Friday, October 30, 2009

Talking Energy - an individual perspective

Today's the day when the Telegraph launches its "Talking Energy" feature in association with E.on, the energy supplier.

 One is invited to join the debate . Four of us bloggers are each given individual "home pages" on the website:    Christina O, SabinaA, the recently-arrived Robert  and myself.)

Whether, in the case of E.on,  one calls it a public consultation exercise or a PR campaign, does not worry this blogger unduly. Given the way that the AGW debate has been politicized and polarized, any new forum is to be welcomed if it allows the voice of reason and real science to be heard without all the personal aggro.

So this blogger  has signed up,  asking that any new forum be proactively moderated.  I suggested in an email that it could usefully take a leaf  from New Scientist about how to moderate.  (For example, the NS has no time or patience for those persistent conspiracy theorists who clutter up its comments, and a good thing too.)

"Reactive moderation", as one sees on My.Telegraph,  may be cost-effective, but it degenerates quickly into unseemly dogfights, ending with entire posts and comments - good as well as bad -  being deleted by the tardy moderators.

I received an electronic galley proof of the Telegraph/Eon opening gambit, scheduled for later today tomorrow, and submitted my 600 words yesterday, along with mugshot and bio' as requested. One waits with bated breath (more commonly rendered these days as "baited breath",  with visions of mouse traps and  Cheddar cheese*).

 I'm  not giving any secrets away by telling you that the central message of the exercise is that energy companies like E.on are confronted with what they call a "trilemma".  (A parallel campaign on YouTube   whence came my graphics is already underway with that questionable t-word neologism in prominence). The trilemma refers to so-called "conflicting" demands that future energy supplies be:  1. Green (low-carbon) 2.  Affordable and 3.  Reliable. 

Well,  one could be pedantic  and say there's nothing conflicting there - they are merely three desirable criteria that need to be met simultaneously.  Otherwise our lives would be burdened with trilemma, like where to live (it's got to be a nice area, affordable, handy for public transport).

Rather than nitpick, this blogger decided to focus on renewable energy, and how it might be made more reliable, given fluctuations in wind speed affecting turbine output etc.  Clue:  Dinorwig.

I'll let the Telegraph publish  first, then wait a day or two.

Watch this space!

* Cruel Clever Cat by Geoffrey Taylor:

Sally, having swallowed cheese,
Directs down holes the scented breeze,
Enticing thus with baited breath
Nice mice to an untimely death.

 This little ditty first appeared  in an anthology called Catscript, edited by Marie Angel.  However, it was first published in 1933 in a limited edition of Geoffrey Taylor’s poems entitled A Dash of Garlic.

Additional  reading  E.on powers down to cut carbon and costs 

Interesting to see the spotlight being put on our PCs - and rightly so, when you consider the heat that comes - not just from the laptop itself, but the charger too.

Energy-saving tip: when using one's laptop, switch off a light or other appliance that would normally be on, if it's superfluous to requirements when you are online.

Update:  Thur 5th November: Here's a C&P of my first post on the E.on site.  Having been up for a few days now,  it would not seem a terrible breach of protocol to add it here for archival purposes:

Who can doubt that the future lies with renewable energy, and that we Brits are blessed with the stuff – existing or yet-to-be-realized.
First, there are those wind turbines – not the stuff of Wordsworthian rapture I grant you - but they are increasingly being sited offshore.
Then there’s solar energy, with a choice of two panels for your roof – the older thermal, or the state-of-the-art PV panels that can feed the electricity you don’t use into the National Grid.
And there’s wave power – which is a kind of secondhand solar power, recalling that weather and wind are due to unequal heating of the Earth’s surface.

And there’s even the dear old man in the moon, not wishing to be outshone by his flashy big brother, who contributes the prospect of tidal power. Just wait until we have a hydroelectric barrage across the Severn Estuary, supplying maybe as much as 10 per cent (?) of our power supply. (Yes, there are downsides, needless to say, to any big scheme, in terms of amenity, effect on wildlife, capital cost, the carbon-footprint of setting up etc. But let’s stick with the broad brush today.)

