In England during the Middle Ages 25 December was taken as the start of the year. In the late 12th century the start of the year was shifted by nine months to 25 March. The official start of the year only became the familiar 1 January in 1752, the year in which England adopted the Gregorian Calendar.
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If we extend the line formed by the three stars of Orion's belt towards the north (left in the evening) we reach the reddish star Aldebaran. That star is the brightest star in the constellation of Taurus the Bull.
British astronomer Arthur Stanley Eddington was born on this day in 1882 at Kendal, Westmorland, England. Eddington correctly worked out that stars shine due to the collision and annihilation of atomic particles in the centres of stars.
The bright star at the bottom of Orion in the eastern sky is Betelgeuse. It is a cool giant star many hundreds of times wider than our Sun. Astronomers call such stars, 'red giants'. The name Betelgeuse comes from an Arabic phrase meaning, 'the armpit of the central one'.
To help you learn about the southern night sky, Sydney Observatory provides an audio guide/podcast, transcript of that audio, and a sky map or chart each month. This month's guide is presented by Dr Nick Lomb, Sydney Observatory's Curator of Astronomy.
The middle 'star' of Orion's dagger is not a star at all, but a huge cloud of gas and dust. Located about 1500 light years from us, it is a region where new stars are forming. Through a small telescope it is one of the most spectacular sights in the sky.
The giant planet can be seen in the north-east each evening after sunset. It is still shining brightly as it is only three weeks since it was at its closest to Earth for the year. Tonight the gibbous Moon is above and to the left or north of the planet.
The most successful comet discoverer in history, Jean-Louis Pons, was born on this day in 1761, making today his 251st birthday. As a young man Pons started his astronomical career in the unassuming role of concierge at the observatory in Marseilles.
Yesterday’s summer solstice represented the end of a long cycle of 13 b'ak'tuns or 5125 years in the Mayan calendar. Some people misinterpreted the meaning of the long cycle to the Mayans as well as modern science to suggest disasters such as the Earth crashing into the black hole at the centre of the Galaxy.
Today is the day of the summer solstice for at 10:12 pm Australian Eastern summer time the Sun reached its most southerly position for the year. At midday it is at its highest in the sky for the year and the interval between sunrise and set is the year’s longest.
Close-packed spheres (oranges) in a regular sequence. Picture Nick Lomb Jupiter is the largest planet in the solar system and much larger than the Earth. One way of illustrating the size difference is to ask how many earths could fit inside Jupiter.
Orion the Hunter is low in the eastern sky. The three stars in a row represent his belt while above the rightmost (southern) star of the belt is Orion's dagger. Note that wearing the dagger above the belt was not a Greek fashion; it is just that Orion was first named from the northern hemisphere so that to us he is upside down.
The magnetic field of the Sun at minimum in 2008 and near maximum in 2012. Courtesy Lockheed Martin Solar and Astrophysics Laboratory Quietly, without ceremony, the sun is reversing its polar fields!
In Greek legend Orion the Hunter was the son of Neptune. He was a giant who could wade through the seas with his head above the waters. Nature conservation was not his strong point and he threatened to kill all animals on Earth.
After dusk the constellation of Orion the Hunter can be seen low in the eastern sky. As seen from the southern hemisphere, Orion is upside down. Rigel, the bright star at the top of Orion, represents Orion's left foot.