Buddha, Bohr and Einstein

What I needed, according to a dear friend, was some spirituality to uplift my mid life blues, and I was kindly provided with a copy of the book “Universe in an Atom” written by none other than His Holiness, the Dalai Lama himself. As most impartial observers would appreciate, Dalai Lama has become a global symbol of what a spiritually enlightened being looks like. In comparative terms, if the picture of Einstein immediately conjures up the image of super human genius, the picture of the Dalai Lama conjures up the image of a fully enlightened being while still fully human. Though I had been fascinated by him, and actually had the privilege of listening to him in person when he visited Birmingham last year, I never had the privilege of reading a book by him. While I expected what he would be writing – the importance of spirituality and the Buddhist ideals of “Ahimsa” or “non violence”, I was very pleasantly surprised after reading this book on the depth of understanding the Dalai Lama shows in the modern sciences, especially in the fields of quantum mechanics, relativistic cosmology and consciousness research, and provide valuable pointers to places where Buddhist (and ancient Indian) philosophy can meet modern science, and at times even fill the gaps in our understanding of issues on the borders of physics and metaphysics. This is a humble review and summary of the book. For anyone interested in a deeper understanding I strongly recommend to read the full book, which can be finished in 2-3 hours but is full of useful information as well profound insights.

Many religious leaders and scholars have written books claiming to connect their particular faith with modern ideas of science. Almost all of them are written to prove the author’s particular theology has pre-dated or even predicted all or part of modern science. However this book offers something much wiser and more humble; this book is written by a compassionate and well read religious leader who not only respects science but, for the most part, embraces it. "If scientific analysis were conclusively to demonstrate certain claims in Buddhism to be false, then we must accept the findings of science and abandon those claims," he writes. No one who wants to understand the world "can ignore the basic insights of theories as key as evolution, relativity and quantum mechanics."

That is an extraordinary concession compared with other religious leaders who conducts seminars and conferences devoted to “reconciling” science and their particular faith. These “dialogues", some of which I had attended or watched online, implicitly begin with the non negotiable like  “Jesus was born of virgin mother, and after death on the cross He was bodily resurrected into heaven. . ."  then seek scientific justification for what is already assumed to be true.

The story of how someone so open-minded became the Tibetan Buddhist equivalent of the Pope reads like a fairy tale. When the 13th Dalai Lama died in 1933 he was facing northeast, so a spiritual search team was sent in that direction to find his reincarnation. The quest narrowed further when a Lama had a vision pointing to a certain house. The little boy in that house, considered the re incarnation of the previous Dalai Lama, was then taken to the official residence of the Dalai Lama, the Potala Palace. The Buddhist elders soon realized they have indeed selected a very special child, as the little boy showed a wide ranging curiosity and sharp mind, learning not only the ancient traditions and scholarly work, but in his lonely childhood found solace in the very few technological marvels in the ‘otala palace, like a clock and a brass telescope. When he focused it one evening on what Tibetans call "the rabbit on the moon," he saw that it consisted of shadows cast by craters. Although he knew nothing yet about astronomy, he inferred that the moon, like the earth, must be lighted by the sun. He had experienced the thrill of discovery of himself and it appears he continues this tradition of discovery – spiritual and scientific – even today. When I saw him speak at Birmingham, what impressed me most was, despite his age and wise looks, he acted, spoke and most importantly laughed with the innocence of a child. In this book also one can see the insatiable curiosity of a child trying to grasp some of the deepest questions humans have ever faced.

What is remarkable is, despite absolutely no formal training in the fields of mathematics, biology or physics, his childish curiosity would serve him well to have a perfectly adequate understanding of the basic concepts in these fields. In no small part this was helped by his association with some of the greatest scientists and philosophers of the latter half of 20^th century. These scientists and philosophers included American Physicist David Bohm, German Physicist Carl von Weizsäcker (a student of quantum mechanical pioneer Werner Heisenberg) and British philosopher (and a friend of Albert Einstein himself), Sir. Karl Popper. In his humble way he praise these and other scientists and philosophers as “my respected teachers” – he treat them with the same regard he holds for his spiritual masters who taught him while he was a young monk at the Potala palace.

