Time travel?

[Jotaru]

Yar, I've no clue how it could theoretically bend spacetime enough to make a difference like that, but its a semi-decent way to look at it if you've no clue what people are talking about.

[Zhais]

Problem is, the way I see it all, for time travel in either direction ( especially backwards ) you have to view/accept that time is kinda a solid entity... something immutable and consistent throughout all viewpoints anywhere throughout the galaxy.

Time as we know it is just a measuring device. We use it to place events in the past/present/future in order to organize our daily lives. Once something is in the past, its simply a memory unless it leaves some sort of residual effect on the three dimensions that effectively bind us. Relatively, there is nothing more significant about events that happened 10,000 years ago and events that happened yesterday. They are in the past, which affect our perceptions and alter what we do due to written records/memory. I've never viewed time as a justifiable dimension in itself, as its just a tool for us.

There are some interesting theories however. Say, for instance, you created yourself a solid box with view holes. This box could withstand any amount of gravitational stress in any direction for unlimited amount of time. You create a gravity well centered around the box, close to that of a black hole. When you look out the window, what do you see? What does someone outside the gravity well see?

Their explanation was that due to the gravitational distortion, you would in effect age less than the outside observer. You would see them move at (normal? I think it was) speed although you only age 1 second for one of their years or something. They would perceive you as moving very slow and have the 'true' perception of the relative flow of time. I may be wrong in this... its been a good 5 years since I read up on this stuff. Some of the differing effects is also due to gravity's effect on light either speeding it up or slowing it down as it travels in and out of the gravitational well.

Depending on how this affects our three dimensions, Khamsin's idea could maybe be plausible. In a sense gravity can be a 4th dimension, as it has noticeable and physical effects on all three dimensions in a much different sense. If a gravitational mass can indeed tear 3rd dimensional space in such a way it bends upon itself, you could at least create inter-spacial travel... about time however I'm not sure.

In short, I believe you can alter your perception of how time passes, but never change the relative moment you are in accordance with others. May just be one of those paradoxes that gets answered as our own time passes (lolirony?)

[Kaylia]

Unlike past ideas for time machines, this new concept does not require exotic, theoretical forms of matter.

Making blackhole isn't considered exotic nowaday?

I supose it work mathematically with relativity model, but there is so many things that need to be clarified. How do you create a "donut shaped" gravity field? It's the opposite of a normal gravity field (shaped like a hole) created by matter. This time space would just crumble on itself the way I understand it, so you would need something almost magical (exotic matter) to stabilize it in that shape. If we can create gravitional field one day using energy and matter, than it could happen, but that goes against the observation and against our definition of gravity.

The "machine" also take wild guess by applying relativity to something that was never tested and/or observed. The undiscovered parameter of physics laws would most likely surface within that enclosed time/space capsule, giving a completly different scenario than the one proposed. That's like using Newton's physics to describe blackhole before they were discovered.

Also, from my understanding, any movement in time/space can be considered as vector. There is no no "negative" position or movement, just a direction and a number. Atm, there is no indications that a vector could be oriented toward the "past", the best we can say is that it's possible to nullify the "time" vector and stop any progress in that direction. In other word, a jump toward the future is possible by stopping time around you, but a jump toward the past would probably require an illegal movement.

Care to explain? I know you are right but I can't get my head around my first impression of why it matters. Whats the difference between the two? Are we talking about a regular jet (or one capable of being built by man)?

Everytime I think about this my head bleeds... I think I need a nap

It's not the jet, it's the speed. Take 2 persons, one walk in circle at 10km/h, the other sit down. After a short time, their clock will give different result.

Ok...not really because it will be in the order of 0.000000000000000000000001 (random number here), which is far under the precision of a normal watch, but if you repeat the experiment at higher speed with high precision clock, it's possible to notice the difference. What consuse you probably is your "3d" vision of the world, with time as something constant. It's really hard to imagine a "4d" vision of our universe, because our eye will never notice that kind of movement.


