Tag Archive | "Physics"

Physics for the Soul


As the United States shuts down its eastern seaboard for Cyclone Sandy, the Philippines will be shutting down as well, for completely different reasons. November 1 marks All Saints’ Day, when many establishments close up, since most people head to cemeteries to gamble and eat among the remains of the dead.

What comes with the holiday is the belief that when our bodies cease to function, even after we are laid into the soil or burned to ash, something survives. We are not just bodies, supernaturalist believers claim. There is a ghost in this machine and it breaks free from its mortal shackles upon death.

Some people claim to see these surviving entities, these spirits or souls, dwelling among the living. Ghostly apparitions are reported with disturbing regularity. Disturbing, in that even in the age of ubiquitous photography, no one has ever gathered any credible support for these ectoplasmic assertions. The reality of disembodied souls would necessarily overturn everything we know about physics. Any scientist would be itching to find evidence for the supernatural—evidence that never seems to turn up, despite the most adamant and most confident protestations of believers.

Human visual perception works because of light, and light works through electromagnetism. Electromagnetic/light particles called photons travel at the speed limit of the universe. When they hit objects, the energy of the photons is absorbed by particles in the object (such as electrons). These particles then release some energy back as another photon. The energy of the photon released determines the color and intensity of the light humans perceive.

If ghosts (under which I include saintly apparitions) can be seen, that means ghosts interact with photons! Electromagnetism is a physical phenomenon. This implies that at least some aspects of ghosts are physical, and therefore investigable by the methods of science. What kinds of photons are these spirits carrying? Are they different from everyday photons?

When people claim to hear ghosts, either through spooky screams or through elaborate homilies about the current geopolitical situation, they are actually claiming that physical objects are being moved by supernatural events. The perception of hearing occurs when the pressure of the air around us is locally fluctuated. When people talk, their vocal folds vibrate and push around air molecules. The air then vibrates the eardrums of animals within earshot. These vibrations correspond to what we hear as sound. The case is similar for those who report interacting with apparitions through touch (except that objects apart from air molecules are being moved, such as a uterus).

The Earth rotates on its own axis at around 1,674.4 km/h. It revolves around the Sun at 108,000 km/h. We don’t even feel these exorbitant speeds because we are moving with the Earth. We move with the Earth because we are on it and its forces are acting on us without variation. Should the Earth suddenly change in speed, however, we would definitely feel a calamitous disturbance. The Earth is tumbling around our galaxy, which is itself moving with respect to the rest of the universe. Should the Earth’s motion stop, we’d fly off into space—like a tetherball released from its rope. For the most part, we can happily ignore that we are hurtling across space because we are physical objects that obey the laws of physics. It is curious, therefore, when even immaterial ghosts follow physical laws.

When people claim to see ghosts, nobody ever reports them appearing one moment then zipping out into space the next, left behind by the Earth’s motion. Rather, people claim to see them stay in place long enough to scare the bejesus out of them, or tell them about some magic water that would heal people. Again, ghosts are eerily physical in all convenient aspects.

Imagine now that you have died. Ignore the paradox that you could not do such imagining because that would be imagining that your imagination could not imagine any longer. For the sake of argument, let us say that souls do exist and you are one right now, formerly in control of a body, currently disembodied.

Where are you? What do you see? Let us suppose that even though you are supernatural, you have some sort of particles that interact electromagnetically. Can you blink? It would be odd to do so, seeing as your soul would need to have eyelids.

At what direction are you looking? When you had a body, your eyeballs would sense a local cone of vision. Now that you’re a ghost, do you see all of existence at once? If so, where in the world are you? Certainly not floating just above your corpse.

When you had a body, you used your vision (and other senses) to determine where you were. You were limited by the local area that could be perceived by your physical sense organs. Now that you are without a body, the question of ‘where’ becomes meaningless. If ghosts exist, then they must be everywhere. They cannot otherwise be.

If these ghosts cannot exist as they have been claimed to be, then it must be that they are wholly in the mind of those who see them. They don’t have photons bouncing off of them, they don’t fly through space, because they’re not in the outside world! They do not exist objectively. These disembodied souls are figments, like how optical illusions, while very convincing, do not really show moving objects.

Our brains are easily fooled into seeing things that do not exist. People who claim to see ghosts often truly believe that they have experienced such a thing. I do not believe that they are all liars (though some must be). However, even though their brush with the supernatural must have felt very real, that does not mean that it was anything more than a psychological episode. The human brain is so adept at pattern recognition that it sees patterns everywhere—from clouds to dog anuses. It is no surprise, then, that ghosts follow the patterns we are so familiar with and that they are so much like normal natural objects, except for that little difficulty of being able to show them to others.

The supernatural world is suspicious to the scientifically literate because it is too convenient. It looks exactly like the natural world except when it’s favorable not to be. It looks like bad science fiction. Ghosts can hover, but not be left behind by a moving Earth. Ghosts can pass through solid walls, but can affect air molecules to produce sound. Ghosts can be perceived but not leave behind any independently-verifiable traces.

Surely some scientist must have left from the spirit world by now to show all his skeptical journal-publishing colleagues that the supernatural does exist. And yet, no scientist has ever come back from the grave to do so. Instead, we have saints who supposedly cure comatose patients, almost 400 years removed.

The vastness of space and time is available to the dead, if we are to believe the claims of the religious. Despite that, what is regularly professed to be done from beyond the grave is so vapid that miraculous claims are barely worth a 30 second spot on the evening news. The deep incongruence between the scale of the universe and the parochial concerns of people betrays the very human imaginations that spawn these stories.

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Quantum Queries: Where Does The Higgs Boson Fit In?


Higgs Hoopla

Last 4th of July, scientists at the European Organization for Nuclear Research (also known as CERN  — don’t ask me why) made the announcement that they have detected a particle that could possibly be the long sought after Higgs boson.

As a non-hipster science fan, I find it heartwarming that a scientific discovery made in the French-Swiss underground scene is finally making it into the mainstream. However, I noticed that many people are at a loss when it comes to comprehending the excitement surrounding this Higgs thingy. After all, where in the big picture of science does this so-called “God particle” fit in?

[Photo credit: betabeat.com]

The Higgs boson is one of the few missing pieces of the Standard Model of particle physics. If the particle detected this week was indeed a Higgs boson, that’s +100 points for the Standard Model. The Standard Model is currently our best theory when it comes to explaining the behavior of our universe’s basic ingredients. Over past decades, it has been very successful at predicting how every known particle behaves and interacts.

If the universe is a stage, the Standard Model gives us the best insider story about the cast of characters and the role each character plays. Before we can describe what part the Higgs boson plays, we must first introduce the other members of the cast.

 

Enter the Leptons

The first members of the cast are the light leptons. There are six kinds of free-living leptons. The first three have charges, and they are called electrons, muons and tau particles. The next three don’t have charges, and they are called neutrinos. There are three kinds of neutrinos: electron neutrinos, muon neutrinos and tau neutrinos.

Electrons are part of the atoms that make up most of the material things we handle everyday. In fact, electrons are the first subatomic particles to be discovered. You can read this article on a computer screen only because humans have mastered the art of making electrons the way they want it to move.

An electron.

Muons are similar to electrons, only they are heavier and short-lived. Tau particles are even heavier and more short-lived! In particle physics jargon, we say that the electron is stable while the muon and tau particle are unstable. (Most people are, unfortunately, like muons in more ways than one.) It is because of their short lives that we do not meet muons and tau particles in our daily affairs.

A muon.

Neutrinos are very light and elusive particles. They are also neutrally charged, which means that they do not get repelled or attracted by other charges. In fact, they very seldom interact with other particles. This is why it took scientists a while before they finally detected them. In this regard, neutrinos are basically ninja particles!