His interest in the intersection of science and spirituality and his willingness to embrace science with an open mind endeared him to spiritually inclined scientists all over the world. He has been conducting the so called "Mind and Life" conferences which have brought physicists, cosmologists, biologists and psychologists to Dharamsala, India, where he now lives in exile from the Chinese occupation of Tibet. He and his guests discuss things like the neuroscientific basis of Buddhist meditation and the similarities between Eastern concepts like the "philosophy of emptiness" and modern field theory. In fact when he visited Birmingham he was the distinguished guest speaker at a seminar organized by UAB Department of Neuroscience on the topic of Neuroplasticity and Healing. 

Dalai Lama is very open when it comes to admitting where scientific reasoning far exceeds the traditional “concrete logic” as used in Buddhist and ancient Indian philosophy. He explains it by describing how Buddhism and science differ in the role of deduction. While in science reason uses highly developed use of profoundly complex mathematical reasoning, Buddhism, like all other classical Indian philosophies, has a very concrete use of logic, whereby reasoning is never divorced from a particular context. In contrast, the mathematical reasoning of science allows a tremendous level of abstraction, so that the validity or invalidity of an argument can be determined purely on the basis of the correctness of an equation. Thus the generalization achievable through mathematics is at a much higher level than is possible in traditional forms of logic.

Dalai Lama explores this further by stating that “given the astounding success of mathematics, it is no wonder some people believe that the laws of mathematics are absolute and that mathematics is the true language of reality, intrinsic to nature herself”.

While accepting the superiority of science in general, Dalai Lama argues against scientists and some non scientists, who appear to believe that all aspects of reality must and will fall within the scope of science, the view also shared by “hard atheists” as well as by Marxist dialectical materialists. He argues against this view, in which science is perceived as having disproved many of the claims of religion, such as the existence of God and the eternal soul. Per him “Such views are effectively philosophical assumptions that reflect their holders’ metaphysical prejudices” which to him sounds very similar to theistic presumptions. He argues that the scientific cannot exhaust all aspects of reality, in particular the nature of human existence, the subjective world of feelings, emotions, thoughts, and the values and spiritual aspirations based on them. One finds it hard to argue with his point that “if we treat this realm of spirit as though it had no constitutive role in our understanding of reality, we lose the richness of our own existence”. Below I have summarized his book in to the following three sub headings. 1) Buddhism and Quantum Mechanics 2) Buddhism and Relativity / Cosmology 3) Buddhism and Life/Consciousness.

Quantum mechanics and the Philosophy of Emptiness:

One of the most important philosophical insights in Buddhism comes from what is known as the "theory of emptiness". Briefly from what I understood, this argues against a “separate self”. Though our every day experience makes us want to think of us (and other sentient beings as well as non sentient matter) appear as discrete particles, the theory of emptiness argues this is just an illusion. Per the theory of emptiness, our individual identity and “separateness” is a persistent but false delusion of the mind. This delusion of separateness leads to our “discrete ego” which in turn leads to many of the ills at individual and societal levels including attachment, loneliness, and development of our numerous prejudices. This theory of emptiness was first systematically expounded by the great Buddhist philosopher Nagarjuna (c. second century C.E.); though little is known of his personal life other than that he came from Southern India, he was—after the Buddha himself—the single most important figure for the formulation of Buddhism. Historians credit him with the emergence of the Middle Way school of Mahayana Buddhism, which remains the predominant school among Tibetan Buddhists to this day. 


Dalai Lama argues the ideas of quantum mechanics leads to very similar conclusions. It is fairly well known even among those who are not very scientifically literate that the microscopic world of quantum mechanics challenges our commonsense understanding. Examples abound, including facts like light can be seen as either a particle or a wave (In fact, the man who won the Nobel Prize for showing that the electron is a wave, George Thomson, was the son of the man who won the same prize for showing that the electron is a particle, J. J. Thomson.), and that the uncertainty principle tells us we can never know at the same time what an electron does and where it is, and the quantum notion of superposition all suggest an entirely different way of understanding the world from that of classical physics, in which objects behave in a deterministic and predictable manner. For instance, in the well-known example of Schrodinger's cat, in which a cat is placed inside a box containing a radioactive source that has a 50 percent chance of releasing a deadly toxin, we are forced to accept that, until the lid is opened, this cat is both dead and alive, seemingly defying the law of contradiction. Dalai Lama argues that to a Mahayana Buddhist exposed to Nagarjuna’s thought, there is an unmistakable resonance between the notion of emptiness and the new physics. If on the quantum level, matter is revealed to be less solid and definable than it appears, it is like science is coming closer to the Buddhist contemplative insights of emptiness and interdependence.

