Ayaank

After a long sleepless night for mommy and daddy, Ayaank finally joined us this morning as the newest member of the family. Coming in at 3.2 kgs and 20 inches, the baby's arrival was truly a moment of ecstasy for both of us.

While mommy (literally) carried all the weight and is now enjoying a well earned rest, daddy had been secretly working on a few tricks of his own.

With the embargo now lifted, I present to you ayaank.com, a little something I had been working on for the past few weeks. For now, it will serve as our scrapbook for documenting the life of its namesake. Once Ayaank comes of age (and inclination), he can claim it for himself. Or force us to take it down. Either ways, we've got a few years to do as we like!

Let me end this post with a fun photo of the family (you know where to find more). It isn't hard to guess that this is one of my favourites.

Is it mommy's favourite too? Well, let's just say that while she appreciates the effort that went into it (quirky paddles don't make themselves), I don't expect a perfect score on humour.

Bitcoin (Part 2)

As we saw previously, by simply using a nifty little trick that digital signature affords us, we were able to create a payment system that required no central authority. And for the most part, it was completely fraud-proof.

I say most because there was one little loophole remaining – one potential bad actor that needed to be reined in. How hard could that be, right?

The hard problem

Let's start by acknowledging that double spending is not a complex problem in itself. There isn't some thickly veiled financial trickery or computer code which makes is hard to spot. To the contrary, every participant can see for themselves that the two transactions are collectively fraudulent.

What they cannot do for themselves is choose which one to approve. But what if everyone chooses to reject both transactions? Well, that would give Alice an easy way to undo transactions. She will pay Frank in return for some goods or services and once that is done, she would broadcast the second message. That will make her payment to Frank (and Grace) void.

And thus, it is by virtue of it being a decentralised system that a problem that seems simple prima facie, becomes a hard one to solve. Bitcoin solves the problem by appointing an arbitrator periodically (every 10 minutes on average). In our example, this arbitrator may choose to accept either one of Alice's two transactions or reject both, but would never accept both transactions. The network then follows suit.

But how does a decentralised network appoint an arbitrator? We seemed to have traded one hard problem for another. Luckily for us, we have a solution for this one. It isn't elegant, but a solution nonetheless.

Bitcoin mining

Miners are a subset of peers on the network that compete for the right to be the next arbitrator. Anyone in the network can opt in or opt out. The example that is commonly cited is that the network poses a difficult mathematical problem and miners try to solve it. The one to solve it first gets selected as the next arbitrator. But perhaps a more apt analogy is to think of it as a treasure hunt with no clues.

As there are no clues, the only approach is to (systematically or randomly) visit each floor, enter each apartment, open every wardrobe and pull out every drawer till you find the treasure. Anyone can win a round. If you a one among 100 miners, you have a 1% chance of being the first to the treasure. If you are one among 1,000 then your chances are 0.1%.

But if 1,000 miners are participating, won't each round conclude more quickly? This is where the concept of difficulty comes in. With 100 miners, you got, say, a 3 floor building. With 1,000 you get a 30 floor building. The treasure hunt keeps getting more difficult the more resources you throw at it. And less difficult if you throw fewer resources. That is where the inefficiency lies.

The billion-dollar problem

Bitcoin network consumes more energy than some developed nations do. Almost all of this goes towards brute-forcing a solution to appoint an arbitrator to approve transactions to keep the network functioning. Could there be a more efficient way? Something that eliminates double spend at its origin? Or uses are different approach to appointing arbitrators?

The fact is, we don't know of one today, at least not without making the network less decentralised. And that, is a billion-dollar problem waiting for someone to solve.

Bitcoin (Part 1)

Understanding how peer-to-peer cryptocurrencies work can be a bit daunting for the newly initiated. A good way is to break this into three parts – a database, an easy problem and a hard problem.

As for the best part, we do not really have an elegant solution to the hard problem. So if you can come up with one, you might have a fortune waiting for you.

The database

As Bitcoin is peer-to-peer, one cannot rely on a central golden source of data. Each participant maintains a local database of every transaction ever happened. If you had been offline for a while, you would ask around if anyone has an up-to-date database and copy from them any transactions that you are missing.

