Do you think it's possible?
If you have a Delorean
and some plutonium
Yeah and then you just need to accelerate to 88 MPH :D
Ok, I love that movie, in fact Back to the Future is one of my favories.
But my question is somewhat serious.
Imho time travel maybe possible but only for traveling to the past. I think future isn't determined yet so you cannot go there. On the other hand, going to the past and changing only a minor thing can lead to huge effects on the present. Just is you go to the past, you've already changed it.
You know the chaos theory. :)
Anyway wether it is possible or not I think time travel remains in the world of sf for a couple more centuries.
I watched a whole show on this on either Discovery, Learning Channel, or oddly enough, History Channel. Maybe I watched it on Nova back when I was still watching Nova.
Anyway, they talked about Einsteinian physics and said that as far as we understand the universe time travel is inherently possible. Science has accepted that. But, what does that mean? Is it possible to go back in time to kill your grandfather before your father is born? That's the paradox question that comes up every time you get into time travel.
The rest is left up to science fiction because science has no answers.
Once we invent the Flux Capacitor...
>>6 Nah, the flux capacitor is most likely a simple wave generator.
I'm more worried about the 1.21 gigawatts of power needed...
We don't have portable plutonium-powered nuclear reactors currently.
>>8 But Mr. Fusion is in the future... TIME PARADOX!
Back to the topic (oh dear god no!! I didn't mean to)
I don't believe so. I'm too tired to explain it, but I thought about it enough to right a 3 copy page essay on it last year.
Good times ^_^
At least thirty years back, there were some papers published discussing the possiblity. I mean scholarly papers, from physicists, who were looking at the mathematical models in Einstein's theory of relativity and examining them under unnatural, possibly impossible conditions.
Google for "Tipler machine," "Kerr metric space warp," or "closed timelike curve" and you will see some very brilliant stuff.
I don't know whether any of it was ever found to be mathematically inconsistent with relativity, or proven to be mathematically impossible, though the reduction-to-practice aspects are daunting.
A Kerr metric space warp, for instance, would require the mass of a star crammed into a superdense black whole whose core was not in the natural spherical shape that gravity would push it into, but, rather, a torus--a ring, in other words--that was spinning at almost the speed of light. Pass through the center, go into the past. Or something like that. It's a fascinating idea but you can't exactly build one in the garage.
>>10 Time travel is a reality. I'm travelling in time right now. And so do you. At 1x speed.
Your humble opinion is completely wrong. Time travel into the future is very easy. Besides the fact that you're travelling there right now, simple special relativity tells you that if you're in a hurry, you just need to go move very fast and you'll get there quicker. Once you're there, though, you're stuck.
Unless the esoteric relativistic solutions like >>11 mentions ever turn out to be feasible, but that's very uncertain. Those are, however, not exactly "time machines", but something much, much stranger.
Using what I've heard and read of time travel and parallel universes, most likely what would be experienced in time travel is just going to a universe that is however far back as you think you've traveled (say 2006 to 1920s, just 86 years behind ours). Because of this, coming back here will show no know changes because it affected another world entirely.
I'm guessing of course.
>>13 Yeah. There is also gravitational time dilation: for example the GPS satellites we have in orbit have their clocks running behind. I guess one could say that the satellites are time-travelling into the past, by a minute amount.
GPS satellites, as they are orbiting or just falling through the vaccum of space, aren't affected (or very little) of gravity. Somehow matter moves at a slower pace when not under gravity. So clocks on satellites tend to stay behind earth-time and need to become updated in a periodic basis.
I think that beings tend to live a little longer when in weightlesness.
I don't know wether time-travel will ever be possible or not. But I have been experimenting a little bit with myself as of how time shifts according to situations. Whenever I sleep with my music on, I can unconciously hear it (sometimes) and notice a faster beat rate, meaning that the music goes faster than what you are accustomed to hear. Therefore, I can say that my body is moving at a slower rate, because it is in sleep mode, and time moves faster. I remember that I once was listening to music when suddenly the phone rang. And because it is located at the other end of my home, I had to run. Once I hung up I continued to listen to my music, but noticed it was moving slower. It seemed that, under that desperate situation, my body modified its biological clock and made time go slower, hence making the music become slower and have a lower pitch.
Maybe different situations make our body change its biological clock to respond correctly and more efficiently to them.
What do you think?
I think biological clocks have as much to do with time travel as sunglasses with have with nuclear fusion.
>>17 Lol. Good analogy.
Yes, time travel is possible under Einsteinian physics. Unfortunately we have no clue how it works nor how to move backwards through time. Since to move backwards in time forces us to break the speed of light, which also under Einsteinian physics is impossible. Tests have shown however that time travel is possible. We have tested and measured small instances of slowing time, most notably through the use of atomic clocks placed in orbit.
You are technically correct that we have "tested and measured small instances of slowing time", but this really is a bit misleading. Not only are experiments confirming this (by necessity) done every day, but many everyday occurances depend on it - notably, GPS navigation.
Adding to my comment >>15, "time travel into the past", I'm still not sure of my assertion. Is it the GPS clock that moves backward in time, or is it the clock on the ground that moves (fast)forward in time?
I think you're misunderstanding. Both are moving in time at the same speed according to the effects of both gravity and motion. Since according to Einsteinian physics the closer you are to a gravitational center the slower you move in time. Also the faster you travel the slower you move in time.
By moving an object away from the center of gravity (Earth) you are minutely moving it faster through time. But! The effects of being away from the center of the earth is negligable compared to the effects of traveling at high speed that slows it down.
Once one atomic clock is seperated from the other and placed in orbit it begins to move at a different rate through time. It's not much but it is measurable because atomic clocks are amazingly accurate.
So to answer you, neither atomic clock (you call them GPS clocks but I imagine you meant atomic clocks) is moving forward or backward in time. They are both moving forward in time at different rates, the one in orbit moves slightly slower through time then the one on the ground because it's slowing time as it approaches the speed of light.
People... "time" doesnt exist...
its invented by humans to make life a little easier, like: "hey lets meet at 7 ok?"
the so called "ageing" is just a procces off cells breaking down
so how can time traveling be possible is there isnt even time to travel with?
sigh but anyway its getting late and its time to go, see you next time!
>>21 Okay, but which time should a time traveller sync his clock to? I suppose that with the Moon orbiting Earth, they are variations in the atomic clocks on the ground as well. Also planets/the Sun moving closer or away. Don't those ground clocks get out of sync with each other at times? Or not?
