What is Time if not relative? (Part 2)

In the post, What is Time, if not relative? , I wrote about slowing down of time at high speeds or Special Relativity and how Einstein discovered it in an attempt to reconcile Newton’s laws of motion with Maxwell’s theory of electromagnetism. Einstein’s discovery was a huge revelation and changed forever our perception of time. The story though does not end here. Einstein spent next ten years of his life investigating how to encompass gravity into relativity and was born the theory of General Relativity. According to the General Relativity, perceived time or the elapsed duration observed between any two events depends upon the gravity of the objects surrounding the observer in addition to the speed of the observer. In simple words, time slows down near a massive object (due to its  gravitational pull). Going back to the example of the readers of this blog, a reader reading this blog on earth will observe a gap of 9 days between this post and the previous post on this topic, however a reader in the outer space near a massive star or a black-hole (provided he is not already sucked into it) is still on the first line of the previous post. This is already looking quite complex and interesting, isn’t it?

Time that we observe is not an absolute but relative to our speed and position in the universe. Our high school Newtonian Physics meticulously trained us to observe the position of an object in 3-dimensional spatial co-ordinates (the way we visually observe objects in space) and how this position changes with time defines its trajectory through space. With General relativity, time is no longer a book-keeping unit for the trajectory of the objects in space but a co-ordinate of the space itself. This is how Einstein’s theory of general relativity is sometimes interpreted, that everything is happening in a 4-dimension space with time being the fourth dimension.

Let me leave you with this thought that your brain is a clever virtual machine and you are navigating through this universe in a virtual world.



What is Time, if not relative?

In the post It is about TIME!, I promised to write about Time and then I got busy doing other things. I have come back today to fulfill my promise after exactly 2 months and 24 days. A gap of almost three months between posts is long enough in the blogging world or may be not? Is it really a gap of  2 months and 24 days between It is about TIME! and this post? Well a physicist might argue that the elapsed time between  It is about TIME!  and this post depends upon the relative speed of the reader with respect to the writer. If the reader is moving at nearly the speed of light, almost no time has elapsed since my last post. In fact such a reader may not even have experienced the time it takes for him to fully read It is about TIME!. The phenomenon of slowing down of time at high speeds was discovered by Einstein and is described precisely by what physicists call “Special Relativity”. If it is the first time you have come to know of slowing down of time at high speeds, take a break and read this whole paragraph again so as to come to terms with this totally counter-intuitive phenomenon. Get used to thinking of the passing of time as an illusion and equip your mind to acknowledge the fact that your friends and family would be old and frail by the time you would return from a quick ten minutes long trip in the outer space at blazingly high speeds like a ‘photon’ bouncing and jumping through the air. How Einstein came to discover this phenomenon is a stuff of the legend. By the early 1900’s Newton’s laws of motion were well known. Time for Newton and his contemporaries was an absolute quantity and was same for every one and every where. One minute is a one minute is a one minute for you on earth, for me on an airplane and for an astronaut in a space ship. Physicists or Natural Scientists of that era also knew that the speed of a moving object was not absolute and was always with respect to some observer. As an example consider yourself riding a train with your best friend, your friend appears stationary to you while you both are on the train, after some time your stop arrives and you get down from the train. At this point, you look at your friend from the platform as the train moves on, and your friend appears to be moving away at the speed of the train. When applying Newton’s laws of motion, you will adjust the velocity of a moving object with respect to the observer. Everything was fine until Einstein tried to apply the concept relative motion to ‘light’. According to relative motion, if you were running towards a beam of light with speed ‘v’, you will observe the light moving towards you at a speed of ‘v + c’, where ‘c’ is the speed of light (and if you were chasing a light beam at a speed ‘v’, you would observe it going away at a speed of ‘c – v’). By the time Einstein was exploring these laws, Maxwell’s theory of electromagnetism indicated that the speed of light was constant (~300,000 km/s) regardless of the speed of the observer. This was a problem, relative motion and Maxwell’s notion of a fixed value for the speed of light were incompatible with each other. Either Maxwell was wrong (which he was not) or Newton’s laws were incomplete. In his attempt to bring order back to the world of physics and make Newton’s laws of motion work with Maxwell’s laws of electromagnetism, Einstein observed that for the speed of light to be always constant, ‘time’ had to rise to the occasion. Hence was discovered the concept of slowing down of time at higher speeds and it has been validated time and again in experiments.

If you can get hold of a very precise clock that can record time to the order of millionth  or billionth of a second, take that clock with you on your next flight and compare the flight time recorded by this clock to that of a stationary clock on earth. Do your little experiment and witness the phenomenon first hand.

