Archive for the ‘Personal’ Category

Would you like to work with me?

July 29, 2017
Lab Panorama

The Acoustic Thermometry Lab at NPL (Photo by Sam Gibbs: thanks ūüôā )

Friends and colleagues,

  • Do you know anyone who would like to work with me?

In the next few months I expect to be starting some new projects at NPL. And this means that I will not be able to work on my existing projects ūüė¶

So NPL have created the opportunity for someone to work with me to help complete those projects.

  • You can read about the job here.
  • It’s also on the NPL web site here where it’s the described as “Research Or Higher Research Scientist – Temperature & Humidity” reference¬†65552.

What’s involved?

Good question. And it is one that is still being decided.

But it would involve working mainly in the acoustic thermometry lab .

Lab Panorama with notes

In acoustic thermometry, the temperature of a gas is inferred from measurements of the speed of sound.

On the left-hand side of the picture is an apparatus that uses a spherical resonator to measure the speed of sound. It is the most accurate thermometer on Earth.

On the right-hand side of the picture is a new apparatus¬†that uses a cylindrical resonator to measure the speed of sound and has been designed to operate up 700 ¬įC.

The job would involve learning¬†about these techniques but that wouldn’t be the main activity.

Running around the lab is 50 metres of bright yellow tubing that we refer to as ‘an acoustic waveguide’.

By measuring the transmission of sound along the tube it is possible to turn it into a useful thermometer. I hope.

Finding out whether this can be made to work practically would be one part of the job. And testing the same idea is smaller tubes would be another.

Finally, by measuring the speed of sound in air it is possible to measure the temperature of the air and we would like to investigate applications of this technology.

What does the job involve?

Well it will involve learning a lot of new stuff. Typically projects involve:

  • Programming in Labview to control instruments and acquire and analyse data.
  • Writing spreadsheets and reports and PowerPoint presentations.
  • Keep track of stuff in a lab book.
  • Using acoustic and optical transducers
  • Signal processing
  • Electronics
  • Mechanical design and construction.
  • Vacuum and gas handling systems – ‘plumbing’.

And lots more. And the chance that someone with those skills will walk through the door is pretty low.

So prior knowledge is great but the key requirement is the mindset to face all those unknown things without letting the bewilderment become overwhelming.

So we are looking for someone with enthusiasm.


Learning new stuff is painful. Especially when it seems endless.

So¬†I couldn’t imagine working with someone who wasn’t enthusiastic about the miracle of physics.

And there is one benefit which isn’t mentioned in the advert.

To cope with the inevitable disappointments and to reward ourselves for our minor successes, our research group has freely available Tunnock’s Caramel Wafers.

Anyway, if this person isn’t you,¬†please do pass on the opportunity to anyone you think might be interested.

The closing date for applications is 28th August 2017.


Gravity Wave Detector#2

July 15, 2017

GEO600 One arm


After presenting a paper at the European Society of Precision Engineering and Nanotechnology (EUSPEN) in Hannover back in May, I was offered the chance to visit a Gravity Wave Detector. Wow! I jumped at the opportunity!

The visiting delegation were driven in a three-minibus convoy for about 30 minutes, ending up in the middle of a field of cabbages.

After artfully turning around and re-tracing our steps, we found a long, straight, gated track running off the cabbage-field track.

Near the gate was a shed, and alongside the road ran some corrugated sheet covering what looked like a drainage ditch.

These were the only clues that we were approaching one of the most sensitive devices that human beings have ever built: the GEO600 gravity-wave detector. (Wikipedia or GEO600 home page)

Even as we drove down the road, the device in ‘the ditch’ was looking for length changes in the 600 metre road of less than one thousandth the diameter of a single proton.

Nothing about how to achieve such sensitivity is obvious. And as my previous article made clear, there have been many false steps along the way.

But even the phenomenal sensitivity of this detector turns out be not quite good enough to detect the gravity waves from colliding black holes.

In order to detect recent events GEO600 would have to have been between 3 and 10 times more sensitive.

The measuring principle

The GEO600 device as it appears above ground is illustrated in the drone movie above.

It consists of a series of huts and an underground laboratory at the intersection of two 600 metre long ‘arms’.