Neutrino = ninja particle.

Their elusiveness aside, neutrinos are actually everywhere! Right this instant, there are billions upon billions of neutrinos whizzing through your body like bullets flying though mist. You are not feeling it precisely because neutrinos mostly ignore other particles and are ignored by other particles. In fact, they can pass through the Earth like the Earth is not there.

Neutrinos recently made the news when some scientists thought they found neutrinos traveling faster than the speed of light. It was later discovered that neutrinos don’t break the universe’s speed limit after all.

 

Six Quarks for Muster Mark

The next members of our cast of characters are the quarks. There are also six of them: the up, down, charm, strange, top, and bottom quarks (aaawww yeah).

The six quarks are grouped according to “generation”. The up and down quarks belong to the first generation, the charm and strange to the second, and the top and bottom to the third. Quarks in each generation are heavier than those in the previous generation.

What distinguishes the quarks from the leptons is the fact that we do not find free-living quarks. Quarks are always tightly glued to other quarks to form hadrons. When a hadron is composed of a quark and its anti-quark glued together, we call it a meson. Meanwhile, when a hadron is composed of a triad of quarks, we call it a baryon.

You have quadrillions of hadrons in you, and so is the computer screen you are staring at right now. Why? Because the nucleus of atoms are made of protons and neutrons, and protons and neutrons are hadrons. To be more specific, they are baryons; protons and neutrons are made of three quarks glued together very tightly. The proton is made of two up quarks and one down quark while the neutron is made of one up quark and two down quarks.

A proton composed of three quarks, two up quarks and one down quark.

 

The Large Hadron Collider (LHC) of CERN is so-called because it was designed to smash together hadrons at very high speed. And also because it’s very large, as far as lab equipment go – it is found in a more or less circular tunnel 27 kilometers in circumference!

 

May the Force Carriers be with You

There are four fundamental forces: gravity, electromagnetic, weak, and strong. According to the Standard Model, the three forces aside from gravity are mediated by particles called force carriers.

Photons are the force carriers of the electromagnetic force. Photons are massless particles that travel at the speed of light, which is not surprising given that photons are the particles of light; light is but a stream of photons. Photons are also responsible for making like charges repel and unlike charges to attract. This means that without photons, atoms won’t exist either, because photons are what keep the electron around the nucleus! Without photons, the universe will be a very dark place indeed.

A photon.

The force carriers of the strong force are called gluons, so-called because they form the “glue” that tightly binds quarks to form hadrons. Like photons, gluons are also massless. Without gluons, protons and neutrons won’t exist.

A gluon.

The weak force, on the other hand, is mediated by heavy force carriers called the W and Z bosons. These particles are around 80-90 times heavier than protons. The obesity of these force carriers is the reason why the weak force, unlike the electromagnetic force, has a very short range. The weak force can only act across distances smaller than an atom. But exotic as it may sound, the weak force is in fact very important to life on Earth. The weak force is responsible for some forms of radioactivity without which our Sun wouldn’t shine and the Earth’s interior wouldn’t be a dynamic fluid.

A W boson.

Of the three forces of the Standard Model, the weak is the weakest and the strong is the strongest (like duh). Compared to the electromagnetic force, the weak force is a trillion times weaker while the strong force is a hundred times stronger.

 

The Punch Line

The Standard Model makes many now well-confirmed predictions about the behavior of the particles that make up our world, but there’s a catch: it seems to say that all the particles of the model (the six leptons, six quarks and the force carriers) have to be massless. Except for photons and gluons, which are indeed massless, this is clearly not the case. This is a problem of the theory. And it’s a major one, too.

This is where the Higgs boson comes to the Standard Model’s rescue. Higgs bosons provide a mechanism that imbues some particles with mass. This happens because Higgs bosons, which are everywhere in the universe, “couple” with some particles and thus supply them mass. The stronger the coupling of the Higgs bosons with a certain particle, the more massive that particle becomes. (Unfortunately, for people who want to lose weight really quickly, changing how you couple with Higgs bosons is not an option.)

In a universe without Higgs bosons, the Standard Model predicts that all particles will be massless and they will all zip across space at the speed of light. Since we find ourselves living in a universe where only photons and gluons can travel at the speed of light, then either Higgs bosons exist or the Standard Model is wrong after all. The discovery of the Higgs boson is therefore a major triumph of the Standard Model.

Higgs boson.

 

In Search of a New Standard

To date, the Standard Model is one of two best theories about the universe. However, it still has a lot of problems. For one, it does not say anything about gravity. For another, it goes haywire when combined with the other theory we have of the universe, General Relativity.

Gravity is the weakest of the four fundamental forces; it is literally weaker than weak. In fact, it is weaker than the weak force by a factor of 10^25 or a thousand million quadrillions! That is why in the world of tiny particles, gravity is negligible. Another problem with gravity is that the Standard Model says nothing about it. But it is the force that keeps you anchored to the Earth, the force that keeps the planets tethered to the Sun, and the force that herds stars into galaxies and galaxies into clusters. Gravity, weak as it may be, is a force to be reckoned with.

Our best theory for gravity is Einstein’s General Relativity, which explains that gravity is the curvature of space and time. General Relativity has passed all experimental and observational tests with flying colors. It powerfully explains the behavior of the universe as a whole from its earliest stages up to the present. But it is not friends with the Standard Model, something that bothers physicists to no end. This is especially bothersome given that the origin of our universe, the moments approaching the Big Bang, is subject to both the laws of General Relativity and the Standard Model.

Another problem with the Standard Model is that it accounts for only 4% of the universe! As for the other 96%, it has nothing to say. In fact, the other 96% is so mysterious to us that we decided to simply call them “dark matter” and “dark energy,” which just goes to show that we know next to nothing about them, except that they exist. (IMHO, calling the other 96% “love” would have been apt.)

The universe pie.

 

The Search Goes On

Let us summarize what we have talked about. The Standard Model is our best theory about the composition of our universe. It tells us that the universe is composed of six leptons that can fly around freely (like electrons and neutrinos), six quarks that are always glued to other quarks (protons and neutrons are just quarks glued together), and force carriers that mediate the interactions between the other particles. But the Standard Model can only account for the mass of some of the particles if a particle known as the Higgs boson exists. If the particle detected last week was a Higgs boson, it would be a major triumph for the Standard Model.

However, it is apparent that the Standard Model cannot be the last say. It has its own problems, chief among these is that it cannot explain gravity, it is not compatible with our best theory explaining gravity, and it can account for only 4% of the universe. And so the search for the solution to the problem of existence has not ended. In fact, the discovery of the Higgs boson opens the door for more furious research; in other words, the search has only begun.

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Quantum Queries: Where’s Amber?


This is a continuation of the story of Amber the electron. Amber’s story is a very important one because it is also the story of physics, the study of the fundamental aspects of our universe. You may learn about the first part of this story by reading ‘Quantum Queries: Is Ours A Clockwork Universe?’

 

Down In Amber’s World

Last time, we saw that up here in the world of familiar objects — bouncing basketballs, falling apples, orbiting planets — the laws that govern our universe make it tick like clockwork. Down in the world of Amber the electron, things can seem very different. We must use a different set of rules to explain the behavior of Amber the electron and similarly small objects like protons, neutrinos, and positrons. These are the rules of quantum mechanics, and objects governed by these rules can be called “quantum objects”. Amber the electron is a quantum object.

Back to the questions that started this discussion: Where’s Amber? And how fast is she going? Where is she headed? There are two things we must know about Amber before we can reasonably answer these questions.

First, everything we can say about Amber is contained in what is known as her wave function. The wave function is represented by the Greek letter Ψ (psi). Basically, Ψ contains everything that we can say of Amber.

