Category: Astrophysics

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Astrophysics cosmology particle physics physics Quantum Mechanics Relativity science string theory

String Theory in 1000 Words (Kind Of)

string-theory-1024x576

By Bradley Stockwell

Because my last two posts were quite lengthy, I’ve decided to limit myself to 1000 words on this one. Before I begin, I must credit the physicist Brian Greene for much of the insight and some of the examples I’m going to use. Without his book The Elegant Universe, I wouldn’t know where to begin in trying to explain string theory.

In short, string theory is the leading candidate for a theory of everything; a solution to the problem of trying to connect quantum mechanics to relativity. Because it has yet to be proven experimentally, many physicists have a hard time accepting it and think of it as nothing more than a mathematical contrivance. However, I must emphasize, it has also yet to be disproven; in fact many of the recent discoveries made in particle physics and cosmology were first predicted by string theory. Like quantum mechanics when it was first conceived, it has divided the physics community in two. Although the theory has enlightened us to some features of our universe and is arguably the most beautiful theory since Einstein’s general relativity, it still lacks definitive evidence for reasons that’ll be obvious later. But there is some hope on the horizon. After two years of upgrades, in the upcoming month, the LHC—the particle accelerator that discovered the Higgs Boson (the God Particle), will be starting up again to dive deeper into some of these enlightenments that string theory has given us and may further serve as evidence for it.

So now that you have a general overview, let’s get to the nitty gritty. According to the theory, our universe is made up of ten to eleven dimensions, however we only experience four of them. Think about the way in which you give someone your location. You tell them you’re on the corner of Main and Broadway on the second floor of such-and-such building. These coordinates represent the three spatial dimensions: left and right, forward and back and up and down that we’re familiar with. Of course you also give a time in which you’ll be at this three dimensional location and that is dimension number four.

Where are these other six to seven dimensions hiding then? They’re rolled up into tiny six dimensional shapes called Calabi-Yau shapes, named after the mathematicians who created them, that are woven into the fabric of the universe. You can sort of imagine them as knots that hold the threads of the universe together. The seventh possible dimension comes from an extension of string theory called M-theory, which basically adds another height dimension, but we can ignore that for now. These Calabi-Yau ‘knots’ are unfathomably small; as small as you can possibly get. This is why string theory has remained unproven, and consequently saves it from being disproven. With all the technology we currently possess, we just can’t probe down that far; down to something called the Planck length. To give you a reference point of the Planck length, imagine if an atom were the size of our entire universe, this length would be about as long as your average tree here on Earth.

string_dimensions

Calabi-Yau shapes, or ‘knots’ that hold the fabric of the universe together.

The exact shape of these six dimensional knots is unknown, but it is important because it has a profound impact on our universe. At its core, string theory imagines everything in our universe as being made of the same material, microscopic strings of energy. And just the way air being funneled through a French horn has vibrational patterns that create various musical notes, strings that are funneled through these six dimensional knots have vibrational patterns that create various particle properties, such as mass, charge and something called spin. These properties dictate how a particle will influence our universe and how it will interact with other particles. Some particles become gravity, others become the forces that attract, glue and pull apart matter particles. This sets the stage for particles like quarks to coalesce into protons and neutrons, which interact with electrons to become atoms. Atoms interact with other atoms to become molecules and molecules interact with other molecules to become matter, until eventually you have this thing we call the universe. Amazing isn’t it? The reality we perceive could be nothing more than a grand symphony of vibrating strings.

Many string theorists have tried to pin down the exact Calabi-Yau shape that created our universe, but the mathematics seems to say it’s not possible; that there is an infinite amount of possibilities. This leads us down an existential rabbit hole of sorts and opens up possibilities that the human brain may never comprehend about reality. Multiverse theorists (the cosmology counterparts to string theorists) have proposed that because there is an infinite number of possible shapes that there is an infinite variety of universes that could all exist within one giant multidimensional form called the multiverse. This ties in with another component of the multiverse theory I’ve mention previously; that behind every black hole is another universe. Because the gravitational pull within a black hole is so great, it would cause these Calabi-Yau ‘knots’ to become detangled and reform into another shape. Changing this shape would change string energy vibrations, which would change particle properties and create an entirely new universe with a new set of laws for physics. Some may be sustainable—such as in the case of our universe—or unsustainable. Trying to guess the exact Calabi-Yau shape a black hole would form would kind of be like trying to calculate the innumerable factors that make up the unique shape of a single snowflake.

