Pulsars

Professor Dame (Susan) Jocelyn Bell Burnell, DBE, FRS, FRAS (born 15 July 1943) is a Northern Irish astrophysicist. In 1967, as a PhD student, she discovered the first radio pulsars while under her thesis supervisor Antony Hewish for which Hewish shared the Nobel Prize in Physics with Martin Ryle. Bell Burnell was left out, because at that time, only the "senior men" would receive credit. Bell Burnell was President of the Royal Astronomical Society from 2002 to 2004, president of the Institute of Physics from October 2008 until October 2010, Her talk was fairly basic and aimed at an audience that had little knowledge of the subject.

A pulsar is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. This radiation can only be observed when the beam of emission is pointing toward the Earth, much the way a lighthouse can only be seen when the light is pointed in the direction of an observer, and is responsible for the pulsed appearance of emission. It is not known how this beam is produced. Of 2000 known pulsars most radiate at radio frequencies or infra-red, but a few, 200, radiate x-ray and gamma rays. The energy level is very low, and needs giant radio telescopes to detect at all. This is a limiting factor in research. Neutron stars are very dense, and have short, regular rotational periods, up to 600 - 700 RPM. This produces a very precise interval between pulses that range from roughly milliseconds to seconds for an individual pulsar.

Pulsars are formed from the collapse into supernovae of stars with more than 20 sun masses. Most of the mass is blasted off into space as the familiar elements. The remainder collapses into a very dense body with a high neutron content. The diameter of a pulsar is reckoned to be about 10KM – any bigger then at 700RPM, the surface would be travelling faster than light which would be impossible. They weigh as much as our sun, ie, 1027 tonnes. A thimble full = 46 million tonnes. This mass produces very strong gravitational effects which bends and red shifts light around them. They have hugely powerful magnetic fields, 108 Tesla CF 10 Tesla for the best man made magnetic field on earth, (CERN=8 Tesla) and generate voltage differentials at a rate of 109 V/Cm. Many pulsars exist as binary star systems, occasionally with other pulsars – one pulsar has been observed to have planets.

Einstein made a theoretical prediction that any mass when accelerated would give off gravitational radiation waves and lose energy. A binary pulsar system would radiate gravitational energy and thus the bodies would over time come closer to each other and their rotation rate would speed up. A Nobel Prize has been won for observations of a pulsar system that confirmed Einstein’s prediction exactly proving that gravitational radiation exists. The variations in the binary orbit are infinitesimal. The bodies involved, will collide in 100 million years.

These observations involve measurement of incredibly low energy levels and time differences to very high levels of accuracy which were not explained.

Stroke

Dame Nancy Rothwell. Vice Chancellor Manchester University

Self Interest. Dame Nanyc’s field was research on metabolism, weight gain and chiefly weight loss due to metabolic factors. Almost by accident, while researching fever and weight loss after strokes she discovered that a normal immune system body chemical causes brain damage after strokes, and this is now her prime research area. Stroke research is difficult as funding is hard to get and has been cut since the 90’s.

The brain is very complex with billions of neurones which are present at birth, and do not replicate or regenerate if damaged. They are very sensitive to oxygen lack if the blood supply fails which it does during a stroke; either a clot or bleed may cause this. Even a small interruption can be fatal. Two million cells can die every minute during a stroke, and someone has one every 5 minutes in the UK. It is the 3rd greatest killer and incidence is socioeconomic and age related, but whereas only 10% of strokes occurred in the under 50’s, in recent years this proportion of under 50’s has risen to over 20%. It is not known why.

Treatment is very limited to initial actions to break down clots and recover blood supply. This requires a CT scan to ensure you don’t make a brain bleed worse. There is a drug TPA which does this but it is still in the trials stage of use. In my case they gave me aspirin which has a similar effect. After strokes, large amounts of “killer” molecules are released in the damaged area which go on to do further damage by killing cells that have survived the initial stroke. One of these is Glutamate, an amino acid which is used in very small quantities as a neurotransmitter in normal brain function but kills cells in large amounts. Blocking the action of Glutamate would seem to be a good treatment, but dosing would be very difficult, as some Glutamate is needed for normal function

However, during her research on rats to investigate fever and weight loss after induced strokes, another factor was found to have profound effects related to immune reaction to the brain damage. What is going on in this damage process is a normal body reaction to disease or damage which is inflammation, swelling, reddening, fever etc. This is caused by a family of proteins called cytokines of which Interleukin 1 is a prime operator and is released by damaged cells in large quantities.