Second, Ψ can be determined using Schrödinger’s equation (named after the colorful German physicist Erwin Schrödinger).

Schrodinger’s equation

Schrödinger’s equation plays the same role in quantum mechanics as Newton’s Second Law does in classical mechanics. Recall that if we know the location and velocity of Bouncy the ball now, we can use Newton’s Second Law to determine his location and velocity at any other time. Likewise, if we know Amber’s wave function Ψ at any given moment, then we can use Schrödinger’s equation to determine Ψ at any later or earlier time. In other words, the way the wave function changes over time is also deterministic.

But wait, where is Amber? And how fast is she going? Where is she headed? Where will we find her at some later time?

To answer these questions, we now turn to the crux of the matter and possibly the source of all the weirdness of quantum mechanics. We turn to the meaning of the wave function, Ψ. What is Ψ anyway and what does it tell us about Amber’s whereabouts and howabouts?

Well, scientists have discovered that Amber’s wave function determines her probability density. Amber’s probability density gives us the likelihood of finding her in some place. To illustrate what this all means, let us use the well-known example of the hydrogen atom.

Suppose Amber is the electron of an atom of hydrogen. We can use Schrödinger’s equation to determine Amber’s wave function Ψ. Once we have determined Ψ, we can then use it to determine Amber’s probability density. In the context of atoms, the probability density of the electron is also called its electron cloud. Why is it called an electron cloud? Well, just take a look at the picture below.

One of Amber’s possible electron clouds. Chemists call this cloud the ‘1s orbital’. [Photo credit: cronodon.com]

The picture shows one of Amber’s possible probability densities, one of her potential electron clouds. (For those who remember their high school chemistry, the electron cloud shown above is what chemists call the ‘1s orbital’.) The darker regions represent regions in space where one is relatively likely to find Amber. Meanwhile, the lighter regions are the regions where finding her is relatively improbable. Notice how Amber’s probability density is diffused throughout space. That is why it’s called an electron cloud– like a cloud, it is not a firm, rigid structure but is instead spread out. Below are more possible electron clouds for Amber. (Chemists call them the 2p, 3p and 3d orbitals, respectively.)

Other possible electron clouds. Chemists call them the 2p, 3d and 3p orbitals, respectively. [Photo credit: cronodon.com]

So, does this mean that Amber is spread out? Well, let us check via experiment. Let us consider again the original electron cloud above. This time, we label some of the points in space. Let’s label them points A, B, C and D. Even before we perform the experiment to determine the whereabouts of Amber, we already know that Amber is more likely to be found in A than in B and less likely to be found in C than in D. Also, Amber is equally likely to be found in A as in D.

However, scientist found that after performing the experiment, they find Amber in a definite location. Say, you perform an experiment and find that Amber is in B. Two questions naturally arise. First, why in B and not A, where she was more likely to be found? Second, does the result imply that Amber was in B all along?

To answer the first question, we note that quantum mechanics is different from classical mechanics in being probabilistic instead of deterministic. In other words, quantum mechanics is about probabilities or likelihood. And in probabilities, an improbable event is still possible and can therefore happen, while a probable event does not have to occur. For example, when you throw a pair of dice, getting a 7 is a likely outcome while getting snake eyes is unlikely. However, when you throw a pair of dice, it is still possible, although unlikely, to get snake eyes instead of a 7. The probabilistic nature of quantum mechanics is what inspired Einstein to compare it to God playing dice with the universe.

Snake eyes: an unlikely but nonetheless possible outcome. [Photo credit: mobilecasino.ie]

Now it’s time to tackle the second and thornier question: If we perform an experiment to locate Amber and, as a result, find her in B, doesn’t that mean she was in B all along? There are three main answers to this question, and they represent the three main interpretations of quantum mechanics. They can be stated as follows:

  1. The realist position says that Amber was in B all along. However, quantum mechanics was not able to tell us this. After all, quantum mechanics says that everything that can be said of Amber is already in Ψ. However, Ψ did not really tell us where we will find Amber, it merely gave us probabilities. Quantum mechanics is therefore incomplete – it does not give us a complete picture of reality. People subscribing to the realist position believe we need to discover what are known as hidden variables. Once these hidden variables are discovered, we can determine that Amber was indeed in B all this time.
  1. The Copenhagen interpretation says that before the experiment, Amber was not in B, nor was she in A, C, D or in some other location. This interpretation tells us that her wave function gives us all we can know about her. This has a very interesting implication: if Amber was not in any place before the search, and was found to be somewhere after the search, that means that the act of looking for her somehow forced her to be somewhere! In the case of our example, that somewhere simply happened to be B, but it could have been A, C, D or some other location.
  1. The agnostic position is to be silent about the whole matter. After all, who are we to say where Amber was before we actually searched for her? And it doesn’t matter whether you take the realist or Copenhagen interpretations because the equations of quantum mechanics give you the correct probabilities anyway.

After decades of furious research, many working physicists find themselves subscribing to the Copenhagen interpretation. (The Copenhagen interpretation got its name from the city of Niels Bohr, one of its main proponents.) And, surprisingly, the agnostic position is already eliminated by a relatively recently discovered theorem known as Bell’s theorem. Bell’s theorem basically says that it does make an observable difference whether Amber was in B all along or whether she was nowhere.  Also, very few working scientists are still hoping to find the hidden variables required by the realist position.

There are, in fact, other interpretations of quantum mechanics currently being considered by scientists. One of the more interesting of them is the many worlds interpretation.

  1. The many worlds interpretation (MWI) says that all possible outcomes (finding Amber in A, B, C, D and all other possible locations) actually happen, but in different worlds! According to the MWI, what is objectively true is the Universe (with a capital U); it is where you find Amber’s electron cloud. When you try to look for Amber, the many worlds of the Universe decohere; that is, they get distinguished from each other. In one of those worlds, you find Amber in B, and in that world, she was in B all along. In another of those worlds, you find her in A, and in that world, she was in A even before you searched for her. And so it goes for the other possible outcomes (finding Amber in C, D, ect.).

Schrödinger’s cat in the many worlds interpretation.

If you are starting to find Amber’s world weird, know that this is only the tip of the iceberg. The world of Amber and her fellow quantum particles is governed by randomness. It is the opposite of the clockwork universe of classical physics.

 

Quantum vs. Classical

Now, one might think it strange that there are different rules governing the universe at different scales, classical mechanics for big things and quantum mechanics for very small things. How does one decide how big is big, anyway? Or how small should a thing be for it to be ruled by quantum mechanics? The truth is, according to the best scientific evidence we currently have, quantum mechanics governs the behavior of everything. Even Bouncy the basketball is governed by quantum mechanics! After all, Bouncy is also made of electrons, protons and neutrons, which are all quantum objects. Everything around us is made of quantum objects! However, for objects the size of Bouncy, classical mechanics is a good enough approximation. In fact, it is a superb approximation, to the point that we could use classical mechanics to predict Bouncy’s behavior without fear of being wrong. In other words, classical mechanics is an excellent estimate of quantum mechanics that is appropriate in the world of everyday objects. In the scale of things we see and touch, the weirdness that quantum mechanics displays on the small scale disappears.

Given these statements, this article is therefore about the fundamental rules that govern the behavior of everything around and within us. Ours is a quantum universe, and God does indeed throw dice on us all.

God throwing dice with the universe. [Photo credit: zendope.com]

Up Next on Quantum Queries:

  • What is the deal with Schrödinger’s cat?
  • What is Heisenberg’s uncertainty principle all about?
  • What is a ‘quantum’ of anything?
  • Why did Einstein find quantum mechanics so repulsive?
  • What is tunneling and how will it render Moore’s law obsolete?
  • What is entanglement and how is it related to teleportation?
  • Can we test the truth of the many worlds interpretation?

