Monday, 11 November 2019

Mercury transit overcast Monday

So, would we see the transit of Mercury?

A little after the time of first contact, the sky was quite cloudy, with the sun hiding.

12:58 GMT, looking south

But the clouds were moving quickly, and there were blue patches.  Then around 2pm, the sky started to clear a bit more.

14:05 GMT, looking south west: blue sky!
lining up the telescope (note the existence of shadows)
We attached a solar filter to the front of our telescope, so it was safe to look through it at the sun.  But we had a very careful protocol: lining up using the tracking eyepiece (not looking through it), then carefully covering that unfiltered eyepiece before looking through the main eyepiece.

And we saw the transit!  A very small, very black spot, clear against the sun’s disk.  Amazing.  (No photographs of it this time, though: much poorer weather than previously, and no time to waste.)

Then it clouded over again; we got about 5 minutes viewing in total.

14:20 GMT, cloudy again: goodby Mercury! it was grest seeing you!

Monday, 28 October 2019


I stumbled across a new word the other day (new to me; it's actually old, and obsolete): apricity, the warmth of the sun in winter.

After a mostly very dull and wet October this year, finally we are experiencing some apricity.  It is one of those lovely clear, still, and crisp autumn days (does autumn count for using this word?), and although the air temperature is just a few degrees above freezing, there is warmth to be felt standing in the sun. 

berries and leaves benefiting from apricity today

Sunday, 27 October 2019

sequestering carbon, several books at a time C

My one-hundredth sequestration post!

The latest batch:

The Kagan book is not upside down; the title is printed on the spine in the opposite orientation to conventional, possibly because it is from a German printer?  Is the convention the opposite in Germany?

Saturday, 26 October 2019

20 years later

It is 20 years to the day since we moved into our newly-built and actually still-in-the-process-of-being-finished house:
Our house in November 1999; still not actually finished!
We were eager to move in asap, as we had sold our previous house, and had been living in B&Bs for a couple of weeks.  Never believe builders’ schedules, even after adding a couple of months to their estimate, as contingency!

Over the last two decades, we’ve had one major repair: the underfloor heating needed to be replaced due to faulty pipework. (No, of course none of the installer’s insurance, the NHBC construction insurance, or our buildings insurance covered it: when do they ever?)

We’ve made one major upgrade: in January 2014 we installed solar panels on the back roof, which conveniently faces south.  Inside, there has been continual shelf-building over the years, as we had 9000 books when we moved in, and have 14000 now.

But the main noticable change from outside is in the maturity of the garden:

our house today; less of a building site, more of a home
Looking forward to many more years here.

Saturday, 19 October 2019

the “customer” is not always right

One way that university lecturers, and departments, are ranked and evaluated, is by student satisfaction surveys.  Such a customer-based model does not inevitably lead to better eduction, however, as students are not necessarily the best judges of what they have learned:

College students think they learn less with an effective teaching method
They don’t even realize they’ve learned more.

While students learned more with active instruction..., every measure of satisfaction was lower.

Personally, I prefer a “fitness instructor”-based model, where the students pay the instructor for improvement opportunites and advice (and these should indeed be as well prepared and appropriate as possible), but they have to put in the time, effort, and sweat.  No pain, no gain.

Wednesday, 16 October 2019


Seen this morning

some orange fruits brightening up a dull day
the mild damp weather is perfect for fungi

Saturday, 12 October 2019

film review: Predestination (2014)

A young man relates his incredible history as an unmarried mother to a sympathetic bartender, who then recruits him into a secret organisation that explains, and causes, all his troubles.

The underlying plot logic is based on Robert Heinlein’s 1959 short story “—All You Zombies—”. I can’t say how comprehensible the movie is without knowing the background; it may need to be viewed twice to pick up earlier clues. To extend it from a short story, certain elements have been added, like more details on the secret organisation, the violin case, the Fizzle Bomber, and the loop’s closure. These additions are all fine, as they tighten the loop. (I do think it would have been interesting to try to include the organisation’s head in the loop, too, but that would have been quite a big deviation from the original story.)

