n00b questions

[Appolinaria]

I'm not really too familiar with physics or science in general, so please excuse the fact that some of these questions might be elementary or just plain dumb... I'm sure you get a lot of these!

 

a. Is the third dimension essentially the addition of time? doesn't depth slow the speed of light, causing time? how would light act in a 2D world?

 

b. If we take a 2D shape, and apply it to a 3D model, such as squares to a cube, are we doing the same with a tesseract? applying 3D models into a 4D model, like the 3D object is a face of the tesseract? can we use this simple structure to conclude anything about time and perhaps infer something about the 4th dimension? What I've really been thinking about is this; take our 3D whole universe and have it be represented as a 3D cube. Now take that cube, and apply it to a tesseract. In this proposed system, wouldn't that mean that our whole 3D existence is being put into motion and changing, which would prove that we have multiple universes coexisting? BASICALLY I'm just trying to figure out what exactly is happening in a tesseract.... I'm not clever enough to understand it yet, haha.

 

c. If we went the speed of light, and our physical form allowed it, would we be conscious of everything all at once? and if we were capable of slowing down to not moving at all, would we be in a state of complete unconscious?

 

d. If the universe is constantly outwardly expanding, is there a core of the universe that gets more dense, or something like that? what I mean is, is there some kind of reverse effect because of the expansion?

 

e. If energy cannot be created or destroyed, is that just relative to our surroundings? or is it true even with the big bang?

 

 

thank youuuuu.

[Daedalus]

I was browsing the forum when I noticed your thread. I can answer most of these within the confines of accepted science, but I will have to explain a few of your questions using my theory : )

 

a.)

• 1.) Relativity defines the fourth dimension as time. Other theories, such as string theory and M theory, add many more dimensions.
• 2.) Depth is just another dimension. Light only slows down when moving through matter - Slow Light
• 3.) Light would act just like it would in a 3D world. It would just have one less dimension to travel through

 

b.)

• 1.) A tesseract is a four-dimensional cube. Yes you can apply 3D geometry to create the 4D hyper-geometery. In essence the Tesseract is to a cube as a cube is to a square.
• 2.) Normally time and length in four dimensions are interpreted much like in relativity where time dilates and lengths contract. This is due to Lorentz transformations.
• 3.) Parallel universes can be derived from M theory. My theory of Temporal Uniformity (read the entire thread) describes something similiar to what you have, except I use a 3-sphere instead of a tesseract.

 

c.) I believe we would be conscious no matter what speed we travelled at. However, we would lose consciousness if we accelerated / decelerated to fast. Obtaining a speed to where you were not moving at all is relative to your frame of reference. If you believe you had obtained such state, I could always choose a coordinate system to where I was stationary and you were moving. So there is no prefered frame of reference or rest frame.

 

d.) Physics currently states that there is no center to the expansion of the universe. Space appears to be expanding everywhere and not from a common center. However, I hypothesize in Temporal Uniformity that the universe is an expanding 3-sphere which is why we do not see this center.

 

e.) This depends on the theory you choose to reference. M theory proposes that two branes came together and that collision provided the energy which created our universe. The Big Bang does not define how the universe began unless you consider the Big Bounce theory. My theory falls more in line with the Big Bounce.

Edited November 4, 2011 by Daedalus

[Appolinaria]

Thanks for taking the time to answer my q's, Daedalus.

 

Honestly, I'm more inclined to believe the universe is a complex structure like the 3-sphere & not just flat.

[Daedalus]

You are welcome Appolinaria. I figured you were just refering to a simple 4D shape such as the tesseract to demonstrate your point. I think you will find that my theory does provide adequate answers to some of your questions. However, Pantheory has a really good theory too which may be able to explain things differently. Here is a link to his theory of Pan : ) He often posts in the forums and will be able to answer some of your questions as well.

[Appolinaria]

Yes yes, thank you.... I'll look at his as well.

[swansont]

c. If we went the speed of light, and our physical form allowed it, would we be conscious of everything all at once? and if we were capable of slowing down to not moving at all, would we be in a state of complete unconscious?

There's no basis for answering this question. There's no theory of physics in which it is possible, so there can be no valid conclusions drawn — you can take almost any answer you want and find some way to support it when you break the laws of physics.

[Appolinaria]

There's no basis for answering this question. There's no theory of physics in which it is possible, so there can be no valid conclusions drawn — you can take almost any answer you want and find some way to support it when you break the laws of physics.

 

 

True, because matter can't travel the speed of light, right?

