• Time Travel
    204 replies, posted
I gotta be honest, I run dry here too. I guess its important to realise that the amount of energy something has is relative to state of the thing observing it. If a ball is flying at you, it may have X amount of energy, but then if you are traveling with it it will appear to have less energy (mass), even being in its ground state if you are exactly in sync with it. Gauge bosons will transfer energy in terms of forces, such as an electron jumping to a higher energy state when it absorbs a photon. I assume this is what transfers kinetic energy, but im not 100% sure... aVon will know, if hes about.
A world that cannot be understood is a world in which science is meaningless. If one has to accept quantum mechanics as nonmechanical (not as in Newtonian and such, but as in abides by an absolute set of rules) then one must also concede that it is impossible to understand and meaningless to explore.
[QUOTE=DONUT KING;22370458]Can we just shut the fuck up about mass converting to energy and just revel in the awesomeness of time travel?[/QUOTE] Revel elsewhere :colbert: this is for science!!! :science:
Again I'd like to distinguish between mass as the scalar of the force gravity acts on it and mass as the total force of impact here.
[QUOTE=BmB;22370560]A world that cannot be understood is a world in which science is meaningless. If one has to accept quantum mechanics as nonmechanical (not as in Newtonian and such, but as in abides by an absolute set of rules) then one must also concede that it is impossible to understand and meaningless to explore.[/QUOTE] Yes, some scientists did see it that way. Quantum theory is very strange. For one, you can't observe the path of particles, only its starting point and its end point. This is due to the fact that any attempt to measure anything on the quantum scale will result in a destruction of the experiment because the measurement would change the path of the particle. This is one reason why, again, many insanely great minds rejected quantum theory. For another, quantum mechanics only measures probabilities, not quantified values. For example, if you were to calculate what an electron would do in the face of certain conditions, you would get something like there's and 80% chance that the electron will stay in its ground state, and a 3% chance that it would go into the next energy level and so on. All very strange stuff. [editline]12:17PM[/editline] [QUOTE=BmB;22370639]Again I'd like to distinguish between mass as the scalar of the force gravity acts on it and mass as the total force of impact here.[/QUOTE] Mass does not measure how an object is affected by gravity; that's weight. Anyways, I'm going to bed. I'm sure some other smarter person will get in here and be able to answer your questions much better than I'm able to. Night.
Then design the experiment around the expectation that the path will be changed, purism is good but it will get you nowhere at times. The mere fact that our measuring equipment is inadequate certainly isn't nonmechanical. In that sense.
I think that this man is of the crazy variety
[QUOTE=billeh!;22369475]Mass is energy. Matter is not.[/QUOTE] According to relativity, matter and energy are the "same thing"
Well that's a failure of terminology then because in my dictionary how massive an object is is the total... well, mass that it has. The density and element weights combined. This isn't measured in any absolute sense by the total force of impact. That is a kinetic scalar of the mass.
[QUOTE=BmB;22370696]Then design the experiment around the expectation that the path will be changed, purism is good but it will get you nowhere at times. The mere fact that our measuring equipment is inadequate certainly isn't nonmechanical. In that sense.[/QUOTE] I've thought of this too, but to design an experiment that does that is extremely complex. Just to 'see' an electron at a certain position, we have to bounce a photon off of it which eradicates any conditions we meant to set up beforehand. Besides, designing these experiments can only go so far and test certain things. There are some experiments that have purposes in which we can't avoid not measuring the paths of particles. [editline]12:25PM[/editline] [QUOTE=wonkadonk;22370757]According to relativity, matter and energy are the "same thing"[/QUOTE] Matter in classical physics is not as separated into individual concepts as quantum physics requires them to be. As a result, matter and mass in E=m(c^2) are often confused. The M variable is the mass, not the matter. [editline]12:26PM[/editline] [QUOTE=KKram16;22370744]I think that this man is of the crazy variety[/QUOTE] Perhaps. Anyways I'm really off to bed now. Night all. [editline]12:28PM[/editline] [QUOTE=BmB;22370764]Well that's a failure of terminology then because in my dictionary how massive an object is is the total... well, mass that it has. The density and element weights combined. This isn't measured in any absolute sense by the total force of impact. That is a kinetic scalar of the mass.[/QUOTE] I think that's mass in the classical sense. I'm not quite sure what you're getting at.
I'm getting at when I say mass that's what I mean, That's what I take it to mean, I really don't know what else to call it. So when someone else tries to correct me with another definition the argument breaks down.