The beginning is a little slow, being mostly narration with flashbacks, but once the narration has caught up to “the present day” (whatever that means in such a time loop) the action carries along on nicely. It follows the original short story’s plot very closely, including the time it is set – the opening bar scene is set in 1970 – which gives it a retro alternate history vibe, 50 years on from then. The main deviation is the added ending, which, amazingly, improves what is already an almost perfect time loop plot.

On the whole, this is a great realisation of a terse and densely plotted short story.

For all my film reviews, see my main website.

Sunday, 6 October 2019

book review: Children of Time

Adrian Tchaikovsky.
Children of Time.
Pan. 2015

A mad scientist in orbit around a newly terraformed planet fails to realise she has accidentally uplifted a spider civilisation. And when the descendants of the last flight from a dying Earth arrive to colonise, they find themselves embroiled in a potentially tragic game of Prisoners Dilemma.

This is simply marvellous. (I’ll grant the uplift virus as the one piece of magic tech allowed.) The millennia-long timespan of the spiders and humans is handled in two very different, but effective ways. The uplifted spiders are some of the best “aliens” I’ve ever come across: their bio-technology, their social structures, their language and communications, their ways of scanning a computer screen, are all so different, yet so plausible. And the ending, although somewhat rushed, works nicely to subvert the humans’ assumptions.

Great stuff.  Really looking forward to the sequel.

For all my book reviews, see my main website.

Saturday, 5 October 2019

book review: Risk Savvy

Gerd Gigerenzer.
Risk Savvy: how to make good decisions.
Penguin. 2014

There are two main points made in this book.

Firstly, you need to use a different reasoning process about situations where you know the risks and their odds, and the uncertain situations where you don’t; and you need to be able to distinguish these cases. In the case of uncertainty, rules of thumb are usually better than trying to calculate unknown odds. Gigerenzer gives some examples. I particularly liked his discussion of the real Monty Hall problem, rather than the “tidied up” version used for probability calculations. The real situation is much messier, and I have pointed out that you need to know the full rules beforehand: the stated solution works only if the host doesn’t cheat.

Secondly, even when the odds and risks are known, most statistics are so badly presented, possibly to make better headlines, that even the experts don’t understand what they say; you need to look at the real underlying rates. Behaviour X doubles the chance of cancer Y may not be a problem, if the chance of cancer Y is extremely small in the first place. Gigerenzer gives examples of a way to present rates rather than conditional probabilities that makes it much easier to see and understand the true risks.

There are many good cases discussed in here, with a large chunk of the book given over to healthcare. For example, there is a lot about medical screening, false positives, and increased “survival” rates being due entirely to earlier diagnosis, and nothing to do with living longer in total if diagnosed earlier (“lead time bias”). Survival rates are different from mortality rates.

Some of the discussions do feel a little disjointed. In particular, there is early emphasis on how most real world issues deal with uncertainty (rules of thumb) rather than risk (calculating odds), yet much of the book is on increasing statistical literacy. No matter; there is much good material in here.

For all my book reviews, see my main website.

Sunday, 29 September 2019

the metamorphosis continues

Less than five hours, and one downpour, after the previous photo:

24 hours later...

Yesterday's mushroom looks rather different today:

Saturday, 28 September 2019

mushroom as a verb

This weird fungus has appeared in less than a day out of the gravel in front of our house.

Friday, 20 September 2019


Usually it takes clouds to help produce a spectacular sunset.  But tonight, a cloud-free sky exhibited a beautiful gradient from gorgeous indigo to glorious orange.

7:29pm, BST

Monday, 9 September 2019

book review: Reality Is Not What It Seems

Carlo Rovelli.
Reality Is Not What It Seems: the journey to quantum gravity.
Penguin. 2016

Rovelli guides us through a brief history of the development of physical theories, to end up with a theory of quantum gravity, one of the big unsolved problems of today. The background, from ancient Greek natural philosophy, to modern quantum mechanics, is an excellent introduction how the ideas gradually reformulated, bringing in concepts of discreteness, fields, and relationships. It is well worn material, but presented in a new, fascinating way. Moving into the final topics is necessarily more limited: the material is both highly technical, and not yet accepted as the standard paradigm.