Time/space compression = 1/sqrt(1-v^2/c^2) where v = your speed and c= lightspeed. The closest you get from our universe speed limit, the fastest your "time speed" is. Basically, you will go toward the futur faster, even if time seem normal for you. That's why something in movement age slower than something that doesn't move.

In this case, the jet that was flying fast fell behind the clock that stayed on Earth after a while. It was tested (with a Satellite I believe..might have been a jet tho). The time compression can also be observed in particles where particles that goes at high speed will "die" slower than they would at normal speed. Those 2 experiments prove that Einstein theories were correct for "slow" speed and 0.97c.

[Kaylia]

I actually heard about this a long while back, not sure if this is from further research on it or just a similar reposting, but whichever.

This is (basically) how it was explained to me. You have to kinda bend your mind around it, as time doesnt have a 2-D 'direction' as it does in this picture, but it shows what it means in a very basic sense.


http://www.photoleech.com/images/118767 ... ru8m4r.png

Your diagram is very misleading. Time and space are indeed curved around any mass, but your "time" line indicate nothing. Basically, the picture you posted just show the normal gravitional effect...kinda like a comet around the sun. The same thing would happen around any masses, even a black hole. The object is simply going to follow the space/time curve and go around it. You don't go back in time, you just go back in space from where you come from.

In the case of high masses (black holes), the gravity acceleration is just so large that nothing can escape it. It create it's own space bubble, kinda like an universe within an universe

[Xavier]

We could always just politely ask God to send us back in time to the Stoneage...oh wait, thats already happening.

[Not Kuno]

We could always just politely ask God to send us back in time to the Stoneage...oh wait, thats already happening.

I don't know about you but I'd love to have my own cave.

[Fallso]

I actually heard about this a long while back, not sure if this is from further research on it or just a similar reposting, but whichever.

This is (basically) how it was explained to me. You have to kinda bend your mind around it, as time doesnt have a 2-D 'direction' as it does in this picture, but it shows what it means in a very basic sense.


http://www.photoleech.com/images/118767 ... ru8m4r.png

Your diagram is very misleading. Time and space are indeed curved around any mass, but your "time" line indicate nothing. Basically, the picture you posted just show the normal gravitional effect...kinda like a comet around the sun. The same thing would happen around any masses, even a black hole. The object is simply going to follow the space/time curve and go around it. You don't go back in time, you just go back in space from where you come from.

In the case of high masses (black holes), the gravity acceleration is just so large that nothing can escape it. It create it's own space bubble, kinda like an universe within an universe

Though even if something did exist in a black hole..we wouldn't know about it cause any form of communication (I would've thought) wouldn't be able to escape the gravitational pull of the black hole. For all we know black holes are actually a gate to another universe, but anything sent in generally wouldn't ever come back out.

Which proves another interesting question. If an object was able to escape the gravitational pull of a black hole by force..what would happen? Two mighty forces clashing together would cause something bad I'd imagine.

[Siniroth]

Also, anything sent in would need some way of resisting the gravitational force enough to stay together instead of being ripped into a line of particles

And yeah, black holes are what connect all the universes as per the multiverse theory.

I dunno what would happen if something were to resist, it would need to give it's own gravitational force, I would think, which would mean anything caught in between would be rightly fucked.

[Skyylya]

I don't know much about the physics and relativity but I remember either reading or watching a documentary on tv about how quasars or something are thought to be the under-sides of black holes, and that there are multiple universes (theoretically or whatever) and that the black holes/quasars are the links between them all.

I have no idea where it was that I heard this or it's validity at all for that matter, but being that black holes pull everything in, and quasars seemingly emit everything at an equal density make this correlation interesting enough to think about. The connection between that and the space-time fabric I have no idea.

Does anyone else know about what i'm referring to, about the multi-universe theories and black hole / quasar connections?

[Daydreamer]

Theory of relativity, using only words that are four letters or less. For the people that don't like science.

http://www.muppetlabs.com/~breadbox/txt/al.html

[Joran]

Also, anything sent in would need some way of resisting the gravitational force enough to stay together instead of being ripped into a line of particles

And yeah, black holes are what connect all the universes as per the multiverse theory.