In the central laboratory, a powerful (30 watt) laser shines light of a single wavelength onto a beam-splitter: a piece of glass with a thin metal coating.

The beam-splitter reflects half the light and transmits the other other half, creating two beams which travel at 90¬į to each other along the two arms of the device.

At the end of the arms, a mirror reflects the light back to the beam-splitter and onto a light detector where the beams re-combine.

Aside from the laser, all the optical components are suspended from anti-vibration mountings inside vacuum tubes about 50 cm in diameter.

When set up optimally, the light traversing the two arms interferes destructively, giving almost zero light signal at the detector.

But a motion of one mirror by half of a wavelength of light (~0.0005 millimetres), will result in a signal going from nearly zero watts (when there is destructive interference) to roughly 30 watts (when there is constructive interference).

So this device Рwhich is called a Michelson Interferometer Рsenses tiny differences in the path of light in the two arms. These differences might be due to the motion of one of the mirrors, or due to light in one arm being delayed with respect to light in the other arm.


The basic sensitivity to motion can be calculated (roughly) as follows.

Shifting one mirror by one half a wavelength (roughly 0.0005 millimetres) results in an optical signal increasing from near zero to roughly 30 watts, a sensitivity of around 60,000 watts per millimetre.

Modern silicon detectors can detect perhaps a pico-watt (10-12 watt) of light.

So the device can detect a motion of just

10-12 watts ÷ 60000 watts per millimetre

or roughly 2 x 10-17 mm which is 10-20 metres. Or one hundred thousandth the diameter of a proton!

If the beam paths are each 600 metres long then the ability to detect displacements is equivalent to a fractional strain of roughly 10-23 in one beam path over the other.

So GEO600 could, in principle, detect a change in length of one arm compared to the other by a fraction:

0.000 000 000 000 000 000 000 01

There are lots of reasons why this sensitivity is not fully realised, but that is the basic operating principle of the interferometer.

The ‘trick’ is isolation

The scientists running the experiment think that a gravity wave passing through the detector will cause tiny, fluctuating changes in the length of one arm of GEO600 compared with the other arm.

The changes they expect are tiny which is why they made GEO600 so sensitive.

But in the same way that a super-sensitive microphone in a noisy room would just makes the noise appear louder, so GEO600 is useless unless it can be isolated from noise and vibrations.

So the ‘trick’ is to place this extraordinarily sensitive ‘microphone’ into an extraordinarily ‘quiet’ environment. This is very difficult.

If one sits in a quiet room, one can slowly become aware of all kinds of noises which were previously present, but of which one was unaware:

  • the sound of the flow of blood in our ears:
  • the sound of the house ‘creaking’
  • other ‘hums’ of indeterminate origin.

Similarly GEO600, can ‘hear’ previously unimaginably ‘quiet’ sounds:

  • the ground vibrations of Atlantic waves crashing on the shores of Europe:
  • the atom-by-atom ‘creeping’ of the suspension holding the mirrors


So during an experiment, the components of GEO600 sit in a vacuum and the mirrors and optical components are suspended from silica (glass) fibres, which are themselves suspended from the end of a spring-on-a-spring-on-a-spring!

In the photograph below, the stainless steel vacuum vessels containing the key components can be seen in the underground ‘hub’ at the intersection of the two arms.

GEO600 Beam Splitter

They are as isolated from the ‘local’ environment as possible.

The output of the detector – the brightness of the light on the detector is shown live on one of the many screens in the control ‘hut’.

GEO 600 Control Centre

But instead of a graph of ‘brightness versus time, the signal is shown as a graph of the frequencies of vibration detected by the silicon detector.


The picture below shows a graph of the strain – the difference in length of the two arms – detected at different frequencies.

[Please note the graph is what scientists call ‘logarithmic’. This means that a given distance on either axis corresponds to a constant multiplier. So the each group of horizontal lines corresponds¬†to a change in strain by a factor 10, and the maximum strain shown on the vertical 10,000 times larger than the smallest strain shown.]

Sensitivity Curve

The picture above shows two traces, which both have three key features:

  • The blue curve showed the signal being detected as we watched. The red curve was the best performance of the detector. So the detector was performing close to its optimal performance.
  • Both curves are large at low frequencies, have a minimum close to 600 Hz, and then rise slowly. This is the background noise of the detector. Ideally they would like this to be about 10 times lower, particularly at low frequencies.
  • Close to the minimum is a large cluster of spikes: these are the natural frequencies of vibration of the mirror suspensions and the other optical components.
  • There are lots of spikes caused by specific noise sources in the environment.

