Time (and existence)
 

Note: Sorry this is kind of long, I have been thinking a lot about time and how it relates to life. This is basically the conclusion that I have drawn based on my own experiences. It is not meant to offend or ridicule anyone, I am just curious what thoughts and arguments people may have.

--------------------------------------------------------------------------------------------------

What is time exactly? The dictionary defines it as “the indefinite continued progress of existence and events in the past, present, and future regarded as a whole.” Progress of existence and events? Progress is defined as the “forward or onward movement toward a destination.” Movement is defined as the “act of changing physical location or position or of having this changed.” So the definition of time could be broken down to:

the indefinite continued change in physical location or position of existence and events in the past, present, and future regarded as a whole.

Does this mean that time cannot exist without change? If when you are reading this sentence, time were to stop for 100 years, would it take you 100 years to read this sentence? No, because nothing changed in that time so that “time” did not exist. The truth is, that time is only a measurement of how much things change in comparison to a set standard. Does a mile exist? Does a gallon or a pound? A mile of land, a gallon of water, and a pound of iron all exist but without the physical matter to measure, the measurements are meaningless. Time is no different.

So is time travel possible? If you think about one instant in time, one freeze-frame, it is simply an array of how each particle of matter in the universe is arranged at that instant. Matter can be neither created nor destroyed, so everything on this Earth, from the food we eat to the elements that compose our bodies, is made up of particles that have existed as long as the universe. It is a crazy thought, but everything on this planet is made up of only three different kinds of particles. Everything is composed of varying combinations of protons, neutrons, and electrons. The complex interactions of these particles create every element on the periodic table. These elements make up everything we experience on this planet. 98% of our body mass consists of only four of these elements: Carbon, Nitrogen, Oxygen, and Hydrogen. It is crazy when you consider that the only thing that makes Oxygen different than Nitrogen is that Oxygen has one more proton in it’s nucleus. The only thing that makes Nitrogen different than Carbon is that Nitrogen has one more proton. That something that seems so small is what made life possible, is hard to imagine.

Evolution is the concept that living organisms developed from simpler organisms, but I think with only a bit of deductive reasoning, it is clear that even “life” evolved from something much simpler. Even protons and neutrons are made up of smaller subunits called “quarks.” That is as basic as technology allows us to get at the moment, but quarks could be made up of something even smaller. If it is true that matter cannot be created or destroyed then it means that the universe has always, and will always be. Everything that exists is just an always-changing form of matter. But if this is true, then we were neither created, nor can we be destroyed. If we are merely a chance combination of molecular building blocks then what is our purpose for living? Why do we laugh and cry and love? If there is no reward for our actions in this life then why do we even live? If there is no punishment for doing awful things then why not indulge ourselves?
The truth is that if everyone believed this, I do not know how people would act. Religion is nice, I go to a Baptist university and I grew up Christian, but it just seems to be a double-edged sword. It gives people hope, purpose, and a reason to wake up in the morning. I believe that it is the main reason that we developed humanistic qualities such as neighborly love and selflessness. On the other hand, it also allows people to justify terrible actions. How many wars have been fought in the name of God? To this day people use the argument that God is on our side to gain support for war. I have yet to read anywhere in the New Testament that says killing people is fine as long as you are fighting for Gods cause. I have yet to understand how a message of ‘love thine enemy’ can be perverted into kill people with different beliefs than you.
I am not trying to bash anyone, but it seems like religion is often only a justification of things that people do not understand. Such as why people have to suffer and how we came to exist and why disasters and miracles exist. I do not claim to understand everything, in fact, I feel as if I know less than most. It seems to me, though, that all of these questions that have plagued mankind throughout history, can be answered with only one explanation. Nearly any “why” question can be answered with the answer “because that is what happens when such a combination of matter interacts with another combination of matter.” For example, “why do we exist?” The question that could be considered the basis for every religion, really seems kind of simple. Life exists because protons bonded with neutrons and attracted electrons. Different combinations of these basic particles lead to amazingly complex compounds. Over untold amounts of time these combinations interacted with other combinations creating new combinations. We know that our planet has existed (in it’s current form) for at least 4.5 billion years. It is believed that we may have developed the ability to control fire about 800,000 years ago. That means that we have only been developing for less than 0.02% of the time that the planet has been developing everything that pre-dated us. We exist because of the reactions that occurred between the different combinations of the basic elements of matter. If you really think about it, we always talk about the end of the world but can the world ever truly end? If the world exploded tomorrow it would be the end of comprehension, but all of the matter that composes everything on the planet would disperse into space and be drawn toward the strongest gravitational pull until it reached a new planet or star and underwent further change. The only rational explanation for the beginning of the universe is that this change is what the “universe” is. Whether or not matter has reached a form as complex as humans, or whether it has reached an even more complex state is unknown but if our most basic concepts of physics are correct then it has always existed in some form. It is also clear that no matter how complex combinations of matter become, they can be broken apart almost instantly. A black hole could reduce everything in our solar system to one dense point, erasing any history of the combinations of matter found before.


