1. what happens when your traveling the distance that surpasses the speed of light?

for example - airplane terminal - moving walkway @ 5mph - human body @ 2mph = 7 mph or distance moved in 1 hour 7 miles.

if enough machines were enclosed and stacked in a way that allowed them to completly move all above them. This would allow an enclosed space to travel a distance faster than light could.

all the above isnt very practical. if one was build and worked correcly how would a light going out from the sides look like and directed forward look?

2.

3. This is similar to the marbles in a tube idea. If you had a very long tube filled with marbles and you pushed at one end, the marbles at the other end wouldn't fall out instantly, the force you use or 'wave' takes the speed of light to travel along the tube because of the way atoms interact with one another.

Because atoms can only interact with each other through electrostatic repulsion which travels at the speed of light, the first walkway can only at the very most interact with the walkway above at the speed of light, same for the next walkway etc. So you would never be able to exceed or even equal the SOL.

Nice idea though.

4. i understand what your saying but thats not what i had in mind.

what i have in mind is more along the lines of.

human inside glass house with wheels inside another glass house
distance that you will travel inside largest house
:--------------------------------------------: largest
<-----:-------------------------------------:next
<----------:--------------------------------:so forth

Each house is in its own space and time- each moving at x speed- so while you only move x feet you actualy traveled distance y

5. Originally Posted by wizbiz
i understand what your saying but thats not what i had in mind.

what i have in mind is more along the lines of.

human inside glass house with wheels inside another glass house
distance that you will travel inside largest house
:--------------------------------------------: largest
<-----:-------------------------------------:next
<----------:--------------------------------:so forth

Each house is in its own space and time- each moving at x speed- so while you only move x feet you actualy traveled distance y
Velocities don't add linearly. In other words not by w=x+u, where x is the velocity of one house to respect to the house it is in, and u is the velocity of the larger house with respect to something else.

You will find that no matter what u and x are. the answer is less than c, the speed of light.

The largest house moves at u with respect to the ground, and the house inside of it move at x. You will get a result of less than c. If you add this to the speed of a house inside the smaller house, you again get a final result of less than c. no matter how many times you nest houses inside of each other, the final house will be moving at less than c relative to the ground.

6. i never said you could obtain the velocity of c- i said you could move the distance gretear than the speed of light-
while doing so in relationship to the outside world/ you would be moving at the speed of light, what would happen say if you had a flash light and pointed it forward,

the light travels outside you glass house while you dont, the relationship changes

could you persay see your self if you traveled far enough ahead?

7. Covering the distance in less time than light is the same as moving faster than light. Also, the light from the flashlight will be going c no matter who's looking at it.

8. Originally Posted by Janus
Originally Posted by wizbiz
i understand what your saying but thats not what i had in mind.

what i have in mind is more along the lines of.

human inside glass house with wheels inside another glass house
distance that you will travel inside largest house
:--------------------------------------------: largest
<-----:-------------------------------------:next
<----------:--------------------------------:so forth

Each house is in its own space and time- each moving at x speed- so while you only move x feet you actualy traveled distance y
Velocities don't add linearly. In other words not by w=x+u, where x is the velocity of one house to respect to the house it is in, and u is the velocity of the larger house with respect to something else.

You will find that no matter what u and x are. the answer is less than c, the speed of light.

The largest house moves at u with respect to the ground, and the house inside of it move at x. You will get a result of less than c. If you add this to the speed of a house inside the smaller house, you again get a final result of less than c. no matter how many times you nest houses inside of each other, the final house will be moving at less than c relative to the ground.

1+1=2 , 1+c =? because something is moving back in time

9. Originally Posted by Janus
Originally Posted by wizbiz
i understand what your saying but thats not what i had in mind.

what i have in mind is more along the lines of.

human inside glass house with wheels inside another glass house
distance that you will travel inside largest house
:--------------------------------------------: largest
<-----:-------------------------------------:next
<----------:--------------------------------:so forth

Each house is in its own space and time- each moving at x speed- so while you only move x feet you actualy traveled distance y
Velocities don't add linearly. In other words not by w=x+u, where x is the velocity of one house to respect to the house it is in, and u is the velocity of the larger house with respect to something else.

You will find that no matter what u and x are. the answer is less than c, the speed of light.

The largest house moves at u with respect to the ground, and the house inside of it move at x. You will get a result of less than c. If you add this to the speed of a house inside the smaller house, you again get a final result of less than c. no matter how many times you nest houses inside of each other, the final house will be moving at less than c relative to the ground.
and it doesn't matter how many velocities you add, it's still a relativistic thing.