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Quantum Queries: Is Ours A Clockwork Universe?


Quelling Quantum Quackery

Along with ‘energy’ and ‘vibration’, the word ‘quantum’ is one of those scientific terms most dear to charlatans. Furthermore, quantum mechanics itself is home to terms and concepts that are easy target to quacks who like to sound scientific. Here’s a sampler of commonly abused words and concepts: entanglement, coherence and decoherence, the uncertainty principle, the many worlds, Schrödinger’s cat, action-at-a-distance, and quantum teleportation.

The ease at which impostors can abuse the terms and concepts of quantum mechanics cannot be blamed on one thing only. However, there is one factor that looms above the rest, and this is the lack of public understanding of quantum mechanics. In fact, one could say that it is a lack of understanding of physics, or worse, the lack of understanding of science as a whole!

This  is why I have decided to start the series ‘Quantum Queries’.  Through this series of articles, I would like to introduce the uninitiated but interested netizen to the amazing world of quantum mechanics. In this series we would tackle — in a way that I hope is entertaining and enlightening — some of the most vexing questions that surround the workings of the world around us. Below is a sample of some of the quantum queries that we will try to answer in this series:

  • What is the deal with Schrödinger’s cat?
  • What is Heisenberg’s uncertainty principle all about?
  • Is the many worlds theory true? And if it is, where are all these other worlds?
  • What is quantum entanglement? And can it really be used for teleportation?

My hope is that this series will give its readers the skill to discriminate between genuine quantum physics and quantum baloney. What follows is the first article in this series. Enjoy!

 

The Quantum and the Classical

Meet Amber. She is an electron. Amber masses 9.11×10-31 kilograms, a mass that makes “featherweight” sound really heavy. (Amber’s mass in decimal form is 0.000000000000000000000000000911 grams!)

Where’s Amber? Also, how fast is she going and where is she headed? Where can we find her later?

Well, answering these questions is not as easy as it sounds. This is because Amber’s behavior is governed by the rules of quantum mechanics, which are quite different from the rules that govern the behavior of familiar objects like falling apples, swinging pendulums or flying cannon balls. The objects familiar to us through everyday experience are governed by the rules of classical mechanics, discovered in the 17th century by Galileo Galilei and Isaac Newton.

How different are the rules governing Amber’s behavior from the rules governing the behavior of, say, a basketball? And where in the world is Amber? To answer these and related questions, let us first review the physics behind the behavior of everyday objects. Let us begin with the classics.

 

Back to the Classics

Meet Bouncy the basketball. Bouncy masses 145 grams. Scientists have discovered that they can describe Bouncy’s behavior using the rules of classical mechanics. When you hear physicists say, “Bouncy behaves classically,” this is what they mean.

So, where’s Bouncy? Also, how fast is he going and where is he headed? There are two things about Bouncy that are relevant in answering these questions. 

First, classical mechanics tells us that at any given moment, we can narrow down the range of Bouncy’s possible locations and speed as much as we want. For instance, it is possible that you at first only know that Bouncy is within Quezon Cityand has a speed somewhere between 1 kph and 4 kph. However, you can always find a way to narrow these ranges so that, after some investigation, you know that Bouncy is in the basketball court of the Araneta Coliseum and is going somewhere between 1.5 kph and 2.5 kph. Finally, it is possible that further investigation will lead you to conclude that Bouncy is, in fact, in the hands of PBA point guard LA Tenorio, and has a speed of 2.00 kph directed 45° from the horizontal. No one could blame you if you say that you have determined exactly where and how fast Bouncy was at that moment – there is practically zero uncertainty in Bouncy’s location and velocity. If you’re wondering how you could’ve known where and how fast bouncy was at a given moment, just imagine watching a replay of a PBA game. By analyzing the video, you can determine Bouncy’s location and velocity at any moment during the game. (For those who forgot their high school physics, velocity is just speed plus the direction.)

Second, classical mechanics allows us to predict where and how fast Bouncy will be at some later time. You can do this by using Bouncy’s classical equation of motion. An equation of motion is an equation that describes, well, the motion of an object. In classical mechanics, the equation of motion, also known as Newton’s Second Law, can be written as follows:

Newton’s Second Law.

So let’s review what’s been said of Bouncy so far. First, we can be more or less certain of Bouncy’s location and velocity at any given moment. Second, if we know Bouncy’s location and velocity now, then we can use Newton’s Second Law to know his location and velocity in the future.

For example, consider the case where LA Tenorio is attempting a shot and Bouncy leaves his hands at the speed of 2.00 kph, projected at an angle of 45°.

Calculations using Newton’s Second Law will allow you to predict, up to a very high precision, where and how fast Bouncy will be after he leaves Tenorio’s hand. This means that you can forecast whether or not Tenorio will make the shot. Of course you can only do it if you are very fast in calculating. A supercomputer watching the basketball game could perform such überfast computation.

Since it is possible to determine and predict the precise location and velocity of everyday objects like Bouncy, classical mechanics is described as deterministic. Note that classical mechanics does not limit you to calculating Bouncy’s future location and velocity; you can also calculate Bouncy’s previous location and velocity. In other words, if you have enough computing capacity and knowledge of the present situation, you can know the location and velocity of classical objects like Bouncy for all time in the history of the universe!

The path of angry birds are classically predetermined. [Photo credit: pamobriensblog.files.wordpress.com]

But the following question will naturally arise in the curious reader’s head: How do we know thatNewton’s Second Law is to be trusted? How do we know that the whole of classical mechanics is correct? As always in science, the ultimate test of correctness is agreement with observation. And hundreds of years of observation have confirmed the accuracy of classical mechanics in describing the behavior of objects ranging from basketballs, cannonballs, and rockets to things the size of planets and stars.

In fact, for centuries the planets and stars themselves became the paragons of Newtonian physics’ sober splendor. The astounding predictability of the dance of the planets made the image of a clockwork universe indelible in the minds of generations of scientists.

A grand orrery: a picture of the clockwork universe. [Photo credit: abyss.uoregon.edu]

One cannot therefore blame scientists for initially thinking that electrons like Amber will also behave like Bouncy and other classical objects, and that the universe will appear to tick like a grandfather clock at all scales. However, the shocking discoveries of the early 20th century revealed to us that in the strange world of Amber and her fellow quantum objects, the clockwork dreams of classical physicists are regularly blown to smithereens.

 

Up Next on Quantum Queries:

  • So, where is Amber?
  • What is Heisenberg’s uncertainty principle all about?
  • What is the wave function?
  • What does the many worlds theory tell us about our Universe?

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What In The World is Laser? (Part 3 of 3)


PART 3

[The author would like to thank the geniuses behind the new Microsoft Paint for making the figures in this part possible.]

How are laser beams produced?

Laser beams are the product of stimulated emission of light. But what is stimulated emission of light? Before we can answer this question, we must first discuss how matter interacts with light.

 

Light absorption

Matter and light interact in two ways: matter can absorb light or it can emit light. When an atom absorbs a photon of light (a photon of light is a quantum of light energy), it takes the energy of that photon and one of its electrons become excited (although not sexually). An electron orbits the nucleus of an atom in one of the possible orbits. Larger orbits (orbits that take the electron farther from the atom) have greater energy. Normally, an electron will orbit the nucleus in the smallest possible orbit. This orbit is called the ground state. When an electron gets excited, it jumps from the ground state to an orbit with a higher energy. Such an orbit is called an “excited state”. An electron is excited when it is on one of the excited states. The excitation of an electron (represented by the symbol e) by a photon is illustrated by Figure 1 below.