This database is called a blockchain and as you may have noticed, it contains transactions, not balances. So how to figure out how much balance Alice has? You have to go through every transaction and filter out the ones with Alice in them.

      Bob pays Alice      6 BTC
      Charlie pays Alice 10 BTC
      Alice pays Dave    13 BTC
      Eve pays Alice      7 BTC

Based on the above, we know that Alice has a balance of 10 bitcoins. In practice, transactions in blockchian do not contain people's names but something similar to an account number. It is called a Bitcoin address. So whilst anyone can figure out how much balance a particular Bitcoin address has, you don't know whose account it is unless the owner tells you.

The easy problem

So now Alice wants to send 8 bitcoins to Frank. Luckily for her, she knows how to use a digital signature. So she creates the following message:

      Alice pays Frank 8 BTC
      Signed:  Alice

At this point, she can just broadcast this message to anyone she is connected with on the P2P network. She does not even need to reveal that she is originating the message. She just says, "Hey there! There is a new transaction, do you want a copy for your local database?". The receiver checks for authenticity and, once convinced, adds it to their database and shares it with anyone they are connected to. The transaction would keep propagating till everyone has a copy of it.

As you would remember, nobody can alter Alice's message because nobody but Alice has the private key needed to sign the message. Once you alter the message, peers will no longer be able to authenticate it and will not include it in their database or propagate it.

The network is, thus, secured from fraud, except from one. That one person is Alice. Given she has the private key, she can very easily create two messages:

      Alice pays Frank 8 BTC
      Signed:  Alice

      and

      Alice pays Grace 8 BTC
      Signed:  Alice

She can then broadcast one message to one peer, then turn around and broadcast the other one to another peer. Both transactions are individually valid but collectively fraudulent.

This is called the problem of double spending. If unchecked, this would split the network into two. Depending on which transaction they received first, some will believe that Frank got paid and others that Grace got paid. And that brings us to the hard problem.

Continue with part 2

Higgs boson

A photon, a neutrino and an electron race to the bar. The photon arrives first, neutrino closely follows, and our electron comes dead last. The electron knows what's to come – not only would it foot the bill, it would also be the target of a long evening of friendly jibes.

Unknown to them, bookies (aka physicists) have been following these races for some time now. And they are forever baffled why the electron never wins.

Inertial mass

It is probably not right to say that we don't know why the races end up the way they do. In fact, we know it quite well. Photon has zero inertial mass, neutrino has just a little and in comparison to the other two, an electron is massive. What we don't know is why the electron is so heavy because when you look at the trio, they all have the same size.

You see, photons, neutrinos and electrons are amongst a score odd elementary particles that are the building blocks of everything we know. And we believe that they all have the same size – they are point particles. Yet their masses are so different. If you thought electron was heavy, meet the particle at the top of this league table, the top quark. Top quark has a mass of about 350,000 electrons. And yet, it flaunts a size-zero!

The Higgs field

One explanation could be that perhaps the mass is not inside the particle but related to something that is outside of it. If we accept this premise, the size of a particle becomes inconsequential. Think of it like your seat-number on a plane; it has nothing to do with what's inside of you, and yet has real world consequences (e.g., how fast you can reach the lavatory).

That was the idea that several researchers, including Peter Higgs, came up with in 1964. They explained it more elegantly, of course. It was hypothesised that maybe the universe is filled with a quantum field. This field acts differently on different particles, letting a photon cruise through unfeterred while making it hard for an electron to speed up.

Higgs boson

The use of fields to explain action at a distance is nothing new. We have all drawn bow-shaped lines around a bar magnet to explain how the magnet alters the magnetic field around it, which in turn moves a nearby piece of iron towards the magnet.

But that trick only works when a field is mediating interaction between objects, not when the field itself is affecting an object. So then, how do we test the existence of Higgs field? Luckily, every quantum field comes with its own signature particle – find the particle and you have found the field. Just like humidity and dew; you may not have the tools to measure humidity but if you can find dew, you can conclude that the air is humid.