Dalai Lama, quoting Nagarjuna, suggests that the theory of emptiness is not a question of the mere conceptual understanding of reality. It has profound psychological and ethical implications. He then recollects a conversation he had with American physicist David Bohm: “From the perspective of modern science, what is wrong with the belief in the independent existence of things?” Bohm responds that “if we examine the various ideologies that tend to divide humanity, such as racism, extreme nationalism, and the Marxist class struggle, one of the key factors of their origin is the tendency to perceive things as inherently divided and disconnected. From this misconception springs the belief that each of these divisions is essentially independent and self-existent”. Bohm’s response, grounded in his work in quantum physics, echoes the ethical concern about harboring such beliefs that had worried Nagarjuna, who wrote nearly two thousand years before. Similarly the “observer effect”, where reality depends on the observer (collapse of the wave function in quantum mechanical language, where a “cat could be alive and dead at the same time as in the Schrödinger’s thought experiment) suggest that we must abolish as a matter of principle the separability of subject and object, the observed and the observer.

Relativity of time in Buddhist philosophy:

Einstein’s theory of relativity showed conclusively that time is “relative” to the speed of the observer. This leads to many of the interesting paradoxes, like the twin’s paradox, time dilation, or the contraction of objects at high velocity. (For those interested to read Einstein's ideas in more depth, click on the link to these blogs What time is it? and How fast does Brahma moves?). Dalai Lama quotes the story from Buddhist mythology of how Asanga was taken to Maitreya’s Heavenly Realm, where he received the five scriptures of Maitreya, a significant set of Mahayana texts, all in the time frame of a few minutes. Thus it appears, according to Buddhist and Ancient Indian principles, the concept of time as relative is not new. Dividing the temporal process into the past, present, and future, the Sautrantikas demonstrated the interdependence of the three and argued for the untenability of any notion of independently real past, present, and future.

EPR Paradox and Buddhism: Named after its creators, Albert Einstein, Boris Podolsky, and Nathan Rosen—which was originally formulated to challenge quantum mechanics, the EPR paper is a famous thought experiment in the early days of quantum mechanics, and was suggested to explain why quantum mechanics can’t be true. Briefly the EPR paradox is this: Assume a pair of particles is created and then separates, moving away from each other in opposite directions. One of the properties of this pair of particles is that their spin must be in opposite directions—so that one is measured as “up” and the other will be found to be “down.” According to quantum mechanics, the correlation of measurements (for example, when one is up, then the other is down) must exist even though the individual attributes are not determined until the experimenters measure one of the particles. Such an entangled particle pair could be at great distances from each other, say at either ends of the visible universe; but a “measurement” of one particle could cause a simultaneous change in the paired particle, even if that particle is at a great distance. Einstein’s relativity conclusively showed nothing can travel faster the speed of light. So how is it possible for this paired particles to communicate instantly across vast cosmic distances? Stranger is the fact that this EPR paradox has now been proved experimentally to actually exist in reality. While the authors of the original EPR paper wrote it to discredit quantum mechanics, it appears EPR phenomenon actually happens. Einstein called the EPR phenomenon “spooky action at a distance”. And it appears nature is spooky after all!

Dalai Lama gets in to this argument as follows: He quotes the so called "Vaisheshika atomism", which substituted a plurality of indivisible “atoms” as the basic units of reality for a single underlying reality. So what appear to be events separated by great distances are in fact connected through this underlying substratum of reality, one that is not obvious to us.

Cosmic origins:

It appears there are two main traditions of cosmology in Buddhism. One is the Abhidharma system, and the Mahayana Buddhism, especially the version of Indian Buddhism known as the Nalanda tradition. The primary work on the Abhidharma system of cosmology that made its way into Tibet was Vasubandhu’s Treasury of Higher Knowledge (Abhidharmakosha). Buddhist writing in the fourth century describes cosmic origin in terms of the theory of “dependent origination”. This theory states that all things arise and come to an end in dependence upon causes and conditions.

The second cosmological tradition in both classical Indian philosophy and Buddhism is called “Kalachakra” or the wheel of time. Both the Abhidharma and Kalachakra suggest ours is one among countless world systems. Evolution of a particular world system is understood in terms of four stages 1) Emptiness 2) Formation 3) Abiding and 4) Destruction. Each of these stages is thought to last a tremendously long time. At the heart of this idea is that there are not only multiple world systems but they are in a constant state of coming in to being and passing away. According to Dalai Lama, the idea of a single beginning, a singular big bang, is inaccurate – because such a singular beginning could suggest one of two things 1) Theism which suggest a universe created by an intelligent designer 2) Universe came in to being with no cause at all as hard atheism suggests. Surprisingly (for me), it appears Buddhism, like science, share a fundamental reluctance to postulate an intelligent designer. Buddhism in turn proposes the following origin story; In the beginning was the vast void; out of which (“emptiness”) a new universe if formed; this universe go through immense period of expansion, and is finally destroyed or turn back to pure emptiness. And the cycle continues. What is remarkable is how closely this indeed resembles our best understanding on the structure and life cycles of the cosmos.