The multiverse theory along with M-theory also leads to the possibility that forces in other universes, or dimensions, may be stronger or weaker than within ours. For example gravity, the weakest of the four fundamental forces in our universe, may be sourced in a neighboring universe or dimension where it is stronger and we are just experiencing the residual effect of what bleeds through. Sort of like muffled music from a neighbor’s house party bleeding through the walls of your house. The importance of this possibility is gravity may be a communication link to other universes or dimensions—something that the movie Interstellar played off of.

Well I’ve gone over by 52 words now (sorry I tried my best!), so until next time, stay curious my friends.

 

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Astronomy Astrophysics cosmology science

Jupiter and Her Moons: Our Key to The Cosmos

Jupiter2

By Bradley Stockwell

Everyone at some point in their lives (or so I hope) has experienced the wonderful reverence of stargazing. That allure to look upon the heavens and ask ‘what the hell is that?’ seems to be what makes us human; what separates us from the almost nine million other life forms we share this planet with. The night sky has inspired legends, religions and philosophies; our ancestors used it to navigate and mark the passage of seasons and animal migration patterns. But in our present day, the union between us and our big starry-spotted buddy has faded in some sense. Its full glory is now often hidden behind city lights and the petty dramas of our daily lives or the ones we find on television.

While I too am not immune to getting caught up in the rigors of daily life or the latest Doctor Who episode, it’s not too often you’ll find me under a clear night sky without my neck craned upwards. There’s something viscerally exciting to me about seeing the cosmos nude. This is why instead of grabbing a beer and the television remote after a stressful day, I’ll typically still grab that beer but I’ll reach for my telescope instead. While admittedly this may seem like a nerdy pastime, I’m going to try my best to convince you it’s not.

If you’ve ever traveled to a foreign land, the first time feels almost as if you’re visiting an alien planet. Suddenly your perspective of the world increases and you come back home changed. Looking through a telescope for the first time is much the same. I know the first time I saw Jupiter or the magnificent rings of Saturn suddenly our place in the solar system became very real. You can read and study about something all you want, but it’s not until you experience it firsthand that it truly becomes real.

The winter sky is my favorite time for stargazing, primarily because the most important astrological sight to the history of astrophysics and arguably modern science is visible: Jupiter and her moons. This sight has been the key to opening up the cosmos and has been crucial in defining our universe. The best thing is it doesn’t require a high-powered telescope to see it either. In fact I recommend using an entry-level telescope (no more than $150) to see Jupiter and her moons much like the great Galileo Galilei did for the first time on January 7, 1610.

When Galileo first pointed his homemade telescope towards Jupiter, he described seeing a linear arrangement of three fixed stars, two to the east and one to the west, cutting through the center of the planet. However the following night all three stars were to the west. Then three days later one disappeared and six days later a fourth one appeared. At first he was baffled, but then it dawned upon him that these were not stars but were orbiting moons! They were in fact Jupiter’s four largest moons, Io, Europa, Ganymede and Callisto, which now bear his namesake as Galilean moons. The discovery would be the beginning of a great change in science, but it did not come without challenges.

At the time, the discovery was highly controversial. You can even say Galileo was putting his life at risk by proposing it. A planet with smaller orbiting bodies was in direct offense to the longstanding view of the Catholic Church which placed Earth at the center of the universe and all celestial bodies orbiting around it. The church had a long history of burning ‘supposed’ heretics at the stake for challenging this model. But upon further observations by other astronomers, the evidence was irrefutable. The church eventually conceded and accepted a model proposed almost 70 years earlier by the astronomer, Nicolaus Copernicus. The model, which Copernicus waited until he was on his deathbed to present in fear of being labeled as a heretic, placed the sun, not the earth, at the center of the universe. Obviously this model, now called the Copernican model, would continue to be updated, but it would lay the foundation for others like Johannes Kepler, Isaac Newton, William Hershel, Edwin Hubble and Albert Einstein to further define our universe. Galileo’s discovery would help ignite a scientific revolution during The Renaissance and finally break down the cage in which the Catholic Church put scientific research in.

