Is it true that time slows down once u are traveling faster than the speed of light?
If so...... what the heck?
u go somewhere super fast...., time still passes at the same rate right?
This has nothing to do with philosophy neither religion but i guess there is no other place you could posted this. 
As a matter of fact a very similar topics were discussed earlier.
Back to your question, you got it wrong, time slows in any speed, up to light speed when it actually stops. You can't travel faster than light, there are a lot of issues involved, like infinite energy needed or that you would have infinite mass when you hit the speed of light etc. If it was possible theoretically you would go back in time.
And yes for you the time still passes at the same rate so if you traveled at the speed of light for like 60 years you would be 60 year older, problem is that everything else has different rate. Here is something I wrote up to explain this phenomenon a while ago. I hope it makes sense. Here I present, a (hopefully) simple explanation of special relativity:
To understand "Einsteinian Relativity," (the cool stuff involving the speed of light) you must first understand "Classical Relativity."
Classical Relativity says that all speed is relative bewteen objects. A car passing you by on the sidewalk may look like it's going 40 miles per hour. However, if you were the driver, the sidewalk would be the one going 40 miles per hour. Common sense says that the car is clearly the moving object and not the sidewalk. But Classical Relativity says otherwise. That an observer could claim either object was moving and still be correct. On Earth, this seems counter-intuitive, because humans generally consider things moving at the same speed as the Earth to be "stopped." However, in space, two moving objects don't have any "frame of reference" to measure their speed, so this theory becomes useful.
Classical Relativity is accredited to Galileo who promoted this theory over 200 years ago. The key is that you can only measure the difference in speed between objects -- one object's speed RELATIVE to another. This is where the word "relativity" comes from.
Now let's take a journey elsewhere, looking at how Einstein came up with his new theory.
All waves travel through a medium. For sound, the medium is air, and for water waves, the medium is water. But light, under the classical theory, is also a wave. If light is a wave, it needs a medium to travel. In a vacuum, though, (space, for example) there is no matter -- no medium -- to conduct light. So how can light travel from the sun to the Earth?
To solve this problem, scientists came up with the idea of a special type of matter called ether. This ether permeated throughout all of space, filling all the vacuum of space. To keep it consistent with the theory especially the essentially zero mass of a vacuum and light’s incredible speed ether possessed extremely strange physical properties. While the ether theory was not an elegant solution, it did seem to fill the need for a medium. However, an inconsistency with ether was soon discovered.
It is taught in high school physics that all waves travel at a constant speed. That speed is relative to the medium's speed. Consider an ice cream truck. If the ice cream truck is moving towards you, the sound waves it broadcasts move faster towards you than if it were stopped. By measuring how fast the waves comes at you, you can tell how fast the ice cream truck is moving.
Knowing this is possible with any kind of wave, it would be possible in theory to figure out the average speed of the ether using light. Knowing this would tell you the "average speed" of the universe. This is important because it would give us an "absolute" frame of reference. If this were true, then we actually could tell the difference between "moving" and "stopped" in direct contradiction to Classical Theory.
So two guys named Michaelson and Morely did some experiments to measure the speed of Earth relative to the ether. What they found out is that Earth seemed to be moving at the same speed as the ether all the time -- as if Earth truly was not moving. However, since we orbit the sun and rotates, we know the Earth must be moving at least some of the time. But no matter what, they found Earth was stopped.
So then Einstein eventually came up with his new theory of Relativity. What it says is that unlike water waves or sound waves, light waves always move at the same speed relative to the observer. This doesn't sound that shocking at first, but it is so counter-intuitive that you don't even realize it.
Since the speed of light is so great, a lot of ways of explaining Special Relativity involves rocket ships in space. Suppose you are in a rocket ship and your friend is on the moon. You are moving at 50% the speed of light (relative to Earth) and your friend is moving at the speed of the earth.
Now, I this is going to be long, so to make this example interesting, say the Earth explodes, emitting light all around it. If the light catches up to you (and it will), you will die from it.
Under classical theory, this is what the explosion looks like (and I really hope this shows up well under BBCode.
Key:
a = you
b = your friend
* = earth's remains
(( = light waves
Each line represents 1 second passing.