A Mahayana text titled “The flower ornament” describes with precision about the large number of “worlds” and the limits of human knowledge. A section titled “incalculable” contains numbers named “the measureless”, the “boundless”, the incomparable” and “square untold” which is “unspeakable” multiplied by itself! Amazing that they were at least thinking of really huge quantities at a time when our everyday experiences did not require use of such large quantities. As any one familiar with modern cosmology must have read, the currently accepted "pre big bang" cosmology mandates vast amount of "parallel universes". And famous Physicist Lawrence Krauss discuss in explicit details in his fascinating book A Universe From Nothing how an entire universe could form literally from "nothing" - where "nothing" is described as unstable quantum form from which, statistically at least, an entire cosmos could arise.

Evolution, life and consciousness in Buddhist traditions:

For a brief overview of the modern ideas on consciousness, please click on the link (Some Random Thoughts on Consciousness) The Buddhist realm consists of three realms of existence – the desire realm, the form realm and the formless realm, each progressively subtler and higher levels of existence. The formless realm transcends physical sensations and lives in a purely mental realm. Human evolution in Buddhist philosophy is somewhat “anti Darwinian” – it suggests humans have “descended” from a higher level of life; from “formless celestial beings”.  This is of course very different from the “upwardly mobile” ideas accepted in science where humans have evolved from apes. Dalia Lama readily accepts the modern Darwinian rules of evolution, though he believes in some of the ancient ideas of Karma and the permeation of energy and consciousness throughout the cosmos, something that cannot be contained in a vessel or within a single body. He argues for additional forces other than “survival of the fittest” should have shaped evolution to explain emotions like love and altruism. At least in this section, His Holiness appear to wobble a bit, as clearly defined Darwinian rules of group selection and even anatomic features (like Mirror neurons) appear to explain these puzzles clearly. Unfortunately even Dalai Lama confuses Darwinian Theory with the much maligned social Darwinism, which has nothing to do with the scientific theory of evolution.

With regards to consciousness and the study of “qualia” or that indescribable “inner feelings”, Dalia Lama gives an excellent over view the Eastern ideas on this most elusive of subjects. He describe that the Tibetan word “Namshe” or Sanskrit “Vijnana” encompasses a much broader range of conscious experiences. Buddhist philosophy describes consciousness as “luminosity” and “cognizance” as the two features of consciousness. As the primary feature of light is to illuminate, so consciousness illuminate the objects. Buddhism suggest three fundamental aspects of the world – 1) Matter consisting of physical objects and energy 2) Mind – subjective experiences 3) Abstract composites or mental formations  like a theorem in Mathematics. Consciousness transcends both the realm of Mind as well as Abstract composites. This is surprisingly similar to the ideas of Karl Popper. 

He asks a very valid question on the nature of consciousness – that while we have known the levels of certain neuro transmitters like serotonin can affect our emotions, could it be also true that the “emotions” came first and changed the level of the neuro transmitter? He briefly also dwells in the controversial topic of quantum mechanics as an explanation of consciousness, including the “non locality” as described above in the EPR paradox and how the observer and observed could be part of a larger quantum system. He talks about the ideas of Buddhist thinker Dharmakirti, who argues that the rational basis of rebirth (that the consciousness comes from a prior instance of cognition, so the consciousness of the new born also must have existed prior to being born). Then he explores how meditative practices could change our consciousness (this is a well researched field with empirical evidence supporting the notion that meditative practice could indeed change our brain’s “wiring” as is shown in several experiments using functional MRI). He quotes the work of Nagarjuna “Praise to the Ultimate Expanse” which argues that essential nature of the mind is pure and the mind can undergo meditative purification from impure thoughts. The modern ideas of neuro plasticity (that new connections between neurons can be formed and brain is highly malleable even in adults) support many of these traditional Buddhist arguments.

