5 ms·

There is no such thing as time, or time travel. There are only positions of particles. To go back in time by 1 minute, all particles in the universe have to be

There is no such thing as time, or time travel. There are only positions of particles. To go back in time by 1 minute, all particles in the universe have to be moved/changed back to their previous position. This is not time travel, but universe manipulation except for one subject. If there were parallel universes with every possible outcome and you traveled to one, this would also not be time travel, but a moving to a place that looks like another place where particles were at a certain position. Time is just a way to label snapshots of particle positions in the universe.

austinjp 10y ago
> this... would not be time travel, but... a different time. Hmmmmm.
- openfuture 10y ago
  He probably should have said 'not time travel but a different world'
  - Retra 10y ago
    That's what different times are.
booleandilemma 10y ago
You make a good point. What if a civilization figured out how to do this on a local level? To finely manipulate particles within a small area? It would be like version control for reality.
- sudhirj 10y ago
  This idea is referenced quite a bit in an Asimov novel, but I can't remember the name. Something about earth in the far future, and called Eternity Circuits. Computers enforce physical arrangement at an atomic level, and redundancy circuits enforce the computer and each other, basically creating systems that last forever.
  - revjx 10y ago
    Arthur C Clarke, The City and the Stars: https://en.wikipedia.org/wiki/The_City_and_the_Stars https://en.wikipedia.org/wiki/The_City_and_the_Stars
- edpichler 10y ago
  Each particle has is own time. Each particle can go forward on time, independently. That's why satellites clocks must be adjusted https://en.wikipedia.org/wiki/Time_dilation https://en.wikipedia.org/wiki/Time_dilation
Mahn 10y ago
OTOH time is relative to the observer and certain universe phenomena, such as black holes, can distort how time passes in different points of the space dimension. The general idea that a point in time is how we define a particular snapshot of particles is probably right, but time as a dimension also appears to be a bit more complex than how we perceive it from Earth, which we should also not forget.
- thinkloop 10y ago
  "Time", aka chemical and physical reactions, can happen faster or slower depending on the environment. But this is only slightly different than putting food in the fridge. The food will mold slower, but it's not time travel. The closest we can get to faking time travel is by manipulating the speed of a subset of reactions (like our body's aging) by going the speed of light or freezing ourselves, etc. But it's still fake, "time" continues, you just managed to manipulate specific reactions in a peculiar way.
  - cyphar 10y ago
    So special relativity, which is a theory that comes out of thought experiments and pure mathematics, is "just a chemical reaction". How do you explain that an observer outside of a moving frame of reference will also see things differently? Also, can you explain what you think "physical reactions" are? What causes them? Why would they happen at different speeds if time doesn't exist? Can you explain which of the two statements you disagree with and provide an explanation: 1. The speed of light is constant in all frames of reference. 2. The laws of Physics apply in all inertial frames of reference. If you disagree with neither of these statements, then the entirety of special relativity must follow from your logic. Which means you have to explain why these physical effects happen without being able to explain it through time dilation and other effects.
allemagne 10y ago
Time travel is dubious, but in what useful sense is there no such thing as time? Define the phenomenon of time dilation or just the concept of motion without it. Particles go from position to position... but describing being at state X and then being at state Y seems to strongly imply the existence of what we understand as time.
- adventured 10y ago
  Time doesn't exist in the sense that it's just a measurement. I'm 6'2", that height does not exist as a tangible thing, it's a mathematical device. Whether we're talking about 60 seconds, or 6 billion years, they're both measurements of distance traveled / motion. We measure one year by the earth's relationship to the sun. Time travel cannot exist because the universe does not keep a record of where everything was at any given point in time, such that you can rewind (adjust) it all back to how it was at every or any given point in time. There is nobody recording that, there is nobody to rewind it, there isn't enough energy to attempt either the recording or the rewinding at an independent macro scale (eg could you properly rewind/adjust a solar system while the wider galaxy acts upon it? would you have to rewind the galaxy? and on it goes up).
  - allemagne 10y ago
    The argument about time seems plausible. I don't think time travel is possible either. I do however think there is such a thing as time and height. Units of measurement are certainly arbitrary but there is something that is being measured.
SomeStupidPoint 10y ago
