Welcome to the January night sky. At the end of the day, as soon as the sky starts to darken, high up in the west the brilliant planet Venus will be easily visible. This planet is at the moment brighter than any star and its light is strong enough to cast a shadow when it gets fully dark.
On the 12th Venus will be at its greatest elongation away from the Sun and, through a small telescope or powerful binoculars, Venus will be seen as exactly 50% illuminated or half Moon phase.
Because of the very thick and deep atmosphere of Venus that is more than 90 times the pressure of our Earth’s atmosphere, the phase effect can sometimes be delayed or advanced by a few days and this was noticed centuries ago and was the first indication of the extreme atmosphere around Venus.
The only other planet easily visible this month is the gas giant Jupiter that can be seen rising in the east in the constellation of Virgo, but you have to stay up until after midnight to see it, and it will be almost dawn before it becomes high in the south.
On the night of the 3rd and on until the morning of the 4th is the peak of the Quadrantids meteor shower. The constellation which is the origin point of these shooting stars no longer exists as it was cancelled during a redrawing of the star maps many years ago but it is close to the star Arcturus near Ursa Major.
January 22 is the 25th anniversary of the detection of the first exoplanet. It was quite an extreme situation as this object was orbiting a pulsar which is a rapidly rotating neutron star, and nobody expected a planet to be there as neutron stars are created when a massive star goes supernova. Since then more than 3,000 exoplanets have been discovered and perhaps the most important of these are exoplanets orbiting Red-Dwarf stars. This is important as these types of stars are by far the most numerous in the universe, accounting for more than three-quarters of the total.
It used to be thought that these types of small stars were unsuitable to have habitable planets, but it is now known that this is not the case. Red-Dwarf stars are the most long-lived type of true star having life times much longer than our Sun, giving plenty of time for life to develop.
Also, the closest star to our solar system is called Proxima-Centauri. This tiny faint star is not visible to the unaided eye but it is an ordinary Red-Dwarf just a few percent the size of our Sun, and we now know it possesses at least one planet of similar size to our Earth with an orbit that allows liquid water to exist assuming that it has some kind of atmosphere.
It might be possible to send a small probe there pushed by a powerful laser but it will be many decades before any results are achieved.
The Moon is at first quarter on the 5th, full on the 12th, last quarter on the 19th and new Moon on January 28.
By Clive Jackson
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Clive Jackson is the Director of the Camera Obscura (next to the Castle in Tavira), specialising in education and public outreach.
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To see the December Sky Map click on the pdf link below