If a gravity wave passed by…

…it would appear as a sudden spike at a particular frequency, and this frequency would then increase, and finally the spike would disappear.

It would be over in less than a second.

And how could they tell¬†it was a gravity wave and not just random noise? Well that’s the second trick: gravity wave detectors hunt in pairs.

The signal from this detector is analysed alongside signals from other gravity wave detectors located thousands of kilometres away.

If the signal came from a gravity wave, then they would expect to see a similar signal in the second detector either just before or just afterwards – within a ‘time window’ consistent with a wave travelling at the speed of light.


Because powerful lasers were in use, visitors were obliged to wear laser google!

Because powerful lasers were in use, visitors were obliged to wear laser goggles!

This was the second gravity wave detector I have seen that has never detected a gravity wave.

But I have seen this in the new era where we now know these waves exist.

People have been actively searching for these waves for roughly 50 years and I am filled with admiration for the nobility of the researchers who spent their careers fruitlessly searching and failing to find gravity waves.

But the collective effect of these decades of ‘failure’ is a collective success: we now know how to the ‘listen’ to the Universe in a new way which will probably revolutionise how we look at the Universe in the coming centuries.

A 12-minute Documentary

Gravity Wave Detector#1

July 6, 2017
Me and Albert Einstein

Not Charlie Chaplin: That’s me and Albert Einstein. A special moment for me. Not so much for him.

I belong to an exclusive club! I have visited two gravity wave detectors in my life.

Neither of the detectors have ever detected gravity waves, but nonetheless, both of them filled me with admiration for their inventors.

Bristol, 1987 

In 1987, the buzz of the discovery of high-temperature superconductors was still intense.

I was in my first post-doctoral appointment at the University of Bristol and I spent many late late nights ‘cooking’ up compounds and carrying out experiments.

As I wandered around the H. H. Wills Physics department late at night I opened a door and discovered a secret corridor underneath the main corridor.

Stretching for perhaps 50 metres¬†along the subterranean hideout was a high-tech arrangement of vacuum tubing, separated every 10 metres or so by a ‘castle’ of vacuum apparatus.

It lay dormant and dusty and silent in the stillness of the night.

The next day I asked about the apparatus at morning tea – a ritual amongst the low-temperature physicists.

It was Peter Aplin who smiled wryly and claimed ownership. Peter was a kindly antipodean physicist, a generalist – and an expert in electronics.

New Scientist article from 1975

New Scientist article from 1975

He explained that it was his new idea for a gravity wave detector.

In each of the ‘castles’ was a mass suspended in vacuum from a spring made of quartz.

He had calculated that by detecting ‘ringing’ in multiple masses, rather than in a single mass, he could make a detector whose sensitivity scaled as its¬†Length2 rather than as its¬†Length.

He had devised the theory; built the apparatus; done the experiment; and written the paper announcing that gravity waves had not been detected with a new limit of sensitivity.

He then submitted the paper to Physical Review. It was at this point that a referee had reminded him that:

When a term in L2 is taken from the left-hand side of the equation to the right-hand side, it changes sign. You will thus find that in your Equation 13, the term in L2 will cancel.

And so his detector was not any more sensitive than anyone else’s.

And so…

If it had been me, I think I might have cried.

But as Peter recounted this tale, he did not cry. He smiled and put it down to experience.

Peter was – and perhaps still is – a brilliant physicist. And amongst the kindest and most helpful people I have ever met.

And I felt inspired by his screw up. Or rather I was inspired by his ability to openly acknowledge his mistake. Smile. And move on.

30 years later…

…I visited Geo 600. And I will describe this dramatically scaled-up experiment in my next article.

P.S. (Aplin)

Peter S Aplin wrote a review of gravitational wave experiments in 1972 and had a paper at a conference called “A novel gravitational wave antenna“. Sadly, I don’t have easy access to either of these sources.


What is Life?

June 28, 2017
Royal Trinity Hospice

A pond in the garden of the Royal Trinity Hospice.