The speed of light = 4 spaces / second
| Code: |
a ((*)) b
a (( * )) b
a (( * )) b
a (( * )) b
a (( * )) b
a (( * ))
a (( *
(( *
This is your friend's frame of reference.
Your friend gets hit after 5 seconds.
You get hit after 7 seconds.
|
You (a) move pretty fast, and don't get "hit" by the light for a while. However, look at this! This is the SAME picture from your frame of reference. The only thing that has been change about this next diagram is that each line has been "shifted" over so the a's line up.
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a ((*)) b
a (( * )) b
a (( * )) b
a (( * )) b
a (( * )) b
a (( * ))
a (( *
(( *
This is your frame of reference under classical theory.
Your friend gets hit after 5 seconds.
You get hit after 7 seconds.
|
Since this is your frame of reference, you (a) stay in the same position (since your speed relative to yourself is always 0), and Earth and your friend are moving away from you. But check your facts. The light waves move only at 50% the speed of light coming at you (2 spaces per second in the diagram) and 150% the speed of light at your friend (6 spaces / second). This is a direct contradiction of what Michaelson and Morely found. What REALLY happens is this.
From your frame of reference:
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a ((*)) b
a (( * )) b
a (( * )) b
a (( * )) b
(( * )) b
* )) b
* )) b
* )) b
* )) b
* ))b
* ))
*
This is your actual frame of reference under special relativity.
You get hit after 4 seconds.
Your friend gets hit after 10 seconds
|
From your frame of reference (keeping the speed of light = to 4 spaces / second), your friend outlasts you by quite a bit. So even though you are going faster, you get hit first.... huh? But above it says that your friend gets hit first? Which is correct?
The answer is both. Both diagrams follow the law that the speed of light remains constant in that frame of reference. Asking which of you gets hit first is a two part question. First you must ask which frame of reference you are in. Only once you have decided on a frame of reference can you decide who gets hit first.
Of course, that is crazy. You die before you see your friend die, but at the same time, your friend dies before he sees you die. How does that make sense?
Einstein had the answer. Simultaneity does not exist for objects moving at different speeds. Einstein explained it this way. That the faster an object is traveling, the slower time moves for it. This is not an illusion of moving light, it is the way the universe works. However, fast moving objects never see themselves as moving at all. Every frame of reference sees itself as stopped, and thus, moving at full speed.
Of course, while this is mind-bogglingly cool, it doesn't really have an effect on our lives. Humans don't move very fast relative to anything of interest to them. According to Einstein's theory, when things are moving at every day speeds, the laws of physics work almost identically to Classical Relativity.
Other interesting facts we know:
* Just in case you didn't know, radio waves, microwaves, visible light, gamma rays, and infrared rays are all "light waves".
* The faster an object is moving, not only does it travel slower through time, but it also gains mass (as stated by the poster above). It's mass increases at such a rate when accelerating near the speed of light that it makes it impossible to put it over the speed of light.
* gravity moves at the speed of light as well. If the sun explodes, we will both see it and stay in its orbit for about 8 minutes before the light vanishes and we go shooting out into space.
* it is generally assumed that NO information can be conveyed faster than the speed of light. That not only can we not move faster than light, but we cannot warn people of incoming radiation.
* Quantum physics is weirder than this shyt. Rules involving the speed of light are somewhat negotiable according to some physicists on an extremely small scale. | We r the SYC wrote: |
Is it true that time slows down once u are traveling faster than the speed of light?
|
actualy you don't need to go FTL. you can measure the difference in timeflow with two simultanious clocks, one on a mountaintop one on the bottom of the sea. through earths rotation the upper clock takes the larger circle in the same time - therefore moves faster. the alteration in the passage of time is rather small, maybe a nanosecond a year..
however GPSsatelites rotate around earth in such speed that the signal needs to be altered.
in theory at speed of light time would pass infinitifly slow
| We r the SYC wrote: |
If so...... what the heck?
u go somewhere super fast...., time still passes at the same rate right? |
kind of...
lets say your journey at high speed would take 6 month, then you turn round and fly back. in this one year of relative time (time as it flows for your ship) 50 years might have past on earth.
you might wan't to read "forever war" it's SciFi , not science but explains pretty good what relativity can do to you.i still could not understand how time slows down to something moving so fast and vice versa. However, I do understand the unnoticed speed difference of two objects relative to earth- if both are at different places like the top of everest and the abyss of the deepest ocean at the same time. But I still can't understand how time hastens or slows down with respect to speed.