I kind of got away from the original topic about time, but to get back on the subject of time travel…
I cannot understand the argument that going faster than the speed of light is a form of time travel. I understand that we can see stars that are no longer in existence because the light takes so long to reach our planet. What I do not understand is how traveling away from earth faster than the light that is being emitted by earth is supposed to be able to allow us to see into the past. Theoretically we would be catching up to light that existed on Earth thousands, or even millions, of years before we existed, but how would that be traveling through time? We would be looking at light, not history. That light is not from the “past,” it is just light that has been traveling for a long time. The most we could learn from that is when the Earth began to emit light.

Another form of time travel I have heard of is traveling to a different dimension that is actually a previous or future time. I think this model has been displayed as something similar to a film reel, where each individual shot is a moment in time. Like the shots on the roll of film, every instant of time exists simultaneously. I have been told that there are scientific theories that state that it would be possible to “jump” to one of these instants. I have two arguments against this one. First of all, I don’t see any scientific evidence to support multiple dimensions. I had to go to a string theory lecture for one of my classes once that attempted to explain how string theory supports the idea of multiple dimensions. I am sorry, but I just thought it was kind of ridiculous. I do not understand how the mathematics of knots explains that there are other dimensions. Also, if there were multiple dimensions then wouldn’t they have to exist completely independently of our dimension? To travel to another dimension would be to add, or “create,” matter in that dimension. Since there is a set amount of matter, wouldn’t taking matter out of this universe and adding it to another defy that concept?

Finally, it is commonly said that time is a “fourth dimension.” I was always very against that idea. I never really gave it consideration because I did not see a relation between height, width, and length compared to time. When I considered the definition of the word dimension though- “a measurable extent of some kind”- I could agree with that title. I think that change can be measured, so time could be considered a 4th dimension. This also makes sense because we can “travel” through time. After all we age, things decay, and so on. This is similar to the way we travel through the other dimensions. My only problem with this is the connotation that it creates. That we can travel through it implies that we are in control, like we are in control of where we travel on Earth. However, change is a one way road, things can change but never has something un-changed. To change something is to change the position or structure of matter in some way, the only way to “undo” this is to change it again, back to how it was. This, to me, means that the only way to go “back” in time is to change every particle in the universe back to its exact position in space at a given instant. Even if we could miraculously achieve this, that would have been a change occurring in the present, we would not be traveling through time, we would simply be changing the position and state of matter. However, I do think that would be similar to time travel because things would play out in exactly the same way they had. Every molecule would have the same forces acting on it that it had had, so when you jumped to this instant every action and reaction would occur the same as it had the first time. Obviously instantaneously changing every bit of matter to a state that it was in before is not possible, I just thought that was an interesting note.

The only form of time travel that seems logical is reaching the temperature of absolute zero. If time truly is defined by change, than the only way to “stop” time is to stop change. At absolute zero every molecule is frozen in place. Nothing changes at all. If you were instantly frozen to absolute zero, every molecule in your body would remain exactly the same for an indefinite amount of time. In this way you would be “unaffected” by time. At some time in the future if you were unfrozen you would have traveled through that time unchanged. You still would have traveled through time at the normal speed of time though.