Yes, a clock set on the moon will move at a different rate then one on Earth, or the Sun, or Jupiter, or wherever it's placed. It's unavoidable. We do the best we can with what we've got though and right now since Greenich standard time is universal on Earth you can assume that it's universal in the Galaxy (assuming of course that we're all there is in intelligent life). Any clock which gets out of sync presumably would be reset to GMT whenever possible.
Since interstellar travel is still a dream we don't know exactly what happens when people begin traveling through space and colonizing other worlds. Right now it's left to science fiction how to handle clocks in that future.
The basic principle of relativity is that there is no preferred reference frame. That is to say, there is no clock to sync to. All clocks run different, and there's nothing you can do about it, except choose an arbitary one to call your standard time. Even if you do, it won't have anything to do with any deeper aspect of reality, it will just be bookkeeping for yourself.
You should also realize that this goes further than that. The concept of "simultaneity" doesn't exist, either. The concept of two things happening in different place simultaneously is meaningless, because this is also dependent on your reference frame (that is, the speed you're moving at, gravity, and such). Things can only happen at the same time if they also happen in the same place.
This is a pain in the ass to wrap your head around, but unfortunately it's how the universe works.
There is another way of timetravelling into the future that hasn't been mentioned above yet, and that's temperature.
For example, food in the fridge decays slower that in the heat.
So this is yet another factor that could influence an atomic clock, isn't it?
Are those forward-timetravel factors (gravity + speed + cold) cumulative?
> But! The effects of being away from the center of the earth is negligable compared to the effects of traveling at high speed that slows it down.
But! all movement is relative, so it isn't actually moving at all.
Cold only slows down the atoms. I don't believe cold has anything to do with slowing time to any degree. It's used to preserve foods because it keeps bacteria and molds inactive.
No. Lay off the acid.
>>28 Wait, wait... if cold is slowing down the atoms, why has it no influence on an atomic clock?
>>30
No. Lay off the acid.
Just because both the statements "slowing down the atoms" and "atomic clock" have the word "atom" in them, does not mean they are directly related.
You don't age more slowly by walking slower.
>>32 Well, okay. I need to look up how an atomic clock works.
Rephrasing my other question: are forward-timetravel factors (gravity + speed) cumulative?
>>33
gravity and speed are the same factor.
Yes, they are cumulative.
Well, it's not as simple as being "cumulative". >>34 has it, they're different sides of the same thing. The important thing is paths through space-time. Figuring out what the result will be with strong gravity and high speed is nowhere near intuitive. You pretty much have to work through the maths to figure it out.
However, in the case of something like GPS satellites orbiting the earth, speed and gravity are both low, and the effects are approximately cumulative. However, the effects also oppose each other.
http://en.wikipedia.org/wiki/Hafele-Keating_experiment has some information on this.
I see. Ok, my next question:
As one's velocity increases, one goes forward in time. The maximum speed is the speed of light, and is a known constant.
As one approaches a strong gravity field, one goes forward in time. I guess there is a maximum for a gravity field too? Is this known?
>>37
black hole?
We are always Time Traveling to the future!!
There is no maximum as such for how strong a gravity field can be. However, a strong enough gravity field can reach the point where spacetime is bent to the point that no particles can escape, even if they move at the speed of light. As a first approximation, you can think of it as a gravity field so strong that the escape velocity is higher than the speed of light (however, you will need to account for relativistic effects when considering this in practice).
As >>38 mentions, a black hole is the prime example of this.
>>40 Something I don't understand here. Light cannot escape a black hole (obviously), but light particles have no mass, which is why they can travel at the speed of light. If a particle has no mass, how come it can be trapped in a gravity well?
Because the simplistic view of gravity as masses acting on masses in the Newtonian model is incorrect.
Actually, that's not the right explanation. Even in the Newtonian model, light is affected by gravity. But it predicts a different result than relativity. Remember, gravitational acceleration is independent of mass: A heavy body falls as fast as a light one. Thus, one without mass entirely falls as fast as one with a tiny, nearly undetectable amount of mass, which in turn falls as fast as a heavy mass.
However, in relativity it turns out this is not actually the case. In relativity, all bodies follow geodesics (that is, locally straight lines in curved space) through space-time, and matter curves space-time. However, light and mass follow different paths.
This was the basis for one of the early experiments to verify relativity: http://sunearthday.nasa.gov/2006/locations/einstein.php
>>42 Is the warping of spacetime temporary?
That is, does a light ray after passing near a strong gravity like a sun (looking bended while doing so), re-take its original trajectory?
In other words, is it just an optical illusion?
Simply put, no.
Optical illusions are created either by the brain misinterpreting information or light passing through a medium like water or air which distorts the image. Neither is happening here.
The Sun's gravity field is actually not all that strong, but it is the strongest we have nearby. And no, it's not temporary - spacetime is warped by the presence of mass. Light moves along straight lines in spacetime. After passing close to a large mass, the direction of the light will have changed.
Ok, I think I get it.
So, near a strong gravity field spacetime is warped, and that includes whatever light ray that passes thru it. Also, time is passing faster.
What if the strong gravity field is inverted? In a mathematical model of an inverted gravity field, is the time factor also inverted?
Time passing faster is not a separate effect. Also, time can pass slower or faster, depending.
Think of it like this: Two people go from point A to point B. one of the passes through an area of warped space-time, and the other does not. When they meet up, they find that less (or more) time has passed for one of them. It is not because "time has moved faster" for one, it is because their paths through spacetime were different.
Also, there are mathematical models for crazy stuff like negative masses creating weird spacetime distortions, but I don't really know anything about them so I will not comment on that.
OK.
Has there been any known instance of black holes vanishing?
Or black holes appearing where there were none before?
blech, you're starting to ask questions that are beyond me. Basically I can answer that stellar phenomenon like the creation of black holes, is not something that occurs in any amount of time we as humans can witness. It basically takes eons to mash stars together or cause them to explode thus creating black holes. I remember reading a short paper by Stephen Hawking that explained that there's a subatomic particle which is created spontaneously in space. If one were to be created on the edge of a black hole (the event horizon) part would spiral back into the black hole while half would break away and return to normal space. This is the only way a black hole can reduce it's mass, eventually decaying over countless millenia. It's been years since I read that article so the science behind it is beyond me now.
We still can't observe black holes directly, only their large-scale effects, and even those can be hard to unambiguously make out. As far as I know we don't have perfectly solid evidence they exist yet (although lots of circumstantial evidence, so to speak).
The main process that can create black holes that we know of are supernovae. There hasn't been one near enough to study closely, which is good, because it'd probably fry us if it was. As >>49 mentions, these things happen over astronomical timescales, which is far longer than humans have been around.
