Archive for September, 2012

So, John Terry has been found guilty by the English Football Association (FA) for racially abusing Anton Ferdinand. But, having been found guilty, the FA have given him the extraordinarily lenient punishment of a 4 match ban and a fine of £220,000. Given that John Terry apparently earns some £140,000 a week, this amounts to 10 days’ wages.

The story of John Terry’s lenient punishment, from the BBC website

I am astounded and saddened that the FA has been so easy on John Terry. In my opinion, he should have faced a lengthy ban, 8 matches or more. A life ban would have been justified in my opinion, but was never going to happen. Contrast Terry’s punishment with the one given to Luis Suarez last year for using the “n” word against Patrick Evra. Suarez received an 8 match ban. And Joey Barton recently received a 12 match ban for persistent violent behaviour on the football field.

What sort of message does this send out about the FA’s commitment to the “kick it out” campaign to rid football of racial abuse? A very weak message I would say. In fact, it leaves the campaign in tatters in the view of many people. I am ashamed to call myself a Chelsea supporter. Chelsea would be, of course, perfectly within their rights to sack John Terry for gross professional misconduct, but that isn’t going to happen. Quite the contrary it would seem, Chelsea have been supportive of their player throughout these proceedings. Terry will undoubtedly receive some offensive chants from opposing fans when Chelsea play their away games, but as he seems to have the skin of a rhinoceros I doubt this will affect him much.

The FA really had a chance to take a proper stance against racism within football and within wider society. They have sadly failed to do so with this token punishment.

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In my first post about the Voyager space craft, I mentioned that I was going to be talking about the Voyager space probes on live TV on Thursday the 27th of September. This has now been shifted to next Thursday, the 4th of October, giving me time to write part 2 of this blog on their incredible journey. In this part I will talk bout the visit of Voyager 1 to Titan, Saturn’s largest moon, and Voyager 2’s visit to Uranus and Neptune. In part 3, which I will post early next week, I will talk about their ongoing journey beyond our Solar System.

Voyager 1’s encounter with Titan

When Pioneer 11 flew by Saturn in 1979 it detected that Titan, Saturn’s largest moon, had a thick, gaseous atmosphere. Titan was discovered by the Dutch astronomer Christiaan Hyugens in 1655, and had long held fascination for planetary scientists. That Titan may have an atmosphere was first suggested by Josep Comas Solà in 1903. This was confirmed by Gerard Kuiper in 1944.

It was decided by NASA’s Jet Propulsion Laboratory to alter the course of Voyager 1 to go and study Titan in more detail by flying close to it. This effectively meant that it would not be able to continue on to visit Uranus and Neptune, as had originally been planned.

Voyager 1 image of Saturn’s largest moon Titan, which was discovered by the Dutch astronomer Christiaan Huygens in 1655

The pictures Voyager 1 took of Titan have proved vital to our understanding of this planet sized moon. This next picture shows the haze that Voyager 1 was able to see in Titan’s atmosphere. The close fly-by of Voyager 1 also showed that Titan’s thick atmosphere is impenetrable at visible wavelengths, so Voyager 1’s cameras were not able to see any surface detail. Voyager 1 was able to determine that the atmospheric pressure at the surface of Titan was about 1.5 times the atmospheric pressure at the surface of the Earth.

Voyager 1 observed a thick layer of haze above Titan’s atmosphere

Voyager’s encounter with Uranus

With Voyager 1’s close fly-by of Titan taking it out of the plane of the Solar System, it was left to Voyager 2 to continue the grand tour on to Uranus and Neptune. Voyager 2 flew by Uranus in January 1986. For both Uranus and Neptune, the images taken by Voyager 2 are still the most detailed we have of these “ice giants”. Voyager 2 discovered several new moons orbiting Uranus, and was able to study its planet’s atmosphere in more detail than before.

Voyager 2’s image of Uranus

A crescent Uranus, taken as Voyager 2 looked back towards Uranus as it heads off towards Neptune.

Voyager 2 also studied the rings of Uranus. These were first discovered in 1977 by the Kuiper Airborne Observatory, during an occultation.

Uranus’ ring system, as imaged by Voyager 2

Voyager’s encounter with Neptune

Voyager 2 finally arrived at Neptune in August 1989. Very little was known about this planet prior to Voyager 2’s visit.