For this reason it seems like the only way to have a true effect on time is for the entire universe to reach absolute zero. At that point nothing would change so time would essentially be stopped. That would, however, also be the end of time. If everything was at a point that change was not possible, nothing could create the change required to unfreeze a single particle. Matter would continue to exist though; there is no change that can be made that stops something from existing. Even in a black hole matter is not destroyed, light does not cease to exist. These things are just trapped in a very dense point. People often show a giant black hole as ending the universe, but eventually the black hole would explode and the matter would spread out again throughout space.

Things are always changing; everything we experience and observe seems just a form of change. Our bodies are the most complex combination of matter that we have yet observed, so it seems counter-intuitive to assume that the answers to our most complex questions come from much more basic concepts. That we are more complex than a vast majority, if not all, of the combinations of matter in the universe is a strange thought to have. It is in our nature to think there is something greater than us out there that is responsible for the way things are. I can not say for sure that there is not, but I can say that everything that we experience in this life is a result of basic particles interacting in extremely complex ways. Human consciousness, dreams, ambitions, they all result from particles reacting to stimulus from other particles. It is my opinion that these reactions, these changes in position of matter, are no different than the change that causes a rock to degrade. Though conscious, we are nothing more than a more complex combination of the same basic building blocks. Upon death we will simply return to a less complex form. These particles will disperse, eventually returning Oxygen, Nitrogen, Carbon, Hydrogen, and the rest of the elements found in our bodies to the atmosphere, free to form new combinations. So in the end time seems irrelevant.

All of these arguments seem logical to me, but normally when someone believes something, they close their minds to other ideas. I am really curious what peoples reactions to any part of what I have said may be. Whether in support or opposition I would appreciate any thoughts or opinions.

Re: Time (and existence)
 

Well.. I think modern science measures time in how long it takes light to propigate in a vacuum.. (http://en.wikipedia.org/wiki/Faster-than-light says its.. 298km/s) I actually was looking at the stuff a few days ago. It actually says they can make lasers travel faster then the speed of light(like 300x the speed of light.. fast) I think on another note Temperature(absolute 0) or rate of entropy is also a really good measurement of time. The thing is I've read that absolute 0 is actually the same as infinite entropy or +infinity degrees, while -0 would as cold as possible. From coldest to hottest its (-0, 1, 100, -100, 0) Its probably hard to understand the idea of negatives in real circumatsances because I always thought of it as a reflection of positives, but I dont know.


Uhm.. im not sure where i want to go with any of that, I think I will come back and edit later.

Re: Time (and existence)
 

That may be true, but I do not see how absolute 0 would be equal to infinite entropy. Entropy is disorder right? and at absolute 0 there is no change in structure so that seems like it would equal 0 entropy. Isn't one of the factors that contributes to entropy that the greater the heat, the greater the entropy? It's been a while, but I seem to remember that being the case. It would make sense cause an increase in heat excites the molecules. I reread what you said though, and maybe that is what you were saying in the first place.

In either case, I do not think it matters what name the temperatures are given. Whether you call the hottest temperature 0 or -0 or 16, it doesn't change the temperature. There are no "real" negatives, a negative is an implied opposite of a positive. They are just descriptive words right?

Re: Time (and existence)
 

It matters without actually having to matter. The name of a temperature doesn't change the temperature itself but it does effect how we know what temperature it is. If one person thinks the hottest temperature is 16 and another person thinks it's 547, than in any case shall they try to communicate about temperature will be a very sad situation.

It is descriptive values which balance along a line of many values for us to understand. It's how we are taught and how we understand anything that changes in value. If 0 became 1 then 1 would become 2 and so on. It's our way of understanding and creating a 'balance' I guess.

Re: Time (and existence)
 

I agree, I was just trying to say that the name doesn't change the fundamental nature. For the purposes of this argument it is the idea, not the name, that is more important I think.

Re: Time (and existence)
 

I think the best answer to this question comes from relativity. Here, time is a property of *space* itself that differentiates between one event and another within that space. Every objective or mass in the universe including me or you is part of the fabric of space in this universe, and thus the fabric of time. Because these two properties are intertwined, if you manipulate one, you manipulate the other.

Because mass, or energy (they can be considered equivalents, see E=mc^2) influences how space is distributed around an object, it also influences how time is distributed around an object. As such, by changing the local mass or energy of an object, you change the property of time that object experiences. The classic example of this is Time Dilation - as velocity increases, the perception of time slows relative to objects outside your -space+time- reference. This is because as velocity increases, so does the energy (E=mc^2/(Sqrt(1-v^2/c^2)).