The story is not over yet, time recorded by a clock contracts and expands not only due to movement through space but also due to the position of the clock in the space. More on that in the next post.





It is about TIME!

The only reason for time is so that everything doesn’t happen at once.

Albert Einstein(?)

In the post Let’s talk about…..!!, I promised that I will write about something that we all complain about not having enough of. One of you guessed that it was TIME. It is time for me to say that the time has come for me to fulfill a promise I made back in time. In the time to come, I will keep my word and devote my time to writing about time. In the post, Democratizing Science!, I made another promise of describing some scientific concepts in simple terms for everyone to understand and what better than time as a first topic. It is a topic that has intrigued philosophers, poets and physicists from time immemorial so much so that Stephen Hawking wrote a whole book ‘A brief history of time’ for all of us to read and ponder over. Speaking of Stephen Hawking, what a marvelous show of human spirit by the man who refused to get sucked in by a black hole called ALS. Instead, he took black holes to the workshop and figured them out for us. Amitabh Trehan wrote a very nice post on his blog : Stephen Hawking: A memoriam in time, to commemorate Stephen Hawking.

I am not a physicist and my knowledge of time is not as deep as that of physicists, but I will try to write whatever little I know. I am not a poet and can’t write a soulful ode to time. I am a computer scientist and I tend to look at time through the prism of computer science. I will hence write in more detail about the various ways in which computer scientists and especially algorithm designers perceive time. Keep watching this space in the coming days and weeks to go with me on a voyage in time.

Before we start our voyage, you may want to pause and ponder over time. What comes to your mind when you think of time:

Is it  clocks, calendars or watches?


 Do you think of it as a finite resource like 10 days, 5 months or 2 years within which to achieve a goal like shedding 5 kilos of that goddamn fat around your waist?


Do you think of a ball of rock spinning tirelessly like a top and revolving around another ball of fire over and over rhythmically?


Do you think of your facebook timeline which gives you a run down of the old and new in your social network. I don’t use facebook more than once a year, but I hear the timeline rolls back and what you see at the top now will come back up again after some time. Do you think time can roll back like your facebook timeline?


Are you a Pink Floyd fan like me and thinking of time makes you sing off-key (in my case) the lines:

“Ticking away the moments that make up a dull day,

You fritter and waste the hours in an off-hand way

Kicking around on a piece of ground in your home town

Waiting for someone or something to show you the way”

Until next time, think about time and listen to the masterpiece by Pink Floyd.









Democratizing Science!

“Alice: This is impossible.
The Mad Hatter: Only if you believe it is.”  – Alice in Wonderland

In the posts “A child’s journey”  and “Because the child was human”, I argued that the process children follow in exploring the world around them is inherently scientific. They hypothesize, test and update their hypotheses just like a scientist is expected to.

The question is if human brain’s cognitive circuits are designed to follow the scientific method, why so few of us grow up to enjoy science. Why do some of us tend to skip over a science program on TV or find science magazines boring? I have heard many friends say,  I did so bad in science in high school; there is no way I can sit through a science program on TV”. This is very confusing to me. There is nothing in those science programs that a normal human being can not process. It is this aura of mystery around science created and perpetuated by our flawed grades based education system which discourages many people from believing in their innate abilities. The course grades at every level, if at all, are a measure of your skills and not your talent. Talent is an inherent human quality and skills are acquired knowledge about a subject. Newton did not do well in school, but his talent and passion enabled him to make remarkable contributions to the fields of science and mathematics.

Long story short, I am trying to advocate the democratization of science or making science available to all. Every one of us should be able to access the latest and the greatest of  scientific discoveries and their significance. Science should not be an elitist practice but a collective human pursuit of knowledge. I am not saying everyone is inherently a career scientist. Science as a career needs a lot of other skills, mathematics being the most important one. Mathematics is the language of science and the most beautiful one at that. It helps express the laws governing the nature in a succinct, precise and formal way; but it is a means not an end. Quoting Einstein, “Imagination is more important than knowledge.” If you have the curiosity and imagination to understand the world around you, you already are half a scientist. If Grand Canyon and Pyramids intrigue you and you visit the Mystery Point for a lot more than a mere selfie, you have enough qualifications to read a science magazine. To a curious mind, no hurdle is big enough, not even mathematics. Persi Diaconis (PDiaconis) learned probability for his love for card games and became a professor of statistics at Stanford University.

We need to demystify science and encourage people to nurture their quest for answers. The way to do that is to make science available in a language that people are most comfortable in. Again quoting Einstein here, “All physical theories, their mathematical expressions apart ought to lend themselves to so simple a description that even a child could understand them.”. Thanks to BBC, they make some amazing documentaries about some awe-inspiring scientific discoveries. They strip away the esoteric terms and the mathematics involved and present to the audience an easy to follow and engaging account of a scientific discovery. I believe, more effort needs to be invested in this direction.