The problem with most of the renewable schemes is that the end-product – electricity, that energy-carrier par excellence – is generated at scattered locations across the country, supply may be intermittent, or supply may not match demand around the clock or calendar.

Is there a solution? Yes, there probably is, though it’s not always a panacea. One is talking about big money upfront, and, more to the point, big commitment.

But unless or until fusion power becomes a reality – which may take decades, centuries even – then there is no Plan B, assuming one is not a unbudgeable climate change denialist who thinks the world's scientists in their droves have abandoned all reason in condemning those fossil fuels.

So what is the solution? Simply go to the wiki page on Pumped Hydroelectric Storage, and it’s all there.
Britain already has 4 PHS stations – two in Scotland, two in Wales, and now needs a lot more in different shapes and sizes.

The principle is simple. One has two bodies of water – a lower and upper level. When there’s a surplus of electrical power, say from wind farms during the night, water is pumped from the lower to the upper level. When there’s extra demand, and the conventional stations are struggling to cope, water runs back through turbines, generating electricity.

It’s the closest one can get to “storing” electricity as the potential energy of a head of water. What’s more, the efficiency is surprisingly high – 80 per cent or more they claim in a well-designed system.

Do read the article, to see the new and imaginative ways of developing the principle. The Japanese have used the sea on Okinawa as one of the two levels, the other being a reservoir at the top of the headland.

The Danes have a plan that does not even need two levels – the water is simply pumped into a giant bladder which gradually plumps up, creating its own head. Sand is laid on top to get extra oomph.

My favourite is the salt-mine idea. We have lots of worked-out salt-mines in Cheshire and elsewhere. You pump water down into the old-workings, and site your upper reservoir on the surface. Yes, the water becomes brine, so all the equipment has to be corrosion-resistant. But there’s an upside too: once the water becomes saturated brine, it’s 20 per cent heavier than pure water, so becomes a more efficient energy-transfer medium.

What is it they say – where there’s a will, there’s a way!

Tuesday, October 20, 2009

Can entropy decrease in a Big Crunch - without defying the Second Law of Thermodynamics?

The Universe, we're told,  is expanding, and has been from the beginning of time - reckoned to be some 13.6 billion years ago. Extrapolate back, and the Universe must have started as something incredibly small, hot and dense - a singularity. Something caused that singularity to explode, in a Big Bang.  So far, I'm telling you nothing you have not already heard or read many times.

Will the Universe go on expanding for ever? If you believe in Dark Matter and Dark Energy, then the answer is probably yes.  But so far, neither of those hypothetical entities has yet been detected. 

So there's another scenario that cannot be dismissed - that expansion will slow, and the Universe will cease expanding and then start collapsing  back on itself, ending in a Big Crunch.

 Some, myself included, are attracted to this idea, especially as it makes possible the idea of a new Big Bang, indeed, a never-ending series of Bangs and Crunches.

But some objections, or at any rate difficulties, have been raised with the idea of a Big Crunch. One of them is to do with entropy (eg  link to Yahoo forum) , and the Second Law of Thermodynamics, which is the one I intend to discuss briefly here today and tomorrow.

The essential idea conveyed by the Second Law is that while energy is never created or destroyed, energy is gradually dispersed, becoming less and less useful.  Engines use concentrated energy - fuel - to operate. The end product is waste heat - too dispersed for it to be recaptured and re-used. Indeed, the very act of trying to do that would be self-defeating, incurring a greater energy cost than that recouped.  Entropy - the spontaneous tendency for systems to become chaotic, more dispersed, has been successfully analysed statistically in terms of order/disorder, more specifically to do with numbers of possible arrangements. The example I used to give students was this. Imagine you have a neat and tidy bedroom, and there's a strong gust of wind through an open window. Papers get scattered, things fall off shelves etc.  Suppose one started with a disordered bedroom, and there was a gust of wind. You would be very surprised if you ended with a tidy bedroom.  The probability of a chance event - in this case the wind - producing disorder is hugely greater than that of producing order. Why?   Because there are relatively few ordered arrangements compared  to the number of disordered ones.

