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 Email any questions to [email protected]