Archive for February, 2013

On Tuesday (26th of February) I heard the sad news of a hot air balloon crashing above Luxor in Egypt, killing 19 tourists on board. 25 months ago, this could have been me. In January 2011 I stayed for a week in Luxor, and as part of my week there did a hot air balloon ride over the Valley of the Kings and the West bank of the Nile. This was my first (and so far only) hot air balloon ride, and it was a truly memorable experience.

Here are some videos I took

One of the neighbouring hot air balloons going up

The safety briefing before we went up in the hot air balloon

In the basket of the hot air balloon

This is not the first time that a tragedy has befallen somewhere that I have myself been. In 1983 I was on my way to Harrods in London when the IRA bomb exploded there. 20 minutes earlier and I would have been in the shop. And a year to the day after I had waited for about 2 hours for a bus at the station in Columbia, Sri Lanka, a huge bomb ripped through the place and killed pretty much everyone there.

Quite sobering.

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Whitney Houston had a massive hit with I will always love you in the early 1990s, but I wonder how many of you have heard the original version by Dolly Parton. It was originally released in 1974 by Parton. Although I like the Whitney Houston version, and it certainly displays her incredible vocal talents, I think the original by Dolly Parton is better. It is less of a power ballad and more of a love song, more tender. Which is how Parton intended it to be.


The story behind the song is that she wrote it for her one time mentor and professional partner Porter Wagoner. Parton used to present a TV show with Wagoner in the early 1970s. When she decided to leave the show, she wrote this song for him. Parton later re-recorded the song in the early 1980s for the movie The best little whorehouse in Texas.

Which version do you prefer, Parton’s or Whitney Houston’s?

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Types of particles

The Universe can be divided into three types of particles: matter, anti-matter and radiation (in the modern Quantum-mechanical view of Nature, radiation can also be treated as particles). Anti-matter is not just a science fiction idea, it was first proposed by Paul Dirac in the 1920s and is made every day in particle accelerators as well as in Nature. Today we can even make anti-hydrogen atoms. Clearly what we see in the Universe is composed of matter, not anti-matter. When matter and anti-matter come together they annihilate each other, producing lots of radiation in the form of high energy gamma rays. In a future blog I will discuss the ideas physicists have as to why our Universe seems to have more matter than anti-matter (if the amounts were exactly balanced all the matter and anti-matter would have mutually annihilated and there would be no matter left in the Universe, and hence no “us”).


The Universe is divided into matter, anti-matter and radiation.

The Universe is divided into matter, anti-matter and radiation.


The discovery of atoms

The word “atom” comes from the Greek word “atomos” which means “indivisible”. The idea of atoms thus dates back a couple of thousand years, but it was only in the 19th Century that evidence for their existence was really found. Through the work of John Dalton and others in the field of Chemistry, strong evidence was established that matter was composed of elementary building blocks, with each element being a different building block with different chemical properties. The Periodic Table of the elements was drawn up in the mid 1800s, and by the end of the 19th Century scientists had measurements of the masses of different elements, noting that e.g. Carbon was more massive than Hydrogen.

The first sub-atomic particle to be discovered was the electron, by J.J. Thomson in 1897. Then, in a series of experiments in 1909-10 the atomic nucleus was discovered by Ernest Rutherford and co-workes. Thus the modern picture of the atom emerged, negatively charged electrons in orbit around a positively charged nucleus. This is the so called “solar system model” because of its similarity to our Solar System. By the early 1930s it was known that the nucleus consisted of positively charged protons and of neutrons, which have no electrical charge.


The "solar system" model of the atom has the electrons orbiting the nucleus.

The “solar system” model of the atom has the electrons orbiting the nucleus.


The particle zoo

In the 1950s particle accelerators were used to probe the structure of matter. Initially electrons were accelerated to close to the speed of light, and smashed into stationary targets. As accelerators got more powerful physicists started accelerating protons, which are nearly 2,000 times more massive than electrons and hence much harder to accelerate. Physicists found a plethora of particles emerging from these particle accelerator collisions. Below is a picture of particle tracks in a typical bubble chamber, the device used for detecting these sub-atomic particles.


