As is traditional, the OAS Christmas meeting had no formal speaker. However, we did have a healthy quantity of Christmas food, and whe had the now-traditional Solstice Quiz, set this year by Tony Sizer. It was a close-fought and sometimes hotly disputed battle, and in the end the Tardigrades won by a single point...

This evening's talk, with the title "Are We Alone?", was given by Robin Catchpole.Report to follow...

This evening's talk was given by Chris Lintott, familiar to many as co-presenter of the BBC TV programme The Sky at Night. His talk, with the title "Who, What and When?" was an animated and enthusiastic run-through of progress in our understanding of the Universe and our place in it. He began with "When?", starting with Olber's Paradox, and leading through events such as the discovery of red-shifted galaxies and of the cosmic microwave background to our current understanding of the expanding universe which started 13.7 billion years ago. Moving on to "What?", he then explained how the structure of the Universe, with its many clusters of galaxies, requires not just ordinary matter, but dark matter and dark energy as well. Finally, for "Who?", he took the Drake equation, and showed us just how far we've got in determining whether we're alone in the Universe.

This evening's talk on "Black Holes" was given by Phil Uttley of Southampton University. He gave us an interesting and well-illustrated talk which covered the subject of black holes thoroughly, beginning with the first suggestion of "dark stars" by Rev. John Mitchell in 1784. In the 19th century the idea was set aside when light was shown to behave as a wave, but the work of Einstein at the beginning of the 20th century brought the concept back into consideration. Schwarzchild's solution of Einstein's field equations for a spherical non-rotating body showed that in certain situations the gradient of space-time became infinite, so that nothing could escape. Eddington and Finkelstein refined this, and showed that material could, however, cross the "event horizon" and enter the zone so delimited. The term "black hole" was coined by Wheeler in 1967.

Phil went on to describe the ways black holes might be observed, first pointing out that, as they emit no light, it is very difficult to observe them directly. However, if they're part of a binary system then they'll develop a hot accretion disk. Cygnus X1 is though to be coming from an accretion disk round a black hole accompanying an observable blue super-giant star. Lone black holes might be detected because they could cause gravitational micro-lensing. Quasars and active galaxies have something very energetic at their hearts, and super-massive black holes are considered the most likely explanation. Stars at the very centre of the Milky Way have been observed to be orbiting a point at which nothing can be observed, but their behaviour implies that there must be a very massive black hole at that point. Observations of other galaxies have also led to the conclusion that there are super-massive black holes at the centres of most (and maybe, all) galaxies.It is even possible that these black holes may control the size of their galaxies through a process of active galaxy feedback, where excess material is thrown out along massive jets from the black hole's poles.

Black holes are clearly going to be a subject for research for some time to come.

This evening was a Members Evening. The first half followed the usual pattern, with Society Notes from our Chairman Jim Mehta, and Sky Notes and Society Images from our Observing Officer Mike McRoberts. The second half of the evening was split three ways. First up was Jeff Harries, who gave us a short talk about observing asteroids. Next, Luke gave us a talk on Time Travel, the Possibilities. Finally, Mike McRoberts gave us a talk about Voyager 1.

Sue Peters writes:

The three talks at this month’s members evening provided an excellent,diverse programme covering a range of aspects of Astronomy and were enjoyed by all present.

Jeff Harries shared his interest in observing asteroids explaining the peculiarities of their orbits and included a comprehensive list of recent observations and best observing opportunities for some of the brightest minor planets coming up in the next few years. Jeff’s list should appear shortly on the web site. He offered a challenge to the imagers to capture some of these elusive near neighbours and also Pluto, so we will await results with interest.

Luke Punnet presented a fascinating talk on time travel. He used examples from the media; clips from science fiction films and reference to literature to introduce the concept and then gave an overview of the physics underlying current theories including discussion on the possibilities/pitfalls of time travel.  His enthusiasm for the subject was evident and he answered questions from the floor at the end knowledgably and with confidence. I think that Luke is probably the youngest speaker we have had at the society and look forward to hearing more from him in the future.

The last talk was by Mike McRoberts on the Voyager missions. An amazing story well illustrated. There were a lot of details about the mission that I had been unaware of. I particularly enjoyed hearing some snippets of the recording for the ‘Aliens’ that might find the craft travelling beyond our solar system. It was fascinating to hear how these tiny craft are still working and now providing a unique insight into the Heliosphere. They are so far away it now takes over 15 hours for signals to be relayed each way. Mike directed us to the Voyager web site to discover more about the missions.  He finished his talk with the poignant piece written by Carl Sagen about human kind on our unique earth (pictured by Voyager as a pale blue dot in the vastness of space). Very thought provoking.
 

Our Observing Officer and past vice-chairman Mike McRoberts gave us some intriguing insights into the life and times of Tycho Brahe and the Uraniborg Observatory. More to follow...

Joanna Haigh, Professor of Atmospheric Physics in the Space and Atmospheric Physics research group at Imperial College, gave us an interesting talk on the subject of Solar Variability and Climate. Full report to follow...

The Society Annual General Meeting was held at BEECHE, High Elms. After the normal business including officers' reports and the election of the committee for 2009, Mike McRoberts gave us his monthly Sky Notes. He reported on a successful Deep Sky Camp, and showed us his pick of the recent images taken by society members.

Carole Pope writes: After the break our President Gilbert Satterthwaite gave an interesting talk on becoming an Astronomer, beginning with his own experience as a grammar school boy in Dorset and his ambition to become an Astronomer which was dashed for a while by a Careers officer who said he might be able to do something with a 1st degree in Maths. Gilbert studied all the right subjects and eventually plucked up the courage to write to the Astronomer Royal for advice, who subsequently sent him lots of paperwork. Gilbert found to his surprise that he was already qualified to apply and applied for an Assistant's post at the Royal Observatory Greenwich. He sat a very difficult mathematical entrance test and was delighted to be offered a position. At first he did not do any observing, but following the departure of an observing assistant was quickly trained up to measure and records transits of many heavenly bodies and often required to sit up all night. He was also doing a lot of studying at the same time including a degree course.

Gilbert showed many books of logarithms and trigonometric tables. These days, Gilbert's work has been taken over by electronic computers. He spoke about how Astronomy has changed over the years and that images taken with the best telescopes years ago are these days being far surpassed by our members amateur equipment.

The speaker at our January meeting was Alan Longstaff. He gave us an interesting introduction to the subject of Cosmology. Full report to follow...