Jupiter and her moons would again make history when the astronomer, Giovanni Domenico Cassini, observed them between 1666 and 1668. He was the first to notice discrepancies in their orbits. To explain these discrepancies, he theorized that light coming from them must have a finite speed. Shortly after, another astronomer, Ole Romer, took this concept further when he realized that indeed the time it took for Io, the innermost Galilean moon, to orbit was shorter when Earth was closer to Jupiter and longer when Earth was farther away. From these observations, Romer was able to calculate the speed of light; approximately 186,000 miles per second. Putting a speed limit on light would forever change how we view the universe for when we peer into the cosmos we now know we are looking back in time! In fact we can now look at light as far back as the beginning of the universe. A telescope is not only a ship with which to sail the cosmos but also time.

In addition to aiding our view of the universe, Europa, the second innermost Galilean moon, may be a likely candidate for harboring alien life! This moon is covered in a thick layer of ice made of water. Because of heat generated from the contraction and expansion of the moon by Jupiter’s powerful gravitational force, many astronomers believe there is liquid water below the surface which could possibly host microbial life.

Jupiter and her moons is but one of the many wonders awaiting your gazing eyes. Although I am not religious, spying through my telescope is the closest thing I have to prayer. It gives me a better vantage point on life and puts things, or should I say the earth, into a humble perspective. While I’m certain life exists somewhere else in the universe, the right conditions to produce it are rare; and intelligent life, extremely rare. In fact from research and astronomical observations alone, it’s not a stretch to say that out of the hundreds of billions of other planets in the galaxy, Earth may be the only one with advanced life. Granted our galaxy is but one among 350 billion in the observable universe, but this perspective suddenly increases the value of our existence. How lucky are we that the winds of energy that control the cosmos happened to deposit matter in the form of the human race? Regardless of how you believe that came to be, there’s no need for theology to tell you how special your existence actually is. I think if we as humans realized this more, we’d start behaving differently. We’d start looking out for ourselves and this world better because right now as a species we don’t particularly have a universal view on life. It’s rather shortsighted in my opinion. Well until next time, stay curious my friends!

 

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Astrophysics Biology chemistry Life Lessons particle physics physics religion science spirituality

The Spirituality of Science

colonoscopy

An obviously very doped-up me after my colonoscopy 

By Bradley Stockwell

To spare you of the intimate details, I’ll just say recently I’ve had some ‘digestive issues’. Two weeks ago I had a colonoscopy to check out these issues. Although I realized the possibility that they may be caused by something serious such as cancer, when my doctor presented me with that reality, it dug in a lot more than I thought. Fortunately, it seems this world is stuck with me a little longer for all my biopsies came out okay. However during the five days in which I had to wait to hear these results, I couldn’t help but contemplate my own mortality and what death means to me as an atheist.

For lack of a better label, I am an atheist but I am not spiritual-less. I find a deep sense of sanctity and humility in the scientific observations of nature. To make clear, this post is not intended to degrade or disprove anyone’s religious faith. The world is richly diverse in beliefs, cultures and opinions and I think that’s a necessary and beautiful thing. What I do have a problem with is the contention surrounding the subject of faith and I in no part want to contribute to it. The reason I love physics so much is it seeks to find unity amongst division and I apply that same philosophy in all facets of my life. Simply, I’m presenting how I sleep at night without believing in a god(s) or an afterlife because it is an honest question I’m frequently asked.

The primary source of my peace of mind comes from the laws of thermodynamics which describes how energy behaves. The first law, the conservation of energy, states energy cannot be created nor destroyed. This law was exampled in a previous post, Flight of The Timeless Photon, on how the photon (aka energy) is transformed from hydrogen proton mass into the life-providing sunshine we all know. The energy we consume, and consequently life, is all sourced from the sun. And the sun’s energy is sourced from the matter within the universe and to find out where the universe’s energy is sourced, we would’ve had to been around during The Big Bang. However according to multiverse theorists, it’s a good chance that it may have come from the matter of a previous universe which was chopped up and scrambled by a black hole into energy. Regardless, the point I’m trying to make is energy is immortal. It is the driver of the circle of life not just here on Earth but in the entire universe. As special as you think you are, you are nothing more than a temporary capsule of mass for energy to inhabit. Death is nothing more than a dispersion of this energy and this is what I take consolation in. When I die, all the energy that was me, my personality—my soul, my body even, still remains in this world. I’m not gone; just less ordered. I am a part of what keeps the arrow of time moving forward as the universe naturally moves from a higher state of order towards a lower—the second law of thermodynamics.