What's all this got to do with cosmology you may ask?  Well, we see entropy increase around us on a daily basis - eg salt dissolves in water. The ordered structure of a crystal is replaced with the chaos of dispersed ions in solution.  If entropy is steadily increasing, in accordance with the Second Law, then the entropy of the initial singularity must presumably have been minimal, possibly zero - a maximally-ordered  system it would seem.

There's a problem, then, with the idea of contraction back to a singularity - the Big Crunch. Why ? Because if the end result is the same singularity, then entropy would decrease steadily during the contraction. But that would be contrary to the Second Law, would it not?  Other objections have been raised. If we lived in a contracting universe, salt would presumably still dissolve in water, so we would still be seeing the Second  Law in action.

Some have tried to get round the conundrum by introducing the variable of time. It then gets very counter-intuitive, especially the concept of negative time, even history running in reverse!  Let's not go there. 

I believe there is a way of reconciling the concept of a Big Crunch with entropy and the Second Law.

I shall be posting it  here tomorrow!

Wed 21 Oct: Well, tomorrow has arrived, so here's the rest of the story.

It's all to do with the size of the Universe, and its fitness or otherwise to act as an entropy-increasing heat sink. While the Universe is expanding, there is abundant space in which heat can dissipate, or other forms of disorder can occur - eg dilution of gaseous end products etc. In the initial stages of contraction, things would continue much the same while there are still light-years between galaxies, or light-minutes between planets and their nearest neighbours, or even light-seconds between a planet and its moon with intervening space.

But imagine the process of contraction occurring continuously. There will finally come a time when one's perception of nature will change. Galaxies will collide for a start, but let's focus on events at a more local level. Previously there was almost limitless space for heat to dissipate. That will no longer be the case - for two reasons. First there is less space for any new heat to dissipate. Secondly, and more importantly, all the previous heat dissipated into the Universe - which is still out there- will become progressively concentrated. (Reminder; it's not just the contents of space that disappear into a black hole vortex - but the fabric of space-time itself- represented by the mesh in the graphic).

 Temperatures in deep space, presently a few degree above absolute zero, will start to increase. The so-called microwave background radiation,  a left-over from the Big Bang - will gradually shift and start to shorten in wavelength - first to normal radio frequencies, and then into the infra-red region. That's when things start to get interesting. Engines will no longer run so efficiently, because as background temperatures rise, they will find it progressively harder to dissipate exhaust heat.

Let's now look at the salt/water system. Yes, salt will continue to dissolve in water, suggesting that all is well - that the Second Law is still operating.  But as background temperatures increase, the water gets hotter, and if there were still observers around, a point would be reached when the water was no longer liquid at normal temperatures and pressures. In other words, salt could not dissolve in water - if there were no liquid water still in existence!

So there would in fact be a gradual violation of the Second Law as we know it, were the Universe to implode towards a Big Crunch, due to increasing difficulty in dissipating waste heat against a background of rising temperature.  In the final stages, the temperatures would become so great that no heat could be dissipated at all. In that situation, one has returned to a state of minimum entropy, but hugely elevated temperatures.

Had a classical thermodynamicist such as Carnot (of eponymous cycle fame) been born into a contracting Universe he would have enunciated the Second Law of Thermodynamics differently, methinks.  Quite how it would have been worded I would not care to speculate, except to say it would need to have been heavily qualified re differences between open and closed systems. Could a contracting Universe even be described as "open". Only when the system under study was small, with a sizeable temperature difference between it and everything else "out there"?

What then?  See my earlier ideas in the margin (scroll down) which have now been appeared in the MSM - so far with no serious objections being raised. I do not believe that the Big Crunch continues indefinitely. There comes a point when, through frictional forces, the plasma reaches the maximum possible temperature - when its constituent particles (strings?) then  moving/vibrating so rapidly that they reach the speed of light,  and then transform into massless photons. When that occurs,  the system ceases to be a superblack hole, and spectacularly flies apart, creating a new Big Bang...

