Friday, September 03, 2021

Sunny Days

 The precise shifting positions of the rising and setting sun through the year is a phenomenon observed thousands of years ago. The ancient Egyptians aligned their buildings - especially the pyramids - in such a way that sunlight entered the deepest passages only on certain days of the year, such as the summer equinox. The ancient Aztecs did the same, and so did the builders of Angkor Wat, and even the Padmanabha Swamy Temple in Kerala.

While it is relatively easy for communities that have lived at a particular location for many years to accurately predict the play of sunlight and shadows in their buildings through the year, the trick is to figure out how this would change in different parts of the globe. Consider this excerpt from an astronomy website - 

At 40°N latitude (Denver, Colorado / Beijing, China), the sun shifts 7° north. Since the sun's diameter equals 1/2 degrees, that means the sun has been traveling its own diameter (14 days x 1/2 degree = 7 degrees) northwards each day. At 60°N latitude (Fairbanks, Alaska / Siberia), the sun moves about 2 sun diameters or one degree daily.

How did they come to the conclusion that "the sun's diameter equals 1/2 degrees"? What exactly does this mean, especially when you consider the fact that the distance between the earth and the sun varies from summer to winter making it appear larger or smaller across the seasons? 

Things get a little more complicated here. Yet all this has been figured out with such amazing accuracy that we have websites that map the position of the sun to any given location on earth, any time of the year.

What we see here is a sun-path polar chart superimposed on an image from Google Maps. Each point on this is worked out by feeding in the local latitude in relation to the elevation of the sun and the time of day, for that location. For instance, Noida located at approx 28°N would see the sun at an elevation of 62° from the horizon  (90° - 28°) on equinox days (21 Mar., and 21 Sep.).

Solar Altitude (cc - Hartz ) 

This explains why cities located on or near the equator (eg., Singapore - 1.29°N) see very little variation in the position of the sun across seasons. So when a Singaporean stretches his neck to squint at the blazing sun right overhead on an equinox day, a Norwegian resident at the northern-most city in the world, Longyearbyne (78.22°N) would find the same mid-day sun hovering near the horizon all day!




- Noida coordinates - 28.5355° N, 77.3910° E


- TED Talk -



- Sun path -




Wednesday, September 01, 2021

Books of the World


Every now and then the great circus of Whatsapp forwards comes up with a gem, and this is one of them. A beautifully illustrated poster on the "Most Translated Books of the World" by Preply.

A closer look at this tells you that some non-empirical method has been chosen for the selections here.  Perhaps they have excluded books of religious nature, or those that may may be categorised as 'adult literature'. How else can one explain the fact that Paramahamsa Yogananda's "The Autobiography of a Yogi" is listed as the most translated book from India over "The Bhagawad Gita" or "Kamasutra"?   

At least according to the referenced list compiled by Wikipedia, the most translated book from India is the Gita, followed by Isha Upanishad and Yogananda's book in the third place. 

The list has its surprises too. For instance I was surprised to learn that a book we studied at school, "My Name is Aram" by William Saroyan the top book from Armenia. Also Arthur Hailey's "Hotel" is listed as the most translated book from... the Bahamas! 

Minor quibbles aside this remains a beautiful piece of work. The books I have not yet read from this list should keep me busy for a while! :)


NB: This is also the first time I am seeing a digital image presented in the <webP> format. At just over 600kB this seems to pack in a much more scalable image compared to JPEG or TIFF.  Seems to be an innovation from Google that uses a technique called predictive coding.

Wednesday, August 25, 2021

A Tragedy Live-Streamed

"There are decades where nothing happens; and there are weeks where decades happen"--Vladimir Ilyich Lenin

What has been happening at Kabul's HKIA airport from 15 August 2021 onwards has been surreal, incredulous and depressing all at the same time.

Having been through this airport many times, and seen the many layers of its heavily armed perimeter,  it was amazing to see how thousands of people managed to get past its gates, all the way to military aircraft on the runway. It has been a week now and thousands of people continue to remain there all day, blocking the approach roads, clambering atop aircrafts, sitting inside jet-engine air-vents, getting shot at by security guards, and getting killed in the resulting stampede.

Much has already been said about the levels of desperation and panic in parts of Kabul. What has come as a big surprise to me is that for a city that has been under blanket electronic and police surveillance for decades, mobile networks continue to function normally, streaming live video from people all over the place. 