In the 1950s hundreds of new particles were being created in particle accelerators.

In the 1950s hundreds of new particles were being created in particle accelerators.


Physicists gave names to these new particles, sigma particles, pions, rho particles, D particles, kaons etc. So many new particles were being created in these experiments that physicists started running out of names for them. Some patterns started emerging. One was that particles could be divided into either hadrons (from the Greek word “hadròs” meaning “stout, thick”) or leptons (from the Greek word “lepton” meaning “fine, small, thin”).


Matter can be divided into hadrons (heavy particles) and leptons (light particles)

Matter can be divided into hadrons (heavy particles) and leptons (light particles)


Three quarks for Muster Mark

In the 1960s theoreticians tried to find a model which could be used to explain these hundreds of particles and the division into hadrons and leptons. It was Murrray Gell-Mann of Caltech who came up with the idea that the hadrons were composed of more fundamental particles which he called quarks. The word comes from a line in Finnegans Wake, a book written by James Joyce.

Three quarks for Muster Mark!
Sure he has not got much of a bark
And sure any he has it’s all beside the mark.

Initially Gell-Mann proposed three quarks as sufficient to explain all the observed hadrons, these three he called up, down and strange. However, we now believe we need an additional 3, making 6 quarks in all, to explain all hadrons. The names of the other 3 are charm, top and bottom.


The 6 quarks believed to constitute all hadrons
Name Generation Year proposed Year discovered
up 1st 1964 1968
down 1st 1964 1968
strange 2nd 1964 1968
charm 2nd 1970 1974
bottom 3rd 1973 1977
top 3rd 1973 1995


All hadrons are composed of quarks in this model. Protons and neutrons, the most well known examples of hadrons, are composed of 3 quarks. Any hadron which is composed of 3 quarks and which can decay into a proton is called a baryon. It may surprise you to know that a neutron, if it is not in a nucleus, will decay into a proton, with a half-life of about 14 minutes.

The other type of hadron is called a meson. Mesons are made up of just 2 quarks, and always in a quark-antiquark pair. Mesons cannot decay into a proton, as they have too few quarks.


Hadrons can be further divided into baryons and mesons.

Hadrons can be further divided into baryons and mesons.


The standard model

The standard model of particle physics is shown in the figure below.


The standard model of particle physics.

The standard model of particle physics.


You will notice in each box a number of figures. For example, for the up quark it has 2.4 MeV/c^{2} along the top, and 2/3 and 1/2 along the left hand side. The top figure refers to the rest mass of the particle expressed in energy (matter and energy are related via Einstein’s famous equation E=mc^{2}). This is the energy required to create this particle in an accelerator. The next figure, 2/3 in the case of the up quark, is the electric charge. For a proton, the 3 quarks which make it up are u,u and d, giving a charge of 2/3 + 2/3 – 1/3 = 1. For a neutron, the 3 quarks which make it up are u,d and d, giving a charge of 2/3 – 1/3 – 1/3 = 0.

The final figure, 1/2 for the up quark, is the quantum-mechanical spin of the particle. I will explain what this means in a separate blog. All quarks have a spin of 1/2, as do all leptons. Bosons have an integer spin.

The quarks and leptons fall into 3 generations. The first generation is normal matter. The 2nd and 3rd generations of matter seem to be heavier (more massive) versions of the 1st generation, and (apart from the 3 generations of neutrinos) will decay into particles in the 1st generation. We have no idea at the present time as to why Nature has 3 copies of matter, 3 generations. We currently believe that quarks are fundamental particles, and cannot be split up into anything simpler.

The best known example of a lepton is the electron, but another example many people have heard of is the neutrino. The electron and the neutrino are both 1st generation leptons, but there are 2nd and 3rd generation leptons just as there are 2nd and 3rd generation quarks making up the hadrons. We currently believe that leptons are, like quarks, fundamental particles.