 

Figure 1. A photon of light (red oval with wave inside) is absorbed by an atom, resulting in the excitation of one of its electrons (e-, gray dot).

 

The ground state and one excited state shown in Figure 1 are just two of the many possible orbits of an electron around the nucleus. From quantum mechanics we know that the possible orbits are quantized. The quantization of electron orbits is important, so let us stray a bit from the main topic to discuss it.

Using the most important equation of quantum mechanics, Schrodinger’s equation, physicist were able to discover that in a given atom, the electron can only have a certain set of energies. This set of energies is called the spectrum of the atom. The possible energies are denoted by E0, E1, E2, E3 and so on. E0 is the smallest energy that an electron can possibly have. This is called the ground state energy. Obviously, this is the energy of an electron when it is in the ground state. (Recall that ground state is the smallest possible orbit.) E1 is the energy of the first excited state, E2 the energy of the second excited state, and so on. The energy of a higher excited state is always greater than the energy of the excited states before it. In other words, E0 is less than E1, which in turn is less than E2, which again in turn is less than E3 and so on. (E0 < E1 < E2 < E3 < …)  Now, here’s the most important bit. An electron in an atom cannot have energy between E0 and E1. It is simply impossible for an electron to have energy greater than E0 but less than E1. Also, an electron can never have energy between E1 ­and E2, or between E2 and E3, and so on. The set {E0, E1, E2, E3, …} gives the only possible energies of the electron.

Now we go back to absorption. Consider an electron initially in the ground state, so that its energy is initially E0. Suppose then that a photon of light having energy Ephoton hits the electron. This photon will be absorbed by the atom and its energy will then be added to the original energy of the electron. The new energy of the electron after absorbing the photon will therefore be:

 

Enew = E0 + Ephoton.

 

But take note of this very important fact: Enew must be one of the allowed energies of the electron. That is, Enew must be one of the following: E1, E2, E3 and so on. This means that if the energy of the photon, Ephoton­, is such that Enew is not one of the allowed energies of the electron, then the photon will be totally ignored – the atom will not absorb it. An atom will absorb a photon only if it will make Enew be one of the allowed energies of the electron.

Figure 2 below illustrates a particular example. The red photon is ignored by the electron because its energy is not enough to make the electron jump to the first energy level. The purple photon, however, was absorbed, because its energy is just right to make the electron jump from the ground state (where energy is E0) to the first excited state (where energy is E1). In other words, the sum of the red photon’s energy and the ground state energy (Ered + E0) is not equal an allowed energy level, so electron ignores the photon completely. On the other hand, the sum of the energy of the purple photon and the ground state energy (Epurple + E0) is exactly equal to E1. Since E1 is an allowed energy, the electron will absorb the purple photon.

Figure 2. (a) A red photon is ignored since the sum of its energy (Ered) and E0 is not equal to an allowed energy. (b) A purple photon is absorbed since the sum of its energy Epurple and E0 is exactly equal to E1, which is an allowed energy.


Spontaneous Emission

 

The emission of light is just the inverse process of the absorption of light. Here, an electron in a certain energy level (that is, a certain excited state) falls down to a lower energy level (a lower excited state or the ground state). When an electron falls down to a lower energy level, we say that it “relaxes”.

Relaxation is just the inverse process of excitation. (Although this is only true for electrons. In humans, it’s certainly not the case.) When an electron relaxes, it loses energy. The energy lost is of course equal to the difference between the original energy and the new energy. This lost energy becomes the energy of an emitted photon. For example, consider an electron initially in the first excited state. This means that its initial energy is E1. Suppose that this electron relaxes to the ground state, so that its final energy is E0. It is not difficult to see that this electron lost energy, and that the lost energy amounts to E1E0. This energy becomes the energy of the emitted photon.

 

Figure 3. An atom spontaneously emits a photon of light. The energy of the photon is equal to the energy lost by the electron: E1 – E0

 

Of course, an electron does not have to come from the first excited state. It may come from the second excited state, or form the third excited state, and so on. The higher the electron falls, the greater the energy of the photon it emits.

The situation shown on Figure 3, however, is just one type of emission called spontaneous emission (which does not have to be nocturnal). This is called so because the atom spontaneously emits a photon of light. Most light sources we know produce light by spontaneous emission. In a fluorescent light bulb, for example, electricity is used to excite the electrons of the atoms of a gas (usually the gas is mercury vapor). But the excitations are only momentary, because the electrons spontaneously jump back to the ground state and in the process emit photons of light. (These photons of light, however, are not what we “see” when we look at a fluorescent lamp. The photons produced in the said process have wavelengths in the ultraviolet region. This means that they are invisible to the human eyes. These invisible ultraviolet photons, however, cause the phosphorescent compound coating the inner lining of the lamp to glow. The phosphorescent compound is the white powder that is found inside the bulb.)

Laser beams, however, are not produced by spontaneous emission of light but rather by stimulated emission of light, hence the phrase “stimulated emission of radiation”. The very suggestive and juicy term stimulated emission describes the phenomenon where an atom emits light due to the stimulation of another photon. Basically, stimulated emission is just like spontaneous emission, only that it is not spontaneous.

 

Why Stimulated Emission is Amazing

Stimulated emission has the following remarkable property: when a photon stimulates an atom to emit another photon of light, the emitted photon will have the same wavelength, phase, polarization and direction as the original photon. In short, the emitted photon is just a Doppelganger of the photon that stimulated its emission!

 

Figure 4. A photon stimulates an atom with an electron in the excited state to release another photon. The emitted photon has the same wavelength, phase, polarization and direction as the original. One can think of it s a “clone” of the original.

 

We can now see that when one has enough atoms with electrons in the excited states, then one can use stimulated emission to greatly increase the intensity of a certain light. This is because light intensity can also be measured through the number of photons in a given beam. The more photons there are, the greater the intensity. But notice that stimulated emission has the ability to practically double the number of photons of the given light source. This is illustrated in Figure 5 below, where three atoms with excited electrons are used to double the number of photons from three to six. This is where the “light amplification” part of LASER comes from. (Recall that laser means “light amplification via stimulated emission of radiation”.)

 

Figure 5. There are initially three excited atoms and three photons. Due to stimulated emission of radiation, the number of photons has been doubled from three to six. After emission, the electrons of the atoms are already in the ground state.

 

But the light is not merely amplified by stimulated emission. The beam produced due to stimulated emission has the remarkable property of being composed to photons with the same wavelength (and therefore color), phase, polarization and direction. This is the reason why laser beams are highly monochromatic and coherent. Remember that to be monochromatic means to be composed of only one color. Since a laser is practically composed of an army of photon clones, a laser beam is very monochromatic indeed. Also, since the emitted photons have the same phase (which can be thought of as the tempo or vibration rhythm of the photon), polarization and direction, a laser beam has very high spatial and temporal coherence. In short, all the remarkable properties of laser beams are derived from a very remarkable property of stimulated emission!

 

Laser Devices

 

But now I hear the result-oriented and practically-minded among you say: “But how do we prepare a collection of atoms with excited electrons? Does this not mean that we also need photons to excite these electrons? And does this not mean that we are cancelling the amplifying effect of stimulated emission because we will be using photons to double the number of photons? Isn’t it like investing 500 pesos to gain 500 pesos?” Well, the answer is that light absorption is not the only way to excite electrons. There are many other ways to cause electrons to become excited, like hitting them with electricity or heating to very high temperatures them. There are many different kinds of lasers and each kind uses a different strategy to prepare atoms with excited electrons. But once such atoms are prepared, stimulated emission can then be exploited to double the number of photons from a certain light source, thereby increasing the intensity of the light.