Your position is inconsistent: the arrangement of particles changing is time, so your explanation of there not being time... asserts that time happens! Putting the universe back as it was except for you is time travel. You've traveled your state to a different time (previous state) of the universe. Your semantic game sounds very clever, but is actually just inconsistent and borderline ignorant of what people mean by those terms.
- thinkloop 10y ago
  > Putting the universe back as it was except for you is time travel. You've traveled your state to a different time (previous state) of the universe. > Your semantic game sounds very clever, but is actually just inconsistent and borderline ignorant of what people mean by those terms. I don't think that's how most people think of time travel. For example, say I proceeded to invoke reactions to get all particles back to exactly how they were on Jan.1 2000. Say this took me a year, and finally, in 2018, I execute the final reaction that places the last particle, so that the universe is exactly like it was Jan.1, 2000. Have I been time travelling for a year? Does making 2018 look like 2000 what people generally think of as time travel? What about that you yourself did not change, where are those particles coming from? What about the old you existing in that time as well, there aren't enough particles in the universe to have two you's. What about the time you travelled from remaining in existence while you're gone, and the changes you invoke in the "past" propagating there? I get that it would provide a similar experience in many ways, but it doesn't involve travelling, nor time, just changes in particle positions - which is the nuance I am highlighting.
  - SomeStupidPoint 10y ago
    You have to give up the idea of a universal clock: you only have a local one. In your example: since you erased the elapsed computation in other regions, you (by putting the particles back) are literally rewinding every clock but yours. In whatever sense they were ever in 2000, they're back there, though you're in (your) 2018. Having your 2018 be their 2000 seems like a sensible definition of time travel. (And yes, you'd have spent a year time traveling, though in many senses you always are time traveling forward, and you just happened to spend a year going fast "backwards".) For the rest of your points, I agree that they're sensible objections to being able to do it, but they don't make the concept not mean anything, which was your original point. Why would the future remain? You destroyed it when you time traveled, and any changes in the future would require time traveling forward to see. (Forward is less erasure heavy, because you're just stalling instead of rewinding.) It's not just a similar experience, it's the literal definition of what that term means. > nor time, just changes in particle positions Uh... It's comments like this which makes me question your position. Changes in particle positions is time! Literally: time is just that thing a clock does, which is tick. If particles change position, that's (by definition) time.
443633456 10y ago
"There are no particles, only waves."
- cyphar 10y ago
  But waves are described by the wave equation, which is defined in terms of acceleration and curvature. Checkmate! Time is real. :P
Retra 10y ago
> There is no such thing as time [...] Time is [something that exists.] Why even bother with this whole pointless facade? Just because you have a preferred model of time doesn't mean it doesn't exist. All things that are said to exist do so as models. You're saying "time is fake, it's just labels" like somehow everything else in the universe isn't also just labels and just as real. Things are what they are. You find a useful way to talk about them. You don't spend your time laboring over meticulously irrelevant descriptions, ironically putting down 'mere labels' as though your whole argument here isn't just a grand exercise in label worship. One could fairly trivially write a faithful version of your post on literally any subject. "Position doesn't exist, it's merely a manifestation of the relative relations between subsets of human experiences!" "Your HN post doesn't exist, it's merely electronic patterns in a transient configuration!"
cyphar 10y ago
> There is no such thing as time, or time travel. There are only positions of particles. To go back in time by 1 minute, all particles in the universe have to be moved/changed back to their previous position. How do you explain acceleration? Or things like entropy that appear to indicate that the "arrow of time" does exist. Or general relativity / cosmology that clearly shows that your "snapshots of particles" appear different in different frames and there are physical effects that change how time progresses for them all. > Time is just a way to label snapshots of particle positions in the universe. You're not saying anything new here, apart from saying that "time isn't real". Is any dimension real? Spacial dimensions are even weirder because they're unlabelled and you can pick and three vectors to define a basis.
edpichler 10y ago
You are wrong. As far as I know, each particle has is own time. Each particle can go forward on time, independently. That's why satellites clocks must be adjusted https://en.wikipedia.org/wiki/Time_dilation https://en.wikipedia.org/wiki/Time_dilation
deleted 10y ago
[deleted]

austinjp 10y ago

> this... would not be time travel, but... a different time. Hmmmmm.