I dunno what would happen if something were to resist, it would need to give it's own gravitational force, I would think, which would mean anything caught in between would be rightly fucked.

Yeah, at this point it seems as if the only thing we know of that could potentially resist the effects of a black hole is another black hole. Its like saying that the only thing hard enough to cut a diamond is another diamond. Black holes reside at the extreme maximum end of what we know to be the strength of a gravitational field. Nothing but another black hole could hope to match its effects and effectively anything caught in the exact center between the two would be torn asunder, half of it going in each direction. Of course I suppose its theoretically possible that if you were to happen to survive a trip past the event horizon of a black hole that you might find the exit point more easily accessible than the entry point because the flow of the gravitational field is paridoxically reversed. Either that or you would just be trapped at the exact center forever.

In any case, one thing I do know is that if we do create a time machine, never send pokemon from the future into the past that didn't exist in the past. Otherwise you'll make the machine explode and then nobody will be able to use it. :D

[Siniroth]

XD

[Khamsin]

Here's some random questions to think about:

Say I build a time machine and set a particular waypoint in time. Later, I decide to use it to return to that waypoint. What would happen?

1a) My physical self is transported to the past, such that there are two of me in the past.
1b) I travel to the past within my own body, yet my mind retains future knowledge.
1c) I travel to the past within my own body, but the chemicals and electrical signals in my brain are in the same state they were in the past, such that I have no knowledge of having made the trip. I am trapped in a personal time loop.

2a) I am instantly transported to the past.
2b) I begin travelling backward in time, much as I am now naturally travelling forward in time. Once I reach the waypoint, time then begins flowing forward naturally again.

3a) I am the only passenger of time travel, and experience the trip differently than everybody else.
3b) Time itself, for everybody and everything, goes back. The universe is at the waypoint in time again, and it's just as if it was our first time around and nobody knows any better. The universe is trapped in a time loop.

4a) I am capable of going into the past myself.
4b) Some physical object is capable of going into the past, but I am not.
4c) No physical object may go into the past. However, data or information transmittal of some kind, possibly using obscure or creative means, may reach the past.

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In the event of a personal time loop as depicted in 1c...

5a) There is no future for me, but the universe goes on.
5b) There is no future for me, or the rest of the universe.
5c) There is a future for me, from the perspective of the rest of the universe, but there is a split between the part of my consciousness that keeps going back to the past (because every time I reach that point in the future, I always go back) and the part that lives beyond that point.

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How will the universe end?

6a) The universe will one day end naturally, from heat death, another big bang, or some other typical end-of-the-universe theory.
6b) The universe will end before its time, because someone fucks up space-time.
6c) The universe will get trapped in some sort of time loop for whatever reason, and will never truly end.

[Kaylia]

Though even if something did exist in a black hole..we wouldn't know about it cause any form of communication (I would've thought) wouldn't be able to escape the gravitational pull of the black hole. For all we know black holes are actually a gate to another universe, but anything sent in generally wouldn't ever come back out.

Which proves another interesting question. If an object was able to escape the gravitational pull of a black hole by force..what would happen? Two mighty forces clashing together would cause something bad I'd imagine.

In the case of a black hole, the time space is curved completely on itself, so you can't escape it, not even with brute force...well, assuming the shape is perfectly circular and stable. Might still be able to escape from the extremity since our current model aren't complete, but we don't know that.

You would need "infinite energy", and this is not possible in any of our model to reach such speed/force. Either way, there is no way that matter survive the entrance in a black hole. The tide effect caused by gravity on your body is strong enough to ripe atoms nucleus apart, so nothing could go through it.

One possible form of communication would be gravitational wave maybe, but there is no hint that it will ever be possible to create those artificially.

don't know much about the physics and relativity but I remember either reading or watching a documentary on tv about how quasars or something are thought to be the under-sides of black holes, and that there are multiple universes (theoretically or whatever) and that the black holes/quasars are the links between them all.