I think the words 'matter' and 'mass' are a bit vague in definition here. Mass, as I understand it, is the total kinetic energy of an object/particle combined with its rest mass. So an electron would have its momentum energy [I]plus[/I] "9.11 × 10−31 kilograms or about 5.486 × 10−4 atomic mass units, equivalent to an energy of about 8.19 × 10−14 joules or about 0.511 megaelectronvolts." - [url]http://en.wikipedia.org/wiki/Electron_rest_mass[/url] Matter is more of an archaic term, echoing back to a time when we used to think atoms were little solid balls and Newtonian laws governed them. Nowadays the word matter is pretty redundant.
Yeah that's kind of stupid. What do you call mass as the constant, innate property divorced from any variable forces that act on it then?
Could you kill your self if you went back in time, because if you killed your self you would be dead and couldn't kill your self, you'd be dead. :o <-- Off topic kinda I know
Novikov says no.
I have my own way of traveling through time: I keep drinking until I forget that the last week ever happened.
[QUOTE=BmB;22371674]Yeah that's kind of stupid. What do you call mass as the constant, innate property divorced from any variable forces that act on it then?[/QUOTE] I suppose mass is either just the 'rest mass' of a particle which I always visualize a being a deviation from the quantum vacuum/fabric of space-time (so like a blip or a hill on an otherwise flat line - this is just how I picture a particle), OR its 'momentum', which has no physical existence other then being a [I]difference[/I] in a particles velocity relative to another.
[QUOTE=GranaMan;22313797]If time travel was possible, i think we would have some kind of records in the history that some futuristic guy came and said "Oh Hejo, im korean!". And then fucked up the whole time line.[/QUOTE] Not necessarily. Alternative distinct timelines are a solution to this.
Either that or time travel is EXTREMELY regulated, be it by people or some form of omnitemporal force (a Time God, if you will).
[img]http://imageshack.dk/imagesfree/IDT78421.jpg[/img] [sp]It had to happen. You knew it.[/sp]
[QUOTE=aVoN;22373808]Not necessarily. Alternative distinct timelines are a solution to this.[/QUOTE] Which means M theory correct? :buddy:
Again, I fail to see the need for any of that when you have Novikov.
Well the fact that M theory in its fledgling state has the best hopes of uniting both relativity and quantum physics could have something to do with it.
Buy a ticket, go to the other side of the earth. The time just changed :D
Alternate timelines are pretty impossible as far as I can see, unless we're going with an entirely different universe with entirely different starting conditions, which would completely change everything in the universe, and would have nothing to do with the pop culture idea of alternate timelines. No matter how many times something is repeated, as long as the conditions are exactly the same (ie all atoms are in the exact same position and moving in the same direction with the same force) the outcome will always be the same. If there's different starting conditions for the universe, it'll be an entirely different universe. Anyway, we don't even fully understand the concept of the universe. How can we say we can jump between them and they'll be "jush liek in docta hoo" (no offense to doctor who fans, just using it as an example) when we still have no idea how the universe works? This is pretty optimistic IMO.
Wait, correct me if I'm wrong but to go to the future, you travel close to the speed of light, to travel to the past go faster than the speed of light.
[QUOTE=ProWaffle;22383561]Alternate timelines are pretty impossible as far as I can see, unless we're going with an entirely different universe with entirely different starting conditions, which would completely change everything in the universe, and would have nothing to do with the pop culture idea of alternate timelines. No matter how many times something is repeated, as long as the conditions are exactly the same (ie all atoms are in the exact same position and moving in the same direction with the same force) the outcome will always be the same. If there's different starting conditions for the universe, it'll be an entirely different universe. Anyway, we don't even fully understand the concept of the universe. How can we say we can jump between them and they'll be "jush liek in docta hoo" (no offense to doctor who fans, just using it as an example) when we still have no idea how the universe works? This is pretty optimistic IMO.[/QUOTE] Per your second paragraph - you need to read up on quantum mechanics! The whole universe isn't pre-determinable as it was thought to be in Newtonian physics. Everything is probabilistic. Particles exist as a wave of probability rather then a point with a definite place and velocity. This probabilistic nature [I]isn't[/I] a by product of our ignorance to some deeper workings of physics, as it has been confirmed by experiment (such as work done by John Bell) to be an inherent quality of fundamental particles. It is this quality in fact which gives rise to Quantum Tunneling - a process used to make the sun shine, make transistors work etc. I'm sure you are aware of young's double slit experiment ([url]http://en.wikipedia.org/wiki/Young%27s_Double_Slit_Experiment[/url]). Well this confirmed that, when unobserved, particles can and do exist in more then one, if not all possible, states at the same time. A branch off of this is the Many Worlds interpretation of