In short, this is an unusual book written by an unusual and charismatic Religious leader. Even though the category of "science and spirituality" is a subject matter of many books, this book shines through for it's simplicity, humility and deeply spiritual writing, just as the author Himself. His Holiness, who appears to possess the inquisitiveness of a child while also deeply well read not only about classical Indian and Buddhist philosophy but also well versed in the language of modern science, shows science and spirituality can not only co exist but inform and strengthens each other. A must read for anyone interested in these timeless questions.

What time is it - Part 2

Please read Part 1 of this blog here: What time is it? Part 1

Time Dilation and Time Travel:

Einstein showed time is "relative" to the speed of the observer, and time can be “dilated” or "slowed" when something or some one is moving very fast – at relativistic velocities approaching speed of light "C" – through the spatial dimension. Another of Einstein's revolutionary idea was the force we call gravity is nothing but "distortions" in the fabric of space time created by massive objects and energy. Gravity in turn changes how time moves, just like how velocity along spatial dimension changes how time moves. A clock at lower gravity will tick faster than will a clock at higher gravity. In other words, if you live in a multi story apartment, time passes more quickly in the top floor penthouse apartment than it does in your basement apartment! The slowing is of such a minute quantity it would go un noticed and billions of years will have to pass before your clock will gain one extra second before your penthouse neighbour. However at conditions of extreme gravity, time indeed slows down significantly. The poster boys for extreme gravity are the Black Holes. What happens to time at the center of black holes? Well it actually comes to a standstill – just as a photon don’t perceive the passage of time, time also comes to an absolute standstill at the center of a black hole. 

Strange as it may be, but what is remarkable is that the so-called time dilation effects have been verified in a number of experiments, which used to depend on large scales of distance or velocity. However with exquisitely sensitive modern clocks, scientists are now able to document the extremely small time dilation that happens in ordinary situation. In a series of experiments described in the September 24, 2010, Science, researchers at the National Institute of Standards and Technology (NIST) registered differences in the passage of time between two high-precision optical atomic clocks when one was elevated by just a third of a meter or when one was set in motion at speeds of less than 10 meters per second!

Time travel is a favorite of ploy of fiction writers. But what does Einstein’s theory of general relativity says about time travel? As noted, the faster one moves in the space dimension, the slower the same person’s movement in the time dimension. So time travel to the future is quite feasible, theoretically at least – and the two ways to do this is either to travel very, very fast, or get inside an intense gravitational field. However to have a meaningful time travel to the future, the “fast” means travelling very close to the speed of light, or to be in a gravitational field so intense that can only be provided by a structure like a black hole. 

As an example, one could imagine an astronaut taking off from earth in an imaginary rocket that can travel at 99.995 % the speed of light in year 2015. Let us assume he travels at this speed to a star around 500 light years and then travel back to earth. Due to relativistic time dilation (see my blog How fast does Brahma moves? for details), as far as the astronaut is concerned, the whole trip would have lasted only 10 years! While for earth and earthlings, moving leisurely around the sun (at speeds far less than the speed of light), time would have moved on by 1000 years, and when the astronaut is back, 10 years older, earth year would be AD 3015! Again, though it may appear confusing – both the astronaut and earth has moved the same distance in “space time”. The difference is that while most of the astronaut’s movement was in the “space” dimension of space time, for earthlings, most of the movement occurred in the “time” dimension of space time. 

How about going backward in time? This is much harder, even theoretically. In fact Einstein’s special theory of relativity forbade both backward travel as well as travelling faster than speed of light. However Einstein’s general theory of relativity lifted this restriction. The first person to use general relativity to describe a universe that permits time travel into the past was Kurt Godel, one of the towering mathematicians of the 20th century. The story is that Godel presented this model universe (where time can move backwards) as a gift to Einstein on his 70th birthday. 

The universe Godel described is mathematically complex but accurate, and remains within the bounds of general relativity. These mathematical models or trajectories where time can "flow" backwards is called “closed time like curves.”

A closed time like curve is any path through space time that loops back on itself. In Godel’s model of a rotating cosmos, such a curve would circle around the entire universe, like a latitude line on Earth’s surface. Though it was mathematically accurate, Einstein did not like a universe where time could flow backwards – since if such a curve exists, it would question some our fundamental notions of causality as could be shown by the classic "Grandfather's paradox"“ (What happens to a time traveler who kills his or her grandfather before the grandfather meets the grandmother? Would the time traveler ever be born?)

Fortunately, there is no evidence universe actually has any “closed time like curves”. Godel might not have devised a realistic model of the universe, but he did prove that closed time like curves are completely consistent with the equations of general relativity. The laws of physics do not rule out traveling to the past.