In my mind, if i were moving really fast, objects around me seem to move fast-- but time is still constant. I guess this directly has something to do with how fast the brain processes information. We simply cannot think faster because we travel faster.
Anyway, please do hit me if i've got it all wrong. I find the topic really interesting, but i just can't seem to fully understand it. My brain needs an upgrade.
| tingkagol wrote: |
| I guess this directly has something to do with how fast the brain processes information. We simply cannot think faster because we travel faster. |
It has nothing to do with human ability to think at all. Experiments have been done in space using atomic clocks. Two clocks are set to the same time on Earth. Then, one is sent into space on a shuttle. When the shuttle returns, it has been found the clock in space is slightly behind the one that stayed on Earth.
| tingkagol wrote: |
| Anyway, please do hit me if i've got it all wrong. I find the topic really interesting, but i just can't seem to fully understand it. My brain needs an upgrade. |
It's quite an intellectual leap, so don't worry if you don't 'get' it immediately.
Just remember that, when dealing with near light speeds, before asking "how fast" or "when"-type questions, you must first decide on "who." Who is doing the observing and how fast are they going? Different "whos" give different "whens" and "how fasts."Check out Dr. Fred Alan Wolf's Seminar
Part One:
To download this audio, right click Here and select "Save Target." You can then save the MP3 file anywhere on your local hard disk.
Part Two:
To download this audio, right click Here and select "Save Target." You can then save the MP3 file anywhere on your local hard disk.
Also goto http://www.fredalanwolf.com | Tac-Tics wrote: |
| It has nothing to do with human ability to think at all. Experiments have been done in space using atomic clocks. Two clocks are set to the same time on Earth. Then, one is sent into space on a shuttle. When the shuttle returns, it has been found the clock in space is slightly behind the one that stayed on Earth. |
Can you elaborate more? Or if you have already discussed this in your previous posts, can you pinpoint the explanation to this particular phenomena? Thanks.
I need spoonfeeding. teeheeA classic example of the perception of time is to compare
animals with very high metabolisms like a shrew or hummingbird
and look at how they must percieve the world and compare that to
how a slow moving animal like a turtle must percieve the world.
The faster animals must percieve smaller and smaller increments of time
so relative to our perception of time they will view our time segments as slower and slower the faster they get.
Another thing is E=MC2
E=energy
M=mass
C=speed of light= distance/time
As mass approaches C it physicly starts distorting and elongating.
As mass approaches C squared it becomes pure energy.
And speed being distance/time,
as the absolute value of speed increases
the relative value of time has to decrease
with respect to the value of the distance traveled.
| tingkagol wrote: |
| Tac-Tics wrote: | | It has nothing to do with human ability to think at all. Experiments have been done in space using atomic clocks. Two clocks are set to the same time on Earth. Then, one is sent into space on a shuttle. When the shuttle returns, it has been found the clock in space is slightly behind the one that stayed on Earth. |
Can you elaborate more? Or if you have already discussed this in your previous posts, can you pinpoint the explanation to this particular phenomena? Thanks.
I need spoonfeeding. teehee |
It's really quite simple. Time ACTUALLY slows down for moving objects.
The above experiment actually relies on a more complete version of Einstein's theory called General Relativity. General Relativity takes into account that acceleration screws with space time as well. I haven't looked that far into it, but I do know that accelerating bodies seem to permanently "lose" time in this manner. | Tac-Tics wrote: |
| It has nothing to do with human ability to think at all. |
Einstein came up with all of his realizations about Relativity while sitting at the park doing “thought experiments” in 4D geometry. All of Relativity can be derived geometrically by extending Euclid’s 10 axioms to 4 dimensions and adding an 11th axiom. The 11th axiom has to do with the frame of reference through which you interact with masses traveling at other speeds. As something speeds up it’s frame of reference tilts upwards temporally in the direction of travel:
| Code: |
OBJECT
/ = frame of ref
/ =
/ =
/ =
/ =
=/
= /
= /
= /
= /
= / |
At the speed of light the frame of reference cuts straight through the temporal axis of the object, so it has infinite mass along it’s own frame of reference and the place where the frame of reference intersects a stationary object doesn’t change, i.e. time slows down. | Tac-Tics wrote: |
| Code: |
a ((*)) b
a (( * )) b
a (( * )) b
a (( * )) b
(( * )) b
* )) b
* )) b
* )) b
* )) b
* ))b
* ))
*
This is your actual frame of reference under special relativity.
