Here’s a short video I just found featuring our own Winfried Hensinger, Professor of Quantum Technologies at the University of Sussex.
It’s part of a pilot documentary that explores the connection between science fiction and science reality. Here is the official blurb:
“The science fiction genre has a history of playing with our imagination; inventing “impossible” technologies and concepts such as time travel and teleportation. The “spooky” discoveries that quantum physicists have recently made are challenging the very “impossibility” of sci-fi. This documentary will explore the ways in which sci-fi has catalysed the imagination of scientists who are pioneering these discoveries.
The theme will explore the causal link between science and science fiction, using the inner workings of the quantum computer that Dr Winfried Hensinger is currently developing as a case study. Dr Hensinger, the head of the Sussex Ion Quantum Technology research group, was inspired early on by the well known 60s science fiction television show Star Trek. Having led multiple breakthroughs in the field of Quantum Computing research, he speaks to the importance of not losing our imagination, citing his childhood desire to be the science officer on Star Trek’s Enterprise as the prime motivator of going into the scientific field. Exploring the relationship between the human beings developing this technology and the non-human genre of science fiction, we will demonstrate that the boundaries between imagination and reality are blurrier than conventionally thought.”
I’ll take the opportunity presented by this video to remind you that the University of Sussex is the only university in the UK to offer an MSc course in Quantum Technologies, and this year there are special bursaries that make this an extremely attractive option for students seeking to extend their studies into this burgeoning new area. We’ve already seen a big surge in applications for this course this course so if you’re thinking of applying don’t wait too long or it might fill up!
It’s been a while since I posted a cute physics problem, so try this one for size. It is taken from a book of examples I was given in 1984 to illustrate a course on Physical Applications of Complex Variables I took during the a 4-week course I took in Long Vacation immediately prior to my third year as an undergraduate at Cambridge. Students intending to specialise in Theoretical Physics in Part II of the Natural Sciences Tripos (as I was) had to do this course, which lasted about 10 days and was followed by a pretty tough test. Those who failed the test had to switch to Experimental Physics, and spend the rest of the summer programme doing laboratory work, while those who passed it carried on with further theoretical courses for the rest of the Long Vacation programme. I managed to get through, to find that what followed wasn’t anywhere near as tough as the first bit. I inferred that Physical Applications of Complex Variables was primarily there in order to separate the wheat from the chaff. It’s always been an issue with Theoretical Physics courses that they attract two sorts of student: one that likes mathematical work and really wants to do theory, and another that hates experimental physics slightly more than he/she hates everything else. This course, and especially the test after it, was intended to minimize the number of the second type getting into Part II Theoretical Physics.
Another piece of information that readers might find interesting is that the lecturer for Physical Applications of Complex Variables was a young Mark Birkinshaw, now William P. Coldrick Professor of Cosmology and Astrophysics at the University of Bristol.
As it happens, this term I have been teaching a module on Theoretical Physics to second-year undergraduates at the University of Sussex. This covers many of the topics I studied at Cambridge in the second year, including the calculus of variations, relativistic electrodynamics, Green’s functions and, of course, complex functions. In fact I’ve used some of the notes I took as an undergraduate, and have kept all these years, to prepare material for my own lectures. I am pretty adamant therefore that the academic level at which we’re teaching this material now is no lower than it was thirty years ago.
Anyway, here’s a typically eccentric problem from the workbook, from a set of problems chosen to illustrate applications of conformal transformations (which I’ve just finished teaching this term). See how you get on with it. The first correct answer submitted through the comments box gets a round of applaud.
Today provides me with an occasion for a short post in a very irregular series marking the momentous events that unfolded seventy years ago.
At 1000 hours on 24th March 1945, nine battalions of the 6th British Airborne Division together with six from 17th US Airborne Division began landing on the German (east) side of the River Rhine, near Wesel. This was the last mass parachute and glider assault of the Second World War, and was designed to pierce the final great physical barrier to a ground advance into Nazi Germany. It was codenamed Operation Varsity.
The airborne troops were given the task of seizing and holding high ground overlooking a stretch of the Rhine which was to be crossed by elements of the British 21st Army Group, which included the British Second Army. The airborneassault involved 540 aircraft towing 1300 gliders into heavy anti-aircraft fire, so casualties during the first phase of the operation were heavy. However, within six hours of the commencement of the operation, all objectives were taken and the airborne troops subsequently linked up with ground forces who had crossed the river in assault boats in what was known as Operation Plunder.