10. Originally Posted by Water Nosfim

1+1=2 ,
With velocities, it depends on what units the "1" is in. If it's km/sec, dor instance, then the answer is 1.999999999977777777778024691358... km/sec.

1+c =?
c, regardless of the units of the "1"

because something is moving back in time
There is no backwards time travel involved.

11. Originally Posted by wizbiz
i never said you could obtain the velocity of c- i said you could move the distance gretear than the speed of light-
same difference

while doing so in relationship to the outside world/ you would be moving at the speed of light, what would happen say if you had a flash light and pointed it forward,

the light travels outside you glass house while you dont, the relationship changes

could you persay see your self if you traveled far enough ahead?
You would see the light relative to you at c. Someone on the ground would see it moving at c relative to them. In fact, everyone in every one of the nested houses would see it moving at c relative to them.

This is one of the cornerstones of Relativity; That all observers will measure light(in a vacuum) as moving at c relative to themselves, regardless of any relative velocity between themselves and the source.

This in turn, leads to the conclusion that no two physical objects can measure a relative velocity of c or greater between them.

12. lemy rephrase this to account for a few things to better set the stage.

were not taking into account some forces that would affect this.
my understanding that light moves at a constant speed

machine / contraption distance is equal to 10 secs of light travel.

inside the contraption there is 134123326 objects on top of each other inside there own enclosed space moving at 4.4704m/sec. if objects were positioned in a way to move for only 5secs inside the space surrounding them. a person is able to be in the smallest contraption.

if there was a machine that allowed for a beam of light , say a flash light to turn on and at the same time allow the machines to all start moving past set positions.

1. presuming that above is correct the person should be at end of contraption twice the speed of light.
2. getting out you would be in a new time compared to the start of time of where you started relative to the time where you started.

to my understadanding this accounts for all forces people talked about above. and only 2 reasons exist for this not to be possible. 1 an object like this to in size is not buildable. 2. the energy to move all contraptions would be ~ possibly

13. Originally Posted by wizbiz
lemy rephrase this to account for a few things to better set the stage.

were not taking into account some forces that would affect this.
my understanding that light moves at a constant speed

machine / contraption distance is equal to 10 secs of light travel.

inside the contraption there is 134123326 objects on top of each other inside there own enclosed space moving at 4.4704m/sec. if objects were positioned in a way to move for only 5secs inside the space surrounding them. a person is able to be in the smallest contraption.

if there was a machine that allowed for a beam of light , say a flash light to turn on and at the same time allow the machines to all start moving past set positions.

1. presuming that above is correct the person should be at end of contraption twice the speed of light.
2. getting out you would be in a new time compared to the start of time of where you started relative to the time where you started.

to my understadanding this accounts for all forces people talked about above. and only 2 reasons exist for this not to be possible. 1 an object like this to in size is not buildable. 2. the energy to move all contraptions would be ~ possibly

The above is incorrect. Each moves at 4.4704 m/s relative to the machine directly below it. Relativistically, time dilation and length contraction will control it such that, after all that, you are only at about 95-99% c, (too lazy to run that math at the moment)

14. Relativistically, time dilation and length contraction
im pretty sure the last two have no affect on you beacuse your not moving faster than 10 miles an hour or the above stated speed. or are you stating the velocity are combined> which is apprently wrong posted by someone above comment

early someone said that velocitys are combined and that you then would only be traveling in relationship to the machine below you at the speed its traveling. so why would in your statement affects that only occur at objects traveling at high speeds close to c be in affect here if your only traveling at 4 meters a second roughly.

lemy put my problem one more way. if i were to ask you how far someone traveled in 5 secs with the machines stated above , how far did they travel?
and how far did light travel
-wiz

15. There's one question you're forgetting to answer. Who's view are you trying to calculate this from?

17. Originally Posted by wizbiz
And where am I standing? On one of the carts or on the ground? It's an important distiction.

18. think of a machine as a house with doors that open and close and lock enviroment into its own enclosure. so the situation is that outisde the machine would be point a with a flash light or some kind of devise that shoots light and as soon as you start the devise all the machines can proceed forward. you would walk into the machine hit a button starting the experiment. which would be tobeat light at the exit of the machine on the other side.

19. also to someone at the exit of the machine on the other side while you traveled towards them, as well as someone watching you leave.

so you in the machine after time has elasped from the start,

someone outside the machine where you started watching you
and at the exit of the machine wathcing you arrive

20. It doesn't matter how small the individual velocities are or how many layer's there are, the final velocity always end up being smaller than c.

