Time travelling is not posible :(

[r-ID]

Nostalgiia, this is the wrong interpretation of relativity, let's say you move 0.99c to the one direction, you will see no difference in light movement, at all. Light in any direction will travel at the speed of... guess what... light (http://en.wikipedia.org/wiki/Postulates ... relativity) (read second postulate) So speed is relative, so is the distance and the mass and everything else. I was digging deep in the time i started this topic, i can do calculate some of relative effects now.

you wonder why nobody has come back

Time goes one way, time travel is possible, we do that all the time (relative to something) just it is one way journey.

The interesting thing about timespace is that you can never go to the past but you can go to the future, you can't see the future but you can see the past. How can you see the past? I do have an idea how. All you see in the universe is old, the farther you look, further you see. You can even see yourself (at some point), by looking to the black hole you can see yourself, it's hard to explain but black hole can bend photons back to you, so basically it's a mirror (wiki gravitational lenzing effect) (there are billions of blackholes! with different images, so ALL the past is visible to the whole universe)

Example: you think time dilation effects are really small? LHC http://en.wikipedia.org/wiki/Large_Hadron_Collider can spin particles at the speed of 0.999999991 c (pretty fast ha?) Lorentz factor at such speed is 7450 (Knoble's formula) that means that if LHC was spinning 7450 years, only 1 year would pass for the matter that was spinning.

If the universe is rotating, then if you travel at the opposite direction, around the entire universe, faster than the universe is traveling, then you will arrive on earth before you left.

This is stupid because speed is relative.

Another is a loop hole. If you put two dots on separate ends of piece of paper, then fold the paper, the dots are on the same spot. So if you could somehow create a loop hole then you'd be able to be at two times at once. Or something like that.

This is stupid too because you can't put any two space points together, you can only bend (or should i say stretch) spacetime.

Knoble gave the right formula to calculate Lorentz factor, time dilation, mass increase, and length contraction effects.

Another example:
let's say a man from the left goes towards me at the 0.8c speed, so does the man from the right, how would that look for the man from the left? 1.6c? no
s = (v + u) / (1 + ((v * u)/c^2)
that's how (0.8c + 0.8c) / (1 + (0.8c*0.8c)/c^2)) = 1.6c / 1.64 = 0.9756c

where the speed gone? it's relative.

[Knoble]

so this was a question on my relativity final..I think i fucked it up a bit but, I'll see if anyone here can do it.

two lamps are separated by 2000 m. an object is moving at 0.5 c towards one of the lamps at at time = 0 the lamps are switched on. How long does the light moving in the opposite direction of the object take to reach the object, and how long does the light moving in the same direction take. somehow i got the same answer for both directions so i think i fucked up but i thought id post it.

[r-ID]

so this was a question on my relativity final..I think i fucked it up a bit but, I'll see if anyone here can do it.

two lamps are separated by 2000 m. an object is moving at 0.5 c towards one of the lamps at at time = 0 the lamps are switched on. How long does the light moving in the opposite direction of the object take to reach the object, and how long does the light moving in the same direction take. somehow i got the same answer for both directions so i think i fucked up but i thought id post it.

a--------<<<b--------c

time dilation at 0.5c is about 16%

1) the light from b will reach a after 1000M/C relative to a
2) the light from b will reach c after 1000M/C relative to c
3) the light from a will reach b after 1000M/(C + 0.5C) relative to a
5) the light from a will reach b after 1000M/(C + 0.5C) relative to b
4) the light from c will reach b after 1000M/(C - 0.5C) relative to c
6) the light from c will reach b after 1000M/(C - 0.5C) relative to b
7) a thinks that time to reach the light from a to b for b is 1000M/(C + 0.5C) * 0.84
8) b thinks that time to reach the light from a to b for a is 1000M/(C + 0.5C) * 0.84
9) c thinks that time to reach the light from c to b for b is 1000M/(C - 0.5C) * 0.84
10) b thinks that time to reach the light from c to b for c is 1000M/(C - 0.5C) * 0.84