Before we get to the quantum gravity, we move through Rovelli’s relational interpretation of quantum mechanics, which (modulo Leibniz) is a completely different way of conceptualising systems purely in terms of their relationships (interactions) with other systems: there is no state of an isolated system, only state revealed by its relationships and interactions. The concept of a Newtonian-like schema of a separately existing time that flows independently of everything else disappear in this relational model:
[p157] If we want to understand the world widely, if we want to understand how it functions in the less familiar situations where quantum gravity matters, we need to abandon this schema. The idea of a time t which flows by itself, and in relation to which all things evolve, is no longer a useful one. The world is not described by equations of evolution in time t. What we must do is simply to enumerate the variables A, B, C…. which we actually observe, and write equations expressing relations between these variables, and nothing else: that is, equations for the relations A(B), B(C), C(A)… which we observe, and not for the functions A(t), B(t), C(t)… which we do not observe.
Finally, we get to the particular quantum gravity theory here: a complex superposition of quanta of space interacting and relating.
[p166-7] Space is a spin network whose nodes represent its elementary grains, and whose links describe their proximity relations. Spacetime is generated by processes in which these spin networks transform into one another, and these processes are described by sums over spinfoams. A spinfoam represents a history of a spin network, hence a granular spacetime where the nodes of the graph combine and separate.
That summary from the book makes sense in the context of all the material that has gone before. Go and read the whole thing yourself; it is beautifully written, includes fascinating perspectives on the development of physics, many great insights into contemporary quantum theory, and is as clear as anything about such a technical subject can be without actually invoking the technicalities.

Highly recommended.

For all my book reviews, see my main website.

Tuesday, 27 August 2019

don't uplift them

This window at work today looks like the setup for an Adrian Tchaikovsky novel...

at least they're on the outside ... for now

Monday, 26 August 2019

book review: The Book of Why

Judea Pearl, Dana Mackenzie.
The Book of Why: the new science of cause and effect.
Penguin. 2018

We have all heard the old saying “correlation is not causation”. This is a problem for statistics, since all it can measure is correlation. Pearl here argues that this is because statisticians are restricting themselves too much, and that it is possible to do more. There is no magic; to get this more, you have to add something into the system, but that something is very reasonable: a causal model.

He organises his argument using the three-runged “ladder of causation”. On the bottom rung is pure statistics, reasoning about observations: what is the probability of recovery, found from observing these people who have taken a drug. The second rung allows reasoning about interventions: what is the probability of recovery, if I were to give these other people the drug. And the top rung includes reasoning about counterfactuals: what would have happened if that person had not received the drug?
Intervention (rung 2) is different from observation alone (rung 1) because the observations may be (almost certainly are) of a biassed group: observing only those who took the drug for whatever reason, maybe because they were already sick in a particular hospital, or because they were rich enough to afford it, or some other confounding variable. The intervention, however, is a different case: people are specifically given the drug. The purely statistical way of moving up to rung 2 is to run a randomised control trial (RCT), to remove the effect of confounding variables, and thereby to make the observed results the same as the results from intervention. The RCT is often known as the “gold standard” for experimental research for this reason.

But here’s the thing: what is a confounding variable, and what is not? In order to know what to control for, and what to ignore, the experimenter has to have some kind of implicit causal model in their head. It has to be implicit, because statisticians are not allowed to talk about causality! Yet it must exist to some degree, otherwise how do we even know which variables to measure, let alone control for? Pearl argues to make this causal model explicit, and use it in the experimental design. Then, with respect to this now explicit causal model, it is possible to reason about results more powerfully. (He does not address how to discover this model: that is a different part of the scientific process, of modelling the world. However, observations can be used to test the model to some degree: some models are simply too causally strong to support the observed situation.)