It was suspected that blocking the action of Interleukin 1 would inhibit this process and reduce some of the fever and weight loss effects of strokes. An IL 1 blocker is naturally produced in the body and was obtainable in appropriate quantities for tests. Fever and weight loss was found to be reduced. Almost as a side issue, the effect of IL 1 on the post stroke brain damage was also investigated, and an astonishing outcome of this work was a finding that damage was reduced by 50% by the use of IL 1 blockers. This result has been repeated during a very small trial with a human patient group. A larger trial of 140 patients is about to start, and if effective may move immediately into a large scale trial. The exciting prospect is that IL 1 blockers may prove effective in a wide range of brain diseases. However, since IL 1 is a natural product that fights infection, its prolonged use will reduce natural immunity and 1 – 3 days treatment may be the limit.

In the longer term Dame Nancy believed that work to find out how to repair and regenerate brain cells after strokes will be the way ahead.

Liquid Crystals – Prof Stephen Kelly Hull University

Prof Kelly went through the history of liquid crystal displays starting with Friedrich Reinitzer in 1888 who extracted chlorestorol and isolated chlorestorol benzoate, the first liquid crystal. On investigating its properties, he discovered that it could exist in a transitional stage between solid and liquid dependent on temperature – a fourth property, liquid crystal, to join solid, liquid and gas. While in this state, it refracted light as it passed through it, and this refraction could be varied by the application of an electric voltage. It has since been discovered that 10% of compounds exhibit this liquid crystal state and refract light variably with applied electric charge. If a liquid crystal is placed between two polarising filter layers, application of a voltage can make it opaque or able to transmit light – this can produce a black and white contrast display.

The first commercial development of liquid crystal displays .were made in the 1970 arising from PhD research by Prof Kelly at Hull University. The display was taken up by Swiss and Japanese watch companies, and by the MOD anxious to find an alternative to high licence costs paid to RCA the owner of CRT patents. Early LCDs were limited in information content by the need to wire the individual element contacts cured by creating multiplexing grid wiring, an later by integrated circuits permitting individual pixel addressing. Later improvements to liquid crystal compounds enable better contrast, wider viewing angles, and the introduction of colour filters to permit full cl0our displays.

LCD displays are now universal, and have replaced CRTs and permitted the huge range of screen devices we use every day. The liquid crystal compounds themselves are every expensive but, in order to give a fast reaction time, eg moving displays, the gap between the glass sheets containing the liquid crystal is only 5 microns so the amount of liquid crystal used is very small. The costliest LCD displays are TV screens. These require the electric pixel addressing conductors to be printed on silicon sheet substrates. These are very expensive as silicon sheets larger than 6” across are hard to make. Each 1” increase in size, doubles the cost.

The future of LCD lies in the fact that they are semi-conductors. Research at Hull is looking at light emitting LCDs which would save a lot of energy. Our TV screens are illuminated from the rear, and only 3% of the light at the back comes out of the front. LCDs will also form part of the growing use of plastic electronics, and they will also make possible very cheap, very robust solar cells – not nearly as efficient as silicon, but which could bring cheap electricity for small uses in the third world where there isn't any.


Eight Great Technologies – David Willetts – Minister for Science and the Universities

Mr Willetts suggested that while it was fashionable to decry British industry as in decline and that the development of ideas to business was poor, this was not the cast. There were grounds for great optimism about the UK’s place in the world and potential of our science and induastrial base. In Government, priorities for investment and development had to be identified, and this was his task. He had identified 8 future technology areas where the Government was going to back endeavour in those fields.