Voyager 2 image of Neptune

Voyager 2 also took an image of Neptune and its largest moon Triton as it continued on its journey to the outer reaches of the Solar System.

Voyager 2 looks back at Neptune and its largest moon Triton as it continues on its journey to the outer reaches of the Solar System

Part 1 of this post is here, and part 3 is here.

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Today (Wednesday the 26th of September) is a big day for students of Coleg Morgannwg, where I have recently become head of Physics. It is the official opening of the brand new building that has been built in Nantgarw. To mark the occasion, the College has invited Dr. Lyn Evans, who is lead scientist of the Large Hadron Collider at CERN, to be part of the opening. Dr. Evans, known by the press as “Evans the atom“, grew up in Aberdare, which is up the valley from Nantgarw. He studied Physics at Swansea University, and then went on to also study for his PhD at Swansea. He has gone on to work at CERN and become leader of the Large Hadron Collider, the biggest and most expensive scientific experiment ever built.

Dr. Lyn Evans, from Aberdare in South Wales, is lead scientist at the Large Hadron Collider in CERN

The official opening of Coleg Morgannwg’s new campus will take place today, Wednesday the 26th of September. Dr. Lyn Evans will be the guest of honour

Coleg Morgannwg primarily serves the Rhondda Cynon Taf area of South Wales, an area which has seen huge social deprivation since the collapse of the mining industry in the 1980s. I only hope that the students who get to see and meet Dr. Evans today will be inspired to work hard and achieve their goals, as he is testimony that, with a good education, anything is possible for the young people of the South Wales valleys.

[Before you assume that Dr. Lyn Evans and this Dr. Evans are related, I should point out that Evans is an incredibly common last name in Wales. Why this is so will have to be explained in a future blog.]

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If any of you have seen the wonderful film Dead Poets Society, you will be familiar with this poem O Captain! My Captain!by Walt Whitman. The poem is used in the film to dramatic effect, but I won’t spoil it for those of you yet to see the film.

O CAPTAIN! my Captain! our fearful trip is done;
The ship has weather’d every rack, the prize we sought is won;
The port is near, the bells I hear, the people all exulting,
While follow eyes the steady keel, the vessel grim and daring:
But O heart! heart! heart!
O the bleeding drops of red,
Where on the deck my Captain lies,
Fallen cold and dead.

O Captain! my Captain! rise up and hear the bells;
Rise up—for you the flag is flung—for you the bugle trills;
For you bouquets and ribbon’d wreaths—for you the shores a-crowding;
For you they call, the swaying mass, their eager faces turning;
Here Captain! dear father!
This arm beneath your head;
It is some dream that on the deck,
You’ve fallen cold and dead.

My Captain does not answer, his lips are pale and still;
My father does not feel my arm, he has no pulse nor will;
The ship is anchor’d safe and sound, its voyage closed and done;
From fearful trip, the victor ship, comes in with object won;
Exult, O shores, and ring, O bells!
But I, with mournful tread,
Walk the deck my Captain lies,
Fallen cold and dead.

The poem concerns the death of American President Abraham Lincoln, who was assassinated in 1865 by John Wilkes Booth whilst attending the theatre in Washington D.C.

The American poet Walt Whitman (1819-1892)

What is your favourite Walt Whitman poem?

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I was lucky enough to be at Live Aid, an extraordinary day in July 1985 that I will never forget. Of the many bands who performed that day, the two who stood out for me were Queen and U2. At the time, U2 were not a particularly well-known band. Their 4th album Unforgettable Fire had been released in October 1984, and was very much their breakthrough album. It had Pride (In The Name of Love) as its big hit. So, by the time of Live Aid I, and probably quite a few others there, knew of them and had maybe even gone back to listen to their first three albums, Boy, October and War.

The Irish band U2, in their early days in the mid 1980s.

At Live Aid they played several songs, but the one which stole the show for me was Bad. The version they played at Live Aid lasted for over 10 minutes, and included Bono leaping down from the stage and inviting a female member of the crowd to join him for a few seconds of a tender dance. It stole the show in my opinion.

Here is the Live Aid performance in its entirety. Enjoy!

What is your favourite U2 song?