For example let's have each layer move at 0.1c relative to the layer below it.

first level is 0.1c added to 0.1 c gives a result of:

0.198019802c

The next level adds 0.1c to this giving:

0.29223301c

The next level gives
0.381096123c
And the next sixteen levels in order give:
0.463434802c
0.538479776c
0.605855673c
0.665533923c
0.717764275c
0.762998937c
0.801820145c
0.83487795c
0.862841237c
0.886362247c
0.906053119c
0.922472235c
0.936117953c
0.947427558c
0.95677962c
0.964498381c

after 50 levels you reach

0.999941223c

No matter how far you go, you end up at less than c.

This is the way the universe works and there is nogetting around it. No matter what scheme you come up with, it will not let you get from A to B faster than light does.

21. You say speed and state velocitys etc

please solve and explain why last problem is impossible

22. What if you wanted to travel quickly to a place that is 10 light years away?

You just construct a tunnel, inside that construct a conveyor belt that's rotating at light speed, and on top of that drive a car that is also driving at light speed.

Why wouldn't it take 5 instead of 10 years? (From the standpoint of someone at the starting point, receiving a message from the traveler 5 years too early of a save arrival.)

"We" don't understand it if you just post an equation , so could you explain the equation (instead of putting in some numbers) or use another method to explain why it wouldn't work?

Maybe a link to a video

Or Janus, maybe you can add an explanation why this wouldn't work in your "Special Relativity Primer"?

23. http://www.thescienceforum.com/Speci...mer-19044t.php

The point is that human intuition sucks when it comes to things outside everyday experiences. The universe doesn't work the way most people would like it to. Once you accept that, it becomes easier to understand how things like this work.

From the viewpoint of someone in the 50th cart of a 100 cart stack (each moving 0.1c relative to the next one), the innermost cart will appear to be going 0.999941223c in one direction and the outermost will appear to be going 0.999941223c in the other. From the ground's point of view, the outermost cart looks like its going 0.1c and the innermost cart looks like its going 0.999999998c.

Also, it's impossible to have any matter going at the speed of light, so you couldn't build that converyor or that car. If they were going 0.9c instead, putting the car on the conveyor would only get you up to 0.994475138c.

The equation given is actually pretty simple. If you have a gun that fires at speed a and a car that goes at speed b, then when you fire the gun forward from the car, the bullet will be going relative to the ground. (If you're measuring things in fractions of the speed of light, you can just drop the c, since it'd be 1 in those units.)

24. Originally Posted by calimero
What if you wanted to travel quickly to a place that is 10 light years away?

You just construct a tunnel, inside that construct a conveyor belt that's rotating at light speed, and on top of that drive a car that is also driving at light speed.

Why wouldn't it take 5 instead of 10 years? (From the standpoint of someone at the starting point, receiving a message from the traveler 5 years too early of a save arrival.)

"We" don't understand it if you just post an equation , so could you explain the equation (instead of putting in some numbers) or use another method to explain why it wouldn't work?

Maybe a link to a video

Or Janus, maybe you can add an explanation why this wouldn't work in your "Special Relativity Primer"?
I'll try, but it isn't easy without the math.

Consider a rail way car traveling on a track. with someone running from one end to the other in the same direction as the car is traveling. The car is ten meters long. There are two clocks(A&B) on the car, one at each end, and according to the car, they read the same. The car is traveling at 1 m/s relative to the ground, and the person is moving at 1 m/s relative to the car.

So, how fast it the person moving relative to the ground?

With regular Newtonian physics, it would work like this:

The runner leaves clock A when it reads 0 and reaches the clock B when it reads 10 sec. Since both clocks read the same, it took 10 sec to for him to travel the distance. In that one sec, the whole car moved 10 meters relative to the ground, meaning clock B has moved 10 meters also. relative to the ground, the runner has moved 20 meters in 1 sec, or 2 m/s relative to the ground.

However, all this assumes that someone on the ground and someone in the car measure distances and time identically. In Relativity, this is not the case.

First, the car will be length contracted and slightly less than 10 m long, Second, the clocks will run slow, and third, the clocks at the ends of the car will not read the same time.

So the runner still leaves clock A when it reads 0 and arrives at clock B when it reads 10 sec, However, this does not mean that it took 10 secs by the clock on the ground for this to take place. Also, since the car is not 10m long as measured from the ground, he did not travel 20 meters, but some distance slightly less.

From the ground, he will have traveled slightly less than 20 meters in slightly more than 10 sec, meaning he traveled at slightly less than 2 m/s.

