Saturday, April 5, 2014

Special Theory of Relativity

Chapter 5
Special Theory of Relativity
The Theory of Relativity is something I have been very fascinated with since taking physics. The idea that nothing is absolute is hard for one to understand.  Let’s lay the foundational understanding of relativity. For example, if you ask someone standing next to a highway if the cars are moving, they will say “of course” then you ask them how they know that the cars are moving, they will describe to you some fixed position they believe to be unmoving, such as the light pole next to the highway, or maybe the over pass as cars go underneath it. In other words, we describe motion based on our perception of motion. To the observer “standing still” it is obvious to say the cars are moving past, because it is relative to His or her fixed location. In reality it is just as accurate to say we are moving and the cars are standing still. Take another example; what if we were traveling on a train from Sacramento California to Stockton California, it would be just as accurate to say that Stockton was coming to us, as it would be to say that we were traveling to Stockton.
Think of another situation; what if we were traveling through space on a space ship at thousands of miles per hour. How would we be able to tell we were in fact moving if we had no external reference point for our motion? The fact is that there is no way to tell if the observer or the surroundings of the observer are moving. All motion in the universe is relative. The planet is spinning but only in relation to other things in the universe around it. Asteroids fly by the earth only from our point of view, to the asteroid it appears as if it is standing still and a giant, blue planet just flew by at thousands of miles an hour. In fact, our solar system is thought to be traveling around the universe at a speed close to half a million miles an hour, yet to us, it appears as though everything is standing still, we cannot tell that our solar system is in fact moving. Our earth orbits the sun at a speed of about 100,000 K/hr, yet to us we cannot sense this speed besides tracking the position of the sun. Our earth rotates at around 1,000 mph, yet we stand here on the surface oblivious to the fact that we are in fact traveling faster than sound. This is the base on which relativity rests that movement is relative.

 The only apparent universal standard by which we can compare our speed in the universe is the Universal speed limit of light, 299,800 km a second or 186,000 Miles a second. This brought up a problem however, because no matter what reference frame an observer is in, he or she will always measure the exact same number for the speed of light. No matter how fast you are traveling or in what direction, the speed of light is always measured as 299,800 km/s if in a vacuum, which space happens to be for practical purposes.
For instance, in classical mechanics, if you are driving in a car at 20 mph and you throw a ball forward at 10 mph the total speed of the ball will be 30 mph. The speed at which you threw the ball will add vectorely to the speed at which you are traveling. This is not the case, however, when you are dealing with light. Nothing in the universe can travel faster than the speed of light, thus when you are traveling in a space ship, and you shoot a beam of light forward, you will measure the speed of light relative to you, as 2.998 x105 km/s. An observer on planet X, will measure this beam of light you just shot forward as the exact same speed.
The speed of light never changes, it does not add to your current speed and is always measured as the exact same value. So what changes in order to make this true? The answer is that time changes. Einstein theorized that each unit of space time, had its own coordinate system. Space and time were bent in comparison to each other. In the reference frame of the person traveling in the space ship, they are traveling in a straight line, but to those outside of this reference frame, the space ship travels at an angle, relative to space time, thus it appears to those outside as if the beam of light is traveling a greater distance than it actually does.
Picture it this way, if you are traveling in a car and you throw up a ball, it comes straight back down to your hand, as it normally would. What does it look like to someone outside however? It appears to those outside that the ball travels in a parabolic fashion, traveling upwards in an arch and coming back down to your hands, because as the ball goes up, you are also moving forward. Thus in your coordinate system, moving forward at 60 mph, the ball goes up and comes straight back down, because you are moving at the same speed as the ball, but to those outside the car who are in their own coordinate system “standing still” it appears that the ball travels in an arch, moving forward at 60 mph.
When you approach the speed of light, the same thing happens with light and objects. If you are traveling very fast, and you shoot a beam of light straight up toward the ceiling, it would appear to you that it traveled a straight path, but to those outside the space ship, it would appear that the light actually traveled in an arch, that took longer to get to its destination than it actually did. Likewise, objects become contracted at extremely high speeds approaching the speed of light, so that a1 foot long ruler measured on a space ship traveling near the speed of light would be 1 foot. Yet, outside the ruler would be contracted by the amount of the Lorentz Transformation Principle. Where v is the speed at which the object is traveling and c is the speed of light.