And black holes are thought to disappear by Hawking radiation, but the timescales involved for that are beyond anything you can imagine.
OK. It seems we'll have to wait for the CERN's LH Collider in 2007 to (hopefully) crank out mini black holes to study before we can map fully the black hole's properties.
Before you can ask yourself "is time travel possible?", you first must ask yourslef "what is the nature of time?". We don't know for sure that time really physically exists at all, it may just be a concept that we associate with the changes in the world around us, and use to chart the progress of those changes, a concept we have become so dependant on that we view it as something physical that can be seen or changed or altered. The fact is we don't know for sure that time is a physical thing at all, it may just be all in our heads, a psychological crutch, if you will.
On the other hand maybe it is. And then you have to wonder what it's physical propertys are. Is it a dimension, a fourth axis on which we are constantly moving? Or perhaps it's some other physical thing. The fact is, it is at our current stage of thought impossible to prove or disprove even the EXISTANCE of time, let alone weather we can alter it's course.
Before you can ask yourself "is space travel possible?", you first must ask yourslef "what is the nature of space?". We don't know for sure that space really physically exists at all, it may just be a concept that we associate with the changes in the world around us, and use to chart the progress of those changes, a concept we have become so dependant on that we view it as something physical that can be seen or changed or altered. The fact is we don't know for sure that space is a physical thing at all, it may just be all in our heads, a psychological crutch, if you will.
On the other hand maybe it is. And then you have to wonder what it's physical propertys are. Is it a dimension, a fourth axis on which we are constantly moving? Or perhaps it's some other physical thing. The fact is, it is at our current stage of thought impossible to prove or disprove even the EXISTANCE of space, let alone weather we can alter it's course.
>>53 Um, we're not talking about the philosophy of existence but the observable nature of spacetime. So, please don't bring psychology into a discussion of physics. You may be correct, we could all be brains placed in a jar and fed stimulation to see our reactions but since we can't measure that scientifically we discuss the things we can measure. And by our mathematics and knowledge of physics time travel IS possible.
> The fact is we don't know for sure that time is a physical thing at all, it may just be all in our heads, a psychological crutch, if you will.
Spoken like a true philosopher with no knowledge whatsoever about the actual physics of what he is talking about. When you say "we", you really mean "I", don't you?
Before you sprout statements like this again, maybe you should take some time to study what we actually do know about time?
To understand timetravel one must first understand time and if this 'time' really exists.
Is traveling faster than the light timetravel? We are looking up at the stars and looking back in "time" beacuse the light is extremely slow when it comes to interstellar distances.
When we look at the moon it is 1 second in the past and if there was an astronaut up there we would know he sees us 1 sec in the past aswell.
How is it possible for us to look back in time yet not be able to travel there?
> Is traveling faster than the light timetravel?
No, because there is no such thing as "traveling faster than light".
> How is it possible for us to look back in time yet not be able to travel there?
How is it possible for me to look at women yet not be able to become one?
To understand spacetravel one must first understand space and if this 'space' really exists.
(...wait, I already did this joke earlier in this thread.)
>No, because there is no such thing as "traveling faster than light".
I know we aren't able to travel faster than light.. YET!
Why can you travel @ the speed of light (light does this) but not actually go 1m/s faster than it?
Just because you cant see an object doesn't mean it stops to exist.
We can travel faster than sound, but it doesn't mean that sound stops to exist (pilots still hear themselves breathe and stuff).
and i mean 'faster than the speed of light'.. not light itself -__-;
>How is it possible for me to look at women yet not be able to become one?
Becoming something is not the same as traveling to something.
> Why can you travel @ the speed of light (light does this) but not actually go 1m/s faster than it?
Because "1m/s faster than light" is a meaningless concept. You only think it makes sense because you are used to very low velocities. Your intuitive image of the universe is nowhere near correct, and it is that incorrect image which makes you think moving faster than light makes sense.
It has nothing to do with light itself. Light just happens to move at the maximum possible speed. The structure of the universe is such that moving faster than light is not something that can happen.
> Becoming something is not the same as traveling to something.
Similarly, seeing something is not the same as travelling to it.
>the maximum possible speed. The structure of the universe is such that moving faster than light is not something that can happen.
yeah, and there cant be life without water... lolz
I am telling you the truth, but you refuse to listen, so what can I do? Well, I guess I can tell you what happens if you try to go faster than light. Please try and read and understand at least some of this.
Let's say you build a rocket with a REALLY big and powerful, yet extremely light-weight, engine. This is currently impossible, but that might just be engineering so we can easily disregard it, as you like to do.
In the first case, let's just set off the rocket and watch it go. You'll see it accelerate up towards the speed of light, just as you expect. However, when it starts to get close, you notice it's not accelerating as much as it should any longer. This is pretty confusing, since the engine is still putting out just as much thrust. Investigating closer (with your strange futuristic equipment), you notice that although the engine is still running correctly, the rocket is suddenly heavier. You will also notice that the close to the speed of light you get, the heavier the rocket will become, and the less it will accelerate.
When the rocket gets really close to the speed of light, its mass has grown enormous. The engine still tries to accelerate it, but it's not doing much good any longer. It will never reach the speed of light, but if it did, its mass would be infinite, and the engine could no longer move the rocket.
Incidentially, you will also find that the rocket has become shorter, and that clocks on board it are running slow. If the rocket should ever reach the speed of light, it would be completely flat, and time would stand still on board it.
Now, in the second test, let's jump aboard that rocket and try to ride it up to the speed of light. At first, everything goes well. The rocket accelerates just as it should. From our previous experiment, we might expect that it will soon stop doing this, because of the mass increase. However, to our surprise, everything is working just fine. But when we look out of the window, we suddenly notice that the entire universe around is shrinking along the direction of travel. Even though we keep accelerating, we never seem to get past the speed of light relative to anything outside the rocket - we reach places that used to be far away quickly, but it is not because we ourselves are moving fast, it's because the rest of the universe is shrinking!
We will reach Alpha Centauri in, say, three hours. But we know from our previous experiment that that rocket reached Alpha Centauri in three hours too, by its internal clock, which was running slow!. Sitting outside the rocket and waiting for it to reach Alpha Centauri took the expected four years, but the internal clock had slowed down so much, it only ever counted up three hours.
