What's wrong with a Time Machine?

[Souron]

There are particles that travel backwards through time, instead of forwards. I forget which ones though.

Yes, they are called anti-particles. But even anti particles are subject to the second law of thermodynamics. So while anti particles can be seen as particles traveling backwords in time, they still tend to move from order to disorder forward in time.
Because of this and anti particle being would still experience time the same way as we do.

 

[Lotus49]

Einstein's theories revolve around the idea that the Universe is made of space-time, time being a dimension.

I'm well aware of this. However this part is the main Einstein theory I do not concur with. If it is ever proven to be fact, then great, that's exciting. Otherwise, I just can't see it. Basically I'm saying the old man just went a little to far into deep-thought, abstract creative speculation, on this one.

I know his theory, and can respect it - but unlike most other aspects of his theories I just cannot concur with the space-time continuum. I might be willing to believe that something can be suspended, accelerated, and projected forward in time, to some limited degree, and perhaps that it may be possible to have a particle be in two places, at nearly the same time in the present... but, this idea that 'time' is like a VCR, that you can rewind, play, fast-forward, etc... is not realistic.

There simply is no master device that is recording everything that happens in real time, that we can manipulate in order to go revisit them (the past). Likewise, there is no 'future', that can be visited before it arrives/manifests.

That's my hang-up. Time is linear... and it only moves forward. It's not something you can bend, and sculpt, like Michelangelo. Again, I say 'time' only exists in the abstract within the minds of men, as a specific measurement, which they have created and labelled how they see fit. Particle manipulation that we've seen accomplished to this point, I would argue is not 'time travel', but rather a completely new and different field, more along the lines of transport, within the THREE dimensions we have available... via a massively huge power-to-mass/weight ratio. If you want to think of time as a 4th dimension, for record-keeping, or planning purposes, then fine. But it's actually not a real physical dimension.

That's what I think, based on using my intellectual instincts for understanding the creation around me... same thing Albert was doing. And we're here to discuss, so...

 

[Souron]

I'm well aware of this. However this part is the main Einstein theory I do not concur with. If it is ever proven to be fact, then great, that's exciting. Otherwise, I just can't see it. Basically I'm saying the old man just went a little to far into deep-thought, abstract creative speculation, on this one.

I know his theory, and can respect it - but unlike most other aspects of his theories I just cannot concur with the space-time continuum. I might be willing to believe that something can be suspended, accelerated, and projected forward in time, to some limited degree, and perhaps that it may be possible to have a particle be in two places, at nearly the same time in the present... but, this idea that 'time' is like a VCR, that you can rewind, play, fast-forward, etc... is not realistic.

There simply is no master device that is recording everything that happens in real time, that we can manipulate in order to go revisit them (the past). Likewise, there is no 'future', that can be visited before it arrives/manifests.

That's my hang-up. Time is linear... and it only moves forward. It's not something you can bend, and sculpt, like Michelangelo. Again, I say 'time' only exists in the abstract within the minds of men, as a specific measurement, which they have created and labelled how they see fit. Particle manipulation that we've seen accomplished to this point, I would argue is not 'time travel', but rather a completely new and different field, more along the lines of transport, within the THREE dimensions we have available... via a massively huge power-to-mass/weight ratio. If you want to think of time as a 4th dimension, for record-keeping, or planning purposes, then fine. But it's actually not a real physical dimension.

That's what I think, based on using my intellectual instincts for understanding the creation around me... same thing Albert was doing. And we're here to discuss, so...

You're misunderstanding the theory here. Eignstien did believe that time was linear. Nothing in his theory sais that you can time travel. You can't rewind time, and you can't skip over time.

But you can slow down and speed up time. That is, time progresses at different rates for different observers, depending on their relitive speed and gravitational feilds. Time flows flows slower for fast moving objects and for stronger gravitational feilds. For example, a timing mechanism measured at sea level will disagree with a clock places on top of a high mountains. It would only be off by a little, but such variations have been measured.

This is the direct result of the speed of light being constant. If there can be a constant speed that is the same for all observers, regardless of there own relative speeds, then distance and time have to be variable. Otherwise an observer moving towards a light source would see the light moving faster than an observer moving away. But with time and distance being variable, the observer moving closer toward the light sourse sees light as constant, but moving a shorter distance over a shorter period of time than the observer moving away from the light source (I hope that's not backwords). In practice this distance is measure as doppler shift.

 

[Masquerouge]

I would say it would be okay to help you improve, provided everybody could also do it.
But actually if time travel was possible a lot of things would be different, including education.

 

[carmen510]

It's hard to say whether time travelling is actually not moral, because some history is better off not happening. But if we assasinated Hitler, for example, some things might happen, such as the Cold War happening before a WW2 with nukes flying all over.

 

[mdwh]

It's fun to speculate, however I have a hard time subscribing to the idea that time is the '4th dimension', which somehow records all events, that can be revisited... given the right warping mechanism.

I think of time as nothing but an artifical measurement, like a gram, kilometer, or degree (or your choice). Nothing more. The only place in which it exists, is in the mind of man, in abstract form.

It would be nice, though - if there were some 'master video camera', recording everything, that we could just rewind and edit at will, but that is just a childish daydream.

But that it is an abstract artificial measurement doesn't mean it can't be changed - we can travel in space, and move mass around, after all.

We know that time travel into the future is possible, so in that sense it isn't just some background property we can't change. The question is whether we can travel back into the past.

I'm well aware of this. However this part is the main Einstein theory I do not concur with. If it is ever proven to be fact, then great, that's exciting. Otherwise, I just can't see it. Basically I'm saying the old man just went a little to far into deep-thought, abstract creative speculation, on this one.

Einstein's theories of relativity are supported by a large amount evidence - basically yes, it's proven (bearing in mind that nothing in the real world is 100% proven).

but, this idea that 'time' is like a VCR, that you can rewind, play, fast-forward, etc... is not realistic.

There simply is no master device that is recording everything that happens in real time, that we can manipulate in order to go revisit them (the past). Likewise, there is no 'future', that can be visited before it arrives/manifests.

I don't think there's anything in relativity which says this as such.

Indeed, relativity says that there isn't a *master* device - there isn't a single linear timeline which flows at a constant rate, rather it flows differently for different observers, and different observers may not even agree on whether things happen in the same time (or something like that...).

That's my hang-up. Time is linear... and it only moves forward. It's not something you can bend, and sculpt, like Michelangelo.

Do you agree we can change the rate at which we travel into the future (which is basically what "bending" does)?

If you want to think of time as a 4th dimension, for record-keeping, or planning purposes, then fine. But it's actually not a real physical dimension.

This is like arguing angels on a pinhead:

Representing time as a dimension is just a way of modelling or representing it in the equations - as you say. Whether it's a "real physical dimension" is a meaningless question unless you define what it means for a dimension to be "real" and "physical"?

Consider things like mass, forces and energy - these are extremely useful scientific concepts - but do they "really physically exist"? What actually *is* a force? What does it mean for a force to "really physically exist"?

The point is that science only defines things as far as is needed for the theory - speculating beyond that, and discussing things which are untestable, is philosophy.