On Monday, my good friend Paula Chandler died.

It seems shocking to me that I can even type those words.

She had cancer, and was in a hospice, and her passing was no surprise to her or those who loved her. But it was, and still is, a terrible shock.

It is unthinkable to me that we will never converse again.

How can someone be alive and completely self-aware and witty on Saturday; exchanging texts on Sunday evening; and then simply gone on Monday morning?

Her body was still there, but the essential spark that anyone would recognise as being ‘Paula’, was gone.

As I sat in the garden of the Royal Trinity Hospice, I reflected on a number of things.

And surrounded by teeming beautiful life, the question of “What is Life?” came to my mind. Paula would have been interested in this question.

What is life?

In particular I tried to recall the details of the eponymous book by Addy Pross.

In honesty I can’t recommend the book because it singularly fails to answer the question it sets itself.

In the same way that a book called “How to become rich” might provide an answer for the author but not the reader, so Addy Pross’s book was probably valuable for Addy Pross as he tried to clarify his thoughts. And to that extent the book is worth reading.

Life is ubiquitous on Earth, and after surveying previous authors’ reflections, Addy Pross focuses the question of “What is Life?” at one specific place: the interface between chemistry and biology:

  • In chemistry, reactions run their course blindly and become exhausted.
  • In biology, chemistry seeks out energy sources to maintain what Addy Pross calls a¬†dynamic, kinetic stability.

So how does chemistry ‘become’ biology?

In the same way that a spinning top is stable as long as it spins. Or a vortex persists in a flowing fluid. Similarly life seems to be a set of chemical reactions which exhibit an ability to ‘keep themselves going’.

What is life?

Re-naming ‘life’ as ‘dynamic kinetic stability’ does not seem to me to be particularly satisfactory.

It doesn’t explain how or why things spontaneously acquire dynamic kinetic stability any more than saying something is alive explains its aliveness.

I do expect that one day¬†someone will answer the question of “What is Life?” in a meaningful technical way.

But for now, as I think about Paula, and the shocking disappearance of her unique dynamic kinetic stability, I am simply lost for words.

Not everything is getting worse!

April 19, 2017

Carbon Intensity April 2017

Friends, I find it hard to believe, but I think I have found something happening in the world which is not bad. Who knew such things still happened?

The news comes from the fantastic web site MyGridGB which charts the development of electricity generation in the UK.

On the site I read that:

  • At lunchtime on Sunday 9th April 2017, ¬†8 GW of solar power was generated.
  • On Friday¬†all coal power stations in the UK were off.
  • On Saturday, strong winds and solar combined with low demand to briefly provide 73% of power.

All three of these facts fill me with hope. Just think:

  • 8 gigawatts of solar power. In the UK! IN APRIL!!!
  • And no coal generation at all!
  • And renewable energy providing 73% of our power!

Even a few years ago each of these facts would have been unthinkable!

And even more wonderfully: nobody noticed!

Of course, these were just transients, but they show we have the potential to generate electricity which has a significantly low carbon intensity.

Carbon Intensity is a measure of the amount of carbon dioxide emitted into the atmosphere for each unit (kWh) of electricity generated.

Wikipedia tells me that electricity generated from:

  • Coal has a carbon intensity of about 1.0 kg of CO2 per kWh
  • Gas has a carbon intensity of about 0.47 kg of CO2 per kWh
  • Biomass has a carbon intensity of about 0.23¬†kg of CO2 per kWh
  • Solar PV has a carbon intensity of about 0.05¬†kg of CO2 per kW
  • Nuclear has a carbon intensity of about 0.02 kg of CO2 per kWh
  • Wind¬†has a carbon intensity of about 0.01 kg of CO2 per kWh

The graph at the head of the page shows that in April 2017 the generating mix in the UK has a carbon intensity of about 0.25 kg of CO2 per kWh.

MyGridGB’s mastermind is Andrew Crossland. On the site he¬†has published a manifesto outlining a plan which would¬†actually reduce¬†our carbon intensity to less than 0.1¬†kg of CO2 per kWh.

What I like about the manifesto is that it is eminently doable.

And who knows? Perhaps we might actually do it?

Ahhhh. Thank you Andrew.

Even thinking that a good thing might still be possible makes me feel better.