You get hit after 4 seconds.
Your friend gets hit after 10 seconds
|
From your frame of reference (keeping the speed of light = to 4 spaces / second), your friend outlasts you by quite a bit. So even though you are going faster, you get hit first.... huh? But above it says that your friend gets hit first? Which is correct?
The answer is both. Both diagrams follow the law that the speed of light remains constant in that frame of reference. Asking which of you gets hit first is a two part question. First you must ask which frame of reference you are in. Only once you have decided on a frame of reference can you decide who gets hit first.
Of course, that is crazy. You die before you see your friend die, but at the same time, your friend dies before he sees you die. How does that make sense?
Einstein had the answer. Simultaneity does not exist for objects moving at different speeds. Einstein explained it this way. That the faster an object is traveling, the slower time moves for it. This is not an illusion of moving light, it is the way the universe works. However, fast moving objects never see themselves as moving at all. Every frame of reference sees itself as stopped, and thus, moving at full speed. |
I think i've finally got around this a little. So, an object, even if it's moving at say, LIGHT SPEED, seems it weren't moving right? So, basing from the example above, let's say i were moving 100% the speed of light, yet the light from the explosion still hits me first than my friend? Isn't the reference for the light explosion ALWAYS the earth (its source)? Are you then saying the speed of light is not constant for different frames of references yet remains constant for a specific reference?
or is it INFINITE? travelling 50% its speed (and away from the light) really does nothing to slow the time down before it reaches you?
i find the 3rd diagram erroneous. much because it relies heavily on the concept that an object moving at high speeds seems not moving at all in its own frame of reference. I believe if i were moving in almost the speed of light, i'd be stretched into one long spaghetti strap.
Or does it mean i'd be ok, but the people on earth will see me die and transform into a spaghetti???
I believe your "special relativity" will happen only if the WHOLE UNIVERSE MOVES WITH YOU. Do you believe that?
Anyway, keep it coming.the stuff at howstuffworks.com pretty much covers all the factors.
http://www.howstuffworks.com/relativity.htm
still confused with some of the concepts given... like the light clock. Time dilation is measured using the Lorentz Transformation, a method of translating coordinates from a stationary frame of reference to a moving frame of reference.
The equation is (for movement is only one dimension):
Clocks in a moving frame run slower than clocks in a stationary frame, so we can compare the passage of time measured in each by modifying the above equation:
For small values of v, or basically everyday movement, the dilation is negligible. c is approximately 300,000,000 m/s, so let's say one is moving at 300 m/s, which is pretty fast in terrestrial terms (slightly less than the speed of sound). In that case, T in the stationary frame will be 1.0000000000005 times T0 in the moving frame. However, as one beings to approach c, the dilation becomes much more noticeable, until at v=c, T=T0 times infinity. In other words, the passage of time in the moving reference frame is 0. Perhaps the more interesting consequence of this is, of course, that if one would be able to move at v>c, then the object in the moving reference frame would start to move backwards through time.
There is a good little tutorial on this here. Nice formulas!
Here is an object at rest:
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^ |
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T ===========|=============== hyperplane of mass interaction
I |
M |
E |
SPACE--> |object |
And then in motion:
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space-->
T / /hyperplane
I / / of mass
M / / interaction
E / /
| / /
| / /
V / /
/
//
/ /
/ /
/ /
/ /object
|
The reason that the speed of light is a barrier is because as you approach the speed of light the hyperplane of mass interaction tilts forward in time in the direction of travel, as shown. At the speed of light relative to another object, this hyperplane cuts directly through the temporal axis. Since matter is infinitely long on the temporal access it is presumed that mass would become infinite, but this can only be the case at constant velocity with no acceleration.
However, at massive accelerations it is guaranteed that no hyperplane slice of the object can be infinite, the acceleration makes the object too curved and so the volume of the slice would have to be finite.