In fact, in laser devices, the number of photons is not merely doubled, but is increased by several orders of magnitude. This is done by placing the gain medium in an optical resonator, as shown in Figure 6 below. The gain medium is the material that is used to amplify light. An optical resonator is a combination of two mirrors that make light bounce back and forth between them. One of these mirrors is a totally reflective mirror, while the other is a partially reflective and mirror. The partially reflective mirror allows some of the laser beam to pass while it reflects the rest. The beam that is reflected back can again stimulate even more atoms with excited electrons to emit photons. When it reaches the other end, it will be reflected by the totally reflecting mirror, and will then pass through the gain medium again, before reaching the partially reflecting mirror, where the cycle begins again. Notice, however, that once an atom is stimulated to emit radiation, its electron has already relaxed to the ground state. This means that after several rounds of stimulated emission, all the atoms will have ground state electrons only. So that the production of the beam is continuous, a “pumping energy” must be supplied to the gain medium constantly so that the atoms of the gain medium always have excited electrons.

 

Figure 6. A simple schematic of a generic laser device.

 

Summary

 

Now let us sum up all that we have discussed in this series. We started this series with a question: What in the world is laser? Well, laser is short for Light Amplification via Stimulated Emission of Radiation. A laser device is a device that produces laser beams via a phenomenon known as stimulated emission. Because of the remarkable properties of stimulated emission, laser beams have the extraordinary property of being monochromatic and coherent. By saying that it is monochromatic, we mean that it only has one wavelength. By saying that it is coherent, we are saying that its photons are oscillating or vibrating “to the same rhythm and beat”.

Now I hear the astute ones among you say, “Wait a minute, I see an inconsistency here. One minute you describe light as being made up of waves; electromagnetic waves, to be precise. But now you are describing them using particle-like entities called photons. What really is light made of, electromagnetic waves or photons?” This is a very good question, and it has a very remarkable answer: Light is made both of electromagnetic waves and photons. But how is that possible?

Now that is a topic for a separate series.

 

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What In The World is Laser? (Part 2 of 3)


PART 2

 

What do we mean by “highly coherent, usually monochromatic beam of electromagnetic waves”?

 

For the sake of brevity, from now on we will use the word ‘light’ to denote not only visible light (electromagnetic waves our eyes can see) but electromagnetic waves in general. That is, when we say ‘light’ we mean electromagnetic waves, including radio waves, gamma rays and ultraviolet.

Now, a monochromatic ray of light is one in which the waves have the same wavelength or frequency. (The word ‘monochromatic’ came from the Greek words mono, meaning one, and chromos, meaning color.) A ray of white light is not monochromatic since it consists of waves of different wavelengths. In other words, white light is made up of light of different colors. On the other hand, the light emitted by a colored light emitting diode (LED) is usually monochromatic. A blue LED emits only blue light.

The fact that laser beams are highly monochromatic finds use in many scientific and engineering applications, such as spectroscopy. In spectroscopy, laser beams with a very specific wavelength are sent through a sample to be analyzed.

The next important property of laser beams is their high coherence. (What is certain is that they more coherent than the CBCP or the Vatican.) In the language of wave physics, coherence is the property of having waves that oscillate in phase of each other. Coherence comes in two kinds, temporal coherence (coherence in time) and spatial coherence (coherence in space).

Temporal coherence (coherence in time) would be best explained by an analogy in dance: for two dancers to be able dance the tango well, their stepping must have the same tempo. In other words, dancers performing a ballroom dance must have temporally coherent foot movements.

Temporal coherence is very closely related to monochromaticity. In fact, temporal coherence is used to measure monochromaticity. Another important aspect of temporal coherence is uniform polarization. This gives laser beams their characteristic ‘glare’, which makes them dangerous to the eyes. Sometimes, the glare of laser beams is used by the police or the military to disorient a pursued individual or an enemy.

Spatial coherence, on the other hand, means that a ray of laser light can be focused to a very narrow beam, often called a “pencil beam”. In other words, laser light can be focused to a very small spot. This makes laser beams ideal for applications that require great precision, like reading digital information encoded in a CD, cutting intricate patterns into metal or wood, burning away tumors without destroying neighboring healthy cells, or correcting vision problems without further damaging the patient’s eyesight. In microscopy, lasers are used to obtain blur-free images of very small objects at various depths, and this is possible because laser beams can be very narrow. And do not forget the use of lasers in increasing the chance of a headshot.

 

 

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Spatial coherence is also the reason why lasers have high intensity. To understand why, it is important to know what intensity is in physics. Intensity is defined as the power distributed over a given area. In equation form,

Here, power is the energy delivered by a source of light per second. The more energy a source is releasing in a second, the more power it delivers. Power is measured in watts (W). We are all familiar with the fact that different household appliances have different “power ratings”. The higher the power rating of an appliance, the more energy it delivers per second. In the case of light bulbs, a light bulb with greater power rating delivers more light energy per second than another light bulb with a lower power rating. For example, the light energy released per second by 20-W light bulb is two times more than the light energy released by a 10-W light bulb.

But notice that intensity is power over area. If power is distributed over a large area, then the intensity will be low. For this reason, the intensity of light from a normal light bulb dies down quickly as one go away from the source. In a normal light source, light energy is distributed over an area that becomes larger as one goes farther from the source. On the other hand, because of the spatial coherence of light emitted by lasers, the light energy they emit is concentrated in a very small area. This results in a very high intensity beam. The difference between a normal light bulb and a laser is illustrated by Figure 2 below. Figure 2a depicts the light emitted by a normal light source (like the light bulbs used at home). Figure 2b depicts the light emitted by a laser.

 

 

Because laser beams are composed of light rays that are concentrated in a very tiny area, they have very great intensity. Any Star Wars fan knows this; in the hands of an evil Empire, the high intensity of lasers can be used to wipe out whole races and destroy entire planets in a single colorful display of lights (all while orchestra music plays in the background, of course).

Back to the real world, the great intensity of laser beams finds countless industrial applications such as in laser cutting, laser wielding, laser brazing, laser melting and laser bending.

As with almost all technologies, the limits of laser technology depend only in the imagination of the engineer. In the hands of a very creating engineer (hopefully not an engineer of the Empire), the applications of lasers is limitless. Other current laser applications are laser ranging (using lasers to measure great distances), pollution monitoring, therapeutic skin treatments, holography, and nuclear fusion (where lasers are used to compress a nuclear fuel tight enough to cause a fusion).

And can you still imagine using a ball mouse? I can’t. So in summary: lasers rule!

We are now ready to address the last question: how are such beams of electromagnetic radiation produced in the first place? In the last part of this series we will see how.

 

 

Figure 3. A test sample bursts into flames as a laser beam (here invisible to the naked eye) hits it.

 

PART 3: How are laser beams produced?

 

 

 

References:

[1] Hitz, Ewing and Hecht, Introduction to Laser Technology, 3rd ed. IEEE Press, 1998.

[2] Griffiths, Introduction to Electrodynamics. Prentice-Hall, 1999.

[3] Harris, Nonclassical Physics. Addison-Wesley, 1999.

[4] www.knowledgerush.com

 

 

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What In The World is Laser? (Part 1 of 3)


What in the world is laser?


PART 1

 

[Disclaimer: The author does not own Figures 1-4, nor does he own Yoda, although he certainly wishes that he does.]

 

We use them to point at things in a slide presentation; snipers use them to point at heads ready to be shot. They make cool technologies possible, from CDs and grocery store barcode scanners to metal cutters. We often hear that they can cause blindness, but we also know that they are used in surgical methods to correct many vision problems. In science fiction movies they shoot out of space ships, one can engage in duels using swords made of them, and there are ships which can destroy entire planets using them. Laser beams — they are both boon and bane. But what in the world are they?

