Watch out for the end of year spectacular shooting star show

Many people look out for the annual Perseid meteor shower, which occurs in August. It is, however, not the most spectacular meteor shower. The Geminids hold that title and they can be seen this month. The Geminids reach maximum on the night of December 13-14 when up to 120 meteors per hour might be seen.

Meteors are connected with comets. As a comet, which is essentially a dirty snowball, travels around the Sun, it leaves a trail of dust behind it. If the Earth happens to pass through such a trail we see a meteor shower.

The Earth passes through many such streams each year. Some of the meteor showers are spectacular; others less so, but they are all predictable. The Geminids are so called because the meteors all seem to come from the constellation of Gemini the Twins. They are special because they are associated not with a comet but with an asteroid, called Phaethon.

The pieces of dust produced by asteroids are slightly larger than those produced by comets and because of this they travel through the Earth’s atmosphere more slowly, making them much brighter than the usual meteors. The Geminids travel at about twenty miles a second, while most other meteors travel at speeds closer to forty miles per second. The dust particles burn up due to friction in the Earth’s atmosphere.

If there are no clouds we should be in for a spectacular event. If you see a meteor or shooting star in the sky, remember to make a wish!

This month all the main signposts in the night sky are on view: the Plough; Orion; Cassiopeia and the Square of Pegasus.

The Plough can be found in the North East, standing on its handle with the pointers (the two stars furthest from the handle) pointing to the North Star.

Orion is not yet at its best but it dominates the south eastern part of the sky. Capella, in the constellation of Auriga the Charioteer, has not yet arrived at the zenith but it is very high up. As for the Summer Triangle, only Deneb can be found, low in the west. The Square of Pegasus can be found in the south west. The bright star Fomalhaut in Piscis Austrinus, the Southern Fish, has now set.

The constellation of Perseus is now high in the sky, so this is a good time to find the star Algol which in legend marks the eye of the Medusa slain by Perseus.

Medusa was the creature with hair made from snakes, and one look at it would turn the observer to stone. The star names are Arabic and the word Algol means the ‘Winking Demon’. Algol is what is referred to as a 'variable star', so called because its light changes in brightness over a period of a few days. These light variations, which were first explained by astronomer John Goodricke in York in the 1780s, are very regular and predictable. It was Goodricke who suggested that the variations were caused by two stars eclipsing each other. It wasn’t until around one hundred years after his death that astronomers were to prove his ideas correct.

While talking about events in the December sky people sometimes think about that most famous of all stars, the Star of Bethlehem. Many people have wondered what it could have been. I have my own ideas about the star but I expect it will always remain a mystery.

The Planets in December The very bright white dot that can be seen in the south is the planet Jupiter, which will dominate the night sky again this month. On December 22 Jupiter can be seen just below the Moon; a wonderful sight close to Christmas. Saturn is now much lower in the south west and will set by around 10pm.

Anyone up very early in the morning will be able to see the planet Venus, which this month rises in the south east at about 4am. As in November the other naked eye planets Mars and Mercury are too close to the Sun to be seen.

Meteors Showers After the Geminids another meteor shower, the Ursids, peaks on the night of December 22//23 when it is usual for about ten meteors an hour to be seen. The Ursids appear close to Christmas and with our focus on celebrations they are poorly observed. The Ursids have been known to produce outbursts of large numbers of meteors in the past so it is worth watching out for them. If you see an Ursid meteor or shooting star, don't forget to make a special Christmas wish.

The Ursids appear to come from the constellation of Ursa Minor, the Small Bear. The North Star is actually the end star of the tail of the small bear.

Phases of the Moon for December Last Quarter 5; New Moon 11; First Quarter 19; Full Moon 27 The Full Moon in December is usually known as the 'Before Yule Moon'. However, the feast of Yule is celebrated on December 21 and this year the Full Moon in December falls on December 27. This means that the full moon in December this year will be known as the 'Cold Moon'. The naming of the full moons this year became disrupted because of the Blue Moon in September.

The Winter Solstice The winter solstice, when the Sun lies at its lowest point in the sky, occurs on December 22 this year. It is the shortest day and longest night of the year. This is when winter officially begins in the northern hemisphere and summer begins in the southern hemisphere.