Over the moon: astronomy

Round & About


Tony Hersh of Newbury Astronomy Society explains more about what we can see in the skies above us this month.

This month we have a supermoon visible from the UK! The moon is in a slightly elliptical orbit around the Earth so varies in its distance from us. On Tuesday, 19th February, it is at its closest distance, some 356,846 kilometres away and it will appear 14% bigger and 30% brighter compared to a full moon when it’s most distant from Earth (406,700 km).

But 14% isn’t a huge amount bigger so don’t expect a sight vastly different from usual. This month is a good time to see Venus and Saturn, which appear very close to each other and near the moon at 6am on Monday, 18th February.

Object of the month

All stars are created and work the same way. Vast clouds of gas (mostly hydrogen) in the universe, gradually coalesce into spheres of material. The rate of coalescing speeds up as the mass increases and gravity attracts more and more material together. After mass of hydrogen exceeds a vast but specific quantity (2.5 with 28 zeroes after it kilograms!), the pressure in the centre is so huge temperatures reach 10 million degrees Centigrade and nuclear fusion starts. It’s the nuclear fusion, combining the hydrogen into helium, that releases the energy making stars shine. Stars vary enormously in size and temperature, some being much heavier, fusing hydrogen much faster and so being hotter and blueish in colour, others have lower mass and have slower fusion reactions so are cooler and appear reddish in colour.

Find out more at Newbury Astronomical Society’s monthly meetings.

    Visit www.newburyastro.org.uk. Email any questions to [email protected]

Seeing red

Round & About


Tony Hersh of Newbury Astronomy Group explains more about what we can see in the skies above us this month, including the red moon.

July is exciting for astronomers due to the total lunar eclipse between 8.45pm and 9.30pm on Friday, 27th.

During this event Earth comes between the moon and sun. Instead of plunging the moon into darkness from Earth’s shadow, something unusual happens. Sunlight is made of light of all the colours of the rainbow mixed together, but as it travels through Earth’s atmosphere, the path of the light changes as it hits air molecules and particles. Colours with shorter wavelengths, such as blue, are scattered off in random directions but colours with longer wavelengths, such as the reds, are scattered less. So the light that emerges after being bent in the Earth’s atmosphere has more red colour and turns the moon an amazing ruby hue. Have a look out and see how red the moon becomes!

Turning to constellations, see if you can find part of Sagittarius which is visible low in the sky directly south and appears as the shape of a teapot. Planets are difficult to spot in a lightish sky but Mars is at its largest and brightest all year this month and should be visible close to the moon on the first of the month. Venus should be clearly visible just to the left of a crescent moon at 9.30pm on 15th July and Saturn again just to the left of the moon around the same time on 24th.

Object of the month

When a comet approaches the sun, the frozen gases trapped beneath its surface evaporate and dislodge dust grains from the surface of the comet which can be seen from Earth as the comet’s “tail”. In 2014, after a 10-year journey, the European Space Agency’s Rosetta spacecraft finally reached its destination with Comet 67P/Churyumov-Gerasimenko. For the next two years, Rosetta orbited the rubber-duck-shaped comet, analysing the dust the comet was losing. Recently a landmark study was published, reporting about half of the 35,000 dust grains captured and analysed by the Rosetta probe were made of organic molecules; carbon-based molecules such as proteins, carbohydrates, and nucleic acids. The finding adds weight to the suggestion that comets were responsible for “seeding” the early Earth with organic matter which eventually gave rise to life.

Newbury Astronomical Society hosts monthly meetings for beginners and experienced astronomers. Visit www.newburyastro.org.uk. Email any questions to [email protected]