A Universe that birth itself: 

Godel conjured an entire universe that allowed CTCs, but more recent interest is in warped space time within parts of our universe. As noted previously, according to general relativity, planets, stars, galaxies and other massive bodies warp space time. Warped space time, in turn,guides the motions of those massive bodies. Physicist John Wheeler put it succinctly, “Space time tells matter  how to move; matter tells space time how to curve.” In extreme cases, space time might bend enough to create a path from the present back to the past. Kip S. Thorne, a physicist at the California Institute of Technology, was the first to explore the possibility that a type of closed time like curve called a "wormhole" —a kind of tunnel joining two different locations in space time— might allow for time travel into the past. If we can connect two different regions of space, we are also connecting two different regions of time! (of note: Kip Thorne was deeply involved in the recent blockbuster movie “Interstellar” which explores these possibilities in a fictionalized way)

As correctly portrayed in the movie, the entrance into a wormhole would be spherical—a three dimensional entrance into a four dimensional tunnel in space time. However the theory predicts that, even for a traveler going through a wormhole, time flows forward at one second per second. It’s just that the traveller’s version of ‘forward’ might be globally out of sync with the rest of the universe.  Although physicists can write equations that describe wormholes and other closed time like curves, all the models have serious problems. For one thing, to get a wormhole in the first place, one need negative energy. Negative energy is when the energy in a volume of space spontaneously fluctuates to less than zero.  Without negative energy, a wormhole’s spherical entrance and four-dimensional tunnel would instantaneously implode. But a wormhole held open by negative energy “seems to be hard, probably impossible,” As per Sean Carroll. Moreover as the particles moving through a wormhole would loop back an infinite number of times, leading to an infinite amount of energy. And as energy deforms space time, the entire thing would collapse into a black hole—an infinitely dense point in space time.   Unlike black holes, which are a natural consequence of general relativity, wormholes and closed time like curves in general are completely artificial constructs— a way of testing the bounds of the theory. 

A recent publication (Can the Universe Create Itself? by Gott and Li) on the origin of universe argue that closed time like curves were not merely possible but essential to explain the origin of the universe.  They investigated the possibility of whether the universe could be its own mother— whether a time loop at the beginning of the universe would allow the universe to create itself! Gott and Li’s universe “starts” with a bout of inflation—just as in standard big bang cosmology, where an all-pervasive energy field drove the universe’s initial expansion. Many cosmologists now believe that inflation gave rise to countless other universes besides our own. “Inflation is very hard to stop once it gets started,” Gott says. “It makes an infinitely branching tree. We’re one of the branches. But you have to ask yourself, where did the trunk come from? Our theory suggest that one of the branches just loops around and grows up to be the trunk.” A simple two-dimensional sketch of Gott and Li’s self-starting universe looks like the number “6,” with the space time loop at the bottom and our present-era universe as the top stem. A burst of inflation, Gott and Li theorized, allowed the universe to escape from the time loop and expand into the cosmos we inhabit today. 

       Gott-Li Model of a Universe Giving birth to itself with Closed Time Like Curves                           (Note that each funnel like structure represent separate universes) 

It is difficult to contemplate the model, but its main appeal, Gott says, is that it eliminates the need for creating a universe out of nothing. (Note here that Stephen Hawking and Lawrence Krauss have proposed models in which the universe does indeed arise out of nothing. According to the laws of quantum mechanics, empty space is not really empty but is filled with “virtual” particles that spontaneously pop into and out of existence. Hawking and his colleagues theorized that the universe burst into being from the same quantum-vacuum stew). But in Gott’s view, the universe is not made out of nothing; it is made out of something—itself.

These wildly speculative ideas may be closer to philosophy than to physics. But for now, quantum mechanics and general relativity—powerful, counter intuitive theories—are all we have to figure out the universe.

Singularities and the End of time: 

Just like origins, we are equally fascinated by endings. In our experience, nothing really ends – when we die, our bodies decay and the material in them returns to the earth and the air, allowing for the creation of new life. But will that always be the case? Might there come a point sometime in the future when there is no “after”? Modern physics suggests the answer is yes. Time itself could end. All activity would cease, and there would be no renewal or recovery. The end of time would be the end of endings.