The right hand column of the figure are bosons. In the modern quantum mechanical view of Nature, forces are carried (mediated) by particles called bosons. The photon is an example of a boson. It is a “particle of light”, but also the particle responsible for the electro-magnetic force. The weak nuclear force (responsible for radioctive decay) is mediated by the W and Z bosons, and the strong nuclear force (responsible for holding the nucleus together) is mediated by gluons.

You will notice that this figure does not include the famous Higgs boson. I will post a separate blog in the near future about the Higgs boson, why it was proposed, and whether CERN has actually discovered it with the Large Hadron Collider.

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The 3rd weekend of the 2013 6 Nations saw England stay on course for the Grand Slam, Wales continue to get their campaign back on track, and Ireland go down to a surprise defeat to Scotland.

Italy v Wales

The first match of the weekend was Italy against Wales in Rome. The match was played in terrible conditions, lashing rain and winds. It was certainly not the most interesting game, but Wales never looked in danger of losing. They ran in two tries, and won comfortably by 26-9. The Welsh camp will be pleased with several things. Firstly they kept their try-line unbreached for the second game in a row. Secondly, they have now strung together 2 good matches, and hopefully the confidence which saw Wales win the Grand Slam last season is now returning to the squad.


England v France

This was the big game of the weekend, le crunch. France certainly raised their game compared to their two poor performances against Italy and Wales. Their coach, Philip Saint-André changed 7 players from the side that lost to Wales in Paris two weeks ago. In fact, France were leading England at half time, with the scoreline at 9-10. However, in the second half England started to gain more and more control of the game. Their dominance was helped by some strange substitionts by Saint-André, removing the half-back pair of Parra and Trinh-Duc, which seemed to play into England’s hands. A try by England in the second half saw them emerge as victors by 23-13. This leaves England on course for their first Grand Slam since 2003.


Scotland v Ireland

I have not seen this game, but I did hear the last 10 minutes on the radio. From what I’ve heard and read, it was a game that Ireland threw away. Gavin Hastings said Ireland “snatched defeat from the jaws of victory”. It seems Ireland squandered many chances to run in several tries, and paid the price by going down to a surprise defeat. This now sets up an intriguing match against Wales in two week’s time; both Scotland and Wales will go into the match with two successive victories under their belts. This is the first time Scotland have won two successive games in the 6 Nations since 2001!


The 4th weekend of the 2013 6 Nations

The 6 Nations now takes another break, with the next round of matches in two weeks’ time. The first game will be Scotland v Wales in Murrayfield. I am confident, with Welsh confidence coming back, that we can win there, but after saying that many good Welsh teams have lost to Scotland in Murrayfield. Also, after Scotland’s surprise victory over Ireland, their confidence will also be high. The second game of the weekend is Ireland v France in Dublin. The final game of the weekend, on the Sunday, is England v Italy at Twickenham. This should be a fairly easy win for England, I cannot see Italy troubling the on-form England team. Should both Wales and England win it will set up a mouth-watering match between them in Cardiff the following week, with England going for the Grand Slam and Wales hoping to stop them and win the Championships themselves.

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Tonight (Sunday the 24th of February) is the 85th Academy Awards (Oscars), and Daniel Day-Lewis stands on the threshold of history. He is nominated in the best actor category for his role as Lincoln in the movie of the same name. Should he win he will become the first male actor in the 84 year history of the Academy Awards to win the best actor category Oscar 3 times.


Currently eight other actors have won two best actor awards, including Jack Nicholson, Sean Penn, Gary Cooper and Tom Hanks. But none has ever won three times. Tom Hanks actually came very close to not only winning three, but winning three in a row. He won best actor for Philadelphia in 1993, and for Forrest Gump in 1994, and the following year played the lead role in Apollo 13, but was not nominated.

Day-Lewis won his first Oscar in 1989 for playing the role of paraplegic Christy Brown in My Left Foot. He won his second Oscar in 2007 for playing Daniel Plainview in There Will Be Blood (which I have not seen). I have, however, seen Day-Lewis in many other memorable roles, including My Beautiful Laundrette, A Room With A View, The Unbearable Lightness of Being, The Last of the Mohicans and In The Name of the Father.