One particular video clip stands out.  This is a C-17 US military plane attempting to take off from Kabul airport. It is a monster of an aircraft - over 50m long, and capable of carrying over 275 tonnes, but here, as it lumbers on the runway, we see thousands of men were running alongside; some are waving cheerfully at the cameras, a few perched on the wheel carriages or flaps. Among them was one man in a dark Pathan suit, sitting precariously over on a winglet, looking intently looking into his mobile phone!

Incredibly, there is also a clip titled "Last video from the plane" in which we have a man in the same group recording the almost festive spirit of the group perched precariously there. Even as the jet engines rev up into a roar, he is talking a selfie shot, smiling into the camera, panning it around to show his companions waving cheerfully at his friends. Apache helicopters can be seen flying alongside, trying in vain to disperse the crowds. One can almost feel the wind lashing on on those faces, the roar jet engines drowning out the crowds. 

Then another phone records the C-17 taking off. As it climbs up sharply a few men can be seen slipping off and falling to their deaths. One was seen tangles in the concertina wires of a boundary wall, another spattered on a rooftop, and in yet another mobile, recording from inside the aircraft, the body of a man can be seen flailing in the winds, like a rag-doll stuck on a dumpster.

Not one of them would have survived. One can only imagine the levels of desperation and ignorance that led these men to their deaths. One wonders how the "last video" managed to reach FB and Twitter, and how many of them really thought they could get away sitting out there?



Wednesday, August 11, 2021

Gokhale's China

 Indians have been suckers for more than six decades. This was my main takeaway from Vijay Gokhale's recent book, "The Long Game - How the Chinese Negotiate with India".

In this elegantly written book, Gokhale traces the path taken by India-China relations from 1950 onwards - from the time when the government of India became one of the first to recognise the communist regime, of giving it a leg up to become a permanent member of the UN Security Council, through its military take-over of Tibet, escape of the Dalai Lama, the 1962 war, nuclear tests, all the way to the border dispute that festers to this day. 

All through this, the author may have wanted to show the Indian Foreign Service (IFS) in favourable light but seems to have just the opposite effect. One gets the impression that even though the  IFS may have had some of our brightest officers, as an institution it was slow on the uptake, and, as far as China is concerned, it has been incapable of guiding the political leaders through a prudent course of action. 

One of our weaknesses is that we love to talk. Combine this with our lack of meticulous preparations, the ease with which we can be flattered and what you get is a long line of ineffective negotiators. The Chinese, on the other hand, were always better prepared, weighed each word that was spoken and recorded everything and clearly saw that our eagerness to please, to play the 'good neighbour', was a weakness that could be exploited to tie us down with unilateral commitments.

Over the years, it seems some Chinese tactics have become predictable -- setting the agenda by insisting on 'principles' that suit them; things that they do not want to discuss are stonewalled through silence or deemed "not ripe for settlement"; the interpreter ploy of pretending not to know a language to gain time to think through and formulate a response, etc..

We also seem to have realised that that Chinese diplomats are ideological agents of the communist party- not government representatives amenable to logic or reason. Also their leaders, who prefer to stay in the background to "save face" are actually thin-skinned, and that unsettling them by impugning their self-image and how they want the rest of the world to view them can work to the other side's advantage.

Gokhale laments that the dignified and gracious Chinese negotiators of the past have been replaced by the assertive 'wolf warriors' who tend to display aggression, arrogance, irritation and other disagreeable traits. 

Maybe this is just as well because we seem to be better at handling in-your-face aggression rather than the gentle art of gracious negotiations. 



* Gokhale, Vijay (2021): THE LONG GAME - How the Chinese Negotiate With India, Penguin-

Tuesday, July 27, 2021

Down the Road to Chaos?

Once again, Afghanistan has hit the headlines; once again for all the wrong reasons.

Unlike my earlier post which was written after the most recent attack on Kabul University, this one is triggered by a global event - the withdrawal of USA and its allies after over 20  years in Afghanistan. The withdrawal has enabled the Taliban to sweep across the country with almost daily reports of deaths in bombings, attacks and counterattacks. A sense of uncertainty about the country seems poised to spread across its borders, to the rest of South Asia and the world.

As someone with a bit of experience in Afghanistan(2018-19), I have been approached by friends for an opinion on how things are going to unfold in the months to come. This was my response in a WhatsApp group a few days ago:

Ethnic and tribal loyalties are becoming more important than the "Afghan" identity for surviving this crisis.

Did you see that clip where a Talib asks a man if he's a Hazara and then shoots him dead? The Hazaras will avenge that. The 22 commandos who were killed after they surrendered; the Afghan ambassadors daughter who got abducted in Islamabad today... these too will be avenged, and at the tribal level all this will fuel old blood-feuds on both sides of the Durand line.