This scary prospect was also an unanticipated prediction of Einstein's general theory of relativity. Albert Einstein showed that time can slow down, or stretch out, or let it rip. Time not only affects what matter does but also responds to what matter is doing. But when time begins or ends we call them singularities. The term actually refers to any boundary of time, be it beginning or end. The best known is the big bang, the instant 13.7 billion years ago when our universe—and, with it, time—burst into existence and began expanding. If the universe ever stops expanding and starts contracting again, it will go into something like the big bang in reverse—the big crunch—and bring time crashing to a halt.

Time needn't perish everywhere. Relativity says it expires inside black holes while carrying on in the universe at large. It took physicists decades to accept that relativity theory would predict something so unsettling as end of time itself. To this day, they aren't quite sure what to make of it. Singularities are arguably the leading reason that physicists seek to create a unified theory of physics, which would merge Einstein's brainchild with quantum mechanics to create a quantum theory of gravity. They do so partly in the hope they might explain singularities away. Still, one need to be careful what you wish for. Time's end is hard to imagine, but time's not ending may be equally paradoxical.

To figure out what goes on will take a more encompassing theory, a quantum theory of gravity. Physicists are still working on such a theory, and they figure that it will incorporate the central insight of quantum mechanics: that matter, like light, has wavelike properties. These properties should smear the putative singularity into a small wad, rather than a point, and thereby banish the divide-by-zero error. If so, time may not, in fact, end.

Physicists argue it both ways. Some think time does end. The trouble with this option is that the known laws of physics operate within time and describe how things move and evolve. Time's end points are would have to be governed not just by a new law of physics but by a new type of law of physics, one that does not have temporal concepts such as motion and change in favor of timeless ones such as geometric elegance. One such notion comes from Brett McInnes of the National University of Singapore who used string theory to explain away the singularities. He suggested that the primordial wad of a universe had the shape of a torus; because of mathematical theorems concerning tori, it had to be perfectly uniform and smooth. Such a geometric law of physics differs from the usual dynamical laws in a crucial sense: it is not symmetrical in time. The end wouldn't just be the beginning played backward.

Other quantum gravity researchers think that time stretches on forever, with neither beginning nor end. In their view, the big bang was simply a dramatic transition in the eternal life of the universe. Perhaps the "pre bangian" universe started to undergo a big crunch and turned around when the density got too high—a big bounce. Artifacts of this prehistory may even have made it through to the present day.

By supposing that time marches on, proponents of this approach avoid the need to speculate about a new type of law of physics. Yet they, too, run into trouble. For instance, the universe gets steadily more disordered with time. If it has been around forever, why is it not in total disarray by now?

The bottom line is that physicists struggle with these questions no less than philosophers have. Faced with this dilemma, some people throw up their hands and conclude that science can never resolve whether time ends. It would seem that the boundaries of time are also the boundaries of reason and empirical observation. 

Is time continuous or granular (quantized)?

About 100 years ago, most people thought of matter as continuous. Although since ancient times some philosophers and scientists had speculated that if matter were broken up into small enough bits, it might turn out to be made up of very tiny atoms, few thought the existence of atoms could ever be proved. Today we have imaged individual atoms and have studied the particles that compose them. The granularity of matter is old news.

In recent decades physicists and mathematicians have asked if space is also made of discrete pieces. Is it continuous, as we learn in school, or is it more like a piece of cloth, woven out of individual fibers? If we could probe to size scales that were small enough, would we see “atoms” of space, irreducible pieces of volume that cannot be broken into anything smaller? And what about time: Does nature change continuously, or does the world evolve in a series of very tiny steps, acting more like a digital computer?

The past 25 years have seen great progress on these questions. A theory with the strange name of “loop quantum gravity” predicts that space and time are indeed made of discrete pieces. The picture revealed by calculations carried out within the framework of this theory is both simple and beautiful. The theory has deepened our understanding of puzzling phenomena having to do with black holes and the big bang. Best of all, it is possible that current experiments might be able to detect signals of the atomic structure of space-time—if this structure actually exists—in the near future.

Quanta of time

The theory of quantum mechanics was formulated in the first quarter of the 20th century, a development that was closely connected with the confirmation that matter is made of atoms. The equations of quantum mechanics require that certain quantities, such as the energy of an atom, can come only in specific, discrete units. Quantum theory successfully predicts the properties and behavior of atoms and the elementary particles and forces that compose them. No theory in the history of science has been more successful than quantum theory. It underlies our understanding of chemistry, atomic and subatomic physics, electronics and even biology.

