Cold Dark Matter – Is it cold, dark or matter? - Lecture by Dr Julian Onions – 15th May 2019

Prof_Julian_Onions.jpeg

Getting to the answers to the questions posed in the title of this stimulating lecture proved quite a challenge for our speaker from Nottingham University, Dr Julian Onions – and not for the want of trying but because the answers are proving rather elusive. To tackle the issue and give us some background, he asked three further questions – why do we believe it exists, what could it be and how could we find it?

It is currently believed that the Universe consists of Atoms (4.6%), Dark Energy (72%) and Dark Matter (23%). In much the same way that the postulations of the Neutrino and Higgs Boson well pre-dated their actual discoveries, so too has the notion of Dark Matter, first proposed in the 1930’s by Fritz Zwicky following his studies of the motions of galaxies and the amount of light emitted in the Coma Cluster. The concept of Dark Matter was required to account for the observation that the gravitational mass of the galaxies within the cluster was at least four hundred times greater than expected from their luminosity. Later modelling studies of galaxy formation also didn’t reflect what was going on without dark matter being part of the models. Yet further evidence for its existence came from work on Gravitational Lensing and studies of the Cosmic Microwave Background.

Quite what it could it be, Dr Onions continued, brought us candidates such as axions, sterile neutrinos, weakly interacting massive particles (WIMPs), gravitationally-interacting massive particles (GIMPs), super-symmetric particles, and primordial black holes. Not to forget MACHO’s (Massive Compact Halo Objects)! But right now there is no technology available to detect dark matter – and the cost of it makes the price of the Large Hadron Collider and the LIGO detectors seem just like petty cash!

So what conclusions can be drawn?

  • Is it Cold? – Maybe, but it might be warmish.

  • Is it Dark? – Also maybe, but it could just be transparent.

  • Is it Matter? – Mmm, not really.

And in the end, does it matter? Well, probably yes! Because if we discard it as a concept, we might need to completely rewrite our understanding of physics and quantum mechanics … and gravity … and relativity … and cosmology ….

Sandy Giles

“One Small Step” – Lecture by Andy Green – 17th April 2019

Green_lecture_composite.jpg

Having lived through the time of the Apollo Lunar Landings in the late 1960s and early 1970s, having watched (almost) all of them live on TV and having just given a lecture myself on the subject to Tylers Green Middle School, I thought I knew quite a lot about these mission.  Er … no! My knowledge paled into insignificance in comparison to Andy Green’s encyclopaedic grasp of the subject!

His well illustrated and excellently presented lecture covered the history of rocketry from Werner von Braun’s time in the Second World War, through the Mercury and Gemini programmes and culminating with the might Saturn V multistage rocket of the Apollo missions. Each major Apollo mission was covered: Apollo 1 and its fire, Apollo 7 the first proper test flight around the Earth, Apollo 8 to the Moon and back, Apollo 9 where the Command and Lunar Modules were tested together, Apollo 10 (the one that’s in the Science Museum!) and then Apollo 11 the first actual lunar landing, fifty years ago. And he didn’t stop there – on to Apollo 12 launched in a thunderstorm, Apollo 13 the doomed mission accurately portrayed in the movie, Apollo 15 when the first buggy was used and finally Apollo 17 which took place during the Vietnam War, involved a night time launch and led to the discovery of orange rocks on the Moon.

Andy Green has met about half of the astronauts who walked on the Moon and had a couple of Apollo artefacts to show, for example a test block from a Heat Shield. He also dismissed the notion that the missions were a hoax and just carried out in a studio – thousands of companies and over 40,000 individuals were involved. Astronauts and support staff were over 100 and 383 kg of Moon rocks (different from those found on Earth) were brought back. Even the first Russian space walker, Alexei Leonov, believed they were true – if you were going to plot a hoax, he observed, you’d only do it once – not six times!

Article: Sandy Giles

Pictures: Paul Phillips

Wycombe Museum Outreach Event – 8th April 2019

Wycombe-Museum-April-2019.jpg

Bearing in mind it snowed last time we did an outreach event at Wycombe Museum, we were extraordinarily lucky this time – our guests actually saw something!

52 guests, about half of them youngsters, enjoyed a dinner whilst listening to a presentation from Sandy Giles about the 1969 Apollo 11 lunar landing mission and about the Moon. The cloudy weather showed little sign of clearing so Gary Taylor, Paul Phillips and Brian Greenow prepared to set up their scopes in the Museum buildings for a show-and-tell session.

But just as Sandy was finishing his presentation the sky semi-cleared, sufficient that at least the Moon could be observed through scopes. Hastily the scopes were re-positioned outside and our guests quickly lined up to catch it before the clouds returned.

Everyone enjoyed the evening, several guests were keen to come along to our meetings and a number expressed an interest in actually buying a telescope. Wycombe Sound Radio also attended the event and Brian and a couple of the guests gave interviews.

As we packed up, the clouds returned – it even started to rain. However, it was a very successful outreach event (we’ve been invited back for another Stargazing Evening on 16th November 2019). But we really were lucky!

Sandy

Thank You from Tylers Green Middle School

IMG_8127.JPG

Sandy Giles’s visit to Tylers Green Middle School in January to talk about the Apollo 11 mission fifty years ago clearly excited and motivated the children. They sent over 100 individual thank you letters and pictures, some of them begging for him to return. As one of the children from Class 4F wrote “Thank you for giving up your free time so you could come and see us – we all really appreciated that. Being a lover of space is great!”

Some of the children and their parents plan to attend our next Field Astronomy session on 7th March and we very much look forward to welcoming them.

Science Week at Tylers Green Middle School – 21st January 2019

Tylers Green.jpg

Tylers Green Middle School are celebrating their 50th Anniversary this year by holding a Science Week to study the technological advances made over the last half a century. Wycombe Astronomical Society were invited to participate and we provided our contribution with a short lecture from Sandy Giles to the whole school on the Apollo 11 Lunar landing in 1969. Sandy also went round to the individual year groups fielding questions about astronomy from the children. “I was rather nervous about the questions, but fortunately the teachers had vetted them first. There was a refreshing simplicity to some of them which nevertheless required careful answers – for example why does the Moon sometimes change colour.” The school are entering their budgeting phase for next year and the purchase of a telescope is now actively being pursued.