About ~$10 billion of annual aid that drove the Afghan economy is now the turning off... resources are limited... people are losing jobs, schools and small businesses are closing down, families are getting split and displaced...a whole new generation is dealing with the jehadis and their insular, medieval mindset.

So far there is no sign of a strong unifying national leader,  so the Tajiks, Uzbeks and Hazaras (Shias) will fight against the talibs (mostly sunni Pashto)...and the Pashtos tribes will fight each other to control the border posts (tax revenue) and poppy fields.

The Pakistanis will of course try to push more of these displaced jehadis into Kashmir/India.

Sad days ahead 😞

I hope my rather simplistic assessment is wrong. I hope an amicable solution will be found to prevent a repeat of the devastation that visited Afghanistan two decades ago. I hope all the good work done by the UN and other international agencies - especially in primary education, infrastructure and agriculture - will not go down the drain.

And yet, an interview I saw recently seemed to confirm that this is going to be another long bloody struggle. A retired Pakistani general, Tariq Khan, a Pathan officer who led a government offensive against the "Pakistani Taliban" or TTP, seemed quite sure that the Taliban will take over Kabul in a few weeks because the city is already under a "soft siege" because supplies to the city - especially of fuel - is already being disrupted. While this may be true it is not clear if the Taliban have what it takes to dominate the rest of the country - especially non-Pashtun areas.

Unlike the Soviet occupation era when the mujahids had a strong backing in terms of armaments (USA) and petrodollars (Saudi Arabia), things are a lot more complicated now. This time, money is not so easily available; there is some in Afghanistan's biggest exports - Poppy - but the Taliban is known to be against it;  the non-Pashto groups are better armed and may not give up the cities without a bitter fight, and there seems to be little in terms of common ground between the countries that have a direct interest in the final outcome -- Iran, Russia, China, Pakistan, USA, Turkey, and India.

If the Taliban continue with their refusal to share power with people who represent half the country, what they ultimately get may be a Pyrrhic victory, and the peaceful silence of graveyards. This may not come as an explosion of a grenade with a missing pin but as a slow, painful descent to chaos. 



* 26 July 2021 - Turkey eyeing a new sphere of influence in Afghanistan -

* 18 July 2021 - Gen. Tariq Khan's interview -

Wednesday, June 09, 2021

Experts vs. Dart-Throwing Monkeys


Statistics was never one of my favourite subjects. When faced with grades at the wrong end of the bell-curve, I would console myself with a quote attributed to Mark Twain - "There is lies, damn lies, and statistics"!

However, over the years, I have warmed-up to the subject - thanks largely to the stunning visualisations of Hans Rosling, and books like Daniel Kahneman's "Thinking Fast, Thinking Slow". This post is about the latter. 

The nudge for this came about ten days ago when a friend posted a book recommendation with a quote by Richard Feynman - "The first rule in science is that you must not fool yourself, and you are the easiest person to fool". The book in question was - "The power and paradox of self-deception" by Shankar Vedantam.

The first question that came to my mind was - Is this any different from the ideas described so well in Kahneman's book?  I went back to the book and found that he discussed not only all sorts of cognitive biases but also ways in which the intuitions of subject experts can be built into robust decision-making models.

What I like about Kahneman is that he is a practitioner who moved to academia. Unlike most ivory tower theorists, he served in the fledgeling Israeli Army in the 1950s, setting SoPs (still in use) for officer selection before moving to a university in USA, and winning the first Nobel prize for psychology/economics in 2002. 

Two of my key takeaways from this book were on Subjective Confidence and Intuitions vs. Formulas. Here are two quotes from the book on the topics which are perhaps best described in the author's own words. 

First, Subjective Confidence.

Facts that challenge...basic assumptions - and thereby threaten people's livelihood and self esteem - are simply not absorbed. The mind does not digest them. This is particularly true of statistical studies of performance, which provide base rate information that people generally ignore when it clashes with their personal impressions

We know that people can maintain an unshakable faith in any proposition, however absurd, when they are sustained by a community of like-minded believers

In other words, people who spend their time, and earn their living, studying a particular topic produce poorer predictions than dart-throwing monkeys who would have distributed their choices evenly over the options. Even in the region they knew best, experts were not significantly better than non-specialists...The reason is that a person who acquired more knowledge develops an enhanced illusion of her skill and becomes unrealistically overconfident. 