So, time is a way of differentiating between one event in space, and another, and is a property of space itself.

It's impossible to say at this point for sure, but under the previous definition, the answer is no. Time can be *manipulated*, just as space can be manipulated, but because time is a property of space itself, you're really traveling through it all the time. That doesn't mean there is any physical way of skipping over events that have yet to happen and getting yourself into the future, or somehow reversing time and going to the past - you'd have to ...reverse or fast forward space itself and I don't think that makes any sense to either of us :P

It's a bit hard to understand, but in all honesty you don't need to understand it, because it's not possible. See: (E=mc^2/(Sqrt(1-v^2/c^2)) - faster than c velocities are a violation of physics! (Energy would *exceed* infinity, lol :P)

It's also impossible to reach absolute zero. Even in 50 billion years, when the universe is expanding so quickly it rips itself apart, it will never cool to absolute zero.

It's not, though. According to relativity and the space-time equivalency, you effect time all the time, simply by moving. Just by getting up and walking around you're changing the fabric of space around you, and thus time. It's by a tiny amount...so small you can't notice it, but in more extreme cases it can be measured and quantified.


They're not actually moving faster than light. They're *cheating* a bit, if you will - they're getting from A to B faster than light would, but moving at or slower than the speed of light.

Imagine you're playing a game of Mario Kart, and you're racing light. Light is going to go around the track normally, and you could never win normally, because light is always faster than you are. However, you could take a shortcut and beat light to the finish line. That's what they're doing in this experiment (It's still an impressive feat!)

Re: Time (and existence)
 

I don't see why people talk about time as something that can actually be manipulated. Just because the concept of time that was artificially created has been used to solve many practical applications doesn't mean it is actually there. For something like time to actually exist there would have to be some form of its existence. Time travel could only work if that point in time still existed in some way.

I'd like to see some kind of evidence that shows that speed has ever relatively effected that object in the perspective of time. From my understand things just happen because of all matter trying to move to the path of least resistance.

Also I'd like to thing that if some matter ever did hit absolute zero that something fun would happen like a super black hole.

Re: Time (and existence)
 

Thanks for the input Reach, I think we agreed on basically everything, we just said it in different ways. This was the only thing that I had a "problem" with:

Moving around is causing change, which is what I equated time to. It doesn't cause much change, but if say, you could move a planet, or a galaxy, that would change a lot. After all, by all accounts the moon is more or less a big rock, but it's position is detrimental to life on Earth. Is moving a planet really affecting time though? Or is it just causing measurable and quantifiable change in the universe?

It seems the one thing we differ on is that I see time as just a term to describe change.
You see it as part of the fabric of space (I think). But you *did* say that traveling through time would require rewinding or fast-forwarding the universe. That implies that you believe a set time is a location of each individual bit of matter in the universe. So one time is only different from another based on the change of location of that matter within the time span. If you do believe this than I do not understand how you can think that time is part of the fabric of space. Matter will change location based on the forces of other matter acting on it. A big change or a small change doesn't change the *fundamental* nature of anything. One instant will still only be different than the previous because matter is in a position that it was not in before, the magnitude of change seems irrelevant(unless it is 0).



Agreed, I think the whole argument about speed slowing down a clock at high enough speeds is kind of ridiculous. First of all, if a person were to go that fast they would die. Second of all, and more importantly, no matter how slow you perceive time to be going, it is not changing at all. Everything continues to change at the same rate, you just have different forces acting on you at faster speeds than at standstill. That is not affecting "time."

Also, I agree with Reach that matter *cannot* ever reach absolute zero, because for something to change from a state of change to a state of absolutely no change through a process of change makes no sense. What change could be induced that could create a state of no change? It is a conundrum. But IF it DID happen we could all party because we would get to live forever! (It would be a boring party though, we wouldnt even know it had happened).

Re: Time (and existence)
 

Well the reason absolute zero is impossible is because if there is nothing of a lower temperature then absolute zero then nothing can be used to get something to absolute zero. You would have to take some matter below zero and put it next to something right above zero for it to get there. But since that's impossible it doesn't matter.