Pearl uses this framework to show how and why the RCT works. More importantly, he also shows that it is possible to reason about interventions sometimes from observations alone (hence data mining pure observations becomes more powerful), or sometimes with fewer controlled variables, without the need for a full RCT. This is extremely useful, since there are many cases where RCTs are unethical, impractical, or too expensive. RCTs are not the “gold standard” after all; they are basically a dumb sledgehammer approach. He also shows how to use the causal model to calculate which variables do need to be controlled for, and how controlling for certain variables is precisely the wrong thing to do.

Using such causal models also allows us to ascend to the third rung: reasoning about counterfactuals, where experiments are in principle impossible. This gives us power to reason about different worlds: What’s the probability that Fred would have died from lung cancer if he hadn’t smoked? What’s the probability that heat wave would have happened with less CO2 in the atmosphere?
[p51] probabilities encode our beliefs about a static world, causality tells us whether and how probabilities change when the world changes, be it by intervention or by act of imagination. 

This is a very nicely written book, with many real world examples. The historical detail included shows how and why statisticians neglected causality. It is not always an easy read – the concepts are quite intricate in places – but it is a crucially important read. We should never again bow down to “correlation is not causation”: we now know how to discover when it is.

Highly recommended.

For all my book reviews, see my main website.

Tuesday, 20 August 2019

Wicklow Mountains coach tour

The Worldcon is over, and we have an extra day to enjoy Ireland.  Yesterday evening we went on a bus tour of Dublin; today we went on a longer coach tour, to the Wicklow mountains.  We had tried to book the Newgrange tour, but it was sold out.  As we were wondering whether to take the Wicklow tour instead, another customer in the Tourist Office, who had also been at the Worldcon, highly recommended it.  Thanks!  You were right!

First stop was the Glencree Cemetry and Barracks, for a cuppa and a loo break.  There was also the Glencree Grotto down in a beautiful small valley.

everything is so green

Next stop was a photo-op at the "P.S. I Love You" bridge.

the bridge that features in a film I have never heard of

Then another photo-op, at the Guinness Lake.

The Guinness Lake -- so called not because it is made of Guinness, or used to make Guinness, but because the land was owned by the Guinness family (until recently)

Then the main stop -- Glendalough ("Glen of the two Loughs").  We had two hours to walk round the loughs; it didn't start raining until we were nearly back!

walking along the woodland path, along the south side of the smaller Lower Lough
between the loughs: view across the larger Upper Lough, with the rain clouds beginning to thicken
view from the boardwalk along the north side of the Lower Lough: a magnificent Rowan, laden with brilliant red berries, with the Lough in the background
mossy branches; the boardwalk was well clear of the very boggy ground
an impressive range of lichens
The rain set in quite seriously at this point, but we were nearly back at the coach, so no problem.

Then off to our final stop at Avoca Village, and a late lunch at Fitzgerald's pub.  The exterior of this pub starred in the TV series Ballykissangel (which I have heard of, and seen, although long enough ago I have no memory of the pub).

After that, we returned to Dublin along the motorway, rather than via the windy backroads we had travelled down.

A great day out.

Friday, 16 August 2019

how tall is that?

Walking back and forth in Dublin over the last couple of days, we noticed a strange construction in O’Connell Strret.

It’s difficult to get a picture of the whole thing on a mere phone camera.  Here’s the base:

a spike with a shiny base (and, apparently, a bit of my finger).

And here’s the rest of it:

all the way to the top

How tall is that?  It seems to go up forever.  It’s a cunning optical illusion, though: The Spire of Dublin is “only” 120m tall, but the way it tapers gives a false perspective view that makes it look a lot taller from the base.  Neat.

Wednesday, 14 August 2019

view from a hotel window

We have arrived in Dublin, for the Science Fiction Worldcon.  We didn’t manage to book a room in a nearby hotel (they were sold out about 10 minutes after booking opened), so have a bit of a trek from Parnell Street.