 

Laser, what in the world is, hmmm?

 

What in the world is laser?

 

The word laser stands for Light Amplification through the Stimulated Emission of Radiation. Originally, ‘laser’ is a term for the light emission mechanism that produces a beam of laser light (a laser beam).  Today, however, ‘laser’ is used to denote devices that use the said mechanism to amplify light via stimulated emission of radiation.

Now, a laser beam is a beam of highly coherent, often monochromatic electromagnetic waves. Laser beams are produced when stimulation emission of electromagnetic waves amplifies light. If you think that these are quite a mouthful, then grieve not, for in this series we will explain what they mean.

 

But what is an electromagnetic wave?

 

An electromagnetic wave is an oscillation or vibration in the electromagnetic field in a certain region of space. All the colors of the rainbow our eyes can see are electromagnetic waves of different wavelengths. Among the colors of the rainbow, red has the longest wavelength while violet has the shortest. All the other colors have wavelengths between that of red and violet. The closer to red a color is the longer its wavelength, while the closer a color is to violet the shorter its wavelength. White light is the result of the combination of all the colors of the rainbow.

But the colors of the rainbow (or of the LGTB flag) comprise only a sliver of a segment in the electromagnetic spectrum. The electromagnetic spectrum is the continuum of all possible wavelengths (or frequencies) of electromagnetic waves, and the segment of the electromagnetic spectrum comprising the wavelengths visible to our eyes is called the visible light region. Other kinds of electromagnetic waves are invisible to our eyes, such as infrared rays, which have wavelengths longer than those of red light, and ultraviolet rays, which have wavelengths shorter than those of violet light. Radio waves, the kinds of electromagnetic waves we use to transmit radio signals, have wavelengths even longer than those of infrared light. X-rays and gamma rays, on the other hand, have wavelengths shorter than those of ultraviolet rays. (We can also describe electromagnetic waves using their frequency. Frequency is the inverse of wavelength, so that as wavelength becomes longer frequency decreases, and as frequency increases wavelength becomes shorter.)

 

Figure 1. The electromagnetic spectrum.

But what is an electromagnetic field?

Let us start with electric fields and magnetic fields. An electric field is a force field created by a charged particle (such as an electron or an ion) or by an object with an excess of charged particles. A magnetic field, on the other hand, is a force field created by a piece of magnetic material (such as a bar magnet) or by a steady electric current. The electric field is a vector field specifying the electric force that will be experienced by a particle of unit charge if it were located at a specified point in space, while the magnetic field is a vector field specifying the magnetic force that will be experienced by a unit current if it were located at a specified point in space.

In the early 19th century, Michel Faraday (an English chap who had nothing better to do but study current-carrying wires and magnets) discovered that a changing magnetic field also creates an electric field. Then in the latter part of the same century, James Clerk Maxwell (another English chap who had nothing better to do than to make mathematical models out of other scientists’ observations) discovered that if the law of the conservation of charges is to be valid, then a changing electric field must also create a magnetic field. This latter discovery by Maxwell led to the famous Maxwell’s equations. It is hard to overstate the importance of Maxwell’s equations. The four equations of Maxwell are among the most important, if not the most important equations of physics.

One profound implication of Maxwell’s equations is that electricity and magnetism turn out to be two facets of the same phenomenon; this phenomenon is known electromagnetism. Because of Maxwell’s discovery, we know that an electric field and a magnetic field are just different manifestations of the same field, the electromagnetic field.

Another equally profound implication of Maxwell’s equations is that visible light is an electromagnetic wave. In short, light is just a vibration in the electromagnetic field in a certain region in space! This realization led to the discovery that there are a host of other electromagnetic waves, all of them invisible to the human eyes. As mentioned, the radio waves we use to transmit radio signals and the X-rays we use in medicine are, like the LGTB flag, just dancing electromagnetic fields.

 

Figure 2. The electromagnetic field lines (blue) near a pair of charged particles. The red lines represent points with the same electric potential.

 

Figure 3. Iron filings lining up near a bar magnet. The pattern of the iron filings reveals the pattern of the invisible magnetic field lines.

 

Figure 4. Light waves as electromagnetic waves. The oscillations in the magnetic field and in the electric field are shown.

To be continued.

 

Part 2: What do we mean by “highly coherent, usually monochromatic beam of electromagnetic waves”?

 

Part 3: How are laser beams produced?

 

[1] Hitz, Ewing and Hecht, Introduction to Laser Technology, 3rd ed. IEEE Press, 1998.

[2] Griffiths, Introduction to Electrodynamics. Prentice-Hall, 1999.

[3] Harris, Nonclassical Physics. Addison-Wesley, 1999.

[4] Ask a Mathematician/Ask a Physicist, http://www.askamathematician.com

[5] Coherence, http://electron9.phys.utk.edu/optics421/modules/m5/Coherence.htm

 

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Short review on ‘The Big Bang Theory’ episode ‘The Einstein Approximation’


Warning: For those who haven’t seen this episode yet, spoiler alert!

This is the first, and hopefully won’t be the last, of a series of short reviews I’ll try doing each week for ‘The Big Bang Theory’.

This week The Big Bang Theory (TBBT) episode ‘The Einstein Approximation’ came out,  and is the 14th episode of the show’s 3rd season.
Let me just start this quick and short review of the episode by further stating what the guys there and I have in common, apart from the quite obvious facts that we’re all geeks/nerds by heart.
Even before TBBT, I’ve admired and idolized Einstein myself, because of his great mental feats (which were of course, backed up by other physical theories and experiments at his time). Great because by just the power of his mind Einstein was able to revolutionize our lives and the 20th century, paving ways for faster transportation, not to mention telecommunication and computing, which drove and is still driving the information revolution today. And of course, so much more benefits which we more or less take for granted in our daily lives. In fact, Einstein is oftentimes synonymous with the word ‘genius’.
Einstein was also very much interested in philosophy and politics, not just physics. He’s written several books, articles, letters to people outside the scientific community. He also has a quirky sense of humor, as seen from this  picture of him. At first I thought this photo of Einstein was edited. But as it turns out it was really him, tongue hanging out and all. :) It was at the time he was making fun of people taking pictures of him. Great stuff.

Silly Einstein

Of course Einstein is not without criticisms. Great and accomplished a scientist he maybe, history tells us he left much to be desired when it came to being a father or a husband.

Now, back to the episode review of TBBT. At this point I shall establish a partially objective, partially subjective point system of each episode relative to the earlier 2 seasons (which I have watched at least 2 times…) and a number of judging criteria.

This episode is a classic Sheldon episode, which is great in itself. Again we expected lots of ‘weird’ humor: Sheldon’s ability to complicate relatively simple things, as well as him belittling his friends, most noticeably Penny. Hilarious stuff once again. Bravo to TBBT production team.
Not a lot of scifi or comic book references were made though. But lines such as:

Howard: How long has he been stuck? (referring to Sheldon)
Leonard: Umm…intellectually about 30 hours, emotionally about 29 years.

And

Howard: Have you tried rebooting him? (referring to Sheldon)
Leonard: No I think it’s a firmware problem.

Are classics. :)

The part where Leonard and Sheldon were arguing inside the ‘ball play room’, with Sheldon going ‘bazinga’ everytime, was also hilarious.

Sheldon, and of course the rest of ‘the guys’ are fans of Einstein no doubt. Sheldon of course thinks he’s at the same level with Einstein so he tries to do what Einstein did in order to come at the epiphany that is the special theory of relativity: to work for a menial job so he can occupy his basal ganglia with a routine task so he can apparently free his pre-frontal cortex to solve his physics problem.