 

but what I was really getting at is the relation of cause/effect, our perception of time, and the speed we are traveling... it's a concept that's hard for me to grasp.

Edited November 4, 2011 by Appolinaria

[swansont]

True, because matter can't travel the speed of light, right?

 

but what I was really getting at is the relation of cause/effect, our perception of time, and the speed we are traveling... it's a concept that's hard for me to grasp.

Right.

 

The question of why time is related to speed is one of physics. While the explanation is straightforward it is, as you say, a hard concept to grasp. For most of us it takes a lot of playing around before it even starts to become intuitive. It derives from light always having the same speed in any inertial reference frame, which itself is a hard concept to grasp. Once that is held invariant, though, time and length cannot be. Here's an example of that

 

http://Galileo.phys.Virginia.EDU/classes/109N/lectures/srelwhat.html

[Daedalus]

There's no basis for answering this question. There's no theory of physics in which it is possible, so there can be no valid conclusions drawn — you can take almost any answer you want and find some way to support it when you break the laws of physics.

 

Agreed. However, I based my response on the fact that you experience no force while travelling at a constant speed (ignoring gravity of course). That is why I made a statement about acceleration in that [math]F=m\, a[/math]. Even though the question was a hypothetical about if we somehow managed to move at the speed of light in our three dimensional space, one could argue that we are moving at the speed of light in four dimensions because the magnitude of the 4-velocity of a massive particle in the rest frame is equal to c. However, I did not answer whether we would be conscious of everything all at once. Just that we would still have consciousness.

Edited November 4, 2011 by Daedalus

[Appolinaria]

Right.

 

The question of why time is related to speed is one of physics. While the explanation is straightforward it is, as you say, a hard concept to grasp. For most of us it takes a lot of playing around before it even starts to become intuitive. It derives from light always having the same speed in any inertial reference frame, which itself is a hard concept to grasp. Once that is held invariant, though, time and length cannot be. Here's an example of that

 

http://Galileo.phys....s/srelwhat.html

 

That link was absolutely perfect, thank you so much!

 

 

So basically, whether Jack is moving from Jill, or Jill is moving from Jack, it doesn't matter which one is in the train. One is simply moving away from the other, which affects their clocks... Jill on the train could be stationary, and Jack is moving, or vice versa.. it doesn't matter?

 

 

 

 

According to the Fitzgerald contraction, Jill who is on the train in motion, will be seeing the notches closer together, everything will be "squashed". Because of her motion, distance is actually much shorter but her perception of time stays the same... so she is on the train, where time is still the same to her, but she's witnessing more notches than if she were going a slower speed. She is aware of more notches, more of her surroundings, because of her speed?

 

So the perception of time is the same to both of them, but their perception of distance isn't, simply because of motion?

[swansont]

That link was absolutely perfect, thank you so much!

 

 

So basically, whether Jack is moving from Jill, or Jill is moving from Jack, it doesn't matter which one is in the train. One is simply moving away from the other, which affects their clocks... Jill on the train could be stationary, and Jack is moving, or vice versa.. it doesn't matter?

 

As long as there are no accelerations, the effect is symmetrical. With acceleration you still have the effects, but the one who accelerates will end up with a clock that has run slow.

 

According to the Fitzgerald contraction, Jill who is on the train in motion, will be seeing the notches closer together, everything will be "squashed". Because of her motion, distance is actually much shorter but her perception of time stays the same... so she is on the train, where time is still the same to her, but she's witnessing more notches than if she were going a slower speed. She is aware of more notches, more of her surroundings, because of her speed?

 

So the perception of time is the same to both of them, but their perception of distance isn't, simply because of motion?

The effects are there for both, but what is seen to be stationary and what is moving (and is therefore length-contracted) is different for each. If Jill in on the train, the whole world is in motion relative to her, so the trip is length contracted. To Jack, only the train is moving, so the train is length contracted.

[Appolinaria]

As long as there are no accelerations, the effect is symmetrical. With acceleration you still have the effects, but the one who accelerates will end up with a clock that has run slow.

 

Okay, but from Jill's perspective, Jack's clock will be going slow... even though she is the one accelerating.. couldn't I say the planet is in motion away from the stationary train? Isn't it the same?

 

 

The effects are there for both, but what is seen to be stationary and what is moving (and is therefore length-contracted) is different for each. If Jill in on the train, the whole world is in motion relative to her, so the trip is length contracted. To Jack, only the train is moving, so the train is length contracted.