25 years ago…

April 4, 2017

25 years ago, the atmospheric concentration of carbon dioxide was 350 ppm  Рjust 70 ppm higher than its pre-industrial concentration.

Oh yes. And I got married.

Objectively, I can describe this elapsed time as 9131 days. Or almost 789 million seconds.

And I can describe the way in which the atmospheric concentration of carbon dioxide has changed since then by more than 50 ppm.

And I can even describe the wonder of seeing two new human beings come into the world and evolve from being babies to being adults.

But subjectively, words fail me.

Version 2

But it is a fact that on this date, 25 years ago, friends and relatives gathered and supported Stephanie and myself as we got married.

And this post is just to say ‘Thank you’ to everyone who was there that day, and whose good wishes felt like a very tangible blessing.¬†Our¬†aim this year is to try to visit each of you. We have¬†a list and¬†you have been warned!

But whether you were there or not, I leave with you the Epithalamion written by my brother Sean and read by him at the wedding.

Epithalamion for Michael and Stephanie

Young people dance and drink a lot,
Draw close in metaphysical discussion,
Make light of commitments in making love
Celebrate the sadness of casual encounters,
Make art from them, and then repeat them.
Moments exhilarate; memory excruciates; the future’s a dream.
Years pass; what was painfully beautiful becomes untenable.
There comes time to move from testing the limits of resilience
To exploring the possibilities of permanence

Flitting is fine for adolescents and Peter Pan,
But now this woman is a woman, and this man a man.

Michael played guitar and sang a lot.
Went with women, but not a lot;
Sought the wrong thing in the wrong places,
And thus made the necessary errors;
Skirted sanity’s edge and touched insanity’s terrors.
I knew him as an orphaned six-year old; I have known
the need, and comfort of, his hand.
I have sought the warmth of his palm; welcomed his embrace;
Suffered the full force of his anger
‚ÄĒ And see! Here I am unharmed.
And here is the baby I held in my arms
Become an adult who,
In looking for his mother, found a lover;
And in loving a lover, found a wife;
And, after a long search,
The needed even tenor of a stable life.

In seeking after women, he was never a Don Juan;
But now the child whose hand I held is become a man.

I don’t know Stephanie’s past;
However I strongly suspect
That happy women don’t jump from Aeroplanes;
And I know for a fact
That Ireland is the best
But least happy nation to stem from;
And that an uncertain constitution of your blood
Doesn’t do your humour any good.
This is not to carp, but just to establish
A youth that was below emotional perfection,
So that future adventures ‚Äď this moment ‚Äď
Might allow scope for improvement.
How sad, if all her relations, now full-stomached and dyspeptic,
Were also silently lamenting her deteriorating spirit,
Her vanished prospects,
The poor calibre of chap who’s landed in it!
To them I would say:
“The Chosen Path is the best!
And this is it!‚ÄĚ

Today Stephanie puts on her Bridal Gown
To follow a dream that is her own.
Today good faith and trust may light hope’s flame;
She thus assumes perfection and a woman’s name.

Today is the ceremonial,
The tip of the huge and hidden thing to come;
The speckle and glass-glint of sun on the sea’s surface,
Eye-pleasing and transient, above depths that would terrify.
Today is about sex and the containment of sex;
About fear and the overcoming of fear;
About flesh and the fact flesh is fertile;
And the fact flesh decays;
And the fact flesh is human and lovely.
Today, too, is about family,
About what your Mother and Father do to you,
And for you;
It is about fertility and the bearing of children,
About the repetition of familiar things ‚ÄĒ and old errors;
The discovery of particular new joys,
New ways of two people meeting,
The miracle, perhaps, of new human beings.
Today is about what ‚ÄĒ what no ceremony could proclaim ‚ÄĒ
Informing the mundane with a proper focus,
With the laser intensity of life, and making it last;
About enlivening the drudge of living,
The dulling-ness of day to day.

It is about making do, and doing the best you can.
It is about Stephanie being a woman, and Michael a man.