openfuture 10y ago
He probably should have said 'not time travel but a different world'
- Retra 10y ago
  That's what different times are.

booleandilemma 10y ago

You make a good point. What if a civilization figured out how to do this on a local level? To finely manipulate particles within a small area? It would be like version control for reality.

sudhirj 10y ago
This idea is referenced quite a bit in an Asimov novel, but I can't remember the name. Something about earth in the far future, and called Eternity Circuits. Computers enforce physical arrangement at an atomic level, and redundancy circuits enforce the computer and each other, basically creating systems that last forever.
- revjx 10y ago
  Arthur C Clarke, The City and the Stars: https://en.wikipedia.org/wiki/The_City_and_the_Stars https://en.wikipedia.org/wiki/The_City_and_the_Stars
edpichler 10y ago
Each particle has is own time. Each particle can go forward on time, independently. That's why satellites clocks must be adjusted https://en.wikipedia.org/wiki/Time_dilation https://en.wikipedia.org/wiki/Time_dilation

Mahn 10y ago

OTOH time is relative to the observer and certain universe phenomena, such as black holes, can distort how time passes in different points of the space dimension. The general idea that a point in time is how we define a particular snapshot of particles is probably right, but time as a dimension also appears to be a bit more complex than how we perceive it from Earth, which we should also not forget.

thinkloop 10y ago
"Time", aka chemical and physical reactions, can happen faster or slower depending on the environment. But this is only slightly different than putting food in the fridge. The food will mold slower, but it's not time travel. The closest we can get to faking time travel is by manipulating the speed of a subset of reactions (like our body's aging) by going the speed of light or freezing ourselves, etc. But it's still fake, "time" continues, you just managed to manipulate specific reactions in a peculiar way.
- cyphar 10y ago
  So special relativity, which is a theory that comes out of thought experiments and pure mathematics, is "just a chemical reaction". How do you explain that an observer outside of a moving frame of reference will also see things differently? Also, can you explain what you think "physical reactions" are? What causes them? Why would they happen at different speeds if time doesn't exist? Can you explain which of the two statements you disagree with and provide an explanation: 1. The speed of light is constant in all frames of reference. 2. The laws of Physics apply in all inertial frames of reference. If you disagree with neither of these statements, then the entirety of special relativity must follow from your logic. Which means you have to explain why these physical effects happen without being able to explain it through time dilation and other effects.

allemagne 10y ago

Time travel is dubious, but in what useful sense is there no such thing as time? Define the phenomenon of time dilation or just the concept of motion without it. Particles go from position to position... but describing being at state X and then being at state Y seems to strongly imply the existence of what we understand as time.

adventured 10y ago
Time doesn't exist in the sense that it's just a measurement. I'm 6'2", that height does not exist as a tangible thing, it's a mathematical device. Whether we're talking about 60 seconds, or 6 billion years, they're both measurements of distance traveled / motion. We measure one year by the earth's relationship to the sun. Time travel cannot exist because the universe does not keep a record of where everything was at any given point in time, such that you can rewind (adjust) it all back to how it was at every or any given point in time. There is nobody recording that, there is nobody to rewind it, there isn't enough energy to attempt either the recording or the rewinding at an independent macro scale (eg could you properly rewind/adjust a solar system while the wider galaxy acts upon it? would you have to rewind the galaxy? and on it goes up).
- allemagne 10y ago
  The argument about time seems plausible. I don't think time travel is possible either. I do however think there is such a thing as time and height. Units of measurement are certainly arbitrary but there is something that is being measured.