None of this is fanciful theory - this is all confirmed every single day, by particle accelerators and GPS satellites. This is how the universe works. It seems very strange, and it seems totally wrong compared to our experience, but it is actually our experience that is incorrect.
ok suppose that we have a looooooooooong tube with inside diameter of 1 cm and length of 10 light seconds. and in side this tube is full of small 0.9 cm metallic spheres lined up from one end to the other. so you push the first sphere. with common sense, you might think that on the other end of our tube, a sphere drops instantaneously right? I mean, nothing is moving faster that the speed of light right? you are just pushing one sphere slowly and on the other end, no matter how long the tube is, one should come out of the tube.
sorry pal, but that’s not the case, its going to take 10 seconds. Practical observation: electricity , more or less is the same concept and it doesn’t travel faster than light. if can’t defy space. how are you going to defy time? the two are closely connect as far as I have heard. so nope: no time travel unless you break space and the laws of universe in some manner.
scientists are known to have slowed the speed of light down, and there was an incident in a russian nuclear reactor, i cant remember what it was, but there was some matter that travelet faster than the speed of light.
google for it, it's there..
Light travels at less than "the speed of light" in a medium. When people say "the speed of light", they actually mean "the speed of light in a vacuum", also known as c. Travelling faster than the speed of light in a medium is not only possible, it happens all the time around nuclear reactors. It causes a phenomenom known as Cherenkov radiation, which incidentially is quite pretty: http://images.vertmarkets.com/crlive/files/Images/8B3B7B58-B579-11D4-8C77-009027DE0829/jgglow.jpg
This is why the "light" part of "the speed of light" is not important. Light doesn't always travel at the "speed of light". The constant c exists independently of the fact that light travels at that speed in a vaccuum. Other things travel at that speed too - gravity being one of them.
im not talking about light itself.. just the speed it has.
Didn't Kurt Godel have something important to say about time travel in relative space.
Gödel was a mathematician, not a physicist.
From Wikipedia's article on "Kurt Godel."
"In the late 1940s, Gödel demonstrated the existence of paradoxical solutions to Albert Einstein's field equations in general relativity. These 'rotating universes' would allow time travel and caused Einstein to have doubts about his own theory."
More detailed information about this body of work can be found here:
http://infoshare1.princeton.edu/libraries/firestone/rbsc/finding_aids/mathoral/pmcxgod0.htm
Also, 72GET!!!
Well, you learn something new every day!
almost. it does happen pretty much simultaneously with the first ball. it will simply take 10 seconds to observe the ball fall out of place, because of the distance the light has to travel to reach back to you. an observer at the other end will see the ball fall out of the tube before you push it, in theory. thats also assuming you can even move that many small metal bearings. they should weigh in the vicinity of several tonnes.
That's plain and simply wrong. It will take at least 10 seconds, in practice much, much longer, before the last ball starts to move. The reason it takes longer is that the pressure will move through the system at the speed of sound, not the speed of light. The speed of sound in a metal is pretty high, but it's much less than the speed of light.
>>75
so the energy you apply to item #1 moves to item #2 and so on. but, assuming we has something strong enough to push them all, wouldnt that mean that either 1) the metallic bearings would change shape, or even break under the pressure or 2) two bearings will occupy the same space at the same time. assuming the bearings are indestructable, neither scenario seems likely. but im also imagining a constant application of pressure, not a impact, like you see on those desk-ornaments with the balls on string.
using that balls-on-string example, lets say you have one of those desk ornaments. if you pick up one ball, and let go, the last ball moves. i understand thats because of the energy wave moving, and i understand it happens at the speed of sound. but do you mean to tell me that if, for instance, you had those five balls at rest next to each other, and you pushed one, (not drawing it back and releasing, just pushing it foward) that the balls dont move as if they were one object? the same thing should happen in this tube. if one thing is pushing on these bearings, then all the bearings should move in unison, so long as the force is sufficient enough to move them all.
> wouldnt that mean that either 1) the metallic bearings would change shape, or even break under the pressure
Yes.
> assuming the bearings are indestructable
They are not, and no such material exists, or even can exist.
> but do you mean to tell me that if, for instance, you had those five balls at rest next to each other, and you pushed one, (not drawing it back and releasing, just pushing it foward) that the balls dont move as if they were one object?
Yes, I mean exactly that. It is not noticable under normal circumstances because the speed of sound in the material is so high in comparison to the speed you move them at, which is why your intuitive sense of the world does not accept it easily.
>>59 The only way to travel faster than the speed of light is by cheating. Usually this involves parallel dimensions or creating a "warp bubble" around you spaceship.
The reason you can't travel faster than light is, basically, because you can't.
It's possible. Very likely too if you consider the following "time travel"
You could build spaceship that accelerates at 1g. It would take you 24 years to get to Andromeda galaxy in your time frame, remember you would be going at relativistic speeds (time dilation). But us here on earth, we would see you on your way for millions of years.
http://www.dailygalaxy.com/my_weblog/2007/07/weird-science-2.html
There. I guess it's not just normal people who believe this shit. The project funders must have too much money in their hands.
If time travel to the past was possible, we'd currently be flooded by otakus from the future who want to catch original broadcasts of Lucky Star.
>>82 The RIAA from the future will not allow it for copyright reasons.
Believe Einstein. I think you can go into the future if you can travel at the speed of light. I think it's true that it is relative to the space you are in so as you travel at the speed of light it might not seem like you have aged but you return and everyone else will be older depending on how long you were away. Maybe it is not time travel but age travel.
Semantics.
I'm going into the future right now!
reverse the polarity.
Great Scott! Where are you going to find 1.21 gigawatts??
all time is occurring simultaneously. It's like pictures in a flip-book. All other informationis classified.
no its not possible, period.
It's real, and I can prove it!
I just don't feel like it...
SEE I DID IT!!
Nobody managed to go backward, and so far it seems impossible,...
I can go backward any time, the problem is how to bring my body with me.
I managed to do it at least to years ending in "5", and then I had to go and wreck the delorean... At least now I have something that travels between years ending in "7", so welcome summer of love!
Stephen Hawking once tried to prove time travel was impossible by means of a convoluted argument that took into account several factors, and then tried to argue that all of them didn't work, probably in an effort to explain why he considered such things as the "grandfather paradox" to be impossible. Seems to run afoul of Occam's Razor to me (but I wish I remembered the argument). There is another school of thought: that if people were to travel back in time and change history, they'd wind up in an alternative universe or in another timeline (and THAT has spawned an entire science fiction subgenre itself).
Some physicists (such as Michio Kaku) have argued that time travel is possible in theory, via means such as wormholes and heating up things so much that wormholes appear. Hawking contends that wormholes would collapse as soon as someone attempts to send light (or information) back in time through it. (And some s.f. authors, such as Stephen Baxter, have tried to cash in on such subjects - "The Light of Other Days", along with time travel stories).