This was all a part of a coordinated series of airborne and amphibious attacks by British, Canadian and American forces that began overnight on 23rd March 1945 and went on during the morning of 24th March 1945. The Applied troops, crossing the River Rhine in large numbers and beginning a rapid advance into Germany. By 27 March, they had established a bridgehead 35 miles (56 km) wide and 20 miles (32 km) deep.
Following the link-up with the ground troops, the 6th Airborne led a 300 mile advance through Germany, marching approximately 11 miles per day until they managed to capture enough enemy transport. Second Army reached the Weser on 4 April, the Elbe on 19 April, the shore of the Baltic Sea at Lübeck on 2 May. On 3 May, Hamburg capitulated. By 7 May the Soviet Army had met up with the British forces at the Baltic port of Wismar.
I mention this because one of the troops that crossed the Rhine the British Second Army that day was a new recruit, a young man by the name of Richard Shaw, my mother’s brother. He took part in the subsequent advance through Germany and spent most of the year after the end of the Second World War stationed in Hamburg. He died just a few years ago, after a fall in his home, at the age of 85.
Time for another quick plug of this year’s Royal Astronomical SocietyNational Astronomy Meeting, which will be taking place at the splendid Venue Cymru conference centre, Llandudno, North Wales, from Sunday 5th July to Thursday 9th July 2015. I’ve posted about this before, but I thought I’d post it again because there is just a week left to submit an abstract for a contributed talk or poster; the deadline for doing that is April 1st. I’m actually on the Scientific Organizing Committee for NAM 2015 and as such I’ll be organizing part of this meeting, namely a couple of sessions on Cosmology under the title Cosmology Beyond the Standard Model, with the following description.
Recent observations, particularly those from the Planck satellite, have provided strong empirical foundations for a standard cosmological model that is based on Einstein’s general theory of relativity and which describes a universe which is homogeneous and isotropic on large scales and which is dominated by dark energy and matter components. This session will explore theoretical and observational challenges to this standard picture, including modified gravity theories, models with large-scale inhomogeneity and/or anisotropy, and alternative forms of matter-energy. The aim will be to both take stock of the evidence for, and stimulate further investigation of, physics beyond the standard model.
It’s obviously quite a broad remit so I hope that there will be plenty of contributed talks and posters. NAM is a particularly good opportunity for younger researchers – PhD students and postdocs – to present their work to a big audience so I particularly encourage such persons to submit abstracts. Would more senior readers please pass this message on to anyone they think might want to give a talk? To further whet your appetite, here are some pictures of lovely Llandudno I took at the last National Astronomy Meeting there, back in 2011. If you have any questions please feel free to use the comments box (or contact me privately). Follow @telescoper
The day before last week’s (partial) solar eclipse I posted an item in which I mentioned the apparent coincidence that makes total eclipses possible, namely that the Moon and Sun have very similar angular sizes when seen from Earth.
In the interest of balance I thought I would direct you to a paper by Steve Balbus that develops a detailed argument to the contrary along the lines I described briefly in my earlier post. I am not entirely convinced but do read it and make up your own mind:
Here is the abstract:
The nearly equal lunar and solar angular sizes as subtended at the Earth is generally regarded as a coincidence. This is, however, an incidental consequence of the tidal forces from these bodies being comparable. Comparable magnitudes implies strong temporal modulation, as the forcing frequencies are nearly but not precisely equal. We suggest that on the basis of paleogeographic reconstructions, in the Devonian period, when the first tetrapods appeared on land, a large tidal range would accompany these modulated tides. This would have been conducive to the formation of a network of isolated tidal pools, lending support to A.S. Romer’s classic idea that the evaporation of shallow pools was an evolutionary impetus for the development of chiridian limbs in aquatic tetrapodomorphs. Romer saw this as the reason for the existence of limbs, but strong selection pressure for terrestrial navigation would have been present even if the limbs were aquatic in origin. Since even a modest difference in the Moon’s angular size relative to the Sun’s would lead to a qualitatively different tidal modulation, the fact that we live on a planet with a Sun and Moon of close apparent size is not entirely coincidental: it may have an anthropic basis.
I don’t know if it’s a coincidence or not but I always follow the advice given by my role model, Agatha Christie’s Miss Marple in Nemesis: “Any coincidence is worth noticing. You can throw it away later if it is only a coincidence.”..
