Lecture – “The Sun, Space Weather and Lagrange Points” - 16th October 2019 – Prof Lucie Green, UCL

A large audience turned out to hear an extremely well presented lecture by Prof Lucie Green about solar research and the impact the Sun has on conditions on Earth.

She started by summarising the achievements of the twelve instruments aboard the SOHO solar observatory which provided an uninterrupted view of the Sun for over two solar cycles between 1996 and 2013. A new subject of helioseismology emerged, allowing sounds from the Sun to be used to determine what is happening inside the Sun. Professor Green showed spectacular videos of solar activity including dramatic coronal mass ejections, and it became clear that the planets of the solar system are at the mercy of the Sun’s “atmosphere”.

SOHO’s success arose primarily from the position at which it was placed – namely between the Earth and the Sun, orbiting Lagrange Point L1, thereby affording an uninterrupted view of the Sun.

Lagrange Points, Prof Green explained, are points near two large bodies in orbit (for example the Sun and the Earth) where a smaller object (such as a space telescope) will largely maintain its position relative to the large orbiting bodies.

Lagrange points L1, L2 and L3, which are a little unstable, lie along the line connecting the two large masses. The more stable Lagrange points - L4 and L5 - form the apex of two equilateral triangles that have the large masses at their vertices. L4 leads the orbit of earth, L5 follows.

lagrange.jpg

These Lagrange points potentially have uses. L2, for example, would be a great place to do astrophysics or comet science, with the Sun out of sight.

Prof Green concluded her talk with a discussion of Magnetic Flux Ropes. These are bundles of magnetic fields that are twisted about each other and wrap around a common axis. From above they form an S-shape but they are probably helical in nature. They are believed to constitute the key component of coronal mass ejections.

And this is why Lagrange Point L5 may hold a special place for space weather forecasting. The impact of space weather on the Earth is already clear: in 2003, for example, forty-seven satellites were temporarily blacked out because of solar activity, power outages affected many on Earth and there was some disruption to GPS. A weather station at L5 would allow us to see “round the corner” of the Sun to see what’s coming and could provide an early-warning system for adverse space weather.

Wycombe Astronomical Society was very privileged to have Prof Green as a guest speaker. Let’s hope it won’t be too long before we see her again!

Sandy Giles

2019 Astroimaging exhibition – “probably the best so far”

Moon with plane - by Kevin Hodgson

Moon with plane - by Kevin Hodgson

Wycombe Astronomical Society member Richard Jenkinson declared that the 2019 Astroimaging Exhibition was probably the best so far. He also reckoned the standards are getting higher.

Over seventy images were presented by members at our annual exhibition on 4th July ranging from pictures of a sundial in Marlow to nebulae and galaxies in the night skies. We also saw aurora (including a couple of Richard’s videos of them), many lunar images, some planetary. And not forgetting star clusters.

Some of the images shown can be seen here.

Sandy Giles

HOYS-CAPS citizen science project Lecture by Dr Dirk Froebrich (University of Kent) – 19th June 2019

citizenscience.png

I had expected quite a different, more practically oriented talk about the technical details of providing images for the HOYS-CAPS project (Hunting Outbursting Young Stars with the Centre for Astrophysics and Planet Science), and so I was pleasantly surprised that we instead received (with a great deal of German humour) a very well presented revision lecture on the formation of stars and planets.

Having reminded us how stars form from hydrogen, helium and gravity (but countered by thermal pressure, turbulence and magnetic fields) Dr Froebrich continued to discuss our understanding of planet formation, both rocky planets like our own, and gas giants like Jupiter. Measuring the light output from these stars is central to comprehending this and how recording transient changes in star brightness is helping us understand these processes better.

But the key is data and there is only limited time one can get on the big telescopes like Hubble and ALMA – hence the call to amateur astronomers to provide images . The HOYS-CAPS project involves long term, multi-filter optical photometric monitoring of young, nearby star clusters or star forming regions visible from the northern hemisphere. It currently involves about 55 participants who take images of objects on their target list (e.g. the Orion Nebula, NGC 2264, NGC7129 and the Pelican Nebula), perform a basic data reduction (flat-fielding and dark/bias correction) and submit these reduced images for inclusion into the database via a newly developed web-interface.

Dr Froebrich wants to increase participation in HOYS-CAPS to a much larger number of amateur societies across the entire UK. This potentially includes Wycombe Astronomical Society and/or its members, so the aim of this presentation was for us to gain an understanding of the scientific goals and results of the project and how we can participate.

Judging by the number of questions he received and the animated discussions after his talk, it seems there is some interest amongst our membership to engage in real current scientific research.

Sandy Giles

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