If that’s all, then what’s the point?
Why are we here?
Why not reach for our revolver
And place it in our ear?
Because… because there’s more.
Today is about this…
We need each other;
We are nothing if connected to nothing.
Today we celebrate connectedness;
Cutting the crap we acknowledge love,
And the power of love to sustain.
And love is a light thing ‚ÄĒ
Not just the fleshly decaying ponderousness of sex,
But the shock of seeing, and then seeing afresh.
Today we dignify love,
Erecting a social carapace to protect it,
To allow it, in the private vision of two lovers.
We try to fix a hope ‚ÄĒ that love is not a flimsy.
Can such a light thing ‚ÄĒ love ‚ÄĒ though ever be strong enough?
All brides and all their grooms are optimists or fools.
But. Imagine egg-shell-skating carefulness; Consider how caution kills.
Let’s learn, and be thankful for the lessons of these optimistic fools;
Aristocrats of human risk, they let love open the future.
To feed hope’s flames, their noble folly’s fuel.

Come, then let us thank them; let us now applaud;
Today, this woman is a lady; and this man a lord.

Sean de Podesta , 1992

Climate Reflections

March 28, 2017

I am currently in Exeter attending the 22nd meeting of the WMO GCOS/WCRP AOPC. Let me translate:

In short, I am here to talk about monitoring the global climate with some of the best climate scientists from around the world.

The topics being discussed are diverse, and I am here to talk about one small part of the work. However, I feel honoured to take coffee with these people and to be able to legitimately call them¬†‘colleagues’.

My contribution is to speak on Thursday about creating a reference network of climate monitoring stations.

Historically, we have used records from normal weather stations to monitor the changing climate. But these stations have known biases that have to be detected and corrected.

It would have been really helpful if 100 years ago, scientists¬†had thought to create a reference network where every time a new thermometer screen was installed, they recorded the fact. But they didn’t.

So the idea is to create that reference network now so that in 100 year’s time when climate scientists look back they will say:

“Thank heaven for AOPC-22: that’s when our job got easier! They created a Climate Reference Network that has allowed us to detect anomalies in the climate signal inferred from analysing regular weather stations.

But that’s not what I wanted to talk about.

The mood of the meeting

This meeting is busy. People are mindful of the ability of a roomful of scientists to chat endlessly about details. And to counter this there is a powerful focus on getting things done.

However President Trump casts a shadow over the meeting.

Trump collage

Headlines from news sites today.: BBC, Guardian and Ars Technica

And the news today is that he has signed executive orders that effectively scrap energy policies based on avoiding the worst effects of climate change.

Most people at the meeting find this depressing. And it would be an understatement to say that colleagues from the US are ‘concerned’.

Trump’s policies are ultimately based on a simple belief which is summed up in the graph below from the Gapminder foundation.

2013 data for the countries of the world showing GDP per person versus carbon dioxide emissions per person. Each bubble represents a country and the size of each bubble is proportional to its  population.

2013 data for the countries of the world showing GDP per person versus carbon dioxide emissions per person. Each bubble represents a country and the size of each bubble is proportional to its population.

The graph shows that countries that emit a lot of carbon per person are richer.

However the graph shows correlation not causation. Emitting carbon dioxide of itself does not make anyone richer.

Burning carbon produces energy, and it is access to energy that makes countries rich, and unequivocally improves the quality of people’s lives.

But emitting ~30 billion tonnes of carbon dioxide per year also has another effect which is not documented on the ‘bubble graph’. As the people at this meeting have helped make clear, it has warmed the surface of the planet and will continue to do so for centuries to come. But we no longer need to emit carbon to produce energy.

Currently renewable energy sources are (generally) more expensive than fossil fuels. But there is no reason why that will always be the case.

Indeed, if Trump’s aim is to make America independent of foreign energy sources, the best thing he could do would be to¬†increase exploitation of renewable energy which would reduce its cost.

Personally, I think that it is already too late for coal and that Trump’s efforts to open coal mines and burn more coal will fail, just like efforts to create ‘clean coal’ have utterly failed.


How would you take a dinosaur’s temperature?

March 15, 2017
A tooth from a tyrannosaurus rex.

A tooth from a tyrannosaurus rex.

Were dinosaurs warm-blooded or cold-blooded?

That is an interesting question. And one might imagine that we could infer an answer by looking at fossil skeletons and drawing inferences from analogies with modern animals.

But with dinosaurs all being dead these last 66 million years or so, a direct temperature measurement is obviously impossible.