Update 16th Dec 2014 (5 years later!)

It's temperature that is the key to the conundrum, and the kind of world it creates for those seeking evidence of order/disorder.

In our relatively low temperature world (relying on radiated heat from a single sun that is 92 million miles away) we see lots of evidence of order, notably as the presence of substances as liquids and solids, when at higher temperatures (say in the laboratory) they becomes gases, and at thousands or millions of degrees would be in the plasma state.

But the latter are the temperatures that attain when a Universe contracts down to a black hole,  and then singularity, hypothetically or otherwise. So it's useless to go looking for the kind of ordered, low entropy signatures that we are accustomed to. We have to ask ourselves what the signatures are when temperatures are hugely elevated, such that subatomic particles are travelling at speeds close to those of light, and colliding with each other. Those collisions break down the order of associations, but progressively a simplified plasma emerges in which there are the ultimate particles only, whatever they happen to be, all crushed together. The  original translational energy across sizeable distances now becomes progressively constrained to vibrations about fixed positions (as in a classical earthly solid), obviously with enormous oscillation frequencies. Thus a kind of high-temperature/highly ordered/low entropy state does  (paradoxically perhaps) become finally achievable, but through initial fragmentation, rather than clumping association. In other words, there's more than one route to a low entropy state, depending on temperature.

Saturday, October 10, 2009

What went wrong with NASA's moon crash?

The idea was to crash a spacecraft into the Moon at a chosen spot where ice might be lurking. Hitting the Moon at twice the speed of a bullet would send a plume of debris miles high that could then be analysed spectroscopically for water.

But there appears to have been no plume - only a brief white flash. Why not?  Here's this blogger's explanation for what it's worth, published first on New Scientist and now the Times.

From the latter:

"Maybe a plume was formed but settled too quickly to be seen by the following probe, 4 minutes behind. Don't forget that although gravity is lower on the Moon, making things slower to fall, there's no air to slow the descent - even of dust particles or those hoped-for ice crystals.

There's a classic lab experiment in which a stout glass tube has all the air pumped out. A feather inside then falls as quickly as a ball-bearing.

Let's hope the NASA scientists did not forget their school physics."

Update: Sunday 18 October   Well, halleluja, a plume was captured on camera after all, although the photograph in New Scientist ("Elusive lunar plume caught on camera after all")  was somewhat disappointing. I mean to say - given it was said to be 6-8 kilometres wide, why show us a mere smidgeon of white on a so-called "zoomed image"? Small wonder the conspiracy theorists began falling out of the woodwork!

The fact that a plume was briefly formed lends support to the hypothesis I've ventured above. The plume didn't last long, because the particles fell back faster than many might suppose (given that the Moon's lower gravity seems to dominate most thinking, with the absence of an atmosphere frequently overlooked).

The absence of an atmosphere alters the dynamics of an impact and its aftermath considerably. Dust and other particles (ice?) may well be ejected much higher and further than on Earth, due to absence of a cushioning atmosphere - no air molecules to be pushed aside- but their return to "earth" would look entirely different to an observer or camera. Initially the descent would seem gentle - due to 1/6th Earth's gravity- but acceleration would be continuous, without anything comparable to "terminal velocity" (approx 120 mph on Earth in "old  money"). A quick back- of- envelope calculation using school physics says that while it would take some 30 seconds for dust or ice particles to reach 120mph (which is our earthly terminal velocity), they would go on accelerating indefinitely until they finally hit the surface. There's another factor to consider - which another scribe on NS comments has pointed out :  much of the ice -if present- would be vaporised by the kinetic energy (heat) of impact. The  molecules would be unlikely to re-coalesce in the Moon's near-vacuum, and simply disappear from view - except perhaps to a highly sensitive spectrometer that was set up specifically to look for them - and certainly fail to drop back. Molecules generally don't "drop back" in a vacuum, especially in a weak gravitational field. They would simply spread out, ie diffuse rapidly.