The universe is very cyclical. Life and death are just different stopping points on a grand recycling process. Matter, like our bodies, is created and recycled and energy, like our souls, is immortal and transferred. If you’re familiar with Dharmic beliefs, this probably sounds familiar. It’s funny how the world’s oldest religion, Hinduism, seemed to grasp these concepts thousands of years before science did. While I’m not a practicing Hindu, nor do I plan to be, if forced to choose it would be the closest to my belief system due to the many correlations I find between it and science. One correlation I was most awestruck by was the concept of Brahman to the laws of thermodynamics (aka the laws of energy) mentioned above. According to belief, Brahman is the source of all things in the universe including reality and existence. Everything comes from Brahman and everything returns to Brahman. Brahman is uncreated, external, infinite and all-embracing. You could substitute the word energy for Brahman and get a simple understanding of the applications of the first and second laws of thermodynamics.

If you can’t fathom the thought of an afterlife as some form of your current self, I can understand that. Once again I’m not here to convince you differently, I’m just presenting my viewpoint. However in regards to the value of life, I do hope to convince you that there is no deeper appreciation than through the eyes of science. I only stress this to debunk the perpetuated myth that science somehow devalues the beauty of this world by picking it apart. Once again, the reason I love physics is it widens the perspective of my existence through unifying the universe’s many diverse creations and movements. It connects me to the infinitely larger cosmos above yet also to the infinitely smaller universes below. I have an atomic connection to the stars, a chemical connection to the earth, a biological connection to life and a genetic connection to my fellow humans. When you see the world on so many dimensions, I can personally attest that suddenly everything becomes very interesting. Even the things we don’t give much thought to, like sunshine, weather, the way in which water ripples, or why your friend’s beer overflows when you smack the top of it with yours, become regularly appreciated with a new sense of awe and curiosity. The world becomes much more absorbing than anything a smartphone or television can provide and you find yourself wanting to experience everything it can offer. There’s no greater feeling than the intercourse between knowledge and experience. This perspective is perfectly captured by one of my idols, the great physicist Richard Feynman.

 “I have a friend who’s an artist and has sometimes taken a view which I don’t agree with very well. He’ll hold up a flower and say “look how beautiful it is,” and I’ll agree. Then he says “I as an artist can see how beautiful this is but you as a scientist take this all apart and it becomes a dull thing,” and I think that he’s kind of nutty. First of all, the beauty that he sees is available to other people and to me too, I believe. Although I may not be quite as refined aesthetically as he is … I can appreciate the beauty of a flower. At the same time, I see much more about the flower than he sees. I could imagine the cells in there, the complicated actions inside, which also have a beauty. I mean it’s not just beauty at this dimension, at one centimeter; there’s also beauty at smaller dimensions, the inner structure, also the processes. The fact that the colors in the flower evolved in order to attract insects to pollinate it is interesting; it means that insects can see the color. It adds a question: does this aesthetic sense also exist in the lower forms? Why is it aesthetic? All kinds of interesting questions which the science knowledge only adds to the excitement, the mystery and the awe of a flower. It only adds. I don’t understand how it subtracts.”

When I finally do say goodbye to this world, I hope my friends and family will realize this is not actually the case. Everything that was me is still very much a part of this world, just partaking in a different dimension of it. The energy contained within my body will go back into the earth so that it can provide new life to the flora and fauna which kept me alive as I dined on them throughout my own life. Every joule of energy that was me will be released back into this world to live life anew. And will the unique combination of matter the winds of energy deposited as Bradley Stockwell be forgotten? Well I hope I will have done something impactful enough to be remembered by history, but if not, I can always depend on my beloved light particle, the photon, to ensure my existence will mean something. Explained in detail in my previous post, A Crash Course in Relativity and Quantum Mechanics, according to relative velocity time dilation, the photon’s existence is timeless relative to ours because it moves at the speed of light. A funny thing happens to time at the speed of light—it ceases to exist, at least relative to our perception of time. That is of course until I interrupt this so-called photon’s path by absorbing it as heat and become that photon’s entire existence; forever altering the universe. And this is not the only way the photon will preserve my existence. I of course don’t absorb all the photons I come into contact with—some of them bounce off me and are collected in the photon detectors (aka the eyes) of my friends and family members. These photons then create electromagnetically charged webs of neurons, better known as memories. Well until next time, stay curious my friends!