Re: Time (and existence)
 

Thank you, that is a much better explanation than what I said.

Re: Time (and existence)
 

Moving a planet quickly, like the Earth around the sun, is affecting time quite a bit; however, the Earth cannot experience time so it's a bit inconsequential. The reason that we personally aren't affected by this is because relative to the Earth, we aren't moving, so unless we get up and move around the space around us and thus time are unaffected.

You could measure the effect on time the earth experiences fairly easily. The Earth's orbital velocity is approximately what, 65000 mph? So, using part of the equation I posted earlier, events happening in space that is unchanged experience time at a rate of 1.000000004 times faster than Earth does.

Well, I suppose what I really said is that under the *classical* definition of 'time traveling' you would have to rewind or fast-forward the universe. However, I also pointed out this is a ridiculous point to be making if you consider time to be a property of space itself, since rewinding or fast-forwarding space itself makes no sense whatsoever (unless space is continually being exchanged through higher dimensions of space we cannot perceive or something crazy like that that we haven't discovered yet :P ).

I don't really 'believe' time is a part of space, physics tells me that. Einstein's theory of special and general relativity are incredibly well supported theories, and my position is their position on this matter.

Though, to address your points:

We're starting to get technical here, but according to relativity there aren't 'different times' at all...rather, there is one time, which is space, and this property of space differentiates between quantum events. If this property of space did not exist, then all events would happen simultaneously and it would be impossible to differentiate between one happening and another.

This is precisely how we describe the state of the universe prior to the big bang, because at that point we have a breakdown of space itself, and thus time.

It's not ridiculous, because we've already shown it's true. You can do it relatively easily in the space shuttle. You line up two atomic clocks to measure precisely so they're measuring the same thing, put one on the space shuttle, fly around, and compare them when they get back. They read different times afterward, *precisely* the difference in time that Einstein's relativity would predict.

I don't think you quite understand this yet. You aren't slowing down either of the clocks. You're changing the *space* the clock on the shuttle is in, and thus you change the time it experiences. Both clocks continue to tick at the exact same rate, regardless.

It's hard to understand, but it's true. It seems like a paradox, but the reason it occurs is because by changing the space and thus time around an object, you create two different reference frames in space; one for the clock on Earth, one for the clock on the shuttle. These reference frames create the basis for the difference in time the clocks read.

Also, you don't have to be going fast to get this effect. I know I pointed this out earlier, but this effect is perceived when any movement occurs. It's just...it's easier to measure the change when high speeds are involved.

Re: Time (and existence)
 

But how do you know that isn't caused by something else. Maybe the closer an object gets to the speed of light the atoms react differently because the electrons around the atom are still going the same speed and are having a more and more difficult time keeping track of where the neutrons are.

Re: Time (and existence)
 

This is my problem. The Earth *can* experience time as much as we can, it is just not conscious of it. And this is kind of vague anyway. Because there are different forces on something in space it experiences "time" differently?

Einstein's theory of general relativity is about gravity, one of the fundamental forces of nature. It was proven by the fact that light bends around planets. What implication does this have on time? To say that two things experience time differently because different forces are applied to them seems counterintuitive to me. It just causes them to change differently.


I guess I missed that in Physics, but that sounds really ridiculous to me. Basically what this is saying is that if fundamental laws of nature did not exist everything would happen at once, but LUCKILY things do not just change instantaneously with no regard to the forces of nature. *whew* lucky us!

Again, to me what this is saying is that you change the forces acting on the clock and thus the "time" it experiences. That is not changing time it is changing the rate at which the clock changes due to the forces acting on it.

It seems to me that we think the same thing, I just do not like the word time. It makes much more sense to call it change. Time has too many other connotations.

I think that it is obvious that something is causing the change. It is not that the object experiences a different "time" it is that it is experiencing different forces. This is exactly why I think time is a really bad word for it.

Re: Time (and existence)
 

Ok, my point was that Earth isn't conscious, so it can't perceive time. Really, that's all. This is a weird over analysis of what I said, lol.

