated. Jupiter will be a bright object, shining at around a magnitude of –2.7 in the constellation of Aries, the ram. The pair will also be visible from the southern hemisphere, where they can be easily seen in the northern sky.

This week also brings, happily, the winter solstice for those in the northern hemisphere – the shortest day of the year – and the summer solstice for those in the southern hemisphere. The exact moment of the solstice is 3.27am GMT on 22 December.

The sun will rise over London at 8.01am GMT and set again at 3.53pm GMT giving just about seven hours, 49 minutes and 41 seconds of direct sunlight. The days on either side of the solstice will only be longer by a meagre second or less. In the southern hemisphere, this will be the longest day.