>>98 There is a third option. In some of the Philadelphia Experiments (Scifi or truth? We may never know.) they sent some accomplice back in time to kill the father of some guy, but when the killer came back there was no change in the present. The only thing that changed was that the memory of the father of the guy was somehow fading away.
100 Get
With an infinitely powerful telescope and an unending search of the night sky, perhaps one could peek around the corner of a singularity 500 million light years away and see a billion-year old Earth. Just see what it looked like then, of course.
If it were possible to cause changes in the past that affect the present, I'm sure we'd have know about it already due to the swarm of interlopers coming back to give high-fives to us people from the Stupid Ages.
But what about the possibility that the time machine has to be stationary (a la Ronald Mallett and his "time machine")?
In other words, you don't travel with the time machine like in back to the future, but instead travel TO the time machine at an earlier point in time. This means that it would be impossible to travel back further than when the first time machine existed, because there would be no arrival point.
Meaning, no one from the future can come to this time because a time machine hasn't been invented yet.
(Keep in mind I am basing this off of a documentary I saw a few years ago, so please correct me if I have misrepresented Mr. Mallett's theories).
OK, point on the speed of a tube of ball bearings 10 light second long. It would take approx. 139 hours, assuming the ball bearings are perfectly aligned and made of steel, for the "information" that the first ball bearing moved to reach the last one.
I know the fact it moves at the speed of sound has already been pointed out, I just thought I'd throw a number next to it.
There are two types forces through a median - longitudinal vibrations and transverse vibrations. Since we are compressing the metal bearings, we want longitudinal vibrations. The speed of longitudinal vibrations through steel is about 6000 m/s.
Also, since there seems to have been some misunderstanding...
as long as the ball bearings are all aligned correctly, they behave EXACTLY like a single unit, except for the last one which will pop out.
Interestingly, a cylinder that is infinitely massive would be unable to be compressed, and it seems that the information of a force should be instantaneous through it, right? Not that it would matter, since it could obviously not exist, but still, it's a curious question.
Also, another question. Since light moves at the speed of light (or very, very close to it), from the perspective of the light (if you can imagine such a thing), would the light exist along all of its paths at once, if we ignore any time it hits a medium that slows it down?
> Interestingly, a cylinder that is infinitely massive would be unable to be compressed, and it seems that the information of a force should be instantaneous through it, right?
You're making the usual mistake here of thinking of a "solid" as something that actually exists. "Solid" is an intuitive shorthand we use for something which is actually very, very different.
Think about what a "solid" actually is: It's a bunch of atoms packed together, sometimes in a crystal lattice. An atom, on the other hand, is a tiny nucleus surrounded by an electron cloud.
What happens when sound is transmitted is that the atoms move, and their electron clouds push up against each other, and repel because they have similar charges. Now you question becomes, what do you mean by "infinitely massive"? Do you have infinitely massive nuclei with normal electron clouds? Do you have an infinite number of nuclei packed into a finite volumes? What happens to the electron clouds then?
And so on. The answer you end up with is that your question is meaningless and unanswerable, because the situation makes no sense physically.
Now you question becomes, what do you mean by "infinitely massive"? Do you have infinitely massive nuclei with normal electron clouds? Do you have an infinite number of nuclei packed into a finite volumes?
What happens to the electron clouds then?
Quark-gluon plasma.
>>104
Quark star? Isn't that basically "infinitely compressed", such that it is a solid piece of matter, as much as we understand matter to be? A collection of free quarks gathered together to form, essentially, a single particle of a size similar to a neutron star? If so, that material would be, intuitively at least, unable to support shock waves through it.
And though this is somewhat unrelated, isn't the inside of a black hole considered to be infinitely massive and infinitely small by some? I've read that several times, and it seems blatantly wrong, but maybe it is and I'm just not understanding how gravity works.
> isn't the inside of a black hole considered to be infinitely massive and infinitely small by some?
I imagine that's just poetic license taken by some cheap science fiction writer.
>>107
Actually, cheap science books. Not that there is a huge difference...
That would still be entirely finite.
What about 10 dimensions or M theory?
In the year of '39 assembled here the Volunteers
In the days when lands were few
Here the ship sailed out into the blue and sunny morn
The sweetest sight ever seen.
And the night followed day
And the story tellers say
That the score brave souls inside
For many a lonely day sailed across the milky seas
Ne'er looked back, never feared, never cried.
Don't you hear my call though you're many years away
Don't you hear me calling you
Write your letters in the sand
For the day I take your hand
In the land that our grandchildren knew.
In the year of '39 came a ship in from the blue
The volunteers came home that day
And they bring good news of a world so newly born
Though their hearts so heavily weigh
For the earth is old and grey, little darlin' we'll away
But my love this cannot be
For so many years have gone though I'm older but a year
Your mother's eyes from your eyes cry to me.
Don't you hear my call though you're many years away
Don't you hear me calling you
All the letters in the sand cannot heal me like your hand
For my life
Still ahead
Pity Me.
>>103
I recently read somewhere (I don't remember where) that they're toying with the idea of time as a 4th dimension of space. It seems to me to make sense, but in any case, if it is, I don't think I can say yes to "Since light moves at the speed of light (or very, very close to it), from the perspective of the light (if you can imagine such a thing), would the light exist along all of its paths at once, if we ignore any time it hits a medium that slows it down?"
If time were itself a dimension (what could have happened in this universe without it AND the dimensions of space?), I would have to assume that light moves within the dimensions of space (albeit at an incredible rate), according to the laws of time (which is presumably the only truly 'instantaneous' 'thing'). The actual speed time moves at, as opposed to the speeds things move about inside it, is the speed we have to beat to go forwards. Even then, I don't think we could pin-point A time and zap ourselves there. We'd exist in the 3 dimensions of space, going forwards through time quite literally (as one goes forward through time in their day to day lives). Going backwards seems to me, on this basis, impossible.
Time has been considered a fourth dimension of space-time for a hundred years, soon. Note, however, that that is specifically space-time, not space. The spatial dimensions are different from the time dimension, although they together form a whole.
What about the 6 other dimensions of space!
http://revver.com/video/99898/imagining-the-tenth-dimension/
I wouldn't worry about them until the spring theorists actually manage to find some actual experimental evidence.
But if time is a dimension then it should mean we can go back in time, and we have seen that it's highly unlikely. Therefore time can't be a dimension... or that it's a special, one-way dimension?