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/ *
/ *
/ *
/ *
/ *
/ *
/*
/
/
/*
/ *
/ *
/ * |
This suggests that the speed of light is not an absolute barrier, but that there is instead an escape acceleration for the speed of light. Just as there is an escape velocity for escaping an orbit, there would have to be a continuous acceleration in order to escape the speed of light. | We r the SYC wrote: |
| u go somewhere super fast...., time still passes at the same rate right? |
Yes! Time will pass exactly as before, but that is only from your point of view.
Take the example with the mountain and seafloor clocks. The clocks simply do what they always do - measure the flow of time in their own reference system. It's only when you compare the two clocks you'll know that something has happened.
P.S. I've seen posts about this topic in "Science and Nature" already... | Tac-Tics wrote: |
Here is something I wrote up to explain this phenomenon a while ago. I hope it makes sense. Here I present, a (hopefully) simple explanation of special relativity:
To understand "Einsteinian Relativity," (the cool stuff involving the speed of light) you must first understand "Classical Relativity."
|
I hope you don't mind me butting in here. I recently wrote a little paper on this just as you did, to try to explain it to the non scientist.
I used the standard light clock example and illustrated it with a couple of animated gifs. I've done the standard Galilean math and then gone on to cover the effect on length by looking at 2 clocks. This takes us towards the Lorentz equations without getting too tricky.
Please feel free to copy/use/change the work any way you like - I wrote it to try and presuade a friend that the effect is real and not just a 'trick' but he still won't accept it 
The html source is found on my site - the Campaign for Real Science at :-
http://real-science.org.uk/resources/timedilation.htm
Best wishes
Chrisyou call that an explanation to the non-scientist?
| tingkagol wrote: |
| you call that an explanation to the non-scientist? |
Well, yes, I do. I pitched it at a year 10-11 pupil. I've been out of teaching for a while so I may have it wrong - I'll ask my wife to see if her year 10-11 students (15-16 yrs old) can understand it.
The maths might look a bit frightening at a glance perhaps, but in fact it is extremely simple stuff if you take a bit of time and have at least a basic understanding of algebra. I know for sure that any GCSE maths student could easily cope with this level and I would hope that pupils aged 14 onwards could also cope - maybe with a brief helping outline..
Was it the math you find intimidating ?
Chriscome to think of it, it's simple algebra. It's just lengthy.
| tingkagol wrote: |
| come to think of it, it's simple algebra. It's just lengthy. |
It's lengthy exactly because I wanted it to be accessible - keeping each step simple.i'm just so pissed they didn't teach stuff like these in my school. our colleges here need more professors. hah.
so, i gather everyone seems to be comfortable with time slowing down for a moving object- which pretty much opens the possibility of time travel---- I zip out to space at 3x10^8 m/s and when i return, everybody'll be older than me- I've successfully traveled to the future!
now, how can i travel back to the past? 
| tingkagol wrote: |
i'm just so pissed they didn't teach stuff like these in my school. our colleges here need more professors. hah.
so, i gather everyone seems to be comfortable with time slowing down for a moving object- which pretty much opens the possibility of time travel---- I zip out to space at 3x10^8 m/s and when i return, everybody'll be older than me- I've successfully traveled to the future!
now, how can i travel back to the past? |
Yes, scientists are convinced of relativistic time dilation. This is because experiments have validated the concept. Many experiments have been done - the most famous involved fitting atomic clocks (very accurate) in jet planes and flying them round the world several times. The clocks confirmed dilation by being the predicted amount slower than reference clocks left stationary.
Time travel - yes, in the sense you quote, is possible. The problem is in attaining the high speeds needed. At the moment manking has managed a paltry 40,000 km/h.
Travel to the past. At the moment impossible. Travel at speed faster than light (c) would be to travel back in time. Up to now there is no known method for doing this. Wormholes are a possibility but the energy needed to open a wormhole and keep it stable is thought to be huge - the output of many stars.how is travelling faster than c travelling back to the past?
| tingkagol wrote: |
| how is travelling faster than c travelling back to the past? |
OK...I'll give an example which should demonstrate it (although it will be simplistic for reasons of space).
When you look up at the stars you are looking into the past.