I have no idea where it was that I heard this or it's validity at all for that matter, but being that black holes pull everything in, and quasars seemingly emit everything at an equal density make this correlation interesting enough to think about. The connection between that and the space-time fabric I have no idea.

Does anyone else know about what i'm referring to, about the multi-universe theories and black hole / quasar connections?

TV is usually the worst place to get your science info. Those sciences programs are interesting for sure, but in the end, they vulgarise so much and try to appeals viewer they show little valuable information, just pretty image to make the viewer dream about space.

Quasar: bright halo of matter spinning around a super black hole (galaxy in formation)

Gamma Ray burst:
The majority of observed GRBs appear to be due to collimated emission from the core-collapse of a rapidly rotating high-mass star into a black hole, but a specific subclass of GRBs (the "short" bursts) appears to be due to another process, possibly the collision of two neutron stars orbiting in a binary system. All known GRBs come from outside our own galaxy (though a related class of phenomena, SGR flares, are associated with Galactic magnetars), and most come from billions of light years away.[/quote].

Neutron Star: Also interesting, since they draw the limit between black hole and non black hole. It's basically a black hole that was too small to fully curve the time/space around it. Time slow down same way it would around a black hole, but not enough to reach relativity limit.


While it's not incorrect to say black holes create their own small universe, saying they are connected is a pure guess. We can't really exclude any possibilities, but that hypothesis skip a few step.

[Septimus]

Unlike past ideas for time machines, this new concept does not require exotic, theoretical forms of matter.

Making blackhole isn't considered exotic nowaday?

I supose it work mathematically with relativity model, but there is so many things that need to be clarified. How do you create a "donut shaped" gravity field? It's the opposite of a normal gravity field (shaped like a hole) created by matter. This time space would just crumble on itself the way I understand it, so you would need something almost magical (exotic matter) to stabilize it in that shape. If we can create gravitional field one day using energy and matter, than it could happen, but that goes against the observation and against our definition of gravity.

The "machine" also take wild guess by applying relativity to something that was never tested and/or observed. The undiscovered parameter of physics laws would most likely surface within that enclosed time/space capsule, giving a completly different scenario than the one proposed. That's like using Newton's physics to describe blackhole before they were discovered.

Also, from my understanding, any movement in time/space can be considered as vector. There is no no "negative" position or movement, just a direction and a number. Atm, there is no indications that a vector could be oriented toward the "past", the best we can say is that it's possible to nullify the "time" vector and stop any progress in that direction. In other word, a jump toward the future is possible by stopping time around you, but a jump toward the past would probably require an illegal movement.

What about anti-matter? It's been a while since I've had my Einstein classes, but wouldn't the vector of anti-matter be perpetually pointed to the past? (But only within the confounds of the speed of light like regular matter.)

[Kaylia]

Here's some random questions to think about:

Say I build a time machine and set a particular waypoint in time. Later, I decide to use it to return to that waypoint. What would happen?

1a) My physical self is transported to the past, such that there are two of me in the past.
1b) I travel to the past within my own body, yet my mind retains future knowledge.
1c) I travel to the past within my own body, but the chemicals and electrical signals in my brain are in the same state they were in the past, such that I have no knowledge of having made the trip. I am trapped in a personal time loop.

Just destroy Garland to stop the time loop, you will be fine!

Time traveling create too many paradox to consider it with our physics. Are futur and past connected? Are they instantly updated or not? Is there multiple universe created every time there is a time travel in the past? An universe with multiple path is probably the answers that give us the less trouble, but that doesn't mean it's the case.

The way I see it, the only way to go back in space would be to bring back the universe at the state it was before...which is impossible because of the movement in space of every particles

How will the universe end?

6a) The universe will one day end naturally, from heat death, another big bang, or some other typical end-of-the-universe theory.
6b) The universe will end before its time, because someone fucks up space-time.
6c) The universe will get trapped in some sort of time loop for whatever reason, and will never truly end.