So here was the plan. Find the Higgs boson, prove that the Higgs field exists, and tell the world why the electron never wins. There was just one hurdle, we did not have the gear for the job. So we had to build the Large Hadron Collider specifically to find or disprove the existence of Higgs boson. Construction completed in 2008 and it was only in 2012 that we finally found this elusive particle. The bookies were overjoyed.

And as for our electron, it has always known that the race is rigged. But it doesn't care; it has never been about winning or losing but about having a good time. It orders another round for the table.

The Last of Us

The Last of Us is a PlayStation title. It tells the story of Joel and Ellie, two strangers who develop a father-daughter relationship as they traverse through a zombie-infested America. Through the gameplay, it exposes several facets of human psyche and asks some deep ethical questions, with the one that leaves a lasting impression on the player being an extreme version of the trolley problem.

The plot

The basic setup of the game is very similar to any post-apocalyptic survival story. Infected people turn feral and all that it takes to pass on the infection is a bite or a scratch. Law and order is brought to its breaking point, with people living in small, heavily guarded camps under martial law.

Outside of these small pockets is a dangerous world. Everything and everyone from the infected to that anarchist bands with no morals are out there to get you. So why do Joel and Ellie make this life-threatening journey? Because Ellie has a gift.

The cure

Not very long ago, Ellie discovered that she cannot get infected. For some reasons, her brain cells have developed an immune response against the plague. It might seem like a blessing, almost akin to immortality in a mortal world. But it exacts a heavy toll. Ellie is only thirteen and yet, when she looks back at her life, she has lost everyone she has known, liked or loved.

There seems to be one silver lining to all of this. Apparently, Ellie's immunity can be used to create a cure. But for that, she needs to travel from her camp to a place with the required medical infrastructure. In a regular world, all of humanity would come together to make this happen. But we left regular behind long back. And thus, Joel gets hired to take Ellie to her destination.

The dilemma

So, did Joel and Ellie make it and save the world? Yes and no. You see, what neither of them knew is that the cure involved harvesting Ellie's brain cells, a procedure that she would not survive. The price of an uninfected world was Ellie's life.

Joel realises this in the nick of time as Ellie laid sedated in the facility. And he decided that this was wrong. So he storms the place with all guns blazing, brings down some of the most heavily armed and armoured militia, and escapes with Ellie.

Mercifully, the game director did not place the burden of the decision on the player. But what one does realise is that whilst some decisions might seem hard, you always have an option. The world continued without Ellie's sacrifice. It was a different world, a tougher one for sure, but one in which people held their heads just a little bit higher.

Speed of light

The speed of light is 299,792,458 m/s. Exactly. That infinite precision comes from the fact that it is not measured. Rather, light has been assigned this speed.

That last bit might trigger a question – if it is assigned, why not pick a nice round figure? Say 300,000,000 m/s. Or, even better, 1,000,000 m/s. The answer to this has to do with cakes, or more correctly, a paucity of cakes.

The French Revolution

France in the 18^th century was a great time to be. If you come from royalty, that is. For the rest, comme ci comme ça. Famines were commonplace, and when Queen Marie Antoinette was told that the peasants had no bread, she allegedly said, "Let them eat cake".

Now, of course, who does not like cake! The only problem, there were no cakes either. So, the people concluded that the monarchy had outlived its usefulness, stormed the Tuileries Palace, and declared France a republic. But just like any other serial entrepreneur, the French did not stop at disrupting forms of governments. Their next target was weights and measures.

The metric system

Imperial units of weights and measures are hard. So hard that only the ones who have landed a man on the moon have been able to master it. The revolutionaries realised that one does not need to be a rocket scientist to sell vegetables in the local market. So they invented a new system of weights and measures called the metric system.

And the pièce de résistance was a brand new unit of measure that this system was based on, the metre. It was envisioned to be one ten-millionth of the distance from the North Pole to the Equator, along a path that passes through Paris. An expedition was commissioned which measured a portion of this path, extrapolated it, and after seven long years, presented their work. Accurate or not, the fate of the metre was now sealed.