I have always thought that to defeat that paradox, when you go "back" in time, you are always just traveling to a parallel dimension, therefore no paradox can occur, fine kill the your mum in that universe, your still there and fine.
It is a dimension, but it is a time-like dimension instead of a space-like one. The Minkowski metric, which describes flat space-time, contains ones for the three space-like dimensions, and a -1 for time: http://mathworld.wolfram.com/MinkowskiMetric.html
There is really no explanation for why our universe can be described with such a metric, but it can, and thus we are stuck with three space-like and one time-like dimension.
i think it's more like this:
You travel back in time. INSTANTLY, just by appearing in the "past" you have changed that universe irrevocably. A paralell universe is the result, you kill your grandpa, you travel forward in time to the present. Everything seems fine, you don't die because you're actually from a paralell universe, but in that universe you never existed. and life goes on. however, it is not your universe anymore, and you never return to the "present" of your own universe. Nor does the history of your universe become altered.
now that i type it all out, though, it does all seem rather arbitrary - is there any proof of paralell universes?
> is there any proof of paralell universes?
Not yet, and there may never be any.
Time-travel is indeed possible. We know the mathematics and methods of how to bend time and space. The only problem is our energy constraints. It would take all the energy of our solar system PLUS that of another to actually travel in time.
>>121
So, two portable black holes? Yup, that's what John Titor was/will be using. Created by CERN's Large Hadron Collider in the near furure. Currently scheduled to begin operation in May 2008.
that's just plain false. The likelihood of creating a black hole is small, like one a second, when considering the scale of time with particle physics. Next, the holes themselves would be too unstable as such a small scale, meaning they won't last, and FINALLY, even if a black whole were to be created, and be able to stick around long enough to acrete the earth, it would evaporate instantly from (they still technically unproven) hawking radiation. If making black holes to destroy the earth was that easy, some jerkass would have done it by now - or the universe would be CONSTANTLY hurling black holes everywhere.
>>123
No, those mini black holes created by Man would not destroy the Earth. They probably wouldn't even sink below ground, they would evaporate. The actual danger would come from the evaporation point, with plenty of heat and radiations.
Not all black holes are stellar-size-massive. The braneworld theory predicts the existence of tiny black holes seeded throughout the universe, remnants of the Big Bang. And that thousands of them should exist in our solar system.
that's what i was trying to say, but i guess i forgot to mention they were really tiny, which is important.
Okay. Next, how much energy does a black hole needs to be? If we look at John Tytor's time machine manual, we see in the "Emergency procedures" section: "Unit self-destruct is pilot controlled. The singularities will automatically evaporate with a compromise in the containment field. A nuclear explosion with the equivalent of 2x megatons will detonate upon singularity evaporation."
So we'll need to get the CERN to cram 20-29 megatons of energy into a singularity. Then we'll be able to time travel.
Oh, and incidentally we'll also need to invent that "containment field" first if we don't want the CERN to vanish. So far it doesn't exist yet... :)
>>Not all black holes are stellar-size-massive. The braneworld theory predicts the existence of tiny black holes seeded throughout the universe, remnants of the Big Bang. And that thousands of them should exist in our solar system.
Holy Magnetic Monopoles, Batman! Wasn't this one of Stephen Hawking's predictions from, like, 1972? And hasn't he abandoned it and moved on?
I already figured out time travel. The problem isn't getting to there. It's getting from here.
What's strange in those time-travel stories is that "space" is omitted out of the equation. Time and space are very closely related. A time machine should be able to do space traveling. Even John Titor said that the first problem they had with their time machine is that the machine would re-appear elsewhere, and it puzzled the engineers for a while (it was because the Earth is in motion, while the machine wasn't when operating.) Where are all the space travelers' stories?
This is a very insightful comment,... It sometimes pays of to waste time here
A "straight" time jump of even a few seconds would leave you in cold space. But that's assuming that time travel would somehow use a "fixed" referential. But if there is no such thing, there could still be problems, if time translation warps space translation.
You would add teleportation woes to timetravel headaches.
Not only earth is moving, the system and the galaxy are in motion as well.
>>132-134
all motion is relative, only acceleration is relevant in this case. also, it's quite possible that earth's gravitational field might cause the time machine to follow earth.
Well,... Time travel could be seen as a form of acceleration in space-time. In which case some of this acceleration might result in the problems mentioned... Or not.
>>132
That is very interesting. If you think of time like a space dimension, then jumping forward or backward in time faster than the rate we are going now, is like traveling faster than light. So a time machine is an FTL drive. Cool.
And FTL drives are like time machines? And time travel is full of paradox, so it is impossible. Therefore faster than light travel is not possible...so much for humanity taking over the galaxy.
Actually come to think of it again...we can assume that time travel into the past is impossible and so warp drives would be like going forward in time really fast. Fini.
>>warp drives would be like going forward in time really fast. Fini.
lolwut
srsly, ever heard of the theory of relativity?
>>138
Theory of relativity only deals with sub-light travel. I can make up whatever the hell I want to wrt faster than light travel.
Anyway, I don't know what you are talking about. Explain please.
It's hard enough to get <i>to</i> the speed of light, let alone past it. From the Usenet Physics FAQ:
It is a consequence of relativity that the energy of a particle of rest mass m moving with speed v is given by
E = mc^2/sqrt(1 - v^2/c^2) As the speed approaches the speed of light the energy approaches infinity. Hence is should be impossible to accelerate an object with rest mass to the speed of light and particles with zero rest mass must always go at exactly the speed of light otherwise they would have no energy.
http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/FTL.html
However, none of that explains why time only flows in one direction
>>140
As I said, that only deals with sub-light stuff and using actual down-to-Einstenian-mechanics forces. You can't just use good old classic mechanics when talking about time travel and say oh noes, FTL (faster than light) is impossible.
There could well be a way to "jump" to FTL space and skip the whole energy going to infinity problem. And what I said before was compare going jumping forward (or whatever direction) in space faster than light to jumping forward in time, oh, faster than the current pace time is going. I just never thought of it like that before.
>>141
Time paradox.
it is possible. If i get a plane to somewhere far away, i'll find myself in tomorow or yesterday, lol.
>Time paradox.
That's no answer,... You could imagine a boatload of Space paradoxes (ubiquity, or several objects at the same place), none none prevent you from moving in all directions of space.
>>As I said, that only deals with sub-light stuff
>>that only deals with sub-light stuff
>>sub-light
PROTIP: Star Trek is fantasy.
I'm not sure that you can just turn around and move in the opposite direction through time.