Or so I thought until earlier today when I visited the isotope facilities at the Scottish Universities Environmental Research Centre in East Kilbride.

There they have a plan to make direct physical measurements on dinosaur remains, and from these measurements work out the temperature of the dinosaur during its life.

Their cunning three-step plan goes like this:

  1. Find some dinosaur remains: They have chosen to study the teeth from tyrannosaurs because it transpires that there are plenty of these available and so museums will let them carry out experiments on samples.
  2. Analyse the isotopic composition of carbonate compounds in the teeth. It turns out that the detailed isotopic composition of carbonates changes systematically with the temperature at which the carbonate was formed. Studying the isotopic composition of the carbon dioxide gas given off when the teeth are dissolved reveals that subtle change in carbonate composition, and hence the temperature at which the carbonate was formed.
  3. Study the ‘formation temperature’ of the carbonate in dinosaur teeth discovered in a range of different climates. If dinosaurs were cold-blooded, (i.e. unable to control their own body temperature) then the temperature ought to vary systematically with climate. But if dinosaurs were warm-blooded, then the formation temperature should be the same no matter where they lived (in the same way that human body temperature doesn’t vary with latitude).
A 'paleo-thermometer'

A ‘paleo-thermometer’

I have written out the three step plan above, and I hope it sort of made sense.

So contrary to what I said at the start of this article, it is possible – at least in principle – to measure the temperature of a dinosaur that died at least 66 million years ago.

But in fact work like this is right on the edge of ‘the possible’. It ought to work. And the people doing the work think it will work.

But the complexities of the measurement in Step 2 appeared to me to be¬†so many that it must be possible that it won’t work. Or not as well as hoped.

However I don’t say that as a criticism: I say it with admiration.

To be able to even imagine making such a measurement seems to me to be on a par with measuring the cosmic microwave background, or gravitational waves.

It involves stretching everything we can do to its limits and then studying the faint structures and patterns that we detect. Ghosts from the past, whispering to us through time.

I was inspired.


Thanks to Adrian Boyce and Darren Mark for their time today, and apologies to them both if I have mangled this story!

Light Sabre Research

March 5, 2017


Sometimes one finds oneself by chance at the cutting edge of a new field of research.

This Saturday, I found myself in a secret laboratory in the heart of England, and I was fortunate enough to try out the latest in Light Sabre technology.

It’s risky: It’s scary: but if one is guided by ‘the force’ then great things may be possible.

May the force be with you.

Remarkably Unremarkable

February 24, 2017



‘The future’ is a mysterious place.

And our first encounter with ‘the future’ is ‘the now’.

Today I felt like I encountered the future when I drove a car powered by a hydrogen fuel cell. And far from being mysterious it was remarkably unremarkable.

The raw driving experience was similar to using a conventional car with automatic transmission.

But instead of filling the car with liquid fuel derived from fossil plant matter,  I filled it with hydrogen gas at a pressure 700 times greater than atmospheric pressure.


This was achieved using a pump similar in appearance to a conventional petrol pump.


This was the interface to some industrial plant which generated 80 kg of hydrogen each day from nothing more than electricity and water. This is enough to fill roughly 20 cars.

This is small scale in comparison with a conventional petrol station, but these are early days. We are still at the interface with the future. Or one possible future.

The past

Some years ago, I remember making measurements of the temperature and humidity inside a fuel cell during operation.

The measurements were difficult, and the results surprising Рto me at least.

And at the end of the project I remember thinking “Well, that was interesting, but it¬†will never work in practice”.

Allow me please to eat my words: it works fine.

Today I was enormously impressed by the engineering prowess that made the fuel cell technology transparent to the driver.

The future

What I learned today was that the technology to make cars which emit no pollution at their point of use exists, now.

The range of this car is 300 miles and it takes only 5 minutes to re-fill. When there are more re-filling stations than the dozen or so currently around the UK, this will become a very attractive proposition.

I have no idea if fuel cell cars will become ubiquitous. Or whether they will become novelties like steam-powered cars from the end of the nineteenth century.

Perhaps this will represent the high-water mark of this technology. Or perhaps this will represent the first swallow in a summer of fuel cell cars.

None of us can know the future. But for the present, I was impressed.

It felt like the future was knocking on the door and asking us to hurry up.

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