[Nostalgiia]

@r-id, i think you misinterpreted what i was saying, because if you are moving in the same direction as the light reflected off of an object at +c, since light moves at c, and you look behind you, the object will appear to retrograde in motion because:

Code: Select all

   ^
   |
object                     you moving                  \     |   |  |  |  |  |  |  /
moving                   that way   -->             --  star, aka light source --
that way                                                    / | |  | | | | | |  |  |  \


the star projects light in all directions, and once the light reflects off of the object, you see it, and the light is also, in this situation, moving the same direction as you. if you are moving +c, you are passing old light that has reflected off of the object, and the light that you see appears in reverse (since your coming from behind it) and therefore, makes it appear as if the object is moving backwards, in relation to it's direction at < c speeds. and for this reason, you will never be able to attain time travel with speed alone, maybe with the wormhole that you will most likely open, but not with the speed. you would have to turn around, and the object would flip directions, and double-ish speed.


***Edit***
sorry i had to use the code tag to make my text-illustration render properly lol

[r-ID]

@r-id, i think you misinterpreted what i was saying, because if you are moving in the same direction as the light reflected off of an object at +c, since light moves at c, and you look behind you, the object will appear to retrograde in motion because:

Code: Select all

   ^
   |
object                     you moving                  \     |   |  |  |  |  |  |  /
moving                   that way   -->             --  star, aka light source --
that way                                                    / | |  | | | | | |  |  |  \


the star projects light in all directions, and once the light reflects off of the object, you see it, and the light is also, in this situation, moving the same direction as you. if you are moving +c, you are passing old light that has reflected off of the object, and the light that you see appears in reverse (since your coming from behind it) and therefore, makes it appear as if the object is moving backwards, in relation to it's direction at < c speeds. and for this reason, you will never be able to attain time travel with speed alone, maybe with the wormhole that you will most likely open, but not with the speed. you would have to turn around, and the object would flip directions, and double-ish speed.


***Edit***
sorry i had to use the code tag to make my text-illustration render properly lol

or the illusion of time travel

You don't know what time dilation is.
http://en.wikipedia.org/wiki/Time_dilation
Do you know that time for satellites goes at different rate? it's not some kind of light reflecting effect, it has nothing to do with the light at all, It Is TIME dilation.
if your friend travels at 0.999..999 c he can travel to the end of our galaxy, came back to the earth, and might be only 1s. older (depends on how many 9s there are), but... in the earth hundreds of thousands years might have passed.

[Knoble]

i think there has to be some flaw in special relativity. I mean since photons travel the speed of light...their time dialation becomes infinite, as well as their length contraction. So basically every light photon is everywhere at once forever? Doesn't that seem a bit, far fetched? I know that's in their reference frame but doesn't that mean that light could pass the expansion of the universe, since basically time stands still for them? It just seems weird to me.

[r-ID]

i think there has to be some flaw in special relativity. I mean since photons travel the speed of light...their time dialation becomes infinite, as well as their length contraction. So basically every light photon is everywhere at once forever? Doesn't that seem a bit, far fetched? I know that's in their reference frame but doesn't that mean that light could pass the expansion of the universe, since basically time stands still for them? It just seems weird to me.

This is a very good question. I think that Einstein's relativity isn't entirely correct. Newton was right, as some points, till speed doesn't get very big, so is Einstein. Any formula/theory has it's limits. I can't even interpret what is going on at speed c, formulas do give answers like 0 or infinity. Currently I'm thinking about photons like about waves, photons don't have rest mass and it can only travel at the speed of light. Similar like the gravity does. Let's say you think that a photon is a particle, then yes, you can say that it could travel to any place in no time. Another point of view is to think about everything like particles and to completely forget about waves. Interesting thing is that photons are affected by gravity too - mass/energy attracts another mass/energy E=m and *c^2, but how would someone without a mass and without feeling any time could be affected by gravity? I think it's spacetime curvature, everything gets curved. (me thinks: does the gravity gets curved too? looks like not, blackhole still has gravity but photons can't escape it, so maybe photon is a particle? It is more accepted to think about it like a wave, or should i say wave-particle.
Einstein was right, just his theory doesn't work well at extremes, or should i say that imagination at this point is more important then logical thinking.