Light doesn't 'bend around planets' per say. Light follows straight lines relative to the topology of the space that it is within. If that space is curved, light will curve as well, following the path of space. We observe this effect around objects with extraordinary masses that bend space, and thus time a great deal. The classic example of this is the Black Hole.

Yes, if space, and thus time didn't exist everything would happen instantaneously.

I have no idea what you're going on about in the next sentence though. Space and time *didn't exist* prior to the Big Bang, and thus as far as we can tell, all events at that point occurred simultaneously without any way of differentiating between them.

Yes, we are lucky? If space, and time didn't exist, the universe wouldn't be here, at least not in it's current form, and we wouldn't be having this discussion. I don't see the relevance to your previous point, though.

The clock never changes the rate at which it keeps time. This is ...what I think you're both still missing. If you sat on Earth, or on the Space shuttle, and watched the electrons and neutrons in the clock at exactly every moment during the flight, nothing would change. You'd take the exact same measurements on the ship and on Earth.

The reason the effect occurs is because by distorting space, and thus time, you put the shuttle on a different reference frame. This would cause the person on the shuttle to perceive things on Earth happening faster than normal, and cause the person on Earth to perceive things in the shuttle as happening slower than normal, but inside of both reference frames everything is normal and exactly the same.


So no, it has nothing to do with the 'forces' per say.

Re: Time (and existence)
 

Okay, so really we do not agree at all. I thought we were saying the same thing with different words, but really we are not.


Haha well, I think that is an important point because perception doesn't change what is happening.



Okay so what you are saying is that light travels in straight lines that bend around areas that "space bends." OR light bends around things with a strong force of gravity. Why do you think it takes an extraordinary mass? *Space* isn't bending, the particles around the object are just being drawn toward that massive object. The "classic example" of a black hole is just an object that is so dense that its gravitational pull is so strong that light cannot escape. Space doesn't "bend." It is the particles within that space that are being drawn toward something.


I do not understand why this is so widely believed. If this is the direction that science is going then that is really sad because it doesn't even make sense. Making up ideas to explain things that we do not understand with no proof is no different than me saying that rainbows exist because God needed a reminder not to flood the Earth again. It is believed that space didn't exist before a big bang? There was a reaction of some kind(between nothing apparently because matter 'did not exist') and this magical reaction created empty space and matter to fill it. Ah! I feel much better now.
It makes much more sense that the big bang was a point that all of the matter of the universe was condensed to a single point due to a massive black hole. At such a point "space" would have been inconsequential because matter would have only been occupying one point. Then an energy build up could have caused the black hole to explode and the matter that was trapped within to be released throughout space. Thus giving "birth" to space and matter (which were really there all along).


I think it is you that does not understand this experiment, you and pretty much everyone else. I am curious, what exactly do you think space is? Is space really a malleable thing that can be distorted? Or is it just a medium which can be occupied by matter?

For space to be distorted it has to be made up of something, meaning it would have to be composed of some type of matter. By traveling do you really think you are distorting space, or just the molecules that exist within it? Clearly it does involve 'forces' per say because the speed which induces the "distortion" is causing a force.


When did science turn into science fiction?

Re: Time (and existence)
 

I think you guys need to understand special relativity a bit more to understand what Reach has been saying. So here's a crash course :razz::

One of the most important things we've discovered about the universe is that light always travels at the same speed (through a given medium). This may sound obvious, but if you think about it, it's really weird. Consider standing on a street, and throwing a ball. You are stationary, and you throw the ball and it goes 10 meters per second. Now let's say you hop on your skateboard with the ball. You ride down the street at 5 m/s and throw the ball while on your board with the exact same force as before. Now the ball will travel at 15 m/s, since it's already moving at 5 m/s and you throw it at 10 m/s. Now let's say you repeat both steps, but instead of throwing a ball, you shine a flashlight. The speed of light is about 3X10^8 m/s. So you shine it while standing still and it goes at 3X10^8 m/s. You would think that when you shine the light while moving on your skateboard, it would go 3X10^8 m/s plus the 5 m/s you're already moving, just like the ball. But it doesn't. It still only travels at 3X10^8 m/s. This type of experiment has been done (albeit not exactly in the same way) and proven.