We got the airport bus to the hotel, and checked in.  We then walked to the Convention Centre, to pre-emptively register for tomorrow’s start, and then walked on to the Science Galley for a panel discussion: “Oppy or Armstrong? Autonomous vs human space exploration”.  The panel unanimously agreed we need to send both humans and robots.  We then walked back to the hotel.  We had also done a bit of walking around airports earlier in the day, and my phone’s step counter is registering an impressive (for me) 15100 steps.

That local Tesco will be useful for stocking up on carbs needed to keep going through the weekend.  The trams clang their warning bells as they go past: I hope that doesn’t go on all night!

Saturday, 3 August 2019

invasion of the butterflies

There are supposed to be millions of Painted Lady butterflies this year.  We saw this somewhat bedraggled one in our garden today.

Monday, 29 July 2019

view from a hotel window

I have arrived in Newcastle, ready for the Artificial Life conference.  There are lots of brick buildings visible from my hotel window.

And on my way to my room, I was mildly amused to see this:

room found!

Wednesday, 24 July 2019

sequestering carbon, several books at a time XCVIII

The latest batch, which includes a couple of sub-batches of birthday presents.

Saturday, 20 July 2019

one small step

So, it’s 50 years since the first moon landing.

I have two very vivid memories of the Apollo programme.

First was watching the moonlanding on television.  Not live, but the next day at school.  Our headmistress invited the class to watch on her (gasp!) colour TV.  The rest of the class was excited by seeing a colur TV for the first time; I was excited by seeing the moon landing.

The second memory is during Apollo 13 – sitting around in the cloakroom at school with all the other kids, all being very worried.

I have lots of other memories of the whole programme, but I don’t know if they are memories from the time, memories of repeat showing on TV, or just memories of memories.

Thinking back, one thing that strikes me is how impoverished our information sources were then: TV (real time only), newspapers (whichever one was read in the house), and the odd special isue of a magazine.  No videoing late night programmes to watch later, no iPlayer catchup, no YouTube clips, no NASA website, no googling for more info.  How did we survive?

Since Apollo we’ve learned so much more about our solar system.  Other vivd memories are the pictures from the surface of Mars sent back by Viking (these images really made the hairs on the back of my neck stand up: pictures from the surface of another planet that is just a mere dot in the night sky), and the pictures of all the moons of the outer planets sent back by Voyager.  And, of course, the recent Pluto pictures from New Horizons.

The solar system is a much richer, more detailed place than it was 50 years ago.

But 50 years on from Neil Armstrong and Buzz Aldrin, we still don’t have a moonbase.

I blame you for the moonlit sky
And the dream that died with the eagle’s flight
I blame you for the moonlit nights
When I wonder why are the seas still dry?

Don’t blame this sleeping satellite

Did we fly to the moon too soon?
Did we squander the chance in the rush of the race

Sleeping Satellite, Tasmin Archer, 1992

Tuesday, 9 July 2019

where the rubber meets the road

I did my bit for the environment today.

I have an old pair of Clark's sandals.  They are comfortable, and the uppers are fine, but the original tread on the soles had worn down to a high gloss.  The other day I slipped, and decided they were no longer safe to walk in.

Given the fine condition of the uppers, I took the pair along to out local Timpson's, to see if they could be re-soled.  The guy sucked his teeth and looked dubious.  They probably wouldn't take a re-soling.  We discussed it for a bit, and I explained I just needed the soles made less slippery.  He said he would try "roughening them up" on the machine.

Several minutes and a strong smell of buring rubber later, he returned them to me, with a lovely lattice of grooves carved into the previously smooth soles:

Perfect!  That will keep me going for another few years, until they wear down again, and it saves me having to bin otherwise perfectly good footwear.

Timpson's for the win, again.

Wednesday, 3 July 2019

prices are weird

I had a trip up to Durham today, to visit a colleague.  I bought a coffee at York station to drink on the early train: £2.05.

On the way back, it was lunchtime, so I popped into a Sainsburys near Durham station, and bought a Ginsters Chicken and Mushroom slice, a banana, and a 500ml bottle of Highland Spring water: £1.80 in total.