[sh3llz]

Time travel is always an interesting topic. Unfortunately, my stance on whether or not it is possible often changes. Right now I feel like saying it's possible. Why? Well in short:

Both space and time are dimensions, and as such are comparable to a degree. For example, both dimensions are effected by gravity and both are effected by speed. In-fact, gravity itself is effected by speed so perhaps this should only be considered one example. In any case, the dimensions are, in a sense, tied to each other. They share a mathematical relationship.

With that understood, it's not a great leap to say that if the fabric of space were malleable, so too would be the fabric of time. And in fact they are. However, with the question of time travel, the issue becomes more than simple malleability, but instead - is the fabric of space/time able to be stretched, torn, or more to the point - reversed? My answer - yes. As an example of such an event taking place, one could point to black holes. That's not to say black holes can take someone to the past, just that the fabric of spacetime behaves much like... fabric.

And so while it is of course only theory, I see no reason why this fabric can't be manipulated to our advantage for the purpose of something like time travel. Especially when you continue to view space and time as both similar and intertwined. Doing so reveals the holes in a few very famous paradoxes. To make my thoughts on that subject simple and blunt, I don't believe the past can be changed. So paradoxes can't occur. If someone were to travel to the past (which I believe is theoretically possible) they were of course in the past before so wouldn't be able to make anything new happen. I do realize that this seems to take away "free will" but that's a topic for another time and place.

[Defience]

A bit off topic here but I just watched the movie "The Time Traveler's Wife"......good flick. It doesn't actually deal with some type of machine for time travel, it's more like "Jumper" where the guy was born with some genetic make up that aloud him to do this. He would be in front of someone and then just fade away. What was interesting was that he could travel into the future or into the past and at one point, he's in the future and meets his 10 year old daughter. She informs him that he dies when she's 5. Strange that he could travel beyond his life span but interesting.

[Okeymaker]

I have been big into quantum physics since I was nine years old. (I am only 15.) One of the first things I read about was wormholes. I want more wormholes and time loops in this conversation.
First: I think that when you are discussing this topic, you should stick more to physics than astronomy, because astronomy is mainly based on a bunch of VERY unproven theories.
This is my views:
1. As Eljonto and some other true belivers (xD) said, mass (and don´t forgot energy,) is moving forward. It would be impossible to take it back to exact the same position, (then u would have to reverse the course of energi too) and so on.
2. I belive that moving faster then the rest of the world could be one way to travel in time.

3. I REALLY think that people have a bad habit to confuse* the speed of light with the "speed of time". I think that Einstein´s arguments for lightspeed is poorly explained by nowdays scientists, so that they make sense.
(* confuse may be a bad choice of word?)

Now, moving faster than lightspeed is like everything else just a choice of parable. You can slow down photons by freezing them. A simple natrium cloud could slow them down so much that you can move faster then them. Let´s say you have moved faster than these photons, the light itself could move. Are you in the future? Most probaly not.
Now think of this. Does moving faster than light really means thesame as moving faster then the time itself?
I would say no.

So what IS the "time"? I have always thought, since I was a child, that you may look to this relative. All atoms are constantly moving. Sorts of Quantum (like photons) are too small to actually be able to notice so much that you can explain what they are. We are constantly moving forward. All energy is mass (or at least all mass contains energy) and all mass is floating around in the universe. Now what makes it float from the beggining, this mysterious phenomena that makes mass move from one space to another and makes life possible is what many people would call TIME. I think I will call it god.
(Or at least god´s breathe xD)


PS. If we look to what Einstein said (especially in his special relativity theory,) gravitation may influence on how the mass is floating. Pretty shame that "gravitation is not a known quantum."