So knowing this, we can generate a "thought experiment" which makes use of this curious property of light. Now the actual experiment is impossible to do (hence "thought experiment") but you can figure out a lot from it: Say you are in a spaceship, traveling at a constant speed. The ship has a large window. You have a large transparent cylinder which has mirrors at each end of it. There is a light beam which is continuously bouncing back and forth between these mirrors.

There is also an observer standing on the Earth, stationary. We say that you and the person on the earth are in two different "reference frames" because you are moving while the observer is stationary.

So you're going in your spaceship, and you fly right by the observer while the light is bouncing in the cylinder. You and the observer both see that light travel from the top of the cylinder to the bottom of it. You and the observer both measure how far you saw the light travel. To you, the light went in a vertical line, from top to bottom. So the distance you measure is the length of the cylinder. To the observer, however, the light traveled in a diagonal line, because while it was moving up and down in the cylinder, the ship was also moving sideways past the observer.

Now we can form a right triangle. One side is the distance you saw the light travel. The hypotenuse is the diagonal distance the observer saw the light travel. The other side is the distance the ship traveled while the light went from top to bottom. We know that distance/time = speed. So distance = speed*time. We know that light always travels at the same speed.. We know that the observer saw the light travel a longer distance than you did, because the diagonal side of a right triangle is longer than the other sides. This means that the light traveled two different distances while going at the same speed. Since distance = speed*time, this must mean that you and the observer both experienced two different times. Since the light traveled a shorter distance for you, "your time" was passing slower, relative to the observer.

That's pretty much the basis of it. If you were to use the Pythagorean Theorem on that triangle and fiddle around with it, you would end up with a form of that formula which Reach referenced. But this really shows that the act of traveling through space alters the time which you experience. In fact it slows it down.

Now if you were to use that formula you would see that the faster you travel the slower time passes. When you travel at the speed of light (which isn't really possible) time passes infinitely slowly; or it stops.

edit:

Actually the classic example of a black hole is an object so dense that it bends space so much that every direction you can travel inside the event horizon leads to the center of it. So when light crosses the event horizon, it travels in "straight" lines which lead to the center of the black hole.

Re: Time (and existence)
 

Thanks for the information. However, this does not change anything in my opinion. What you are saying is that the way we *perceive* time changes, but what is *really* happening with the light? Regardless of how the two people perceive it, it is doing the same thing. Because we are limited by our perception does not mean that altering how you perceive something changes the time that passed. To refrence your example, "To the observer, however, the light traveled in a diagonal line, because while it was moving up and down in the cylinder, the ship was also moving sideways past the observer." Is time limited by our perception? Outside of the perception of the two people the light is not doing anything differently. The only thing that is different is that one of them is moving really fast so they perceive a change. The equation d=s*t is irrelevant because that is *supposed* to be measuring only the light, not your perception of it. You are taking a scientific equation and using it to try to rationalize differences in perception.

Edit.
What you said about black holes means the same thing as what I said.

Re: Time (and existence)
 

All I did was explain what Einstein did in formulating special relativity. He used the equation d=s*t with the Pythagorean theorem to derive the Time Dilation formula. That formula accurately predicts the outcomes of experiments which have been performed.

The important thing is that light will always travel at the same speed. How you perceive what the light does matters because if you measure a shorter distance than someone else, your time is passing relatively slower than theirs. It's all relative. The only thing that isn't relative is the speed of light, and that proves that space-time has to be able to somehow bend or slow down to preserve it.

You said that a black hole doesn't bend space. I said that that a black hole bends space so much that all directions lead toward the center.

Re: Time (and existence)
 

Well I see it as the same thing. I am just still waiting for a definition on what "space" is if it is able to be bent and manipulated. Until then I am going to believe that we are saying the same thing because I don't think that anyone is illogical enough to assume that empty space is something that can be bent. Anyway, if we are only talking about relativity then I still say that "time" is not changing for either. You can justify it however you want but I still say they are only experiencing change at different rates because they are experiencing different situations.

Re: Time (and existence)
 

If you don't believe that space can bend, then how do you explain gravity? Our planet is revolving around the sun because it is following a straight line which the mass of the sun has bent. When we look at distant galaxies, their image is physically curved because the mass of a galaxy between them and us bends the space through which their light travels. How else do you explain this?