Thursday, October 8, 2009

The Times "Eureka" magazine - first impressions

I've just spent an hour leafing through the Times's most recent addition to its publishing platform. It's called Eureka, its cover is very green, with an unattractive graphic of a chap who's lost the top half of his skull, with a plethora of sciencey things bursting forth from the exposed remainder.

Personally I find it hard to conceive of an image that is better guaranteed to confirm in the layman's mind that science is a nerdy thing that reveals more than you really want to know - an autistic  lack of the light touch, to say nothing of discretion and good taste .

Well, I hadn't intended to start on so negative a note, but it's sitting there next to me in all its disturbing, stomach-churning  immediacy, so I want to get that off my chest. First impressions still count, do they not?

Second and subsequent impressions are a lot more favourable. One doesn't envy anyone the task of producing a digest of science for the general reader of a newspaper, not even a serious one like The Times. How does one define the target audience, given that a relatively small proportion will  have formal scientific qualifications much beyond GCSE - or O-Level?  Then there is the notorious antipathy that exists towards science and scientists in the UK - one that has produced what someone described some years ago as the "ghettoization" of science.

Scientists are partly to blame themselves - let's not go into all that right now. Suffice it to say that the finger hovers over the remote when a science programme appears on TV. Woe betide any presenter who attempts to get too immersed in detail, or who overdoes the gee-whizzery, pie-in-the-sky delivery. The British public is inured to that kind of thing, and is likely to say "Come back in 10 years when you know some more, or have a workable, marketable product."

The criterion for a good thriller is that it is un-putdown-able. So what should it be for a periodical that appears only once a month?  Not un-putdownable - that would be asking too much, in view of the subject matter. I suggest it should be put-downable, ie nothing too long and demanding of time, but so pick-uppable again that it escapes an early fate in the nether regions of a bulging paper-rack, or worse still the dustbin.  In that sense I believe "Eureka" is over its first hurdle. There's a good mix of light and serious, human and technical, visionary and realistic to make it worth returning to if one only has the time or inclination to dip in now and again.

I'll come back in a day or two with a closer look at some of the features. I do have one or two quite serious gripes with some of the detailed science. In particular the feature "Living in the City" seems to have some unrealistic chemistry and biology. Since when has carbon dioxide reacted with magnesium chloride to give magnesium carbonate? (The reaction proceeds fine in the opposite direction!) But let's not nitpick today. The line-up of writers is impressive - with at least three with solid research experience and qualifications - up to and beyond PhD - and amazingly the Times has secured the services of Martin Rees - President of the Royal Society- whose keynote contribution is worth a read, touching as it does on a host of the issues that confront scientists, and the perception (or misconceptions) re the scientific approach to modern life and the myriad questions it throws up.

 Update: Friday 9 October

The individual articles in Eureka are now online, including the one with the questionable chemistry. Have submitted this comment:

"Hmmm. While one welcomes "out-of-the-box" thinking on technology, the fundamental science has to stay firmly within the box.

It would not seem feasible, for example, to use "magnesium chloride" as a trapping agent for CO2. Magnesium hydroxide, certainly, but since that's made from magnesium carbonate, heating in steam to drive off CO2,  it's self defeating re carbon footprints. 

With magnesium chloride, one is trying to make the following (well known) reaction go in reverse:

magnesium carbonate + hydrochloric acid -> magnesium chloride + water + carbon dioxide

Not only does it prefer to go in the direction shown, but if one did contrive conditions to make it go in reverse one would release hydrochloric acid fumes into the neighbourhood! Hardly environmentally-friendly!

The bacterial illumination look improbable too. Yes, there are strains that react oxygen with luciferin, but the light-show is mediated by the enzyme luciferase, and that catalysis, like the rest of bacterial metabolism, requires an aqueous environment. I doubt whether bacteria would take kindly to being incorporated into coatings if that meant having to exist lichen-like in all weathers. Bacteria - excluding their resistant spores- are a lot more fussy about their environment!"