Is Time Travel Possible?
This equation can be applied to mass, length, and even time. Relativity forever changed the way we view the universe. Space, time, and indeed all of reality, is relative to the observer. For instance, take the well-known twin paradox. My girl friend is an Identical twins, lets say that at one point in their lives say when they are 10 years old, one takes a trip to a world 10 light years away. Traveling at close to the speed of light, say 0.8 times (x) the speed of light (c), our twin on the space ship will see that it takes her a certain amount of time to get to her destination. Her clock will show that she is traveling at a normal speed and that she is years older than when she left. However, to the twin left on earth, it would appear that on the space ship, the twin was moving in slow motion. Viewed from outside, time would be traveling slower than in reality. By the time the twin got back to the earth, 20 years would have gone by for both twins, however, only one will have aged 20 years. Here is why, the twin on the space ship experienced time at a rate of 20yrs/2.24 less than actuality. She will be only 18.9 years old, while her sister will be 30.
How does this work though? If time is relative, shouldn’t it be the same for both twins? Because it is just as easy to say that the twin in the space ship stayed still and the earth receded away from her at a speed of 0.8c. The reason why the twin paradox works is because the twin in the space ship experienced inertia, while the twin in earth does not. So all though the time and speeds are relative to each other, one experiences inertia, while the other does not. This is because, relative to the universe, the twin on earth does not move, while the twin in the space ship does.
In this way, the twin actually traveled in time. Time has also been shown to be affected by the gravitational pull of large masses. For instance, atomic clocks on earth and atomic clocks on satellites orbiting earth do not run at the same speed. The clock on the satellite runs slightly faster than the one on earth, so that time in space is moving faster than time on earth. This has to be accounted for because the clock on the GPS satellite speeds up at a factor of 5 x 10-10 seconds a day. This discrepancy could cause huge calculation errors for GPS devices on earth and would make it impossible to pinpoint exact locations. Scientists actually have to program the clock to run slower each day to account for the time dilation difference. Why is time effected by gravity? That is explained further in the general theory of relativity, which will be our next chapter.
The whole reason for explaining the Special Theory of Relativity to you is for this consideration. The theory explains that nothing can go faster than the speed of light, because as you approach the speed of light the energy needed to propel any mass grows to infinity since energy and momentum are directly related to the speed of light and thus follow the Lorentz equation, growing to infinity as the velocity of the mass approaches the speed of light. Traveling at the speed of light, time would equal zero, no time would pass inside the ship at all, and space would disappear, meaning the mass of the ship would contain zero volume. One book I read stated this, “There is no way to transmit any sort of message through space faster than the speed of light.”[1]
This brings me to an important question, how does God communicate with us? We pray expecting that God hears our prayers instantly, but if nothing travels faster than the speed of light, it would take eternity for our prayers to reach heaven. God cannot be simply a deistic super human living in a place called heaven. The physics does not work. There is no exception for prayer when it comes to the universal speed limit of light. The speed of thought is the speed of light, nothing can break that law. For some, this fact is damaging to faith, they will either reject God, or choose to believe in irrational answer, that prayer is somehow magical. As we study the sciences we must gain a deeper appreciation for how great God is. Rather than trying to stuff God into a box why not broaden our imaginations and believe in a God that is universal, infinite, and nonexistent.
The universe is the mind of God, we exist because God thought. That dawn of time at the big bang was the birth of our 3 dimensional world, God “thought” of a beautiful idea and reality sprang to life. Prayer may indeed connect us to the infinite, but to think of prayer as ascending to heaven is meaningless. God is not so small that He can be contained to a place. Look out across the vast reaches of our universe and you will begin to see a God so much bigger than we can understand.