And then there was light

Since then, the metre has been redefined a few times. But each time we move from an old standard to a new one, we match the new standard to be as close to the old one as possible. And therefore, when we decided to use light as the basis for defining a metre, we did two things. First, we measured the distance light travels in a second based on the existing metre. And then, we assigned that measured speed to light and discarded the old standard.

So that settles it. We did get our chance to pick a round figure but we used it up with the 10 million. But did we at least use it well? Unfortunately not. With better tools and more accurate measurements, we now know that metre is shorter than its vision by around 0.02%. Stated differently, if you walked 10 million metres from the North Pole, you would find yourself standing about two kilometres shy of the Equator.

Digital signature

Three battalions of the Byzantine army are positioned around a city, ready to attack in the morning. If the attacks are synchronised, victory will ensue; if not, a catastrophic defeat.

The generals decide that Alexius, general of the north battalion and the most experienced warrior, will pick a time and run messengers to the other two. There is one weak link in this plan though; what if the messengers tamper with the message?

Verifiable trust

What Alexius needs is a strategy that would allow the other generals, once they receive his message, to easily verify that it is still the one he intended. A signature of sorts. All the same, it needs to be sophisticated enough that it cannot be reverse-engineered.

To resolve his situation, Alexius will need some rudimentary knowledge of residue arithmetic. Luckily, it’s quite simple – all he has to do is work with a fixed set of numbers and when he goes beyond the set, loop back to zero. Let’s take an example where the numbers go up to 99. We call it modulo 100. This is how arithmetic will look like:

      99 + 1  = 0
      50 + 60 = 10
      35 x 4  = 40
      15 ^ 2  = 25

It gets a bit difficult to do the math in our heads if we are not working with a modulo 10 or a modulo 100, but you can convince yourself that the following are true modulo 77:

      76 + 1  = 0
      50 + 60 = 33
      35 x 4  = 63
      15 ^ 2  = 71

A tamper-proof message

Equipped with this new-found knowledge, Alexius calls upon his messengers and hands them the following message:

      Message   : 9 AM
      Signature : 15
      Public-key: 11, modulo 51

To check the validity of the message, the other generals have to do a simple check: Signature ^ Public-key = Message.

Turns out, this works nicely for the original message.

      15 ^ 11 = 9 (modulo 51)

So how do the messengers alter the message now? They cannot just change the message to say 10 or 11 AM. The signature will give their deceit away. Execution could be a very real possibility. Sure they could try different signatures one-by-one to see which one yields a message of their liking, but that would take them a while.

The private key

But hang on, you say. If the rogue messengers are finding it so hard to sign the message, how did Alexius sign it? Well, he used a private key:

Message ^ Private-key = Signature

In this particular example, Alexius's private key is 3. And as long as he keeps the private key to himself, he can go around signing any message he wants without ever worrying about a traitor within his ranks.

      Message   : 9 AM
      Signature : 9 ^ 3 = 15

      Message   : 10 AM
      Signature : 10 ^ 3 = 31

      Message   : 11 AM
      Signature : 11 ^ 3 = 5

And that's it! Verifiability through digital signatures is key to all digital communications, including cryptocurrencies such as Bitcoin that are fundamentally peer-to-peer messaging boards. And on this particular occasion, it helped an army with no concept of physical signatures or seals emerge victorious over a culturally superior foe!

Hawking

Stephen Hawking passed away on March 14, 2018. At that time, I had shared a brief note with my work colleagues, highlighting his work and life.

Although originally intended for a small and specific audience (read: no pressure to fact-check), I wanted to share it more broadly on the occasion of Hawking's death anniversary.

Stephen Hawking (1942–2018)

Stephen Hawking’s work has been a massive leap in our understanding of our universe and of black holes. He quite literally helped us see black holes in a new light, showing that they are not just vacuum cleaners of the universe (as we always thought), but also the most efficient generators of power.

To put it simply, all energy that we see around is produced through conversion of mass into energy. Just that we do it very inefficiently. When you burn gas in your car, you convert a teeny tiny bit of mass to energy. Our nuclear reactors are far better at this conversion, when they ‘burn’ Uranium. But even they are dwarfed by the Sun which uses a much more efficient technology (nuclear fusion).