What is your favourite Daniel Day-Lewis film?


Day-Lewis did win and so has made history. I saw Lincoln this week, and have to say it is a superb film. Day-Lewis’ performance is mesmerising.

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The 2013 Africa Cup of Nations was won by Nigeria (the Super Eagles), beating Burkina Faso 1-0 in the final. This is the 3rd time that Nigeria have won this competition, which started in 1957 and is held every other year. Burkina Faso’s previous best was coming 4th in 1998. In reaching the final, Nigeria beat Mali in one of the semi-finals, Burkina Faso beat Ghana in a penalty shoot-out in the other semi-final. In the 3rd place play-off, Mali beat Ghana 3-1. This may be the first time that all 4 teams reaching the semi-finals have all come from West Africa, and in fact all 4 are very close to each other geographically.

When I was growing up in the 1970s, I do not recall any awareness of African football. The only other part of the World outside of Europe which got any attention was South America, and of course back in those days the great players like Pele did not play in Europe, they played their club football in South America.

But things have changed. Europeans are now used to seeing African footballers, many of the best footballers playing in Europe in the last 20 years come from Africa. Didier Drogba, who was instrumental in my team Chelsea’s successes over the last several years, is from Côte d’Ivoire (Ivory Coast).


Such has been the growth of African football and the interest in it in Europe that this year’s tournament had every match live on the sports channel Eurosport, and many of the matches were also shown in the Disunited Kingdom on the Freeview channel ITV4. With most English Premiership teams having several African players in their squads, the standard of football in the Africa Cup of Nations is very high, probably only surpassed by the standards in the Euro football championships and in the World Cup.

Looking at the list of countries who have reached the final four of the Africa Cup of Nations since its inception in 1957, one can see that football spans the entire African continent. Past winners include Egypt, Morocco, Cameroon, Zambia and South Africa, every corner of the continent. it just shows that football truly is the global game.

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Tomorrow is the third weekend of the 2013 6 Nations. There has been a fortnight’s break since the last round of matches, two weeks in which the Welsh squad have hopefully been able to build on their fantastic win against France in Paris so that they can go to Rome and get a victory against Italy.

On Tuesday (19th of February) Wales announced their team for Saturday. The surprise is that Sam Warburton, who is fit again after his shoulder injury, is not starting but is on the bench. This means that Ryan Jones will captain Wales for the second time this 6 Nations, despite Sam Warburton starting the 6 Nations as captain. I heard Rob Howley, the interim Welsh coach, on Tuesday describe Ryan Jones as a natural leader, and I think I am right in saying he has now captained Wales more times than anyone else in history. One of our other main players Alun Wyn Jones is also back fit after a long layoff and surgery, he too starts on the bench.


On the plus side, Wales have now put together 120 minutes of good rugby, the second half against Ireland and the whole match against France. But, we must not take Italy for granted. Although Italy disappointed against Scotland two weeks ago, they were just as good against France three weeks ago as Wales were two weeks ago. We have lost to Italy before in Rome, and if we lose tomorrow our 6 Nations will go completely off the rails.

If, however, Wales can win tomorrow, then I am optimistic that we can go to Scotland in two weeks’ time and win there. if we manage that, who knows what we can achieve in our final game against England at home in Cardiff in the last game of the 6 Nations.

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My favourite Anglo-Welsh poet (a Welsh poet writing in English) is R.S. Thomas. The first poem of his that I came across was when I was 13. In our school English class we read “Cynddylan on his tractor”. It made me angry when I read it. Thomas seemed to be belittling the Welsh. It took me several poems and several weeks to realise that he was attempting to awaken Welsh people’s apathy towards their country.


Thomas was born in Cardiff to English speaking parents. He went to Bangor University, where he read classics. He then went into the ministry, being ordained as a priest in the Church of Wales. Thomas learnt Welsh when he was 30, but he never wrote poetry in Welsh as he felt it was not his native tongue and so he didn’t feel his Welsh was good enough. Despite learning Welsh in adulthood, Thomas became a keen (some would say extreme) advocate of the Welsh language and the need to protect it against Anglo-American domination.