Caffeine is really expensive, compared to food!

Monday, 24 June 2019

shadows of clouds

A spectacular sunset this evening, with clouds casting shadows on other clouds:

21:30 BST.  The picture is a bit washed out on the horizon: reality was darker and redder.

Zooming in on the base of the shadow, to show the setting sun shining between two bands of coulds:

Saturday, 22 June 2019

Wednesday, 19 June 2019

can this blob of goo compute?

Our new paper published today:
Matthew Dale, Julian F. Miller, Susan Stepney, Martin A. Trefzer.
A substrate-independent framework to characterize reservoir computers.
Proceedings of the Royal Society A, 475(2226), 2019

Somewhat amazingly, various blobs of “goo” can be made to compute simple tasks.  But, given a new blob of goo, can we tell how well it will compute, without having to train it on specific tasks?

That’s what we set out to address in our new paper.  We describe a framework for evaluating the “quality” of a proposed computing substrate, in comparison to a “reference” reservoir computer (an unconventional model of computing that fits well with gooey substrates).

We then use of the framework to evaluate a (physical) carbon nanotube system (it computes, as we knew, but not very much, as we also knew, but now we know exactly how much).  We also use it to evaluate a (simulated) optical delay line, and show that it can be used for many reservoir tasks, but not necessarily all.

We are now going on to generalise this framework to a wider set of computational models and physical substrates, as part of out EPSRC-funded SpInspired project.  Watch this space!

Monday, 17 June 2019

chimneys in the sun

The setting sun lit up a line of golden chimneys:

View of sunlit chimneys, 21:16 BST.  They are not normally golden, but are “white” brick, which reflects more than the red.

View in the other direction, of the sunset lighting up the chimneys, 21:18 BST

Thursday, 13 June 2019

let them not eat cake

This is a few months old, but hasn’t gone the least bit stale:
The only thing we do know is that the people who have been pressing hardest for Brexit are obsessed with cakes. The former Foreign Secretary was convinced in public that we could “have our cake and eat it”. John Redwood, the perfectly normal former Welsh Secretary, talked about making our own cakes instead of helping other countries with their cakes. And UKIP is full of fruitcakes.

So I have decided to explain the Brexit process through the medium of cakes.

(h/t to Danny Yee)

Sunday, 9 June 2019

time to go home

The view from the breakfast bar on the 25th floor, just before I check out to catch the airport bus.

Goodbye, Tokyo!  I had a great time.  An excellent conference, interesting new experiences, lovely people, and a marvellous city.

Thursday, 6 June 2019

boat and dinner

The conference outing and dinner was combined as a boat tour.

Prior to embarkation, we get a good view of the Tokyo Skytree.

As we turn back at the mid-point, we see we are not the only boat on the river.
The view of the Skytree on disembarking.

Monday, 3 June 2019

DIY dinner

Guessing what a menu item might be from a small, interestingly cropped photo, and an ambiguous English translation, can lead to unexpected meals.

a tad undercooked?

The staff helpfully showed us how to cook it all.  And it was very good!

Sunday, 2 June 2019

view from a skyscraper

I’ve arived in Tokyo, after a 12 hour flight, ready for the Unconventional Computation conference starting tomorrow.

Rather than the traditional “view from a hotel window”, I was recommended the “view from a nearby skyscraper”.  So this is the view from the (free) Observation deck in the Tokyo Metropolitan Government Building, on the 45th floor, over Tokyo on a slightly hazy Sunday afternoon.

There are other skyscrapers around here

There is also greenery.  My hotel is the mere 25-storey white block in the centre, the one with the loads of teeny square windows.

One of the many raised roadways.  We have Spaghetti Junction, but Tokyo must be Noodle City!
(Relatively small) tower blocks receding to infinity.  Is this Trantor?

Later on, we went down past the famously huge Shinjuku station (which we will have to navigate tomorrow!) to find a place for dinner: there were plenty to choose from.

A warm Sunday evening in downtown Shinjuku