SCOTLAND’S GEOFF CROSS WINS BEARD OF SIX NATIONS POLL
The Beard Liberation Front, the informal network of beard wearers, has said that with the most hirsute Six Nations rugby Championship ever now concluded, a key contest, the Beard of the Six Nations, has also found a winner.
Scotland’s Geoff Cross beat Wales’s Leigh Halfpenny by several pitch lengths in the on-line poll.
Cross’s beard has been a significant hirsute presence throughout the Six Nations although according to the authoritative Sport BeardWatch, Cross is set to shave his beard for charity, prior to retiring from rugby to become a GP.
The impact of beards on the field has meant that even noted pogonophobes such as Clive Woodward who argued in 2013 on the BBC that he wouldn’t select players with beards, have remained silent on the matter this year.
What a contest the Six Nations Rugby has given us today. I’ve just got my breath back after England’s extraordinary game against France. England won 55-35, a remarkable scoreline at this level, but just not quite enough to win the title.
Going into today’s final round of three games, Wales, Ireland and England were all level on six points, having won three games each. England were on top on points difference but Wales and Ireland had easier opponents, in Italy and Scotland respectively.
The day started with Wales demolishing Italy by 61-20 to give both Ireland and England a lot to do to catch up. Ireland responded by thrashing Scotland 40-10 which put them top with an even bigger points difference. To win the title England had to beat France by 26 points or more.
It was a tall order and, I thought, a shame that the competition was going to be decided by the scale of the whipping delivered to the weakest teams, rather than a head-to-head between the top ones. Of course the fixture list was compiled months ago before anybody knew the results of the earlier games, but it turned out that the script for this particular drama had been written perfectly!
England gave it everything in their match again France. The game contained great rugby, lots of errors, and breathless end-to-end excitement. They might have done it on another day but that last converted try just eluded them.
So congratulations to Ireland, who actually beat England earlier and are worthy champions. The lesson for England is clear from the table: they’re scoring enough points but need to concede fewer if they are to be serious contenders for the World Cup which takes place in the Autumn.
The last day of the Six Nations comes this year immediately after the Vernal Equinox, which happened last night at 22:45 GMT, both sporting and astronomical calendars telling us that spring is here. I hope England’s cricketers put up as much of a fight against the Aussies this summer!
It’s been an astronomical and meteorological rollercoaster of a morning. When I woke up at 6am this morning, the Sun was just rising. There was hazy cloud and there seemed to be every chance that it would break up to allowing viewing of today’s partial solar eclipse. Unfortunately, however, the cloud thickened rather than breaking up so I abandoned my plan to watch from the seafront and headed up to the University of Sussex campus at Falmer. Being higher up and a few miles inland, the weather is often clearer in Falmer than in Brighton. Unfortunately it was even murkier when I got here, so I assumed I was in for a disappointing morning.
Nevertheless I did join the large gathering in Library Square to experience the event. First contact between the Moon and the Sun happened at about 8.30, but the cloud cover was total at that point so nothing was visible. It did get gradually darker, but this happened slowly enough for eyes to adapt to the dark so it wasn’t all that noticeable to us humans. The birds on campus certainly noticed, however, and began to perform display roosting behaviour thinking it was evening. It also got really very cold.
Around 9.30 the coverage of the Sun by the Moon was about its maximum – 85% or so – but everything was still enshrouded in cloud. The crowd waited patiently in the gloom. It was a very British experience, a large group of people sharing their sense of collective disappointment in appropriately stoical fashion.
Gradually the wind seemed to increase, pushing the clouds over more quickly and causing them to break up. Then, suddenly, a small gap in the cloud opened up and there was the eclipse. For about a second. It may have been only a moment, but it generated a huge cheer which, I should add, wasn’t entirely ironic. The breaking up of the clouds continued and we were treated to several good views of the main event. It was definitely worth it.
Most of the pictures I took didn’t come out at all well, but here is one with the famous Meeting House in the foreground:
And here’s a rather nice picture from John Sander of the International Office at Sussex University, showing yours truly during the final stages of the eclipse..
I’ll add more pictures as I find them. Please feel free to share your comments and observations via the appropriate box!
As you will no doubt be aware, tomorrow there will be a Partial Eclipse of the Sun visible from the United Kingdom. Here’s a handy guide, courtesy of the Met Office, to the time and maximum fraction of the Sun’s disk that will be obscured.