 

 

Well, that answers my original question about speed/perception.

 

This shows that the faster you go, the more you're conscious of... Jill can see more notches.

Edited November 5, 2011 by Appolinaria

[swansont]

Okay, but from Jill's perspective, Jack's clock will be going slow... even though she is the one accelerating.. couldn't I say the planet is in motion away from the stationary train? Isn't it the same?

In that example there is no acceleration. Each one sees the other's clock as running slow.

[Appolinaria]

If there is no acceleration, how are they in separate frames of reference?

[Daedalus]

A frame of reference refers to a coordinate system used by an observer to measure position, orientation, and other related properties. Jack is watching the train go by, so from his frame of reference the train is moving and the world is stationary. Jill is on the train, so from her frame of reference the train is stationary and the world is moving.

 

Jack and Jill can choose any frame of reference, but they would typically choose one that would simplify their measurements or calculations. You can think about this much like astronomers did long ago when they tried to determine the motions of the planets. The path of the Mars from an Earth centered coordinate system is very complex with loops, where a sun centered coordinate system showed that Mars has a very simple elliptical path.

Edited November 6, 2011 by Daedalus

[swansont]

If there is no acceleration, how are they in separate frames of reference?

 

There is no acceleration in the scenario. What happened before we start analyzing it doesn't matter — we can set Jack and Jill's clock to the same time at the beginning of the problem, after the train has finished accelerating.

[DrRocket]

If there is no acceleration, how are they in separate frames of reference?

 

They are in separate frames of reference by virtue of thev fact that are each in uniform motion relative to the other. How they came to be in that situation is outside the special theory of relativity.

 

Special relativity is really a theory about space and time and the nature of space and time which is revealed by the fact that observers in relative motion perceive space and time differently. The real key, though a bit abstract, is that what is the same for all observers is a unified entity called spacetime, and a quantity, the spacetime interval. The spacetime interval combines into a "length" both spatial and temporal elements, which vary among observers. Those variations are what are called "time dilation" and "length contraction". But when all elements are considered simultaneously, the interval itself ([math] \Delta s^2 = c\Delta t^2 - \Delta x^2 -\Delta y^2 - \Delta z^2 [/math]) is the same for all observers.

 

When you throw in questions involving acceleration you either have to find a single inertial frame in which to do all of your analysis or, better yet, go to the general theory of relativity. In general relativity you find that space and time are only local concepts (you cannot really talk about "time here" vs "time there" for instance) and that special relativity is just a local approximation.

 

The critical thing to recognize is that relativity is really a radically new theory about the very nature of space and time. The resolution is the emergence of spacetime, and the recognition that it is spacetime, and neither space nor time, that is fundamental. One observer's space includes elements of another observer's time, and vice versa.

[Appolinaria]

They are in separate frames of reference by virtue of thev fact that are each in uniform motion relative to the other. How they came to be in that situation is outside the special theory of relativity.

 

Special relativity is really a theory about space and time and the nature of space and time which is revealed by the fact that observers in relative motion perceive space and time differently. The real key, though a bit abstract, is that what is the same for all observers is a unified entity called spacetime, and a quantity, the spacetime interval. The spacetime interval combines into a "length" both spatial and temporal elements, which vary among observers. Those variations are what are called "time dilation" and "length contraction". But when all elements are considered simultaneously, the interval itself ([math] \Delta s^2 = c\Delta t^2 - \Delta x^2 -\Delta y^2 - \Delta z^2 [/math]) is the same for all observers.

 

When you throw in questions involving acceleration you either have to find a single inertial frame in which to do all of your analysis or, better yet, go to the general theory of relativity. In general relativity you find that space and time are only local concepts (you cannot really talk about "time here" vs "time there" for instance) and that special relativity is just a local approximation.

 

The critical thing to recognize is that relativity is really a radically new theory about the very nature of space and time. The resolution is the emergence of spacetime, and the recognition that it is spacetime, and neither space nor time, that is fundamental. One observer's space includes elements of another observer's time, and vice versa.

 

There is an actual spacetime interval? That's incredible.. or maybe it's completely expected & I'm misinterpreting it all

 

It's just intriguing how for example, time dilation can be measured. It's putting logic to something that seems at first so illogical to me.

 

 

Anyway, I think I might be beginning to have some understanding of spacetime. I'm going to need a lot of time to process it all before I can ask substantial questions, without wasting anyones time.

 

Thanks so much for the excellent response, it is really appreciated.