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.

 

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!