The sun, for example, is 9 light-minutes away. When you see the sun you are actually seeing it as it was 9 minutes ago. If the sun exploded and I left the sun and instantly arrived on earth at your side you will continue to see the sun for 9 more minutes and (if you had a big enough telescope) you would see me in orbit around the sun while at the same time I was stood next to you..
Does that help ?
Christhat's purely a VISUAL ILLUSION. a fallacy. if i had an arm as long as the distance from the earth to the sun, and touched it after 1 minute of the explosion, i would touch nothing, but my eyes from earth would TELL me it's still there because it takes 9 minutes (as assumed) for the last sparks of light to travel from the sun to the earth. Point: What you see isn't always what it seems.
also, our position here on earth never meant we travelled faster than C. and if earth DID travel AWAY from the sun with more than the velocity C, it's yet another fallacy.
Why? What if earth travelled the same speed TO the sun?
| Quote: |
| What you see isn't always what it seems. |
Just to correct this: What you see (observe) IS what it seems and that isn't necessarily what actualy is. | tingkagol wrote: |
| that's purely a VISUAL ILLUSION. a fallacy. if i had an arm as long as the distance from the earth to the sun, and touched it after 1 minute of the explosion, i would touch nothing, but my eyes from earth would TELL me it's still there because it takes 9 minutes (as assumed) for the last sparks of light to travel from the sun to the earth. Point: What you see isn't always what it seems. |
No, it is neither illusion nor fallicy. If your arm were able to touch the sun then your arm would be in a different inertial frame of reference to your eyes but that is an example which doesn't hold up. When I say you see the sun 9 mins ago, that is exactly what I mean - not a trick.
It is down to Special Relativity - nothing can exceed c and, more importantly, c is constant for ALL frames of reference. In other words if you are moving away from me at (say) .5c and I shine a torch at you, the light photons will pass you at c and I will see them move at c.
It can be hard to get your head around, but the upshot of this is that speed varies so something has to give and that is time. Time changes depending on how fast you are moving relative to another reference point.
Anyway...let's not go too deep. Just take my word for this - the time that light takes to reach you is real time and not a trick. If you observe a star 5 light years away you are seeing it LITERALLY as it was 5 years ago.
| Quote: |
also, our position here on earth never meant we travelled faster than C. and if earth DID travel AWAY from the sun with more than the velocity C, it's yet another fallacy. |
It was a thought experiment. If one COULD move from the Sun to the Earth in 0s then one would travel in time by about 9 mins....it's not a guess or a hypothesis - it is solid theory. It DOES happen - it has been tested experimentally in 3 different ways.
ChrisI think I erroneously used the word "illusion". But I still believe it's fallacy- just to preserve time as constant (well, for this scenario anyway). Yes, I believe you would see exactly what happened 9 mins ago, but for simultaniety, i gave the example of the long arm to override our sense of sight--- we depend too much on it. All I'm saying is perception doesn't necessarily show what actually happens.
| Quote: |
| If your arm were able to touch the sun then your arm would be in a different inertial frame of reference to your eyes but that is an example which doesn't hold up. |
I don't really get the technical terms you're using but let's further simplify this. let's say you're staring at an ant crawling on the wall. You see the ant only because of the presence of light. Now, let's say light travels 1 mm per sec, and your eyes are 1 meter away from the wall. So you get to see the specific position of an ant 1000 seconds ago, and when you do touch what you are supposedly "seeing" you would touch nothing but the wall (assuming the ant has moved to a different position)--- this also assuming you know exactly how to accurately manipulate your arm to the position of the ant in "sight" without the aid of vision (with the speed of light in this example, even if you'd extended your arm, you'd probably "see" it still at your side).
All i'm saying is, the concept of
| Quote: |
| Travel at speed faster than light (c) would be to travel back in time. |
is erroneous. It doesn't really mean you travelled to the past, but rather you SEE the past--- you can't really do anything to change or manipulate it. That said, VISION does not tell actuality accurately.