All said and done, one should put one’s money where one’s mouth is. To that end, I will try to post here about some scientific concepts I know well. I will also try to write about some scientific concepts and discoveries in physics and mathematics that are close to my heart and we all can learn together.

Finally, I want to leave you with a question to think about:

What do you think is common between a scientist and an artist? Please post your thoughts in the comments.



Happy St. Patrick’s Day!

DSC_0529Hello world!!!!!

I hope you had a good St. Patrick’s day. I miss the festivities in Belfast. The above picture was taken on our way from Dublin to Belfast two years ago a day after the St. Patrick’s day. In Ireland, the grass is always green on every side.

If  you live in England like me, I hope you are keeping yourself safe from the ‘Mini Beast from the East’. Stay inside, stay warm and let us all hope and wait for better weather days.

I will be back with another post tomorrow.


Because the child was human.

There are only two ways to live your life.

One is as though nothing is a miracle. The other is as though everything is a miracle.  –Albert Einstein (?)

In the previous post, I narrated a childhood story in which I went through a series of steps in discovering the cause of seeing infinitely many images of a statue of  Krishna in a temple.

Let us now analyze the process of discovery followed by the child that was me. This is my analysis, please feel free to contest it if there is anything you don’t agree with. I first attributed it to the God, after some time I observed that the phenomenon that I experienced at the temple did not  reproduce at my home and I then attributed it to a special mirror. Finally the arrangement of two parallel mirrors revealed itself as the cause of the phenomenon I had been rationalizing in my mind. Does this entire process appear scientific to you? Some of you may argue that everything except the last part was unscientific. But let me argue that the entire process was scientific. The Oxford dictionary defines the scientific method as:

A method of procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses.

What is important here is the formulation, testing and modification of hypotheses. As human beings, we are always formulating hypothesis based on existing knowledge and data to explain some phenomenon; what makes the process scientific is the process of testing the hypothesis (by observation and/or experimentation) and subsequently modifying or updating the hypothesis if need be. The process of modifying includes the possibility of completely rejecting the hypothesis if proven wrong .

In science, everything is right only until proven wrong. Now that’s where science and religion/faith are different. Both science and religion start their journey in a hypothesis (God), while science is ever engaged in collecting evidence to support its hypothesis and keeps refining it to be consistent with the new observations, religion stays put at the hypothesis.

Attributing an unexplained phenomenon to the God or for that matter to anything else (physicists fondly called Higgs-Boson the God particle) is not in disagreement with the scientific method, not modifying the hypothesis as and when presented with new knowledge and evidence is. I made a hypothesis at the age of four, tested it at home and modified it and modified it once again after the science class. The point here is not to flaunt my scientific prowess as a child, but to argue by example that as human beings we are naturally wired to follow the scientific method as we observe the world around us. According to a study conducted at MIT (the original paper), children are natural scientists. They build hypotheses, make predictions and update their hypotheses like a scientist is expected to. I defer the details of the MIT study to another post.

If  you have any stories like mine where you followed the scientific method as a child, please do share them in the comments.

As before, I will leave you with a couple of questions:

If we as human beings are naturally wired to be scientific, why do some of us fear science? Why do we caricature scientists as these socially awkward, withdrawn from the real world, creatures?




A child’s journey from mystery to mastery.

Growing up in a sleepy little town in the eastern Punjab, my world view was limited to the things and the people around me. The only happening place we had in town was Gita Bhawan, a big hindu temple right in front of which was a park with not so green lawns and a fountain which never worked.

As children, it was our one and only picnic spot, our Disney Land. I, my brother and a few cousins used to huddle around our grandmother to convince her to take us to Disney Land. After some sweet  persuasion and blackmail she would agree to lead the army of little comrades to their favorite place. Apart from some minor disputes over who will walk next to whom and who is allowed to sing which song, the comrades used to reach their Disney Land unscathed.

Once there, it was mandatory for us to first offer our respect to the Gods at the temple before heading out to the lawns.

Among many different depictions of  the God(s) was this peculiar exhibit, a cubicle with a statue of  Krishna in an exquisite yellow dress playing flute standing next to a smiling Radha also in an exquisite yellow dress. What made this exhibit very interesting was that two of its three walls were made of looking-glass. We would stand in one corner and look into the mirror and lo and behold, we could see an image of Radha-Krishna followed by another image of Radha-Krishna and followed by another and another and…..  As a matter of practice, we would jump to the other corner to witness the phenomenon from the other side.