SomeStupidPoint 10y ago

Your position is inconsistent: the arrangement of particles changing is time, so your explanation of there not being time... asserts that time happens! Putting the universe back as it was except for you is time travel. You've traveled your state to a different time (previous state) of the universe. Your semantic game sounds very clever, but is actually just inconsistent and borderline ignorant of what people mean by those terms.

thinkloop 10y ago
> Putting the universe back as it was except for you is time travel. You've traveled your state to a different time (previous state) of the universe. > Your semantic game sounds very clever, but is actually just inconsistent and borderline ignorant of what people mean by those terms. I don't think that's how most people think of time travel. For example, say I proceeded to invoke reactions to get all particles back to exactly how they were on Jan.1 2000. Say this took me a year, and finally, in 2018, I execute the final reaction that places the last particle, so that the universe is exactly like it was Jan.1, 2000. Have I been time travelling for a year? Does making 2018 look like 2000 what people generally think of as time travel? What about that you yourself did not change, where are those particles coming from? What about the old you existing in that time as well, there aren't enough particles in the universe to have two you's. What about the time you travelled from remaining in existence while you're gone, and the changes you invoke in the "past" propagating there? I get that it would provide a similar experience in many ways, but it doesn't involve travelling, nor time, just changes in particle positions - which is the nuance I am highlighting.
- SomeStupidPoint 10y ago
  You have to give up the idea of a universal clock: you only have a local one. In your example: since you erased the elapsed computation in other regions, you (by putting the particles back) are literally rewinding every clock but yours. In whatever sense they were ever in 2000, they're back there, though you're in (your) 2018. Having your 2018 be their 2000 seems like a sensible definition of time travel. (And yes, you'd have spent a year time traveling, though in many senses you always are time traveling forward, and you just happened to spend a year going fast "backwards".) For the rest of your points, I agree that they're sensible objections to being able to do it, but they don't make the concept not mean anything, which was your original point. Why would the future remain? You destroyed it when you time traveled, and any changes in the future would require time traveling forward to see. (Forward is less erasure heavy, because you're just stalling instead of rewinding.) It's not just a similar experience, it's the literal definition of what that term means. > nor time, just changes in particle positions Uh... It's comments like this which makes me question your position. Changes in particle positions is time! Literally: time is just that thing a clock does, which is tick. If particles change position, that's (by definition) time.

443633456 10y ago

"There are no particles, only waves."

cyphar 10y ago
But waves are described by the wave equation, which is defined in terms of acceleration and curvature. Checkmate! Time is real. :P

Retra 10y ago

> There is no such thing as time [...] Time is [something that exists.] Why even bother with this whole pointless facade? Just because you have a preferred model of time doesn't mean it doesn't exist. All things that are said to exist do so as models. You're saying "time is fake, it's just labels" like somehow everything else in the universe isn't also just labels and just as real. Things are what they are. You find a useful way to talk about them. You don't spend your time laboring over meticulously irrelevant descriptions, ironically putting down 'mere labels' as though your whole argument here isn't just a grand exercise in label worship. One could fairly trivially write a faithful version of your post on literally any subject. "Position doesn't exist, it's merely a manifestation of the relative relations between subsets of human experiences!" "Your HN post doesn't exist, it's merely electronic patterns in a transient configuration!"

cyphar 10y ago

> There is no such thing as time, or time travel. There are only positions of particles. To go back in time by 1 minute, all particles in the universe have to be moved/changed back to their previous position. How do you explain acceleration? Or things like entropy that appear to indicate that the "arrow of time" does exist. Or general relativity / cosmology that clearly shows that your "snapshots of particles" appear different in different frames and there are physical effects that change how time progresses for them all. > Time is just a way to label snapshots of particle positions in the universe. You're not saying anything new here, apart from saying that "time isn't real". Is any dimension real? Spacial dimensions are even weirder because they're unlabelled and you can pick and three vectors to define a basis.

edpichler 10y ago

You are wrong. As far as I know, each particle has is own time. Each particle can go forward on time, independently. That's why satellites clocks must be adjusted https://en.wikipedia.org/wiki/Time_dilation https://en.wikipedia.org/wiki/Time_dilation

deleted 10y ago

[deleted]