quantum mechanics ([url]http://en.wikipedia.org/wiki/Many-worlds_interpretation[/url]) whereby each time a particles probability wavefunction is collapsed (through measurement), the wave function is forced into giving up a location/velocity of the particle in question. Many Worlds alludes to the fact that a new branch of reality is created to fulfill each and every possible outcome from each of these wavefunction collapses. This interpretation solves apparent paradoxes such as the EPR paradox and Schrodinger's cat, and even gives rise to decoherence, which at the moment is our best mechanism for describing the probabilistically additive nature/behavior of interacting particles. Obviously the many worlds interpretation of QM is still only an interpretation, and there are many other interpretations out there (such as the Copenhagen interpretation). The thing that edges it for me is that MW easily dismisses any kind of paradox that could ever arise from the rather counter-intuitive nature of general relativity and quantum mechanics. Both are amazingly successful theories, and both suggest that time travel to the past IS possible. IMO the only way to reconcile this with interpretation of quantum theory is to go with Many Worlds (which to me is a really annoyingly pseudosciencey sounding name to an otherwise brilliant interpretation). I don't think anyone is suggesting any kind of sideways jump between alternate realities, but rather that by going back in time using the method in the OP, one could go down a separate time path to the original. Things that would influence this time path to be different to your previous one would be that, in such a high entropy system (getting higher all the time) such as this universe, the odds of you ending up in the same reality before is impossibly small. On top of that, there IS one small change to the initial starting condition; you and the memories (atoms/energy) that you have carried back with you. This to me suggests that traveling back in time will [I]always[/I] get you on a new time path, with practically no way of ever getting back on your original path.
oh god oh god double split [editline]08:50AM[/editline] And wans't EPR solved by Bohr proposing that the measurements and the observers were 'ghosts' at the conception of the two particles? [editline]08:51AM[/editline] And what is Copenhagen? I haven't heard of it. [editline]08:54AM[/editline] [QUOTE=BmB;22371817]Novikov says no.[/QUOTE] Well Novikov also states that time travel backwards is entirely impossible. Either that, or Novikov could go hand-in-hand with MW.
[QUOTE=billeh!;22390605] And wans't EPR solved by Bohr proposing that the measurements and the observers were 'ghosts' at the conception of the two particles? [/QUOTE] Yeah Bohr kinda hit the nail on the head, but didn't really elaborate past that point. His view was that the wavefunction and probabilistic nature of QM was an abstract mathematical construct which perfectly defined QM and so in fact [I]was[/I] the nature of all particles. Whereas Einstein always argued that the abstract mathematics were just a means to an end; a method of [I]describing [/I]the Quantum world, and nothing more then that. I think over the years Bohr has been shown to have the more accurate philosophy on the whole thing, especially since John Bell came up a method for testing the nature of locality in particles. Einstein always argued that although you cannot know both the exact velocity and position of a particle, that each particle will still always [I]have [/I] a precise velocity and position - and that the Uncertainty Principle was just something blocking us from knowing. Bell managed to prove this to be wrong, and that when particles are not being measured they do not have a definite position or velocity (I just read up on this a few weeks ago, but it was a bit confusing so I wont try to explain it thoroughly). Bohr's ideas on this, combined with Heisenberg's, [I]is [/I]the Copenhagen interpretation of Quantum Mechanics. But now with work on M-theory (particularly Brane theory) it seems that Many worlds could be a kind of 'add-on' pack for the Copenhagen interpretation. I've got to be honest, there are soo many different interpretations out there, all overlapping and agreeing/disagreeing on various points, that its almost akin to religion in some respects - albeit its based on interpreting scientific fact rather then spaghetti monsters. But out of all of them, and from what I've read on QM so far, many worlds seems the most logical and easy to follow. I really don't understand it when people try to use Occam's razor against it, because to me its a simple and beautiful way to explain reality and decoherence - beating most other theory's. Its counter intuitive for sure, and may be practically unfalsifiable in general terms. But with a time machine I suppose you could potentially prove it to yourself/anyone else with you.
Ahh, thanks for clearing that up. I had no idea that Copenhagen had a separate name for itself. I thought it was just part of QM. I also agree with you on MW's, it really is a great theory that explains a lot with a great amount of grace and elegance to boot. Hopefully, ten years down the road, we'll finally find out whether the Higgs boson exists or not. That'll help MW's along a lot, or completely change our view of the universe. If you ask me, I'm fine with either outcome. A revolution in physics in this day and age will be really interesting if it happens to come along.
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