Manchester Thoughts

Posted in Poetry with tags , , on May 23, 2017 by telescoper

I went to bed early last night after a long day, so I only found out about the terrible events in Manchester when I woke up this morning. The lives of 22 people ended last night, and many of those who survived will never be the same again because of their physical injuries or because of the awful things they witnessed.

I know it’s a feeble response, but I send my deepest condolences to the bereaved and wish a speedy recovery to all those injured or in any other way affected.

Words fail in situations like this. Comprehension fails too. How someone purportedly of the same species as me can sit down and systematically plan to murder children and teenagers is quite beyond my ability to fathom. The choice of target was as callous as it was deliberate: an audience of young girls. The murderer blew himself up in the course of this attack, which means he has evaded justice. I just hope the police will identify the remains and wrap up whatever network helped him plan and execute this attack.

There’s enough information in the news to make a reasonably informed guess as to what kind of explosive device was used. It’s not difficult to make a bomb of that type, but it’s a step up in sophistication from the event on Westminster Bridge. Let’s hope it’s not the start of a new wave of terror attacks, but even if it is they will not win.

It’s difficult to concentrate on work when something like this happens, but I think it’s important to force oneself to do so. If we allow ourselves to become distracted, then the bastards have won. I won’t write much more, but I will refer you to a poem by Dylan Thomas, arguably his greatest, which came into my mind this morning as it has done (sadly) many times before.

A Refusal to Mourn the Death by Fire of a Child in London was first published just after the end of the Second World War and was written after Thomas heard news of a young girl who had burned to death when the house she was in was set on fire during an air raid.

The idea behind the poem is complex, and its message double-edged, but Thomas finds a perfect balance between horror and sadness, and between indignation and heartbreak. Children shouldn’t have to die, and neither should anyone else whose life is cut short by another’s hand, but we have to live with the fact that they can and do. There’s no consolation to be found in mourning and in any case it’s hypocritical to favour one death with elegies, when suffering is so widespread. The best we can do is allow the dead some dignity and the bereaved some time to heal.

Here is a short extract from the poem, which sums up my thoughts.

I shall not murder
The mankind of her going with a grave truth
Nor blaspheme down the stations of the breath
With any further
Elegy of innocence and youth.

I won’t post the full poem here, but you can find it elsewhere on this blog.


Data Intensive Research in Exeter

Posted in Uncategorized on May 22, 2017 by telescoper

Just a quick post to mention that today I’m part of a delegation from the Cardiff Data Innovation Research Institute at a workshop on Data-Intensive Research at the University of Exeter, qhich covers a number of themes broadly related to the Environment and Sustainability. This is one of a quartet of such meetings, one at each institution in the GW4 Alliance (i.e. Cardiff, Bristol, Bath and Exeter).

The train journey to Exeter from Cardiff (via Bristol Temple Meads) was pleasant in the sunshine, although I did set out rather early (7am departure from Cardiff Central). We’re actually in the Institute for Arabic and Islamic Studies, a very nice modern building on the University’s attractive campus.

Anyway, I’m looking forward to the meeting, because it’s a chance to find out quite a lot more about the work going on relating to weather and climate which benefits from the presence of the Met Office nearby – it relocated to Exeter from Bracknell in 2003. But that’s just a part of a very wide range of research, so it should be an interesting day.

Well, it proved to be an interesting day of talks and networking opportunities. Now I’m on my way back to Cardiff.

Goodbye, Exeter, and thanks for hosting us so nicely! 

Champions Road

Posted in Cardiff, Football on May 21, 2017 by telescoper

Signs like this have appeared on Cathedral Road near my home in Cardiff.

From the black and white stripes you can see that it celebrates Newcastle United’s victory in the Championship this season.

You learn something new every day, though. I hadn’t previously realised that the way to say ‘Newcastle United’ in Welsh is ‘Juventus’…

Half and Half in Cardiff

Posted in Cardiff on May 20, 2017 by telescoper

In view of the imminent arrival of two hundred thousand visitors to Cardiff for the UEFA Champions League final, I thought I’d post some helpful information about the city for the benefit of our guests.

One of the special delicacies on offer in Cardiff curry houses is the “half and half”, an example of which is shown above.

This is what you ask for if you can’t decide whether to have rice or chips to provide the carbohydrate element to go with your selected curry. In my experience you don’t really get a half- portion of chips and a half-portion of rice, but a full portion of each. ‘Half and half’ is therefore the best choice if you’re really hungry.

A Spot of Hype

Posted in Astrohype, The Universe and Stuff with tags , , on May 19, 2017 by telescoper

A few weeks ago a paper came out in Monthly Notices of the Royal Astronomical Society (accompanied by a press release from the Royal Astronomical Society) about a possible explanation for the now-famous cold spot in the cosmic microwave background sky that I’ve blogged about on a number of occasions:

If the standard model of cosmology is correct then a spot as cold as this and as large as this is quite a rare event, occurring only about 1% of the time in sky patterns simulated using the model assumptions. One possible explanation of this ( which I’ve discussed before) is that this feature is generated not by density fluctuations in the primordial plasma (which are thought to cause the variation of temperature of the cosmic microwave background across the sky), but by something much more recent in the evolution of the Universe, namely a local large void in the matter distribution which would cause a temperature fluctuation by the Sachs-Wolfe Effect.

The latest paper by Mackenzie et al. (which can be found on the arXiv here) pours enough cold water on that explanation to drown it completely and wash away the corpse. A detailed survey of the galaxy distribution in the direction of the cold spot shows no evidence for an under-density deep enough to affect the CMB. But if the cold spot is not caused by a supervoid, what is it caused by?