...Using an analogy from Isaish Berlin's essay on Tolstoy, "The Hedgehog and the Fox" -

Hedgehogs "know one big thing" and have a theory about the world; they account for particular events within a coherent framework, bristle with impatience towards those who do not see things their way, and are confident about their forecasts. They are also especially reluctant to admit error. For hedgehogs, a failed prediction is almost always "off only on timing", or "very nearly right". They are opinionated and clear, which is exactly what televisions producers like to see on their programs. Two hedgehogs on different sides of an issue, each attacking the idiotic ideas of the adversary, make a good show.

Foxes, on the other hand, are complex thinkers. They don't believe that one big thing drives the march of history. Instead the foxes recognise that reality emerges from the interactions of many different agents and forces, including blind luck, often producing large and unpredictable outcomes....Foxes are less likely to to be invited to participate in television debates.

On Intuitions vs. Formulas

Paul Meehl's book - "Clinical vs. Statistical prediction: A Theoretical Analysis and a Review of Evidence"...This 'disturbing little book' presented the results of 20 studies to examine whether Clinical Predictions based on the subjective impressions of trained professionals were more accurate than statistical predictions made by combining a few scores or ratings according to a rule... The formula was more accurate than 11 or 14 counsellors! It was proven again in other studies on violations of payroll, success in pilot training and criminal recidivism.

Princetown economist and wine lover Orley Ashenfelter shows us the compelling power of the power of simple statistics to outdo world renowned experts. Ashenfelter predicted the future value of Bordeaux wines based on info available the year they were made - he converted conventional knowledge into a statistical formula that predicts the price of wine based on three features of the weather - average temp over the summer growing months, the amount of rain at harvest, and the total rainfall during the previous winter.

A key conclusion... to maximise predictive accuracy, final decisions should be left to formulas, especially in low-validity environments

Does Vedanam's new book present any new ideas? I don't know yet. It does seem to me that path-breaking ideas presented in "Thinking Fast, Thinking Slow" may now be getting repackaged in newer books. Perhaps I am suffering from an anchoring bias, but I do believe Kahneman's book is something you need to have on your nearest bookshelf, as a constant reminder that there is more to this world than meets the eye, that intuitions can be trusted - but only to a certain extent. 



* Cognitive Biases -

* Animated book summary -

* The hedgehog and the fox -

* How Big Data can predict the wine of the century -

Thursday, May 20, 2021


Looks like a Van Gogh? - a painting sequel to the Starry Night perhaps? It's actually a projection of wind-speeds visualised by the big data cats at earth.nullschool. This particular one shows Cyclone Tauktae hitting Gujarat square in the jaw a few days ago.

Tauktae means "lizard" in Burmese and is just one of the random names chosen from an annual basket of options prepared by the met department - IMD. In this instance the name seemed rather appropriate - this cyclone has been constantly changing its colours like a chameleon while racing thousands of kilometres across the Arabian Sea.

According to a report: "Tauktae has been intensifying very rapidly. From a depression formed in the southeast Arabian Sea on May 14 morning, it strengthened into a very severe cyclonic storm -VSCS - by the early hours of May 16.. Any tropical cyclone requires energy to stay alive. This energy is typically obtained from warm water and humid air over the tropical ocean. Currently, sea water up to depths of 50 metres has been very warm, supplying ample energy to enable the intensification of Cyclone Tauktae."

And what a build-up of energy it has been! IMD seems surprised by the way in which this tropical cyclone intensified. On 16 May it swept past Kerala, damaging coastal roads and homes, taking two lives it its wake. The windspeed then climbed to 114 mph off the coast of Mumbai and but by the time it hit Diu in Gujarat it was roaring at over 180 kmph. The lives lost in this section was the highest - over 80 oil-rig workers employed by the ONGC are reported dead or missing.

For an event unfolding about 2000 km away, this cyclone has had a surprisingly strong impact in the Delhi area as well. Yesterday was the most unusual summer day.  At a time of the year when the day temperatures hover around 45C with hot dry wind blowing in from the Thar desert, turning the city into an oven, what we got instead was cool, refreshing rain. Not a passing shower that evaporated as soon as it it the ground but rains that went on and on, for a whole day and a night. For the first time in 70 years, temperatures hit a record low of 23.8C for the month of May.

This came as a bit of a relief to those who have been working our Covid hospitals, wearing stuffy all day. The Covid Second Wave also seems to have eased in North India with a sharp fall in infections and increased availability of spare hospital beds, oxygen cylinders and medicines.

Meanwhile, as Cyclone Takutae ebbs, another kind of second wave in brewing on the eastern side, next to the Andaman Islands. This one is called Cyclone Yaas and let us hope the Bay of Bengal has less energy to spare for feeding another super cyclone!