Even though time is a dimension, the arrow of time is a consequence of thermodynamics. Since entropy must always increase,
there is an entropy gradient from 'past' to 'future' across the time dimension. Any information-processing device (such as your brain) is subject to the same physical laws as every other object, and increases the total entropy of the universe every time it it performs an operation. So any information-processor must perceive a total increase in entropy through time in one direction only.
This does not preclude the possibility of closed timelike curves.
>>145
PROTOP: This is a thread of time travel.
>>146
You bring up the classic point of linking time and entropy. Thats fine with me, except for two things:
We use entropy to the issue because it's one of the rare physical laws which is not symmetric, and could thus explain the perceived irreversibility of time.
However you don't know for instance which one is the consequence of the other, or if they are both the consequence of a third unknown factor, or if they have nothing to do, but are both instances of irreversible effects.
Also, if bidirectional time travel exists, then it would increase entropy in the past, which in turn would increase entropy in the future. If so, there would be no obvious break in the second thermodynamic law when you time travel.
Finally, and as you hint, you must take into account the whole system, when you assay the increase in entropy, and thus local time jumps would be possible at the expence of entropy increase somewhere else in the system. Basically, we don't know the link between irreversibility of time and entropy, so it's a bit difficult to explain one with the other. But it's a good starting point for speculation,...
>>141
How do you know time only flows in one direction, or at all?
>>148
How would local reversal of time work though? I tried imagining it and I just can't come up with anything that makes sense.
One, you can't just hop into a time machine and watch the world outside reverse itself. The world is huge and it will take an immense amount of energy...if it's even remotely possible, what with all the tiny atoms and energy and stuff.
You can have an isolated system though, and forward and reverse the stuff inside from the outside (now idea how, but it makes sense).
But let's say we have a bit of space where time is going in reverse. If you throw a rock (or yourself) in there, how is it going to interact with the space?
We have trouble understanding time, because we spend all our life immersed in it. It's a bit like air: in the past people did not realised that air is not just space between objects, it's something in itself. Of course there were hints (water/air interface forming bubbles, winds). Nowadays it's much easier to understand air, because we see all the time applications of our knowledge of it (airplanes, etc).
I have no knowledge of reverse-time physics, but it's not a problem in this case, because all your questions equally apply to time flow variations: as you may know, the flow of time you're in depends on the mass surrounding you and on your speed.
So if you are travelling at close to the speed of light, your time will be very different from all surrounding objects which travel at a slower speed. As you can see, you can induce a local variation in the flow of time without requiring infinite amounts of energy. One could extend the reasoning and assume that you can vary the local flow of time to such an extent, that you might locally revert it. The conceptual difficulties are the same in both cases.
As for your question with the rock, you just have to think about black holes. In a black hole the mass is infinite, and the flow of time is ripped apart (and I think nobody knows what's going on inside a blackhole). So if you throw a rock into the black hole, as the rock travels space, the flow of time it is subjected to will slow down until it reaches singularity, and then it's anyone's guess. Some people have even suggested that matter could emerge in other points of space or time through white holes (it's not only time which is ripped apart, but space too).
Oops, I meant to say 'In a black hole the mass DENSITY is infinite,...'
>>151
In my previous post, I was thinking of time as a consequence of the movement of matter and energy but that's not the case obviously, space-time and all that. So you wouldn't need infinite energy to change your perception of time outside you (or your frame of reference). You need to somehow change your frame of reference so that the outside world is reversing to you. Argh, I need to properly understand special relativity to actually begin to make a guess at this.
>>152
Not necessarily. In order for it to be defined as a black hole, the mass density need only be sufficient that light cannot escape.
We are both right, but at different time points,... You are right that mass density does not need to be infinite to CREATE a black hole (otherwise you'd need infinite amounts of matter and there would be no black holes). What really counts is the amount of matter bound by the gravity well. If this amount is enough to cause collapse and a singularity to occur (a black hole), then the mass density will become infinite. This is why it's called a singularity: all the mass collapsed to a single point in space, the singularity, hence mass density is infinite.
All black holes have the same mass density (infinite), what differs is the amount of mass contained within the singularity. The higher the amount of mass, the wider the event horizon (distance from which light cannot escape the black hole).
Special relativity won't get you much. You need general relativity, and that actually intuitively understanding that may require being insane.
On the topic of time and entropy, though, I recently saw the suggestion made that maybe time itself is only a macroscopic property. That would go some way towards explaining why it's so incredibly hard to define a direction of time from the microscopic theories.
What exactly that would mean in practice sure is food for thought, but without a functioning quantum theory of gravity it may be impossible to even speculate.
>On the topic of time and entropy, though, I recently saw the suggestion made that maybe time itself is only a macroscopic property.
Hard to accept that,... Gravity does not play a role at microscopic scales, but space and time do. Particle accelerators show relativistic effects on time affecting the particles. So it seems it's sleight of hand to suddently consider time a macroscopic property.
>>157
That, and also many kinds of subatomic particles have measurable half-lives which are extended by relativistic travel. This seems to contradict the idea that time is a macroscopic property only.
I think that was more specifically the direction of time being a macroscopic effect, or the flow of time.
I don't see why direction would be macroscopic, while flow remains microscopic. That sounds like a heap of ad hoc contrived postulates,...
ITT we get confused because we used English instead of maths.
Why would you say time has a direction, or flow?
Space does not have direction or flow.
> Why would you say time has a direction, or flow?
Direction: from pas to future
Flow: as your speed/mass increases, your times slows down compared to other objects.
> Space does not have direction or flow.
Direction: space has three (proven) directions, that's why we speak of 3D, three dimensions.
Flow: actually space seems to have a flow, since the universe is expanding. According to latest discoveries, this expansion (called inflation) could eventually lead to disintegration of galaxies, stars, etc,...
CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY CAUSALITY
Loud but short of arguments,...
Newtonian physics causality is independent of time direction. If time started going reverse, it would work equally well.
ITT we are wholly unfamiliar with Feynman diagrams.
>>169
No, I am talking specifically about Feynman diagrams, with time as one axis and space as the other, in which one can see plots of wonderfully counterintuitive ideas like an electron bouncing back and forth in time, turning into a positron when it's traveling backwards, and annihilating itself in a flash of gamma rays, which become an electron-positron pair that is the original electron/positron.
>>164,165
I would say time doesn't have a 'flow', because like we move through space, we move through time (if this perspective is not just a product of a weak three-dimensional brain interpreting the world the only way it can).
Unprovable philosophy and nitpicking semantics, I know, but this thread is about time travel. Complete speculation.
> space has three (proven) directions, that's why we speak of 3D, three dimensions.