Just bending the rules with logic. hehe 
| tingkagol wrote: |
| I think I erroneously used the word "illusion". But I still believe it's fallacy- just to preserve time as constant (well, for this scenario anyway). Yes, I believe you would see exactly what happened 9 mins ago, but for simultaniety, i gave the example of the long arm to override our sense of sight--- we depend too much on it. All I'm saying is perception doesn't necessarily show what actually happens. |
Relativity is completely independant of sight and has been experimentally validated using atomic clocks in fast Jets. There is no fallacy here and time is not preserved in relativity - that is the whole idea.
| Quote: |
I don't really get the technical terms you're using but let's further simplify this. let's say you're staring at an ant crawling on the wall. You see the ant only because of the presence of light. Now, let's say light travels 1 mm per sec, and your eyes are 1 meter away from the wall. So you get to see the specific position of an ant 1000 seconds ago, and when you do touch what you are supposedly "seeing" you would touch nothing but the wall (assuming the ant has moved to a different position)--- this also assuming you know exactly how to accurately manipulate your arm to the position of the ant in "sight" without the aid of vision (with the speed of light in this example, even if you'd extended your arm, you'd probably "see" it still at your side).
|
This is not the same at all. Let me try another analogy which may be easier to accept. The reason for the 'time travel' is the fundamental rule that the speed of light is common to everyone, no matter how fast you are moving relative to each other. If I move away from you at, say, half the speed of light, and you shine a torch at me, you might expect the light photons to be travelling at 1/2c for me. Not so. Relativity specifies that the light will, to you, travel at 186000mph AND ALSO TO ME. Now this is totally counter-intuitive. To illustrate the effect this has on local time (a frame of reference just means the object being considered is in one 'frame' and the person observing is in another) I'll use the light-clock analogy.
Imagine we have a fast spaceship. Further imagine that we have an accurate clock which is a light clock which works as follows :
OK...the beam of light bounces up and down very fast and that is used to set our watches and clocks. This is very similar to a quartz clock in concept.
Now imagine that you and the clock fly across me at high speed.
To me, the clock would appear like this :
OK so far ?
Now, obviously to me the light is travelling further than it is for you - you still see the clock bouncing happily up and down because you are in the same 'frame of reference'. If light were not a constant speed for both of us then thre would be no problem BUT since light is travelling at the same speed for both of iis, and it is travelling further for me, this means that your clock is slow to my eyes. Now, the important point is that this is not an illusion or an effect. Your watch would keep perfect time with the light clock, as would you days and night and, ultimately your life. You would experience time quite normally and would not be aware of anything going on. I, on the other hand, would be in a different time which, again, to me would be perfectly normal and natural. when we next met, however, your watch would have a different time than mine and, if you were gone long enough,. and we started the same age, on your return you would be physically younger than me according to how fast you had travelled.
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All i'm saying is, the concept of | Quote: | | Travel at speed faster than light (c) would be to travel back in time. |
is erroneous. It doesn't really mean you travelled to the past, but rather you SEE the past--- you can't really do anything to change or manipulate it. That said, VISION does not tell actuality accurately.
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No, incorrect. It is a physical reality, not an illusion.
Time dilation is a well documented consequence of Special Relativity (actually it happens under General Relativity because of gravity as well, but that is another story).
Cheers
ChrisWhy are you explaining the whole theory to me again?
I do believe in special relativity. I believe light is constant for different frames of reference, I believe the example of the atomic clocks example, etc etc, blabla. You are explaining things that I already believe. Let's skip to chapter XXX---
Special relativity pretty much opens up the possibility of time travel to the FUTURE- which I AGREE. However, you said time travel to the PAST is POSSIBLE if you travel faster than C (and when I said C, I meant 3x10^8 m/s, NOT light)--- let me quote you again:
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| Travel at speed faster than light (c) would be to travel back in time. |
| Quote: |
| Travel at speed faster than light (c) would be to travel back in time. |
| Quote: |
| Travel at speed faster than light (c) would be to travel back in time. |
...which I do not agree, and you haven't even given an EXAMPLE to this (one object travelling FASTER than 3X10^8m/s vs one object stationary, etc) and I don't see the logic behind "you travelling faster than c" supporting this concept. In fact, i do not believe there's even a viable theory to support the concept of time travel to the PAST.... Once again, TO THE PAST.
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| When you look up at the stars you are looking into the past. |
This is pretty much the bulk of this discussion. LOOKING is different from TRAVELLING. There are senses other than sight, you know. That's why i gave the example of "the ant on the wall" to re-affirm the sense of TOUCH.
That, together with this:
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| Travel at speed faster than light (c) would be to travel back in time. |
Does not make sense to me... where is the "frame of reference travelling faster than C" here? In physics (as in real life) there isn't much point thinking what if this wasn't true or that, etc...