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About this time of year, presumably because we are at the Autumn Equinox, photographs of analemmae seem to pop up a lot on the internet and on FaceBook. I showed an example of an analemma to one of my Physics classes last week, and found that they were unable to explain what it shows. So, I figured there was a need for a clear explanation of what a solar analemma shows.

A solar analemma is a photograph taken at the same time each day from the same place, showing where the Sun is in the sky at that same time each day. If one were to take a photo at midday each day, then one would get an analemma that looks like this (bear in mind that one would not adjust when the clocks go forward. So, when they do, one would take the photograph at e.g. 13:00 instead of 12:00 as 12:00 is the real, Solar time).

An analemma taken when it is local noon, hence the “figure 8” is vertical. This analemma must have been taken in the Northern Hemisphere at a latitude between the Tropic of Cancer and the Arctic Circle.

This is the easiest type of analemma to understand, so I will start by explaining this one before we move on to more complex ones. The “figure of 8” you can see in the photograph above is due to two effects. The first is one everyone is familiar with, the changing height of the Sun in the sky in the middle of the day depending on whether it is summer, autumn, winter or spring. The Sun will reach its highest point in the sky at midday in the Summer, but at the same time in the Winter the Sun will be much lower in the sky. This explains the vertical change in the analemma.

On the Spring (or Autumn) Equinox, the Sun at midday is overhead as seen by someone on the Equator. By the time of the Summer Solstice, it will have moved to be overhead at midday for someone at the Tropic of Cancer. On the Winter Solstice, it will be overhead for someone in the Southern Hemisphere on the Tropic of Capricorn. This wonderful picture (taken from here) shows the path of the Sun on the Winter Solstice, the Spring Equinox and the Summer Solstice as seen from Bursa, Turkey.

The path of the Sun on 3 important days as seen from Bursa, Turkey. The top is the Summer Solstice, the middle one is the Spring (or Autumn) Equinox, and the bottom one is the Winter Solstice

But, what about the horizontal change? Why is the Sun sometimes to the left of the vertical midpoint, and why is it sometimes to the right? This is more difficult to explain. It involves something called the Equation of Time, and I will explain it in part 2 of this blog.

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I have just spent the last week showing my Physics students the wonderful BBC Horizon interview with Richard Feynman “The Pleasure Of Finding Things Out”. I vividly remember seeing this interview myself when I was 17. I already knew I wanted to go into physics, but this interview confirmed what I already knew, that physics was the subject for me. Thankfully for all, the interview is available in its entirety on YouTube.

When I introduce the video, I also quote what Brian Clegg says about Feynman in his introduction to the chapter on Quantum Electrodynamics in his book Light Years.

Richard Feynman, the magician

Ask a person in the street to name the two greatest physicists of the twentieth century and they will almost inevitably come up with Einstein. The second name, though, might prove harder to pin down.

Ask a physicist to come up with the top two and there will be no hesitation – or at least, if there is any hesitation, it will be over which name to put in first place.

The name that ranks alongside Einstein will be that of Richard Feynman.

The title of my blog comes from the words Hans Bethe (who won the Nobel prize in Physics for his work on nucleosynthesis within stars) said about Feynman. The quote in full is

There are two types of genius. Ordinary geniuses do great things, but they leave you room to believe that you could do the same if only you worked hard enough. Then there are magicians, and you can have no idea how they do it. Feynman was a magician.

Enjoy this wonderful interview with a truly remarkable physicist. And, if you want to read more about the crazy adventures he got up to in his colourful life, then read his autobiography ‘Surely You’re Joking Mr. Feynman

Feynman’s autobiography “Surely You’re Joking Mr. Feynman” is a hilarious read

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I have been asked by the BBC to talk on the radio about a recent press release made by the Department of Physics and Astronomy at Cardiff University . The press release is from the department’s Gravitational Physics group. Three members of this group, Ioannis Kamaretsos, Dr. Mark Hannam and the group’s head Professor B. Sathyaprakash have modelled what would happen if two black holes were to merge (coalesce). The work forms part of Mr. Kamaretsos’ PhD thesis.

It has long been predicted by Einstein’s theory of General Relativity that such an event would produce ripples in space, due to the intensity of the gravitational fields produced. This is akin to electrons producing electromagnetic waves when they make certain transitions. In fact, over the last 10 years, astronomers have built gravitational wave detectors to detect these predicted ripples in space. From studying the precise nature of these ripples, astronomers believed one could calculate the mass of the final black hole, and how rapidly it spins.