Unfortunately the weather forecast for Brighton isn’t marvellous so it’s possible that the main event will be obscured by cloud and all we experience is that an already dark and gloomy morning gets even darker and gloomier.
However, in the event that the weather forecast turns out to be inaccurate, which is far from unheard of, please make sure you follow the official Royal Astronomical Society guidelines to make sure you observe it safely.
And while I’m at it, here is a video of a nice lecture by Ian Ridpath explaining all about Solar and Lunar Eclipses.
As a spectacle a partial solar eclipse is pretty exciting – as long as it’s not cloudy – but even a full view of one can’t really be compared with the awesome event that is a total eclipse. I’m lucky enough to have observed one and I can tell you it was truly awe-inspiring.
If you think about it, though, it’s rather odd that such a thing is possible at all. In a total eclipse, the Moon passes between the Earth and the Sun in such a way that it exactly covers the Solar disk. In order for this to happen the apparent angular size of the Moon (as seen from Earth) has to be almost exactly the same as that of the Sun (as seen from Earth). This involves a strange coincidence: the Moon is small (about 1740 km in radius) but very close to the Earth in astronomical terms (about 400,000 km away). The Sun, on the other hand, is both enormously large (radius 700,000 km) and enormously distant (approx. 150,000,000 km). The ratio of radius to distance from Earth of these objects is almost identical at the point of a a total eclipse, so the apparent disk of the Moon almost exactly fits over that of the Sun. Why is this so?
The simple answer is that it is just a coincidence. There seems no particular physical reason why the geometry of the Earth-Moon-Sun system should have turned out this way. Moreover, the system is not static. The tides raised by the Moon on the Earth lead to frictional heating and a loss of orbital energy. The Moon’s orbit is therefore moving slowly outwards from the Earth. I’m not going to tell you exactly how quickly this happens, as it is one of the questions I set my students in the module Astrophysical Concepts I’ll be starting in a few weeks, but eventually the Earth-Moon distance will be too large for total eclipses of the Sun by the Moon to be possible on Earth, although partial and annular eclipses may still be possible.
It seems therefore that we just happen to be living at the right place at the right time to see total eclipses. Perhaps there are other inhabited moonless planets whose inhabitants will never see one. Future inhabitants of Earth will have to content themselves with watching eclipse clips on Youtube.
Things may be more complicated than this though. I’ve heard it argued that the existence of a moon reasonably close to the Earth may have helped the evolution of terrestrial life. The argument – as far as I understand it – is that life presumably began in the oceans, then amphibious forms evolved in tidal margins of some sort wherein conditions favoured both aquatic and land-dwelling creatures. Only then did life fully emerge from the seas and begin to live on land. If it is the case that the existence of significant tides is necessary for life to complete the transition from oceans to solid ground, then maybe the Moon played a key role in the evolution of dinosaurs, mammals, and even ourselves.
I’m not sure I’m convinced of this argument because, although the Moon is the dominant source of the Earth’s tides, it is not overwhelmingly so. The effect of the Sun is also considerable, only a factor of three smaller than the Moon. So maybe the Sun could have done the job on its own. I don’t know.
That’s not really the point of this post, however. What I wanted to comment on is that astronomers generally don’t question the interpretation of the occurence of total eclipses as simply a coincidence. Eclipses just are. There are no doubt many other planets where they aren’t. We’re special in that we live somewhere where something apparently unlikely happens. But this isn’t important because eclipses aren’t really all that significant in cosmic terms, other than that the law of physics allow them.
On the other hand astronomers (and many other people) do make a big deal of the fact that life exists in the Universe. Given what we know about fundamental physics and biology – which admittedly isn’t very much – this also seems unlikely. Perhaps there are many other worlds without life, so the Earth is special once again. Others argue that the existence of life is so unlikely that special provision must have been made to make it possible.
Before I find myself falling into the black hole marked “Anthropic Principle” let me just say that I don’t see the existence of life (including human life) as being of any greater significance than that of a total eclipse. Both phenomena are (subjectively) interesting to humans, both are contingent on particular circumstances, and both will no doubt cease to occur at some point in perhaps not-too-distant the future. Neither tells us much about the true nature of the Universe.
Perhaps we should just face up to the fact that we’re just not very significant….
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In the Dark 