The relativity strictly forbids speeds higher than c (in fact that statement is in the center of theory of relativity: The c is the maximal speed of mater.). As object (of observation) gets closer to the c it's mass increases and theoreticaly when it reaches c it has infinitely high mass. So it's numb. In fact in universe no matter has been observed to have the speed c. 0.99 yes etc. Energy (such as light) travels at this speed (c).
So there is no point (in my opinion) in asking what if you reached speeds higher than c. As this is not possible in this universe we wouldn't exist to ask it (at least not in this form). You might as well be asking what if there was no gravity, etc...
well, impossible stuff like these are always good with beer.
| tingkagol wrote: |
Why are you explaining the whole theory to me again?
I do believe in special relativity. I believe light is constant for different frames of reference, I believe the example of the atomic clocks example, etc etc, blabla. You are explaining things that I already believe. Let's skip to chapter XXX---
Special relativity pretty much opens up the possibility of time travel to the FUTURE- which I AGREE. However, you said time travel to the PAST is POSSIBLE if you travel faster than C (and when I said C, I meant 3x10^8 m/s, NOT light)--- let me quote you again:
| Quote: | | Travel at speed faster than light (c) would be to travel back in time. |
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Well...I thought it was obvious from the example I gave (which is why I gave it). A speeds = c then the light clock is stopped relative to the observer. OK ? Now, extrapolate to speeds > c and you find the light clock is now running backwards relative to the observer.
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...which I do not agree, and you haven't even given an EXAMPLE to this (one object travelling FASTER than 3X10^8m/s vs one object stationary, etc) and I don't see the logic behind "you travelling faster than c" supporting this concept. In fact, i do not believe there's even a viable theory to support the concept of time travel to the PAST.... Once again, TO THE PAST.
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I gave no example because non exists - I have already said clearly that relativity forbids speeds > c for any entity with +ve mass. Consequently you are right to say there is no viable theory for time travel - I completely agree. My point was that speed > c is time travel, not that it is possible, just that conceptually that is the case.
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| Does not make sense to me... where is the "frame of reference travelling faster than C" here? |
Take any frame of reference you like. Move it at speed >c relative to a fixed observer frame. The observer sees the moving frame travel back in time....It arrives before it departs is a simple way of putting it.
ChrisThe reason why travelling faster than light opens up the possiblity of travelling into the past is that it involves swapping a physical dimension with a temporal dimension. What is time for everyone else becomes a physical dimension for the tachyonic traveller, and the missing physical dimension that was replaced by everyone else's temporal axis becomes the traveller's new temporal axis. In terms of everyone else's perspective, you loose control of where you are going in a physical dimension and gain control of where you move in what is their temporal axis.
I don't think anyone here really understands what I just said.
| mike1reynolds wrote: |
The reason why travelling faster than light opens up the possiblity of travelling into the past is that it involves swapping a physical dimension with a temporal dimension. What is time for everyone else becomes a physical dimension for the tachyonic traveller, and the missing physical dimension that was replaced by everyone else's temporal axis becomes the traveller's new temporal axis. In terms of everyone else's perspective, you loose control of where you are going in a physical dimension and gain control of where you move in what is their temporal axis.
I don't think anyone here really understands what I just said. |
Well, pardon this ignoramus for my flawed understanding of your hypothesis...I'll try to keep up.
You say that FTL travel (if it existed - tachyons are now rejected by most particle physics as a mathematical abberation rather than a real solution to GR) involves swapping the dimension of time for one of the spatial dimensions. Which one ? Length, bredth, height ?
Presumably the travellors new temporal dimension would be visible so that as the travellor 'aged' (s)he would get taller, wider or longer ?
Also, following the postulates of dimensional theory, a dimension higher on the ladder can effect one below, but not visa versa.
Methinks this hypothesis is a reworking of the Terry Pratchett scenario in the book 'Pyramids'.
Regards
Chris.now i can't understand anything.
| tingkagol wrote: |
| now i can't understand anything. |
LOL..don' try with this bit. Simply get hold of the Terry Pratchett book 'Pyramids' and you will find it explained in comic details :-)
Chrishaha. 
thanks for the tip man.