Right at the end of the paper the authors discuss a few alternatives,  some of them invoking `exotic’ physics early in the Universe’s history. One such possibility arises if we live in an inflationary Universe in which our observable universe is just one of a (perhaps infinite) collection of bubble-like domains which are now causally disconnected. If our bubble collided with another bubble early on then it might distort the cosmic microwave background in our bubble, in much the same way that a collision with another car might damage your car’s bodywork.

For the record I’ve always found this explanation completely implausible. A simple energy argument suggests that if such a collision were to occur between two inflationary bubbles, it is much more likely to involve their mutual destruction than a small dint. In other words, both cars would be written off.

Nevertheless, the press have seized on this possible explanation, got hold of the wrong end of the stick and proceeded to beat about the bush with it. See, for example, the Independent headline: `Mysterious ‘cold spot’ in space could be proof of a parallel universe, scientists say’.

No. Actually, scientists don’t say that. In particular, the authors of the paper don’t say it either. In fact they don’t mention `proof’ at all. It’s pure hype by the journalists. I don’t blame Mackenzie et al, nor the RAS Press team. It’s just silly reporting.

Anyway, I’m sure I can hear you asking what I think is the origin of the cold spot. Well, the simple answer is that I don’t know for sure. The more complicated answer is that I strongly suspect that at least part of the explanation for why this patch of sky looks as cold as it does is tied up with another anomalous feature of the CMB, i.e. the hemispherical power asymmetry.

In the standard cosmological model the CMB fluctuations are statistically isotropic, which means the variance is the same everywhere on the sky. In observed maps of the microwave background, however, there is a slight but statistically significant variation of the variance, in such a way that the half of the sky that includes the cold spot has larger variance than the opposite half.

My suspicion is that the hemispherical power asymmetry is either an instrumental artifact (i.e. a systematic of the measurement) or is generated by improper substraction of foreground signals (from our galaxy or even from within the Solar system). Whatever causes it, this effect could well modulate the CMB temperature in such a way that it makes the cold spot look more impressive than it actually is. It seems to me that the cold spot could be perfectly consistent with the standard model if this hemispherical anomaly is taken into account. This may not be `exotic’ or `exciting’ or feed the current fetish for the multiverse, but I think it’s the simplest and most probable explanation.

Call me old-fashioned.

P.S. You might like to read this article by Alfredo Carpineti which is similarly sceptical!

Back to Cardiff

Posted in Cardiff, Cricket, Football on May 19, 2017 by telescoper

Despite torrential rain and flooding (in England) and the failure of the electronic passport readers at Heathrow Terminal 5, I managed to get back to Cardiff (via plane, bus and train) more-or-less when I expected and all in one piece, if a little tired. It was good to get home and have a nice cup of tea. I love lots of things about Italy, but I’ve never found anywhere in that wonderful country to have a decent cuppa.

When I walked home from Cardiff Central last night I noticed that road barriers have started to appear on the streets near the Principality Stadium. This is because the final of the UEFA Champions League between Juventus and Real Madrid will take place there on Saturday 3rd June. This will be easily the biggest sporting event ever held in Cardiff, with up to a quarter of a million people coming into the city, only 80,000 or so of whom will be able to watch the event in the Stadium. There’ll be a lot of disruption to traffic in the City Centre, both for security reasons and because of the sheer number of people packing the place.

Hotels in and around Cardiff sold out months ago, and an enormous campsite is being created on Pontcanna fields to house some of the people who couldn’t find a room. I’m not sure I would pay £195 for 3 nights to sleep in a tent, but some will. I just hope it’s not too noisy around my house! I was thinking of going away and renting my house out for the period, but I want to be in Cardiff for my birthday treat – a performance of Der Rosenkavalier by Welsh National Opera.

Talking of sport, since the weather was pleasant when I got up this morning, I decided to reacclimatise after a few days away by popping into the SSE SWALEC Stadium in Sophia Gardens to watch the first sessions’s play of the County Championship match between Glamorgan and Nottingham.

I’m glad I went because it was an absorbing morning’s cricket, with some excellent bowling and fielding by Glamorgan restricting Nottinghamshire to just 64 for 2 off 31 overs. The second wicket to fall involved a superlative catch in the slips by Aneurin Donald. It’s good to see Glamorgan playing with a spring in their step. After a poor start to the season they finished 4th (out of nine teams) in the Royal London One-Day Cup Southern division, which although they missed out on a semi-final place, is a creditable result and a distinct improvement on last year. Let’s hope they can carry on that progress into the County Championship.

Gravity in the Quantum Vacuum

Posted in The Universe and Stuff with tags , , , , , on May 18, 2017 by telescoper

Yeterday I noticed an interesting paper which has been on the arXiv for a few months but which has just been published in Physical Review D and has been highlighted by the Editors of that esteemed journal. The authors are Qingdi Wang, Zhen Zhu and Bill Unruh – all of them from the University of British Columbia in Vancouver.

Here is the abstract:

You can click on the image if it is too small to read. As you will see it suggests that we may have been thinking about the effect of vacuum energy in completely the wrong way in the context of Dark Energy.

It’s a long paper (35 pages) which I haven’t had time to work through completely yet, and I don’t know whether it will stand up. I have to say, though, that I’ve long left that the problem of dark energy will only be solved by a fundamental reappraisal of the underlying physics, rather than adding new fields or other such contrivances.

I’d be interested in comments from people who have read the paper thoroughly. I’m flying back to Blighty this evening so I hope I can study the article more thoroughly on the plane.