Thursday, 23 March 2017

Never say never... but...

Definitely not electric (image from Wikipedia)
It was a little eyebrow-raising to see that a company called Wright Electric is claiming that they will have electric planes flying between London and Paris in 10 years. While we genuinely should never say 'never' with technology, I think the probability is so low that it would be well worth betting against it.

In part, this is a simple competitive edge issue. If the technology existed, it could certainly only cope with short range hops - hence London to Paris. Unfortunately, this is already a highly competitive route because Eurostar offers a far more pleasant journey than flying with similar or better city centre to city centre times. It's not the ideal route to introduce new flight technology on.

Even if London to Paris is attractive, though, this assumes, though that we have coped with 'if the technology existed.' The big problem here is battery technology. I have no doubt at all that batteries will get better in the next few years. But the difficulty faced by a plane, as opposed to a car, is the sheer weight of batteries to provide the same amount of energy as aviation fuel.

Kerosene packs a fearsome amount of energy into a relatively small mass. This is why the 9/11 attack was so devastating - it was the energy in the planes' burning fuel that hugely increased the impact. To get a feel for the difference, kerosene has around 100 times* the usable energy per unit mass as a typical laptop (or car) battery. A plane simply can't afford to carry the extra mass that would be required to be fuelled by batteries. To make the London to Paris electric plane feasible would require at least a 20 times improvement, and quite possibly a 50 times improvement in the energy density available from batteries. This may well happen at some point. But to have it developed on a timescale that allows commercial planes to be using it in 10 years is incredibly unlikely.

I worked for an airline when we were just starting to put computers into planes for cabin management and entertainment. They always ended up being antiquated devices, because the safety requirements for aviation rightly require a long period of being bedded in - typically the tech was at least 5 years old by the time it got into the sky. This means we would need this kind of improvement in just a handful of years to make a ten year horizon viable. So if anyone's up for a bet and will offer decent odds, I'm happy to take it.

This has been a green heretic production

* This figure is about 7 years old, and as battery technology is always advancing it may well be only 90 times by now, but I don't have the latest figures. But batteries haven't changed much in capacity during this period.

Monday, 20 March 2017

Review - The China Governess - Margery Allingham

I am a huge fan of Marjory Allingham's Campion books - but even so, I have to say this is probably one to avoid, unless, like me, you want to have read the entire canon. One of Allingham's late contributions, written in the 1960s four decades after the first Campion books, it lacks the joie de vivre of the earlier titles. It's over-long, and very slow - in fact it verges on the dull in places.

That's not to say it's entirely without interest, but what interest there is remains specialist. It's a sociological museum, with its stiff, emotionally retarded upper-middle class characters, who we are supposed to sympathise with, but who mostly repel. By today's standards it is also horribly un-PC about 'mental defectives'. Some readers will, I suspect, be outraged - but you do have to see this as a fascinating uncovering of just how things were in the early 60s. We tend to look back and think of the sixties as being all hippies and free love and rebellion, but we have to remember this was less than 20 years after the end of the Second World War, and the whole point of what happened in the 60s was a reaction to this establishment stiffness.

Perhaps most fascinating is the reaction of older family members to a historical black sheep in their family. Where in the current TV show Who Do You Think You Are there is a kind of horrified delight at, say, finding a murderer in the family's past, here it causes genuine pain and anger. The family's way of dealing with unpleasant things is to pretend they don't exist. Sadly, though Campion does act as a kind of operational fairy godmother to make things happen (eventually), we see very little opportunity for his usual skills - and Lugg is sadly extremely underused.

So, definitely not a book to read as an introduction to Campion - only worth going for if you do want to see just how uptight and sad the upper-middle class was in the early 1960s.

The China Governess is available from and

Tuesday, 14 March 2017

Is dark matter disappearing altogether?

A few days ago at a talk, I mentioned in passing that in a few years' time we may no longer think that dark matter exists. (In the unlikely event you've not heard of it, dark matter is a hypothetical kind of stuff that only interacts with ordinary matter through gravity, which is thought to exist because large collections of matter, such as galaxies act as if they have more matter in them than they should have.)
A galactic cluster that provides more
gravitational lensing that its ordinary matter
predicts. (Image from Hubble via Wikipedia)
After the talk, a handful of teenage physics enthusiasts collared me and said 'Surely you don't think dark matter doesn't exist?' After asking them not to call me Shirley, I admitted I was a dark matter sceptic. But I felt their pain. When I was their age, the steady state theory of cosmology was still an accepted challenger to the big bang, but its star was fading fast. I preferred steady state in part because it seemed to be a more elegant theory and in part because one of its originators was my teenage physics hero, the remarkable Fred Hoyle. I was genuinely upset when steady state was pushed out of consideration. Science may be objective, but it doesn't stop us from having emotional attachments. 

