2013 promises to be an interesting year for astronomy. High on the list is the possibility that we may be treated to not one but two bright comets. Predicting the brightness of comets several months before they come close to Earth is a hazardous occupation. And comet ISON is at present a very dim object in the outer reaches of the Solar System. Nevertheless, there is at least a 30% probability that this comet, due to appear in our skies around November 2013, could be about as bright as the full moon. If so, it will be truly spectacular.
Nor will it be the only comet this year. Comet C/2011 L4 should be visible as a fairly bright comet in March.
Comets are dirty snowballs, mixtures of ice and dust left over from the formation of the Solar System about 4.5 billion years ago. Billions of them orbit the Sun beyond the orbit of Pluto. Gravitational perturbations sometimes disturb a comet, causing it to fall in towards the Sun. As it gets closer to the Sun, it gradually develops a tail of evaporating debris, which slowly disappears again as it returns to the region from which it came. Unless it suffers further gravitational perturbations, it will continue in this new orbit, making periodic returns to the inner Solar System at regular intervals. The brighter and closer comets are visible from Earth.
The Torbay Astronomical Society will be continuing with its usual series of meetings at Torquay Boys’ Grammar School in Shiphay Manor Drive, starting at 7.30pm.
10 January: Observational evening. Focus on the Orion Nebula and Betelgeuse. Wrap up well!!
24 January: Secretary’s Address. I shall be talking on the topic Measuring the Universe. If you would like to know how we measure the distances to planets, stars and distant galaxies, do come along.
Visitors and new members are always welcome. There is a £3 charge for visitors to the lecture evenings, and a £2 charge for the observational evenings. Annual membership is a mere F15, with a reduction to £10 for senior citizens.