If you work it out mathematically you come up with the equation I gave earlier.

Also if the runner measures the ground's speed relative to him, he get's the same answer. Since the car is moving relative to him, he also notes that it is shortened and that its clocks run slow and are not in sync (though from his perspective, which clock is ahead of the other is reversed. He can apply the same idea as above to a point on the ground using his own clock and measuring stick. and find the same thing, that the relative velocity is slightly less than 2 m/s.

25. Originally Posted by calimero
message from the traveler 5 years too early of a save arrival.)

"We" don't understand it if you just post an equation
They "you" need to improve your skills and understanding. The language of physics is mathematics.

You have only two choices. One is to learn enought mathematics to be able read and converse intelligently about the subject. The other is to remain scientifically illiterate.

The mathematics of special relativity is not particularly difficult. Elementary treatments require only high school algebra. Even advanced treatments require little more than simple linear algebra.

26. I replied in this thread not because I don't understand the principle -- though I don't.

I replied because I found the explanations given not so very good, or not qualifying as explanations.

I think an explanation qualifies as such if it answers the why questions.

What is this equation and why is it relevant?

An equation is a way to succinctly and accurately describe a phenomenon. It isn't an explanation. Only after an explanation will someone be able to understand the equation.

However, all this assumes that someone on the ground and someone in the car measure distances and time identically. In Relativity, this is not the case.

First, the car will be length contracted and slightly less than 10 m long, Second, the clocks will run slow, and third, the clocks at the ends of the car will not read the same time.
Why in Relativity are distances and time not measured identically?

You have to first understand the central idea. This reply didn't address that (I guess). You didn't address why the car was shorter or the measure of time not the same for the observers (I guess), so a critical reader cannot accept your explanation. It became incomprehensible because it left out the most important idea, in trying to simplify the explanation.

Here's a nice quote by Albert Einstein:

"Make everything as simple as possible, but not simpler."

Funny to imagine that maybe he thought of trying to explain his theories when he said this.

This forum has aroused my interest in Physics, so I'll be sure to read Wikipedia on Special Relativity someday, and watch some videos on it. (Don't bother trying to explain it here to me. I'll first study it myself.)

27. In general, science does not answer why. That's philosophy's job. Why are they equations they way they are? Because that's what works (and works very well).

In particular, all of relativity is dervied from two assumptions.
- The laws of physics are the same everywhere
- The speed of light is the same everywhere

Everything else, the equations, time dilation, length contraction, the locality of time, everything comes from those two assumptions.

Now why do we believe in those two assumptions? Because the predictions they make are very, very accurate. That's it.

28. You have to first understand reality before you can make an equation that describes that reality, I imagine.

Einstein had an image in his head how he thought reality worked, described it in an equation, and waited for the equation to be confirmed by experiment and observation. (If I remember correctly)

I'm interested in the image in his head, not necessarily the equation. For anyone to understand the equation, they need to first understand the image, I think.

29. Originally Posted by calimero
You have to first understand reality before you can make an equation that describes that reality, I imagine.

Einstein had an image in his head how he thought reality worked, described it in an equation, and waited for the equation to be confirmed by experiment and observation. (If I remember correctly)

I'm interested in the image in his head, not necessarily the equation. For anyone to understand the equation, they need to first understand the image, I think.
That "image" was that the laws of physics applied to everyone equally despite their relative motion, and that one of those laws was that they measured the speed of light as having a fixed value, regardless of the source.

He then went on to describe how the universe would behave, assuming this was true. The answer he got were the rules governing Relativity.

30. Originally Posted by calimero

I'm interested in the image in his head, not necessarily the equation. For anyone to understand the equation, they need to first understand the image, I think.
Understanding the mathematics and understanding the image are the same thing.

You cannot bypass the mathematics and expect to understand the physics. It is simply not possible, although those lacking he initiative and skills often choose to delude themselves to the contrary.

Mathematics is the language of physics. You can either learn to understand the language, or remain illiterate. Your choice.

31. Clear, succinct and easily remembered. I can use these two posts to inform my exploration of the subject

They start to explain the basis, which before wasn't touched upon so clearly, I think.

(MagiMaster wrote approximately the same, but not so clearly -- for me.)

32. feels like im getting flamed
janus thanks for the answear , so from person inside pespective from point a to point b youv traveled actual distance of x, while realistcally beacuse youve lengthend you didnt actualy .

is this the same with say vaccums?

33. It is clear from your posts you don't understand the basic ideas. I'd suggest you first try to study those.