I'd say for the first time since it became widely acknowledged, dark matter is in danger of being replaced as the best accepted theory within a decade. There has been one challenger for a while in the form of MOND (Modified Newtonian Dynamics), but critics are quick to point out it doesn't explain all the phenomena ascribed to dark matter. (To be fair dark matter isn't 100 per cent either, but that's by the by.) However, there are now at least two other alternatives that explain the behaviour of large collections of matter to some degree without the need for a new type of stuff.

One suggestion is painfully simple - it takes a microscope to those innocent words in the first paragraph 'should have'. The existence of dark matter is based on guestimate of the amount of conventional matter in galaxies and other large collections of space stuff. It is, without doubt, a good guestimate, based on best current knowledge. But the reality is that the calculation has to involve estimation based in part on theory, and that leaves room for error. It only takes a small correction to make dark matter disappear. Again, there are of holes left by making this assumption, but it's a potential line of thought.

The second suggestion is a lot more sophisticated (so some theoreticians may prefer it). The concept of emergent gravity, where gravity is somewhat like thermodynamics in emerging from statistical behaviour, rather than being a true underlying fundamental force, has been put forward by some as a way of providing a mechanism to do away with dark matter. As this semi-technical article by Sabine Hossenfelder shows, there are still significant problems for this explanation, but it is without doubt another strand.

At the moment, then, nothing has knocked dark matter from its 'best accepted theory' perch. But it has never been so strongly challenged. We always need to remember that science is not about black and white, absolute fact, but establishing the best theory we can given the current evidence. Dark matter could recover from its wobble, just as the big bang did with modifications that brought it into line with current data. But there is no doubt that we exist in cosmological (and particle theory) interesting times.

Monday, 13 March 2017

Poor Pret

Image from Wikipedia
I always find it amusing when the bosses of large companies demonstrate an impressive lack of understanding of market forces. A few days ago, the HR director of sandwich/coffee chain Pret a Manger told a parliamentary committee 'I would say one in 50 people who apply to our company are British', citing this as a reason they need to continue having access to cheap foreign labour. She also said that she didn't think pay was an issue, despite a starting package of around £16,000 in London, as after a few years you could earn a lot more.

Picking this apart, I've a few issues with this argument. I don't have any evidence for that 'I would say one in 50' (don't you find 'I would say' suspiciously vague?) - is it true at all? Is it only true of central London stores? Or is that a countrywide average? Without data it's impossible to say. But let's take it at face value. What the market is really saying is that the rewards aren't good enough for the job, and they can only maintain that £16,000 starting salary (resulting in £84 million profit in their results for 2015) by employing people for whom an amount it's difficult to live on in any expensive location seems a lot of money because they come from a country where that is a large pay packet (or they're doing the job for other reasons, such as learning a language).

If the supply of cheap labour dried up there's a simple solution. You put up your starting salary until you do get enough people applying. If you have to put it up so much that you don't make a profit, you don't have a viable business model. That's what market forces are about.

Companies like Pret have had it easy to date, because they operate in a 'pile it high, sell it expensive' market. Their staff costs per head are low, but they sell premium products (i.e. ones where a small increase in cost results in a considerable increase in price). The world is changing, and poor Pret feels sorry for itself. I'm afraid I can't join in the sobbing.

Tuesday, 7 March 2017

Learn from history, don't delete it

Colston Hall (image from Wikipedia)
I'm coming towards the end of two years spending two days a week working at Bristol University. I've had a wonderful time, and have come to love this little gem of a city, getting to know it far better than I did before. One thing that has become obvious is the way that some Bristolians are torn apart by their heritage. Because this is a city that was, to some degree, built on two trades that are now abhorrent - the slave trade and tobacco.

As you go around the city, there are names you often encounter: Colston and Wills. The first refers to Edward Colston, a prominent slave trader and the Wills dynasty was behind the eponymous tobacco company, now part of Imperial Tobacco. Such is the negative feeling that there is currently a petition (2136 signatures at the time of writing) to have the city's premier music venue, Colston Hall, renamed. But I think those who support the petition are wrong.

You don't make the past go away by hiding it - but you can prevent lessons being learned by doing so. History is fundamentally important: I wish it got more priority in schools. There's a reason that Auschwitz was not obliterated. The past should not be forgotten.