What about Angels though? If you believe the Bible than you believe that Angels are real, and if they are real then they are just another creation like us. How do they go back and forth from our world to their own world that we like to call heaven? Even if angels could reach the speed of light time would only slow down for them. They would reach heaven in what seemed to be no time at all to them, but for us on earth it would take eternity. The only way that angels can travel back and forth through space, according to the theory of relativity, is if they actually went backwards in time. How this would actually works is well beyond my ability to comprehend, but if we believe that angels exists and that angels really do travel to and from heaven, than we must conclude that God breaks the universal speed limit of the universe.
I believe that God operates under his own laws. I do not believe God makes laws of physics and then goes and breaks them, (what would be the point of making the law in the first place then?) but remember when we talked about the Big Bang Theory? What created the universe was an infinite amount of energy, with an infinite amount of mass, all contained within zero volume. Does that sound like something we just discussed? To even reach the speed limit, you would need an infinite amount of energy to propel a mass that would contain zero volume. In other words, you would need God. If God is infinitely big, and in Him is contained infinite energy, this problem would be no problem at all.
So what would happen if we breached the speed of light? The theory is a mathematical absurdity. Our math has no way of calculating such a thing since it would mean the use of imaginary numbers. We could calculate something, but since the number we calculate is imaginary, there is no way of evaluating the number we calculate. However, in theory, if you traveled faster than the speed of light, time would began to flow backwards, so that you would reach your destination before you left. An angel wanting to reach earth would leave several days after the actual event and reach earth on the day he intended, in the past.
Think of another situation. Imagine we are in heaven. Have you ever wondered what it will be like to fly from galaxy to galaxy, visiting distant planets and exploring the far reaches of our universe, and maybe even beyond it? All these are wonderful thoughts, but have you ever considered how long it will take you? Many of those galaxies are billions of light years away, so how would you get there? Well, first off, if we really are going to live for all eternity, than relative to eternity, how long is a billion years? It is pointless to state it takes any time at all, but if we can travel at close to the speed of light relative to us, it takes very little time to get there. In fact, as the theory goes, if we actually reach the speed of light, time stops all together and we would get there at the same time we started. Only those we left behind would know any difference, and for them again we run into the same problem. Since we have eternity, the billions years we were gone means absolutely nothing. Think of it this way though, what if we can move faster than the speed of light? Then we arrive at the galaxy we wish to visit before we even leave.
The Bible says,
“…be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day.”[2]
Could it be that this is verse is true because Heaven is in another part of the universe and the apparent time runs differently because of the speed at which it moves? Could it be that time is nothing to God because He has, rather He is, what is needed to travel in time itself? I believe again, that God is greater than his creation, God lives outside of His creation, but the Bible seems to indicate that Jesus, the representation of God to His creation, is forever confined to his human body, thus Jesus, and the angels, who exist in a material universe, must travel in time to traverse the universe.     
            Angels could also beable to travers the 4th dimension of time. If angels are 4th dimensional creatures, then time to them would simply be another direction of travel, they could reach distant places without it taking anytime at all because it would be as simple as traveling in space time. There are many, many theories out there and we do not have time to deeply discuss them all but are you beginning to see a God who is much greater than our tiny understanding of reality? We can’t even understand time! We exist in a world that is ruled by perception, and based off our relative position in the universe. Time is relative to our position and speed, gravity, as we will learn in the next chapter, is relative to our position and time, and even what appears to be a straight line to us, is really just an elongated curve, bending back on itself in accordance with the laws of relativity. As we view all these things we realize how small and created we really are. We live in a mechanical universe that in my opinion was created by the mechanic of the mechanics. We can no longer hold God captive by confining him to our world, and our understanding of space and time. God is infinite, and his reality truly is beyond our ability to find out.




[1] Gardner, Martin. “Relativity Simply Explained” Dover Publications, New York. 1997.
[2] 2 Peter 3:8

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