I always find myself hoping 6b will be the correct answer. I kinda want to see it happen, and 6a) is going to take many billions years before happening

[Not Kuno]

What will have the energy to cause the entire universe to go back in time to loop forever? And on that note, how does a person go back in time without needing some massivly huge energy source?

Also, they're probably fucked on getting back, as well as choosing how far back they go. Plus it would be funny if time travel was very literal. Like.. you decide to go back 1 day and you're floating in the middle of space because the earth wasn't there a day ago. Lulz.

[Kaylia]

What about anti-matter? It's been a while since I've had my Einstein classes, but wouldn't the vector of anti-matter be perpetually pointed to the past? (But only within the confounds of the speed of light like regular matter.)

Antimatter? Or matter that follow an opposite gravitational rule? The first one exist, while the 2nd is an hypothetical.

Antimatter is simply matter composed of anti-particles and follow normal physics law. All of them exist already, but they aren't common. To create antimatter, you replace the electron with positron, proton with antiproton and neutron by anti-neutron. The atoms you just created with the antiparticles works the same way, except the energy holding it together is negative instead of positive. It's like having a N + S magnet, instead of S + N. As long it's not 2 force that reject each other, it will work.

For gravity, the only thing that matter is mass, and anti-matter mass is equal to matter. It won't create anything special, and will bend space the same way.

[Khamsin]

What will have the energy to cause the entire universe to go back in time to loop forever? And on that note, how does a person go back in time without needing some massivly huge energy source?

It depends on whether or not time is tied directly to the specific mass you are trying to send back, or if time in general is being manipulated, and that the entire universe shares the same time axis? Will the energy required be dependent at all on the amount of mass going through temporal changes, or will it be simply a change of viewpoint rather than physically moving the entire universe?

Imagine a piece of 2D paper with a sine curve drawn on it. Take a piece of cardboard and cut a slit in it. Place it on the paper, and slide it slowly across the paper toward the right. There will appear to be a dot bouncing up and down, as viewed through the slit. Slide the cardboard back to the left. The dot is going in reverse. Will time travel be like moving the cardboard to the left, or will it be like somehow separating that dot from the rest of the paper and putting it somewhere else?

[Kaylia]

What will have the energy to cause the entire universe to go back in time to loop forever? And on that note, how does a person go back in time without needing some massivly huge energy source?

Homer did say the universe was shapped like a donut, so it might be a huge time machine. That would explain the time loop! But yeah, doubt universe loop on itself, that wouldnt make a lot of sense.



Did anyone ever heard about "virtual particle". It's one of the cool thing in physics that many people seem to ignore.

Formally, a particle is considered to be an eigenstate of the particle number operator where is the particle annihilation operator and the particle creation operator (sometimes collectively called ladder operators). In many cases, the particle number operator does not commute with the Hamiltonian for the system. This implies the number of particles in an area of space is not a well-defined quantity, but like other quantum observables is represented by a probability distribution. Since these particles do not have a permanent existence, they are called virtual particles or vacuum fluctuations of vacuum energy. In a certain sense, they can be understood to be a manifestation of the time-energy uncertainty principle in the vacuum.

An important example of the "presence" of virtual particles in the vacuum is the Casimir effect. Here, the explanation of the effect requires that the total energy of all of the virtual particles in the vacuum be added together. Thus, although the virtual particles themselves are not directly observable in the laboratory, they do leave an observable effect: their zero-point energy results in forces acting on suitably arranged metal plates or dielectrics.

Thus, virtual particles are often popularly described as coming in pairs, a particle and antiparticle, which can be of any kind. These pairs exist for an extremely short time, and mutually annihilate in short order. In some cases, however, it is possible to boost the pair apart using external energy so that they avoid annihilation and become real particles.

Basically, in an empty space, matter and antimatter will be created for short period of time before annhilathing each other. Those particles are considered virtual, but we can uses force to separate them and make them real.