  1. Big data sets assembly and computing. The UK has 20 of the 100 biggest computers in the world (GCHQ?). We are world leaders in efficient software writing which in turn produces energy saving in computer tasks. IBM SW HQ for Europe in the UK. We have the largest weather and medical datasets in the world. Raspberry Pi which is becoming a world standard for teaching programming to young people was designed, and is built in Wales.


  1. Satellite design and Commercial Space Technology. We are a world leader in the design of small commercial satellites – small = energy efficiency, and lower launch costs. Virgin space tourism vehicle could be used to launch small satellites! US technology and not capable of orbit!



  1. Robotics and Autonomous Systems. The UK is behind on the use of robotics in industry but equal to the best in design capability and precision. The UK is very good at the combination of mechanics and software. The UK is very good at autonomous systems and the European Mars Rover in 2018 will be autonomous CF the US Mars Rover which has a low operating speed because each instruction to move takes 7 minutes to deliver. Wikipedia says that a Canadian Company has the contract to build the Euro Rover. There is an autonomous car project at Oxford similar to the Google vehicle in the US.



  1. Life Sciences and Synthetic Biology. All gene sequencing technology is British and is sold to the US. The NHS is to record the full genome of 100K patients forming a world class dataset which could not be achieved in the US – no NHS. Bioinfomatics. The UK is collaborating with the US and China in creating a standard gene sequencing and construction software architecture to enable the design and creation of specific genes – bit worrying that one!



  1. Regenerative Medicine and Damage Repair. The UK leads research in the use of adult stem cells to create specific cell types for regeneration and repair of damaged tissue.

  1. Agricultural Science. The UK is a leader in GM research partly because we have a long history of agricultural research. Current serendipitous research has revealed that food plants can be given cancer inhibiting effects – in mice at least! Plant research aims to double wheat yields from 10 – 20 tons per acre by 2020 (organic yields are 1 ton per acre) and reduce the requirement for fertiliser and pesticides. Semi-autonomous tractors, precision fertiliser dispensers and satnav, enable fields to be fertilised metre by metre – computing again.

8. Advanced Materials and Nanotechnology. The UK has Nobel Prize winners in this field.

  1. Energy and Energy Storage. Research is going on to improve renewable energy generation efficiency, use hydrogen as fuel and to improve batteries. Lipos were invented in Oxford but the UK has no lipo battery industry. Improving university/industrial links is an on-going project for Government.

Question. What are we going to do about nuclear energy now that we have got rid of all our nuclear expertise.

Answer. Industrial skills have been lost in the past and then regenerated. Nuclear energy may be one of these. The UK is a very major participant in fusion research, and computer expertise at Culham means we can ger more data from experiments because we can measure more accurately.


Autonomous Robots. Prof Alan Winfield Bristol Robotics Lab, Nick Hawes of Birmingham Uni and Abigail Hutty of Astrium, a subsidiary of EADS and a provider of a whole range of space technologies.

NH defined autonomous robots as self-controlling, ie able to sense their environment, choose from response options, and able to execute decision actions. Factory robots in manufacture cannot do this. He demonstrated Dora a robot able to explore and map its local environment by moving around and “seeing” obstacles.

AW was interested in swarm robotics, that is how robots might simulate the actions of insects which, while very simple individually, are able to create very complex systems without any overall controlling actions by a management entity. He demonstrated some very small robots with only two behaviour patterns, 1 turn away from obstacles and 2, follow red lights on the rear of other robots. His operating space was too small for a good demo as the robots should, after random circulation, have ended up in a follow my leader line.

AH Is involved in the design of the European Mars Rover to be launched in 2018. She brought Brenda, a large prototype as a demo. The EADS Mars Rover will have a degree of autonomy in operation in that if given a destination, it will be able to map its locale, and plot a safe route and travel to the given point to do scientific experiments. The current US Mars Rover needs many individual movement messages to do such tasks. Each message takes 7-20 minutes to reach Mars and this severely limits what can be done in the Martian day while solar energy is available to power the Rover.

Astriums prototypes have demonstrated the designed self -navigation ability in simulated mars terrain environments. A big problem is hardening computers against high radiation levels on Mars which slows processing.