What the Cardiff team are proposing in this new theoretical research is not only can studying the details of the ripples tell us about the final, merged black hole, but also about the properties of the two black holes before the merger. This is the first time that research has suggested that something could be learned about the final black hole’s progenitors.

A screen capture of a movie showing a simulation of two black holes merging

The movie of the simulation can be found here

As of yet, astronomers are yet to detect their first gravitational waves, but the hope is that with the recently completed LIGO detectors, and others, that the first detections are not too far away. Let us hope so.

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Only time for a very quick post today. I thought I would post a copy of this wonderful cover from Private Eye magazine, a satirical magazine here in the Disunited Kingdom. I used to subscribe to this magazine back in the 1980s. Nowadays I try to flick through it when catching my bus to work. It never fails to have my eyes watering with laughter, and this cover shows very nicely the wittiness of its writers.

Nick Clegg Private Eye

The cover of the latest (24th August) edition of Private Eye magazine

Do you have a favourite Private Eye cover?

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Next Thursday (27th of September), I am going to be on live TV talking about the Voyager space probes. These remarkable crafts left our small planet in 1977, and are now on the point of entering interstellar space. Voyager 1 is currently 18.2 billion km from the Sun, and Voyager 2 is 14.8 billion km away. They are, by a large margin, the most distant objects human beings have ever sent into space.

This cartoon, from the official NASA Voyager website, shows where the two spacecraft are, compared to the heliopause. The heliopause is a theoretical boundary where the Sun’s Solar wind is stopped by the stellar winds from other, nearby stars. The heliosphere is the sphere of space within which the Sun and the planets reside, as they are within the heliopause, the surface of this sphere (in reality it is not a sphere, it would only be a sphere if the radiation from nearby stars was perfectly uniformly incident on our Solar system).

Voyager 1

This cartoon, from the NASA Voyager website, shows the position of the two Voyager space probes, and the heliosphere and heliopause.

Because these distances are so huge, it is sometimes easier to use larger units. The Astronomical Unit (AU) is defined as the average distance from the Earth to the Sun, so 150 million km. In these units, Voyager 1 is 122 AU from the Sun, and Voyager 2 is 99 AU away. The weak signals that we are still able to receive from the two space craft travel at the speed of light, and are currently taking about 30 hours (not minutes as I previously typed) to get to us.

Voyager 1

The Voyager space probes were identical copies of each other, but were launched a few weeks apart and went on a different journey into the outer Solar System

Voyager 1 and 2 at Jupiter

Voyager 1 arrived at Jupiter in January 1979. Voyager 2 reached the planet in July of the same year. Both space craft returned the most detailed pictures yet of the Solar System’s largest planet. In addition to making important studies of the great red spot, the two probes made the surprising discovery of volcanic activity on Io, Jupiter’s closest moon.

Jupiter's great red spot

A Voyager 1 image of Jupiter’s great red spot

Volcanic activity on Io

The plume of material on the left is a volcanic eruption on the moon Io, the nearest of the Galilean moons.

We now know that Io is the most volcanically active body in the Solar System. The source of its internal heating is the tidal forces from Jupiter. Because it doesn’t orbit Jupiter in a perfect circle, but rather in an ellipse, the Moon gets repeatedly deformed in different directions and this heats its interior up (in the same way that squeezing a tennis ball repeatedly will lead to its getting warm). With a warm molten interior, the conditions are just right for this to escape through the crust as volcanic eruptions.

Voyager at Saturn

In November 1980, Voyager 1 flew past Saturn. By August 1981, Voyager 2 had arrived at the ringed planet. Voyager made important discoveries about Saturn and her moons, in particular about Saturn’s rings. It discovered new ring structures, and even “spokes” in the rings.

Saturn by Voyager 1

A backlit image of Saturn taken by Voyager 1 after its flyby in late 1980.

Spokes in Saturn's rings

Voyager 2 discovered mysterious spokes in Saturn’s rings. It was many years before we understood what causes these.

Later this week I will write a part 2 to this blog, talking about Voyager 2’s encounters with Uranus and Neptune, the famous pale blue dot photograph, and the messages being carried on the probes as they head off into interstellar space.

Here are part 2 and part 3 of this post.

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