The physicist

Hawking showed that that is not the end of the road. If his theories were to be proved correct, a black hole can help generate energy far more efficiently than the conventional approach our universe uses (fusion of Hydrogen).

And this is not just a good to know theory; the implications are profound. It means that we could one day become a Type 3 civilisation (a civilisation so advanced that it requires orders of magnitude more energy than its home star can provide) without even needing to venture out of the solar system. Although I think that we should venture out nonetheless!

And the person

Stephen Hawking was and remains a big inspiration even outside of his contributions to theoretical physics. He is a testament that the only thing that can pin you down and hold you back is your own will power. There is nothing else. At the same time, he was very much human and made his fair share of mistakes, most notably claiming (much to Peter Higgs’s displeasure) that the Higgs boson would never be found.

Hawking never received a Nobel. His theories were, probably, too radical for us to wrap out head around. However, in the far future when we set up our first black hole to harness its energy, we would probably name it the Hawking power station, and would have paid our debts to one of the greatest minds of our times.

Trolley problem

An out-of-control trolley is hurtling down the rail-road. It is on a collision course with five people who will not survive the crash.

You could throw a switch and reroute the locomotive onto a parallel track. Unfortunately, there is a person on the other track as well who will then face a similar consequence. The question is, what should you do?

An ethical dilemma

The trolley problem represents an ethical dilemma – a situation where our moral code falls short of giving a clear direction. There are no right answers. You could take a utilitarian view and choose five lives over one. Or argue that wilfully claiming a life is immoral, no matter the circumstances.

Or, of course, you could brush it all aside as a philosophical thought-experiment with no real-world implications. But could you?

Enter autonomous vehicles. Now, you could ask the same question slightly differently. How should a self-driving car take a decision when there are no good options? As you will see, the dilemma suddenly gets very real.

Moral machine

Let's take an example. In an emergency, should a car swerve left into a biker with helmet (a good law-abiding citizen), swerve right into a biker without helmet (an offender but with the lowest chance of survival), or brake and jeopardise its own occupant (but one with the best odds)?

The fact is, even though this exact situation may never occur, we already know what the car would do because we programmed it. So we better have made our peace with it.

In 2016, researchers at the MIT set up a platform called the Moral Machine. It presents different situations in context of a self-driving car and participants pick what they believe is the least-worst outcome. Perhaps it is one way for us to collectively decide how we would like the machines we build to approach the trolley problem.

TL;DR?

Randall Munroe has very nicely illustrated the trolley problem for people in a rush:

Dark energy

Part 2 of a two-part series. Read part 1

The story of dark energy does not need to start with Einstein but it is an interesting anecdote so let's start there. Einstein realised that Newton's theory of gravity had some flaws. So, he went ahead and came up with a new theory. This happens all the time.

An expanding universe

Interestingly, Einstein's new theory seemed to imply that the universe was expanding. While this is common knowledge today, up until a century ago we thought of the universe as static – things moved around, not apart. Einstein yielded to the prevailing belief and made adjustments to his work such that it predicted a static universe.

Then came along Edwin Hubble. The astronomer established through observations that the universe was indeed expanding. This was just a few years after Einstein published his work. Einstein called it his biggest blunder and we used Hubble's observations to build a neat model of how the universe came into being as a result of a big-bang.

An unanswered question

There was one piece of the puzzle that we were still missing though. As gravity brings everything together, we were sure that the expansion would slow down over time. But would it continue forever, just at an increasingly slower pace? Or would gravity ultimately win, causing the universe to collapse upon itself? The fate of the universe was still unknown.

So astronomers took to the skies again to figure out if expansion was changing over time. And in 1998, we observed that it was. But contrary to our expectation, expansion was accelerating. It appeared as if new energy was being added to the universe, aiding expansion and completely overwhelming gravity. So we named it dark energy.

And there we have it. We don't know what dark energy is, where it comes from or even if it is energy at all. Once again, all we really know is that we have a theory and an observation, and they don't play nice.

Dark matter

Part 1 of a two-part series.