Whoa, whoa -- slow down, egghead!
Wouldn't time travel backward require undoing entropy?
Not if you increase entropy as you move backwards in time,... this has already been discussed ITT
My bad... just asking.
Scientists still believe in time to such a degree that they suggest it is possible to travel through it, just because they've discovered it's just illusional.
Time and travel is the exact same thing, "time travel" is a pleonasm.
You may create such circumstances, through a variety of ways, that you may percieve you're travelling into the "future", sleeping is an easy and natural way to do this. However you cannot travel into the past because there is no such thing, there is only now, and memories of what we're doing in it in different places and other circumstances. Everything is happening at the same time everywhere, but at different locations, being observed at different places. Things are moving through distance, you're observing it through distance. You get a mental image of what you're looking at now, things move and it changes but it is still now, not in the future, and what you just saw wasn't in the past. You call that time, it's more like movement. The sun setting is movement, the universe expanding is movement, you getting older is movement. Within the limit of what speed things may travel, things may happen "faster or slower", but in the end it all comes down to how we percieve it, which is linked to the functions of our brain. It gives us an illusion of time, just as it gives illusions of colours and sounds, other things that do not actually exist.
You're all just musing over a fictional concept with your fractured apprehension of what is real.
> Scientists ... time ... discovered it's just illusional.
> illusions of colours and sounds, other things that do not actually exist.
'Scientists' have also discovered the phenomenon of your mother being so morbidly obese, the only method by which you could theoretically have escaped her reproductive organs is through thermal radiation with a black body spectrum.
>>176
lol
I guess that's your way of saying, that you think I'm wrong. Why not try to convince me instead?
If time is "illusional" then space is too. So find the frequency of the illusional vibration, put it into a computer and wire someone with it. Hop, a time/space machine. :)
See http://en.wikipedia.org/wiki/Montauk_Project
>>178
nooooo!!!
The frequency of the illusion would be a non-physical energy frequency, there probably is no physical frequency. The only way to do it is to master astral pojection, probably. Very scientific.
>>179
Well, if the person can master astral projections, then he can view the past using the Akashic Records.
http://en.wikipedia.org/wiki/Akashic_records
He would have no need for a time machine.
that was my point. Akashic records, or, just find the past, and go hang out in it, lol. Probably just going to the past would be a better idea... you're not really supposed to use the akashic records for entertainment.
Forgot to add-
The thing that had me interested was the possibility of there being an identifiable energy frequency... if someone could find that, it would maybe be a much more accurate way to time travel astrally, instead of just trying to do it, or ending up in the past somewhat randomly. Though then it seems likely that this frequency is alreadfy tied to the akashic records.... hmmm. Anyway, it sounds like something well worth looking into, for real scientists and astral projectors alike.
Hey guys, what do you think of this? Time travel is like a feedback loop connect back through a second dimension of time. And all the changes and paradoxes can be explained by changes that happen in the feedback loop until it stabilizes.
this is fucking idiotic
"The Cambridge physicist Professor Stephen Hawking spent much of his career attempting to prove that time travel is impossible. If it were possible, he reasoned, why have we not been visited by voyagers from the future? But he was forced to conclude that there is actually nothing in the laws of physics that prevents moving in time.
"He changed his mind about 10 years ago," said Kaku, "There was no way to ban time travel from happening. So now he says that time travel is possible, but not practical."
The way it might work would be to take a trip through a worm hole connecting one point in space and time with another. The laws of physics suggest that the intense gravity of a black hole is enough to rip the fabric of space and time, making a worm hole possible.
"What we physicists want to do is create our own wormhole so that if you walk through the looking glass you may go backwards in time," said Kaku. Stabilising a black hole would require large amounts of an exotic form of energy called negative energy, thought to be impossible. "But we can now make it in the laboratory," said Kaku."
http://www.guardian.co.uk/science/2008/apr/02/sciencenews.physicalsciences
Time doesn't actually exist, it's just a social construction to measure change. Of course time travel is not possible. Assuming the laws of the universe holds true and applies that is.
Space doesn't actually exist, it's just a social construction to measure change. Of course space travel is not possible. Assuming the laws of the universe holds true and applies that is.
>>189
Physics is just a social construction. We don't really know what is going on beyond this superficial socially constructed mathematical model for what we perceive our physical universe to be.
Time is just a concept made up by us to explain changes that happen around us. It doesn't really exist; it's just change. Causality. Which is just a concept constructed by humans. It's just a mathematical model to explain cause and effect. Therefore, time doesn't actually exist.
You're just spouting philosophical rhetoric.
Which is just a concept constructed by humans.
>>190 is just a social construction. We don't really know what is going on beyond this superficial socially constructed mathematical model for what we perceive this message board to be.
4-ch is just a concept made up by us for the lulz. It doesn't really exist; it's just change. Causality. Which is just a concept constructed by humans. It's just a mathematical model to explain cause and effect. Therefore, >>190 doesn't actually exist.
>>191
No I am not. What I am saying is the truth.
>>192
Of course I exist. I can think and I can see me, so I know I exist and I can see everything around me, so I know they exist. But physics is just mathematics which is socially constructed and not real. So you can't just say time is real by using physics as proof of it. I can't see time. I can't measure time; clocks only measure themselves, not time itself. So it really doesn't exist, it's just causality.
> I can't measure time; clocks only measure themselves, not time itself. So it really doesn't exist, it's just causality.
You can change time. That alone should give you a hint that it exists.
But you can't change causality. Thus, time and causality are distinct concepts.
It's possible.
> I can see me, so I know I exist and I can see everything around me, so I know they exist.
False. You are solely a brain suspended in a vat of fluid. Everything your experience with your senses is merely your brainself being probed with electrical charges.
I'm going to be visiting earlier in this thread to prove it's possible. Just thought you should know!
Oh, Titor! Choice performance, my friend! Choice performance indeed!
>>196
That still = the person and their surroundings existing. Simply in a different form and context than what was percieved, doesn't cancel out the existence. That's similar to saying that because people a few hundred years ago thought the world was flat, that their world didn't exist. It sure wasn't flat, but it definitely existed.
>>It sure wasn't flat, but it definitely existed.
No it didn't, it was just a social construction.
social constructions exist, duh.
Could my dong be this huge if reality was fake?
Roses are red
Violets are blue
Your dong's a social construction
And so are you
Could my dong be this huge if time travel was impossible?
it's possible, so, shoo, shoo! all of you am powtaytowes.
Is anyone here an actual time traveler?
Yes. We all are traveling in time.