The first time I witnessed those images, I must have been very young, may be four or five. It was mind boggling for my young mind. I thought to myself that this was the power of God and took it as a proof of of His omnipresence. For me, it was God’s presence in the cubicle that made the image appear infinitely many times. I confirmed this with a cousin who was only one year older than me. To my pleasure, not only did she give her seal  of approval but also tattled along that we would have seen the same image appear one thousand crore times in the upward direction, had the ceiling been made of looking glass too.

This  rationalization stayed with me for some time until one day I observed that the picture of God on the calendar hanging in front of the dressing mirror at my home did not project a million images on my retina. This first scared me, there was no God in my house;  was he unhappy because I had stolen a classmate’s English homework notebook? Aah, now the entire world knows that I preferred stealing other children’s notebooks to show to the teacher instead of doing my own homework. My early start at plagiarism was nipped in the bud by my teacher. I was caught despite my clever plan to cover the cover of the notebook with a newspaper.

Luckily the fear of God’s absence in my home because of my misdeeds departed quickly from my mind. I was convinced that it was more than the mere presence of God in that cubicle that caused so many images to appear. I imagined that the temple was in possession of a special kind of mirror- the looking-glass equivalent of the philosopher’s stone: paras pathar as well call it in Punjabi (by then I had read about paras pathar in a story book). I was sure that one needed a paras mirror to experience the extent of power of God. I asked my father if the temple had a special glass and he told me that they had a special arrangement at the temple and that my science teacher would explain properly what that arrangement was.

Finally one day in the science class on reflection and refraction, the teacher told us that placing any object between two parallel mirrors causes the object to have infinite images. This was the paras mirror after all and it worked the same for all objects including the statues and pictures of Gods.

I hope you enjoyed reading the story.

May I now urge you to ponder over the process of discovering the cause of infinite images by the child, that was me.  Do you think that the child’s journey from a state of absolute awe to the knowledge of a scientific principle was scientific? If not, what parts of the journey according to you were not scientific. Please don’t be shy and post your answers in the comments.

I will post my answer in the next post. Until then keep the child in you alive.





Every day is women’s day.

Women’s day  it was yesterday I am told and now it is over. Congratulations were extended, selfies were taken, collages were made and posted on Instagram, cakes were cut and parties were thrown, it was a day for the florists and wine shops to make moolah until the next big day for the trade on the 11th of March, the mother’s day (in the United Kingdom).

Now that all the excitement around the international women’s day has died down and the men and women of this world have gone back to business as usual and the interim special status granted to women has been taken away, let me extend my heartiest congratulations to all my homies for successfully claiming one full day to ourselves after centuries of struggle for equal rights for men and women. Please don’t misconstrue me, I am not ridiculing the significance of the day, I completely understand the symbolic meaning of the day, I am all for celebrating womanhood in all its glory. It’s just a little nudge to bring your attention back to the heaps and piles of what needs to be done. Remember, what lies between every two holidays is a long stretch of work days. Let’s do a little more than taking a selfie in that I am a feminist t-shirt next time, after all, the only cause it serves is the one that of the t-shirt manufacturer. The real cause is clamoring in the background for attention or so it seems to me. Having congratulated each other with selfies and Whatsapp messages, we are back to the real world in which a man who prides himself in being able to get his way with women is the president of the most powerful country of the world and another who has unscrupulously enjoyed sexual favors from women in exchange of a promising career in a prolific film industry is yet to be brought to book. If this is the state of affairs in the most powerful (power I think still lies with the men) country of the world, I need not expound on how a woman is denied the right to education and sometimes even the right to be born in certain parts of the world. A woman is raped every 15 minutes in India. The idea of women being equal to men agitates some men and instigates them to commit such heinous crimes.

It is true that we have come a long way in our struggle for equal rights and have progressed leaps and bounds in certain aspects. Let’s congratulate ourselves for all that has been achieved by us and more importantly by those who walked this earth before us and take note that:

We have plucked but a handful of stars, the whole sky is waiting to be had.

Finally, I am grateful to my favorite writer Ms. A Roy, for giving my thoughts a safe haven to dwell in, a haven that I can go to often and have a hearty chat with my dreams.

This is to you my homies:

The only dream worth having is to dream

that you will live while you are alive,

and die only when you are dead.

To love, to be loved.

To never forget your own insignificance.

To never get used to the unspeakable violence

and vulgar disparity of life around you.

To seek joy in the saddest places.

To pursue beauty to its lair.

To never simplify what is complicated

or complicate what is simple.

To respect strength, never power.

Above all to watch.

To try and understand.

To never look away.

And never, never to forget.

Arundhati Roy.