The team answered questions about their robotics wish list. Desired were soft robotics that look and feel more like living organisms, harder processors to cope with radiation, and infinite computing power and good computer vision.

A consensus was that autonomous robots are proving much harder to develop than was once thought. Integration of sensors with computers to produce decision responses that are easy for animals is near to impossible at the moment, severely limiting how autonomous a robot can be. Real autonomy may not be a good idea anyway.


Great Comets. Prof Alan Fitzsimmons Queen’s Uni, Belfast, Prof David Jewitt UCLA, and Pete Lawrence astronomer and broadcaster.

Too dark for notes my source is memory and Wikipedia.. The team defined Great Comets as being bright enough and in a suitable part of the sky to be obvious to a casual observer. Most comets are not great.

Comets are small rocky icy bodies tens of metres to tens of kilometres in size. When close to the sun dust and water vapour are driven off by the sun’s heat, and are driven away from the sun by solar pressure producing long visible trail.

Comets have a wide range of orbital periods, ranging from a few years to hundreds of thousands of years. Short-period comets have nearly circular orbits and originate in the Kuiper belt of asteroids which lie beyond the orbit of Neptune.

Longer-period comets have very elliptical orbits outside plane of the solar system planets and are thought to originate in the Oort cloud, a hypothesized spherical cloud of icy bodies in the outer Solar System. Long-period comets plunge towards the Sun from the Oort cloud because of gravitational perturbations caused by either the massive outer planets of the Solar System (Jupiter, Saturn, Uranus, and Neptune), or passing stars.

As of January 2011[update] there are a reported 4,185 known comets[6] of which about 1,500 are Kreutz Sungrazers and about 484 are short-period.[7] This number is steadily increasing. However, this represents only a tiny fraction of the total potential comet population: the reservoir of comet-like bodies in the outer Solar System may number one trillion.[8] The number visible to the naked eye averages roughly one per year, though many of these are faint and unspectacular.[9] Particularly bright or notable examples are called "Great Comets".

In 2013 there were/are forecast to be 2 Great Comets, Comet PANSTARRS in April and Comet ISON in December. Comet PANSTARRS was a disappointment being generally too close to the sun or faint for observation (I know I tried). Comet ISON has already been detected by the Hubble telescope out near the orbit of Jupiter, and could be the comet of the century in late November and December.



Mars Curiosity Rover.

Prof Sanjeev Gupta Geologist of Imperial College and Participating Scientist with. NASA.

Dr Lewis Dartnell, University College London, Astrobiologist and NASA biology team

Both men were enormously enthusiastic about their work. (Prof Gupta can be heard talking to Jim Al-Khalili on the BBC programme “The Life Scientific” broadcast on May 14th). Their talk was chiefly showing us images from the Mars Rover Curiosity, and explaining their programme. It was too dark to make notes! An interesting point was that there is almost no mechanical redundancy on the Rover so each movement has to be planned in enormous detail, and enacted on earth on another Rover before instructions are sent to mars. Similarly, because the project could end with mechanical failure at any time, then each days programme is planned and the results assessed one day at a time. The object of the mission is to research the geology, and not to detect life/evidence of life. This is because such a mission would probably fail, and this would probably result in cessation of the funding to NASA.

Any manned mission to Mars while technically possible would face enormous difficulties in that the fuel etc needed for the return trip would make the initial vehicle impossibly large. However, it might be possible to find volunteers to go to Mars and live out their natural life span there! The biggest hazard is radiation and charged particle outbursts from the sun which would be likely to reach fatal levels in even a two year return mission.





Richard Feynman. No Ordinary Genius.

MC Robin Ince, Comedian and BBC Infinite Monkey Cage Presenter.

James Gleick, Feynman’s Biographer.

Christopher Sykes, BBC Documentary maker and Author.

This was a very good free flowing exchange between a bright MC, a man who had written about Feynman but not met him, and a BBC Horizon documentary maker who had spent a lot of time with Feynman, and whose work can be seen via his website www.sykes.easynet.co.uk and also illustrated the session. Again, it was too dark/too difficult to make notes. I strongly recommend Gleicks’s book, and a visit to Christopher Sykes’ website.




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