 

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Astrophysics particle physics physics science

A Crash Course in Relativity and Quantum Mechanics

BH_LMC2

By Bradley Stockwell

In this post, I’m going to attempt to highlight the basics of the two most successful theories in all of physics, relativity and quantum mechanics. Relativity governs objects on astronomic scales; planets, stars, galaxies and so forth, while quantum mechanics governs objects on subatomic scales; particles smaller than an atom. I’m also going to address why while these theories have been proven beyond a doubt, when combined together they are completely incompatible. A theory that successfully combines the two, a theory of quantum gravity, aka “the theory of everything”, is the holy grail of physics because it holds the key to the origins of our universe.

Relativity describes gravity and the universe in a beautifully simplistic way. Think of nothing more than a ball sitting atop a blanket stretched out between two people. The tautness of the blanket between the two people always remains constant. In the language of physics, this is the gravitational constant. The blanket is the fabric of the universe, called spacetime and as the name suggests, not only is it made of space, but also time. This is why the blanket analogy isn’t exactly accurate, because technically spacetime is four dimensional; three dimensions of space and one of time. However the analogy makes the concept easier to comprehend. The ball represents an object in space. The more massive an object, the more it depresses, or distorts the blanket. The distortion is what is known as a gravitational field. The more massive an object, the greater its gravitational field and ability to attract less massive objects. Say a large ball was placed on the blanket with some smaller ones. The smaller balls would naturally gravitate towards the larger one, like planets in our solar system to the sun.

Now one logical question probably came to mind when visualizing this, what keeps those smaller objects from falling completely into the larger one? Or what keeps our planets in orbit instead of falling into the sun? The answer is angular momentum. Objects in space are always moving. If it wasn’t for the gravitational pull of more massive objects, these objects would travel in straight lines. It is this inertia that keeps them in orbit instead of being pulled in completely. Think of a skateboarder riding the walls of an empty bowl-shaped pool. The skateboarder’s momentum keeps him glued to the walls and if he were to stop, he’d roll into the center of the pool. The planets are doing the same thing. They are riding the walls of the depression the sun makes in the fabric of spacetime.

Gravity keeps everything very orderly and very predictable because it obeys certain laws. This is how astronomers are able to predict the timing of cosmic events with amazing accuracy. Isaac Newton was the first to recognize these regularities and calculate them. He believed gravity was the attractive forces between objects in space. This theory survived for over two hundred years until Einstein realized gravity’s close connection to time. Gravity was not an attraction, but a distortion in the fabric of space, spacetime. And when this fabric is distorted, not only is space distorted but so is time. Time is relative to the observer and how distorted spacetime is at his, or her position. Time moves slower the closer you are to an object of mass because the distortion of spacetime is greater. This is called gravitational time dilation. For example, if you were to stand atop Mount Everest, time would move faster (an unperceivably small amount) for you than say someone standing at sea level because those standing at sea level are closer to the gravitational source (the earth) and deeper within the ‘gravity well’. This has been measured in experiments with atomic clocks at differing altitudes and clocks on GPS satellites have to be regularly adjusted because of this. So technically your head ages faster than your feet.

Gravitational time dilation however only applies to relatively stationary objects. Since you atop Mount Everest and the person standing at sea level are both standing on Earth, you both are traveling through spacetime at the same speed. If you or the other person begins to move, another form of time dilation needs to be applied to receive a correct calculation called relative velocity time dilation. According to relative velocity time dilation, the faster an object moves through spacetime, relative to another object, the slower time moves. Time dilation of relative velocity is much stronger than that of gravity. This can be observed with astronauts aboard the International Space Station. According to gravitational time dilation, because of their higher altitude, the astronauts should age faster than humans on Earth. But because they are moving much faster than humans on Earth, they actually age slower—about .007 seconds per six months. As strange as this all sounds, not only has this effect been proven by atomic clocks, but a measurable difference in brain activity has also been observed.