Quantum theory and Einstein's general theory of relativity have each separately been fantastically well confirmed by experiment—but no experiment has explored the regime where both theories predict significant effects. The problem is that quantum effects are most prominent at small size scales, whereas general relativistic effects require large masses, so it takes extraordinary circumstances to combine both conditions.

Allied with this hole in the experimental data is a huge conceptual problem: Einstein's general theory of relativity is thoroughly classical, or nonquantum. For physics as a whole to be logically consistent, there has to be a theory that somehow unites quantum mechanics and general relativity. One of the candidates for this long-sought-after theory is called quantum gravity. Because general relativity deals in the geometry of space-time, a quantum theory of gravity will in addition be a quantum theory of space-time.

The theory of loop quantum gravity predicts that space is like atoms: there is a discrete set of numbers that the volume-measuring experiment can return. In other words, space is not continuous. It comes only in specific quantum units of area and volume. The possible values of volume and area are measured in units of a quantity called the Planck length. This length is related to the strength of gravity, the size of quanta and the speed of light. It measures the scale at which the geometry of space is no longer continuous. The Planck length is very small: 10⁻³³ centimeter. The smallest possible nonzero area is about a square Planck length, or 10⁻⁶⁶ cm2. The smallest nonzero volume is approximately a cubic Planck length, 10⁻⁹⁹ cm3. Thus, the theory predicts that there are about 10⁹⁹ "atoms of volume" in every cubic centimeter of space. The quantum of volume is so tiny that there are 10 million trillion more such quanta in a single cubic centimeter of space than there are atoms in the known universe (estimated to be 10⁸⁰!

In the space-time way of looking at things, a snapshot at a specific time is like a slice cutting across the space-time. But it would be wrong to think of such a slice as moving continuously, like a smooth flow of time. Instead, just as space is defined by discrete geometry, time is defined by the sequence of distinct moves that rearrange the spin network. Time flows not like a river but like the ticking of a clock, with “ticks” that are about as long as the Planck time: 5.4x10⁻⁴⁴ seconds. Or, more precisely, time in our universe flows by the ticking of innumerable clocks—in a sense, at every location in the spin foam where a quantum “move” takes place, a clock at that location has ticked once.

The arrow of time: 

How do we explain the arrow of time—the asymmetry of past and future. This appear one of the most common sense things to most people, that time should always move forward. However our fundamental laws of physic concerning space time are time invariant, meaning they could work equally well in both time moving forward as well as time moving back ward directions. One fundamental law that could explain the arrow of time – always moving to the future - is the second law of thermodynamics, which states that entropy, loosely defined as the amount of disorder within a system, increases with time. Yet no one can really account for the second law.

The leading explanation, put forward by 19th-century Austrian physicist Ludwig Boltzmann, is probabilistic. The basic idea is that there are more ways for a system to be disordered than to be ordered - this is our every day experience too, look at our children's room! If the system is fairly ordered now, it will probably be more disordered a moment from now. As Boltzmann recognized, the only way to ensure that entropy will increase into the future is if it starts off with a low value in the past. Thus, the second law is not so much a fundamental truth but related to events early in the big bang. The entropy or disorder of the very early universe at Big Bang had to be extremely small, so it could create an arrow of time. A common example to describe entropy is that we can break an egg easily, but “all the king’s men and all the king’s horses” can’t put the egg back as unbroken again. Big Bang was the cosmic egg that broke, and entropy has been increasing ever since, and this is what we perceive as the arrow of time.

Let me end my blog by quoting what Einstein himself thought of time, best summarized in a letter he wrote on the death of his beloved lifelong friend Michele Besso. (Especially poignant in that this was written only few weeks prior to Einstein’s own death)  

"...for us physicists belief in the separation between past, present, and future is only an illusion, although a persistent one." 
Dedication: I dedicate this blog to Moossa Koya sir, my Physics teacher from Pre Degree days, for instilling the love of physics in me with gratitude.
Suggested further reading:

1) My previous blog: How fast does Brahma moves?
2) A Brief History of Time: Stephen Hawking

3) From Eternity to Here: Sean Carroll

4) Origins: Cosmos, Earth and Mankind: Reeves, Rosnay, Simonnet and Coppense

5) The First Three Minutes: Steven Weinberg

6) A Universe from Nothing: Lawrence M. Krauss

7) The Meaning Of It All: Richard P. Feynman

8) The Accidental Universe: Alan Lighhtman

9) Time Reborn: Lee Smolin

10) Our Mathematical Universe: Max Tegmark

11) Cosmic Jackpot: Paul Davies