Thomas died in 2000, leaving about two dozen published volumes of poetry, the list is here.

This poem of Thomas’, A Welsh Landscape, is my favourite poem written in the English language. I mentioned it before in this blog, but I did not include the words of this wonderful poem, just a link to where they can be found. I mentioned it in the context of trying to answer my son’s English homework question – “What does it mean to be Welsh?”. If the words and sentiment of A Welsh Landscape resonate with you, then you at least have an understanding of what it is to be Welsh.

Here is the poem in its entirety.

A Welsh Landscape

To live in Wales is to be conscious
At dusk of the spilled blood
That went into the making of the wild sky,
Dyeing the immaculate rivers
In all their courses.
It is to be aware,
Above the noisy tractor
And hum of the machine
Of strife in the strung woods,
Vibrant with sped arrows.
You cannot live in the present,
At least not in Wales.
There is the language for instance,
The soft consonants
Strange to the ear.
There are cries in the dark at night
As owls answer the moon,
And thick ambush of shadows,
Hushed at the fields’ corners.
There is no present in Wales,
And no future;
There is only the past,
Brittle with relics,
Wind-bitten towers and castles
With sham ghosts;
Mouldering quarries and mines;
And an impotent people,
Sick with inbreeding,
Worrying the carcase of an old song.

R. S. Thomas 1913-2000

Which is your favourite R.S. Thomas poem?

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This morning (Tuesday 19th of February) I heard this item on the news about how the Brecon Beacons National Park in South Wales had been granted dark sky status by the International Dark Sky Association. This is wonderful news for Wales. Earlier I had a phone call from the BBC asking me to talk about this on this evening’s news. They are planning to film the item live up in the Brecon Beacons. In the next couple of days I will try and do a video capture of the item and post it on YouTube.


Light Pollution at Yerkes Observatory

I first got involved in light pollution work in 1998. I remember it distinctly, because it was the same week my 2nd child was born. At the time I was working at the World famous Yerkes Observatory, part of the University of Chicago. Yerkes houses the World’s largest lens telescope, the great 40-inch refractor and is where many famous astronomers, including Edwin Hubble, have worked. I was lucky enough to work there for 6 years as a post-doctoral researcher, and I used to try to use the Observatory’s 41-inch (1-metre) reflecting telesocpe for some of my research.


I started using the 41-inch in 1997, but by 1998 it became obvious to me that my images were not as good as they should be, and so I started investigating the darkness of the skies at the Observatory. I took a series of horizon photographs from the catwalk of the 40-inch, and the results surprised me. Yerkes Observatory is about 75 miles North North-West of Chicago, so I fully expected the direction to the South South-East to be the brightest part of the horizon. But in fact it was not, the brightest parts were to the East (the city of Lake Geneva) and to the North-West (the city of Delavan), both within about 7-8 miles of the Observatory.

I knew there was little I could do to influence the light pollution coming from Chicago, but discovering that the main problem was local gave me hope. I consulted with the numerous pages at the IDA website, and drew up a lighting ordinance. I first gave a presentation about the problem to the Village Board of Wiliams Bay, where Yerkes is based. Not surprisingly, with the over 100-year old Observatory in their community, they were very supportive and agreed to adopt the lighting ordinance. I then took it to the other communities, Delavan, Lake Geneva and Elkhorn. The major light polluter was a greyhound racing track about 6 miles North-West of the Observatory on the outskirts of Delavan.

On one occasion the greyhound track’s light pollution prevented a potentially important discovery. In the period 1998-2002 a hot area of research was determining the nature of gamma ray bursts (GRBs). At the time, the satellite which would discover these in the X-ray, a satellite called BeppoSAX, didn’t have enough positional precision to know exactly which object had caused the burst. So it was important to try to find the optical counterpart, something the 41-inch was ideal for as it was under-utilised and so usually available at short notice. One particular GRB in 1999 would have been visible to us at Yerkes, but as bad luck would have it, it was in the direction of the greyhound track, a part of the sky where the light pollution rendered seeing it impossible.

