After dusk each evening we can see the ringed planet Saturn in the north-west sky. After its close approach on Monday and Tuesday evenings the red planet Mars is still above and close by. Tonight the crescent Moon is below and to the left or west of Saturn and so we have an interesting configuration in the sky with two planets and the Moon.
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Scientists studying the microwaves left over from the Big Bang have worked out the makeup of the Universe. Only five per cent is ordinary matter like the matter in people, bricks and air. The rest of the Universe is mysterious dark matter or even more mysterious dark energy.
We cannot see the origin of the Universe at the Big Bang, but scientists can study its afterglow dating from only a few hundred thousand years after the event. To do so they are using the European Space Agency’s Planck spacecraft that circles the Sun at a distance of 1.5 million km from Earth.
Over the last few evenings the elusive planet Mercury has become visible low in the west after dusk. Tonight a very thin crescent Moon can be seen above and to the left or south of the planet. This is the first opportunity to see the crescent after the instant of new Moon that occurred just after midnight on Tuesday morning.
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 Geoffrey Wyatt, Sydney Observatory's Senior Astronomy Educator.
The constellation of Centaurus the Centaur contains the two pointer stars to the Southern Cross as well as Omega Centauri, a famous cluster of a million or so stars. From a dark sky the cluster is easily visible to the naked eye, while through binoculars it looks like a fuzzy blob.
The red planet Mars and the ringed planet Saturn are both in the north-west sky each evening after dusk. Over the last few evenings Mars has been approaching Saturn which has remained sedately still near the star Zubenelgenubi.
Tomorrow Sunday morning early risers can enjoy the sight low in the eastern sky of a thin crescent Moon above and to the right or south of the planet Jupiter. As the sky starts to brighten with the approaching sunrise the bright planet Venus rises above the horizon and forms an equilateral triangle with Jupiter and the Moon.
The two bright stars marking the location of the Southern Cross are called the Pointers. Alpha Centauri, the one that appears furthest from the cross, is the closest star to the Sun at a distance of 4.3 light years from Earth.
The Southern Cross gives us an easy means of finding south on any clear night. Extend its long axis by four and a half times its length to reach a point known as the South Celestial Pole. South is the point on the horizon directly below the pole.
The stars of the Cross all appear to be at the same distance but that is not the case. Like the stars of all constellations, they are physically far apart: the closest star to us in the Cross is Gamma at a distance of 88 light years, while the furthest star Delta is at 364 light years distance.
Today is the anniversary of the birth of the first Astronomer Royal John Flamsteed in 1646 in Denby (near Derby), Derbyshire, England. Flamsteed took charge of the newly built Greenwich Observatory in 1675 and began plotting star positions.
Below Spica, the brightest star of Virgo the Maiden, is the star Porrima, the name of which means the goddess of prophecy. Porrima, also in Virgo, is a double star 38 light years away. The two components circle each other every 170 years.
If the sky is clear it maybe worthwhile rising early tomorrow morning as the two brightest objects in the night sky apart from the Moon, Venus and Jupiter will be close to each other. Separated by less than a moon-width, the two planets will be low in the east in the brightening dawn sky.
These are the 13 constellations that the Sun passes through during the course of a year. Looking from west to east in the early evening the following zodiac constellations are visible: Virgo, Libra, Scorpius, Ophiuchus, Sagittarius, Capricornus and Aquarius.