The Sky At Night

As the dark winter evenings slowly start to give way to lighter spring evenings, there is still time to see some fascinating sights in the winter night sky. The planet Jupiter is currently the brightest object in the evening night sky, and can still be seen close to the western horizon. It sets at 8pm on 10 March here in Devon, and will set ever earlier after that. Good binoculars or a small telescope will show Jupiter’s four large moons, first discovered by Galileo in 1609, just over 400 years ago. Larger telescopes will show Jupiter’s belt system.

Jupiter is easily the largest of the planets. You could fit 1,000 planet Earths inside it, with some room to spare. It is a gas giant, without a visible solid surface, and is made mainly of hydrogen and helium. It takes just under twelve Earth years to go once round the Sun.

The people of Devon are luckier than many, because our skies are a little less light-polluted than those seen from large cities. For a really dark sky, far from any light pollution, you need to go to Dartmoor. From here, on a moonless night, you will be astonished at the vast numbers of stars that you can see.

The constellation of Orion, probably familiar to most people, still dominates the southern night sky in the evening. Take a look at Orion’s belt of three stars. Immediately below the belt is a fuzzy patch of sky, which is actually a gigantic stellar nursery, where new stars are gradually being born inside a colossal cloud of gas and dust. And if you follow a line from the belt eastwards, you will arrive at the star Sirius. Sirius is the brightest star in the sky (outshone only by the Sun, the Moon, and the planets Venus, Jupiter, and Mars). Yet even Sirius, one of the closest stars to Earth, is still an unbelievable 80 million million (that’s 80 followed by twelve zeros) kilometres distant from us.

The early birds among you can spot the planet Venus, rising in the east a couple of hours before the Sun, and outshining Jupiter. Venus is Earth’s “evil twin”. It is about the same size as Earth, but has a thick atmosphere of carbon dioxide, a greenhouse gas which causes the surface temperature of Venus to be a scorching 470º C.



About the Author

I obtained a degree in astronomy and physics before going on to work for British Telecom in London. I took early retirement from BT, and my wife - who was born in Devon - and I have now retired to Torquay, where I have been able to take up my interest in astronomy with renewed enthusiasm.

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