Another classic moment in this episode is the guest starring of Yeardley Smith, the not so well known voice actor behind the famous cartoon character Lisa Simpson (yes, of ‘The Simpsons’ fame). Absolutely entertaining piece of the episode.

Another classic dialog is again with Sheldon and Penny:

Penny: What are you doing here?
Sheldon: A reasonable question. I asked myself, what is the most mind-numbing, pedestrian job conceivable? And 3 answers came to mind: toll booth attendant, an Apple Store “Genius”, and “What Penny does”. Now, since I don’t like touching other people’s coins, and I refuse to contribute to the devaluation of the word “genius”, here I am (meaning at the cheesecake factory).

Lines like these make me think of the real meaning and application of LOL. :)

I suppose myself and those guys, as well as the show’s production team, can’t help cracking jokes at Apple. :D

Overall I’d give this episode the following scores:

* reference to sci-fi, comic books, and other geek/nerd pop culture: 6/10

* reference to physics and other fields of science: 9/10

* dialog humor factor: 9/10

* techie/technology factor: 8/10

which gives an overall score of: 8/10

:)

Article originally published here.

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Secularism and Physics on Death and Immortality


The premise: a problem

It has been said over and over again, as a defense or even as a backlash, by religious men and women that religion has a curative and comforting utility to humankind like no other. It has also been said over and over again by secular people and rationalists that however comforting some belief or idea is, it nevertheless adds nothing to the truth value of the belief or idea. That secularism offers nothing more than a skinny comfort blanket amidst the cold and pouring rain at best. That may well be true, and indeed it leads me to believe that it all boils down to what we really want: happiness or the truth. Happiness may not necessarily be true or what’s really happening, and having the truth may not necessarily make one happy. This conflict reminds me of the doggedly proverbial “The truth hurts” and The X-Files’ “The truth is out there”. This conflict also reminds me of the struggle in the movie The Matrix, wherein to know the truth, one has to be ‘removed’ from the confines of the complacency brought about by the virtual reality of the machines who have taken over. Once one has learned the truth, which involves living as a fugitive or freedom fighter wearing mostly ragged clothing near the center of the Earth, one is left to wonder if it would have been better to have stayed in the fantasy reality, even though it’s all make-believe. I guess it wouldn’t be so surprising considering the fact that human beings, like almost every other animal, are predisposed to follow what is certain to help in the continuation of its species. After all, speaking in ageological time scalehomo sapiens are but cells that have just fertilized, and are beginning to undergo cell division to form a larger animal.

The question

So then, if you will humor my ponderings, what could secularism possibly offer as an answer to one of the most profound questions we humans have asked since the dawn of our consciousness: What is death or what happens when we die? Do we survive death in some form or is there nothing after it?

Setting the mood

Quite a mouthful of questions, and ones that have plagued thinkers or philosophers for centuries upon centuries. But I think before I even begin to give my answer to those questions, a little ‘mood setter’ is in need. Some questions are too frank or too blunt in manner, which sometimes has the effect on the listener or the questioner of making one lose focus on the more relevant and apparent details. The mood setting quote is from the book Unweaving The Rainbow by prof.Richard Dawkins. It’s his reply to people who keep on ranting or complaining or fussing about their deaths. Everytime I read it, especially when I watched and heard prof. Dawkins read it with emotions in a talk at UC Berkeley, I cannot help but be moved by it’s message, wrapped around in romantic scientific prose:

We are going to die, and that makes us the lucky ones. Most people are never going to die because they are never going to be born. The potential people who could have been here in my place but who will in fact never see the light of day outnumber the sand grains of Arabia. Certainly those unborn ghosts include greater poets than Keats, scientists greater than Newton. We know this because the set of possible people allowed by our DNA so massively exceeds the set of actual people. In the teeth of these stupefying odds it is you and I, in our ordinariness, that are here.

And continuing this passage in his talk:

We privileged few, who won the lottery of birth against all odds, how dare we whine at our inevitable return to that prior state, from which the vast majority have never stirred.

Makes one (or at least myself) wonder if we even have the right to feel anger or guilt or even sadness by our undeniable demise.

Physics on death

An episode of The X-Files has agent Mulder talking to agent Scully about starlight. He says that starlight as we see it here on Earth is already billions of years old, and has traveled unimaginable distances (light-years). Stars that are now long dead, but whose light is still traveling through time. Mulder continues that perhaps that’s where souls (our souls, after we die) reside. Today, we know from physicists that the premise is correct (that starlight is very old and still keeps on traveling), but we can’t be certain (or perhaps not at all) about the succeeding statement of Mulder (about souls). Scully, Mulder’s partner, continues Mulder’s statements by saying that the light doesn’t die, and that maybe that’s the only thing that never does. Speaking in a purely Einsteinian fashion when dealing with spirituality and such, perhaps our ’souls’ do reside in starlight, and in that sense our ’souls’ do continue on forever.

Mulder’s statement

Taking the first statement into consideration, that ’souls’ do reside in starlight, to be technical about it, we can probably say that it’s actually not starlight in our case but ‘planetlight’. We know that in order to see an object we have to shine light on it, after which the light bounces back, illuminating the object, back to our eyes. In the same sense, the Sun illuminates Earth at daytime, and at nighttime the Moon or our electrical/electronic devices light us up and our surroundings. In that sense light is shined on us, and so it is reflected back, which eventually reaches outer space and into the vast cosmos. In this way our ’souls’ which in this case means our whole lifetime under some source of light, is ‘framed’ in a ‘wave’ of light cruising the universe. If there are intelligent lifeforms out there in the universe and they can’t come here due to technological constraints (same as our case), once they try viewing our part of the universe, what they’ll be seeing is planetlight (which is reflected starlight, the star being our Sun or light from some other source) containing us, our lifetimes, and our history. What they’ll be seeing of course depends on many factors such as how far they are from us, how sensitive their viewing instruments are, what time they tried viewing us, among other things.

Scully’s statement

As for Scully’s statement, that starlight doesn’t die, technically speaking that can be true, since as long as photons don’t get smashed or absorbed, they keep on travelling in space, most likely till the edge of the universe and (our) time itself. However there is a limit to how long light can travel for one to be able to ‘reconstruct’ the data (in this case our ’souls’) it carries with it. This is because as light travels, similar to a wave, it spreads across time and space. As the light spreads, at some point in the universe very distant from the light source, it will be nearly to absolutely impossible to know what information that light brought with it. In a word, the light will be too ’stretched’ to make any sense out of it. This is similar to research being done on the Big bang. We are in an epoch of the universe where we can still study ‘cosmic background radiation’ (electromagnetic radiation, same as light) leading back to the Big bang. If we were a few millions of years late, we might not be able to analyze the data that comes along with the cosmic background radiation. And so Scully is partially correct since light can possibly not die, but the information in the light may become lost to us or someone viewing us.

Finally, physics on immortality

In essence, our ’souls’, most of our memories, achievements, feats, and other things in our light-stricken lives continue to propagate into inter-stellar space. The propagation duration many orders of magnitude longer than any of our lifetimes combined, which could be treated as practically infinity, and in some ways, immortality.

Originally posted last September 16, 2008 at f241vc15.wordpress.com.

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Holey Space


Nope that’s not a typo and this isn’t technically about religion or another reconversion post. 🙂  This post is about holes in space, namely black holes, wormholes, and the lesser known white holes, and their implications to the physical and metaphysical. The arrangement or flow of exposition of this article, from black to worm to white hole, will become much clearer as you read along the article. So get ready for a layman’s quick rundown on holes (cosmic ones of course), thought experiments, sci-fi love, paradoxes, and various possible implications in our lives and the universe we live in.

Read the full story

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