Dark matter and dark energy are, quite likely, amongst the top questions of contemporary Physics that have caught non-physicists' imagination, alongside perhaps the Higgs boson and the Grand Unified Theory. Let's attempt to understand what these really are.

The best way to approach this is to not think of dark matter and dark energy as matter or energy, but more like placeholder names that we have given to things that we do not yet understand. Think of it this way – I go to bed with a tooth under my pillow and in the morning I find some money. I cannot explain this phenomenon so till such time that I can, I am going to call it a tooth-fairy!

Planets and gravity

Let's start with the solar system. We know that planets go around the Sun because of Sun's gravitational pull. We also know that gravity gets weaker as you move away from the source. So that should lead us to conclude that a planet close to the Sun would travel faster than a planet farther away.

Turns out, this is indeed the case. Mercury, the closest planet, whizzes around the Sun at about 48 km/s while Neptune, the farthest planet, travels at about 5 km/s. Our theory of gravity seems to works fine at a star-system level. But does it work at a galaxy level?

Going fast in the slow lane

Let's now look at the Milky Way. Indeed, stars at the edge of our galaxy move slower than the ones near the centre. But here's the problem – they are not travelling as slow as our current understanding of gravity predicts.

It appears as if the peripheral stars are getting an extra tug of gravity from somewhere to boost their speed; some sort of invisible or dark matter that we cannot see but whose gravity is driving these stars harder. And that is the genesis of the term.

However, the important thing is that this does not mean dark matter exists conclusively and we just need to find it. All it really means is that we have a theory and an observation, and they are currently incompatible. Till such time that someone comes up with an explanation, we have chosen to refer to this conundrum as dark matter.

Continue with part 2

Hello World

It was December of 2020. The time of the year when I get my chance to try out something new. In a year which barely resembled any other, this was indeed a welcome constant.

And thus started my quest to build my own website – a task that would seem easy at first, daunting soon after, then challenging and finally fulfilling. For someone who has not written a serious line of code for over 15 years, it was also a great learning experience.

But website design goes beyond just learning to code in HTML and CSS and JavaScript. It is an art as much as it is technology. What is the personality of your website? Does it convey itself equally well on a computer as it does on the small screen of a mobile? Or a tablet? I had more fun making my website responsive, creating the logo, the icons and the error pages (which I hope you don’t see a lot of) than creating actual content for it.

And then, I finally got to what is simultaneously the most exciting and the most mundane step – buying a domain and leasing a web-server. Et voila! In the early hours of Sunday, January 17, 2021, I finally owned a piece of real estate on the internet that I could call home.

Pilot

Having no idea what to write a blog on, I did what anyone in this day and age would do – go to the internet for advice!

So now, having established that this is not my idea, let's get on with it anyway. I present my responses to a set of 10 ice-breaker questions:

1. What is your favourite quote?

   "You can’t connect the dots looking forward; you can only connect them looking backward" – from Steve Jobs's 2005 Stanford address.

2. Your favourite movie?

   I don't have one right now, but Roberto Benigni's 'Life is Beautiful' was my favourite for a fairly long time. 'A Beautiful Mind' based on John Nash's life was yet another one of my favourites.

3. If you could have a super-power, what would you choose?

   Time travel. Every other super-power could be purchased off Amazon; it's just a matter of time.

4. Do you have any hidden quirks?

   The amount of effort I spend organising the world around me likely approaches quirky territory. No clue how hidden that is.

5. Have you ever committed a crime and gotten away with it?

   I think I am going to take the fifth here.

6. What ability of yours are you most proud of?

   Restricting selection to abilities and skills that are currently unmonetised, I would say my sense of humour.

7. In a hypothetical society where all jobs pay the same, what would you be?

   I would probably be a university professor teaching Physics or Mathematics.

8. If you could get a PhD in any subject, what would you choose?

   I would pick Machine Ethics but this is a recent inclination. Till quite recently I would have picked Cryptography.

9. What technological advancement do you resent the most?

   Loss of privacy – collection and mining of personal data that has become synonymous with the information age.

10. What is the most outdated piece of tech you still use regularly?

    Text messages.