There is, of course, a big difference in feel between a former concentration camp and a building that apparently glorifies someone once involved in an occupation that we now despise. However, I don't think it would be right for Bristol to attempt to sanitise itself this way. It's an action driven by guilt, and guilt for something that happened in your city's past is a waste of energy. Instead, I suggest this should be turned  into something positive. We shouldn't be petitioning for Colston and Wills to be forgotten. It would be far better if the city insisted that major buildings bearing such names should be required to have a prominent, permanent exhibition explaining where the money came from, and at what cost.

That's what history is for. Not something to feel guilty about, apologise for and then attempt to erase. It should be brought out, made very visible and used to learn lessons for the future.

Monday, 6 March 2017

Why it isn't easy being green

Yes, please, if Tesla would like to give me one
(Image from Wikipedia)
As someone with real concern for the environment, I am convinced that electric cars are the future, and the sooner we can get rid of petrol and diesel, the better. When I was younger, my fantasy car was an Aston Martin - now it's a Tesla.

However, as an official green heretic, I have to point out that, like almost all environmental decisions, it's a bit more complex than it first appears. We need to apply logic as well as emotion. Electric cars (and trains, for that matter) are great in terms of emissions - provided they use electricity that itself is produced in an environmentally friendly fashion. It has been pointed out that in Germany, which has an aggressive 'get rid of petrol cars by 2030' policy, there could be a resultant increase in carbon emissions.

The trouble is that Germany is pretty well incapable of being totally green in its electricity production by 2030, because of its irrational decision to close its nuclear power plants. What about wind and solar? They're coming on - but nowhere near fast enough. In fact, Germany has had to slow down its wind expansion because the existing wind supply is already proving disruptive to the grid because of its irregularity. The more you depend on wind, and to an extent solar, the greater need there is for supply that can be switched in quickly to cover troughs in generation.

As a result of the short-sightedness of their supply policy, if Germany does achieve 100 per cent electric cars by 2030 its carbon emissions will go up, due to the extra emissions from the dirty generation that will need to be used to support it.

I am not saying they should hold back on the electric vehicles - on the contrary, I hope we take a similar view of pushing the move to electric vehicles in the UK. (And reversing the terrible decision to cut short the electrification of GWR's trains before reaching Bristol Temple Meads.) But such a policy needs to go hand-in-hand with a transfer of generation to non-emitting sources - which at the moment almost certainly means having more nuclear in the mix as well as more wind and solar.

Thursday, 2 March 2017

No dark ghosts

The nation's favourite TV physicist, Brian Cox, has caused a bit of a ruckus amongst those who like a good ghost. Cox has often, if incorrectly, been represented as saying, as in this letter in the i newspaper, that ghosts don't exist because the Large Hadron Collider 'hasn't found them.'

I ought to stress by the way that many headlines were misleading. The Metro, for example, led with 'The Large Hadron Collider has proved that ghosts don't exist, Brian Cox claims.' It is very difficult to prove something doesn't exist, especially ghosts. To begin with, we need to assume that ghosts are natural rather than supernatural. If the supernatural exists, physics can't help - so as a starting point we need to make this assumption. And even then, as the old saying goes, absence of proof is not proof of absence.

Thankfully, the LHC is not spending any taxpayer money on disproving the existence of ghosts. Instead, Cox was referring to a puzzle that the concept of ghosts presents. If they are natural, then they appear to be some form of insubstantial energy interacting with matter (i.e. us). This immediately rules out, for instance, the dark matter that Mr Wilson mentions in his letter, because dark matter (if it exists) only interacts with ordinary matter via gravity. We see ghosts, which means we need electromagnetic interaction. If ghosts depended on particles like those of dark matter than aren't detectable by the LHC, we also couldn't see them.

Now it's not that there aren't insubstantial energy particles that interact with matter. Photons of light fit that bill. But no existing particles (or, probably more accurately in the minds of physicists, no existing quantum fields) can somehow keep a structure together to make up an insubstantial ghost and at the same time interact with matter. So there has to be something else if ghosts are to exist. And what Cox is point out is that it's surprising that there is no evidence from the LHC supporting the existence of this new stuff. If it interacts with matter in a haunting, it should also be within the range of LHC experiments.

It's not beyond the wit of science to imagine a whole new kind of quantum field/particles that have restrictions that would prevent them appearing in LHC experiments but do allow them to do what ghosts do. Which is why we can't say that the LHC proves ghosts don't exist. However, to require such a major modification of our best model of what stuff is (the standard model of particle physics) would need strong, scientific evidence. And that simply doesn't exist.