Gravity and time can be counteracted by velocity and this is a key component to the wackiness of quantum mechanics.  As I said previously, according to relativity, the faster an object moves through spacetime relative to another object, the more time slows down for that object because the effects of gravity are less until time and gravity become completely irrelevant at the speed of light. To understand this better, let’s go back to the blanket and balls analogy. Think about one of the smaller balls in orbit stuck at the same speed going around the larger ball. Gravity and angular momentum regulate this orbit and speed. But again, gravity is not a strong force; it can be beaten. Let’s say you take another ball and skip it across the surface of the blanket. The effects of gravity, which include time, are less on the ball you threw than the idly orbiting one. Time, compared to the idle ball, moves slower for the one you threw because gravity doesn’t have the same grasp on it. If you were somehow able to throw a ball at the speed of light it would travel so fast that it would catch up to the point before you ever threw it, like a jetfighter catching its own sound waves. However unlike the jetfighter which can break the sound barrier and outpace its sound, it is impossible for the ball to outpace the speed of light, at least as far as we know. At the speed of light the ball is stuck in the light barrier; its future, present and past existences become piled on top of one another and it has now entered the strange world of quantum mechanics. The ball exists at every time in every place. This is what existence is like within an atom because everything within it moves at, or nearly at the speed of light. This is where the term quantum mechanics comes from. The position and time of particles on a subatomic scale can’t be predicted to an absolute certainty. They can only be ‘quantized’ into approximate probabilities.

Let’s go back to our theoretical ball traveling at the speed of light across our spacetime blanket. I’m going to say this ball is a particle of light, a photon, because a photon is massless and only massless particles are able to travel at the speed of light. The reason being, if the ball had any mass it would distort spacetime and therefore has to play by the rules of gravity and consequently time. As we learned in my previous post, a photon is timeless. It is timeless because it has no mass and without mass, time and gravity have no grasp on you. Even if the ball had massive (pun intended) amounts of energy, it could never reach the speed of light because the energy needed would require an infinite amount of mass. As we also learned in my previous post, mass equals energy. The more energy required, the more mass required so the two counteract each other.

spacetime

Light from a star being bent by the curvature of spacetime around the sun so that it appears to be in a different position. Einstein’s Theory of Relativity was proven by comparing the known positions of stars with their positions behind the sun during a solar eclipse. Light travels over the contours of spacetime which are created by massive objects within it. The star’s light bends around the distortion the sun’s mass creates in spacetime and appears to be in a different position when viewed from Earth.

However there are places in the universe where even massless matter, like light, has to give into gravity and the worlds of relativity and quantum mechanics come crashing together. Those places are called black holes. Although light can escape the grasp of gravity, it still has to travel along the contours of spacetime that gravity creates. Imagine our theoretical photon ball traveling across the dips and dents of the blanket created by the mass of the other balls. Now imagine if it were to encounter a hole in the blanket; there would be no escape. A black hole, the afterbirth of a collapsed massive star, is something so massive it completely rips through the fabric of spacetime. This is where the theory of relativity fails. The most dreaded symbol in physics is an infinity sign. If your calculations end in infinity, it means your theory has failed. When calculating the gravitational field of a black hole using relativity it ends in infinity; an impossible amount of mass has to be compressed into an impossibly small area, called a singularity. A spacetime singularity is where the quantities normally used to measure gravitational fields become so strong they curve in on themselves. They become looped much like the wacky world of quantum mechanics. Naturally you’d think a combination of the two, a theory of quantum gravity, would solve this. However it produces an answer that is infinity plus infinity for an infinite amount of times. It is an infinitely bigger failure than relativity at predicting the mechanics of a black hole. String Theory is the closest we’ve come to solving this, but it has yet to be definitively proven. If we could find a successful theory of quantum gravity, we’d most likely discover the origins of our own universe. The reason being, our universe has been continually expanding for the last 13 billion years from a singularity much like the one found inside a black hole. Our universe could be the answer for what’s inside a black hole—well at least one black hole. Pretty trippy to think about, right? Until next time, stay curious my friends!