I arranged a meeting with the manager of the greyhound track to discuss this problem. By this time I had got a light meter via a grant from the American Astronomical Society small grants program, to investigate light pollution levels in the locality. I measured the lighting levels of the metal halide lights the greyhound track had on in its car park all night every night (even though it was only open for races on a Friday and Saturday evening!). They were 10 times (yes, ten times) the level recommended by the IDA and the American Society of Lighting Engineers for a car park of its size. They were even above the level recommended for reading in one’s house!! Even though the car park was tarmac (“black top” as Americans would call it), reflecting maybe 10% of the light from this black surface was leading to a huge dome of light above the area. On the nights when there were races the problem was even worse, as the track itself would have bright stadium lights on too.

I calculated the amount of money the track was wasting by having these lights on all night, and it was in the tens of thousands of dollars per year. Given that the track was making a loss, I thought this might be the best argument to use with the manager. I didn’t think he would particulary care about whether we could or couldn’t see the afterglow of a GRB, but I was sure he would be concered to know that he was wasting so much money.

By the time I left Yerkes Observatory in 2001 most of the communities had adopted the lighting ordinance. The only one which hadn’t was, unfortunately, Delavan.

Light Pollution in Wales

I moved back to Wales in 2001, to the Cardiff area. Of course Cardiff is far more urban that where I had been in Williams Bay, Wisconsin. So initially I thought doing something about light pollution back here was a lost cause. But then I realised that there were areas near Cardiff, like the Brecon Beacons and Pembrokeshire (where I grew up) which were still dark. It was growing up with the dark skies in Pembrokeshire which allowed me as a child to indulge my passion for astronomy and see the stars properly.


I think it was in about 2003 or 2004 that I was first invited to give a talk to an astronomical society based in Mynachlog Ddu in Pembrokeshire. This is one of the darkest places in the Disunited Kingdom. It was darker than the skies I had lived with at Yerkes. Another extremely dark place is, of course, the Brecon Beacons, only an hour north of Cardiff. In about 2006 I wrote to Rhodri Morgan, the then First Minister of Wales, about light pollution and how Wales could profit from some naturally dark skies by preserving and promoting them.

Some 90% of the population of the Disunited Kingdom live in areas where there is substantial light pollution. This means they do not get to see the sky in all its glory. But, of these 90% many thousands are interested in the sky. They are members of astronomical clubs, but struggle to see what they are interested in. The Brecon Beacons will now be able to attract these kinds of people, so called dark sky tourism is a growing area and one which Wales can capitalise on.

The night time sky is part of our shared heritage, and connects us with our ancestors thousands of years ago. It is where myths and legends have been played out by our great story tellers. Each civilisation has its own stories about the pattern of stars we see in the sky. But in the last 50 or so years so much of this shared heritage has disappeared from view due to bad lighting. Hopefully we are slowly beginning to do something about it.


Here is a YouTube clip of the interview

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Recently I was watching my favourite episode of the wonderful HBO series “From the Earth to the Moon“. This episode, called “1968” charts the turbulent year of 1968, which culminated from NASA’s perspetive in their successfully sending astronauts around the Moon for the first time. The 3 astronauts who got the privilage to be the first human beings to see first-hand the far side of the Moon were Frank Borman, Jim Lovell and Bill Anders.

One of the most enduring images from this mission is the one of a beautiful Earth coming up above the bland grey Lunar horizon – an image which has become known as Earthrise.

Earthrise, as seen by the astronauts of Apollo 8 in December 1968.

Earthrise, as seen by the astronauts of Apollo 8 in December 1968.

In all, Apollo 8 orbited the Moon 10 times, taking detailed pictures of potential landing sites which were used for Apollo 11‘s eventual landing on the Moon in July 1969. During their time on the far side of the Moon the Apollo 8 astronauts had no way of communicating with Earth, and were therefore very much alone in Space. Here is the clip from this wonderful series when they see Earthrise for the first time. If you have not seen either this episode or the entire series of From the Earth to the Moon I highly recommend that you do.

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