/sci/ - Science & Math

>>10816689
no

No. All concepts of time travel requires you to break the second law of thermodynamics which is the most important law of physics and what we are most certain of will never be broken.

Hell all of the top physicist of the times like Einstein, Von Neumann, Heisenberg. All agreed upon that the laws of thermodynamics are the most firm science we know and that that is the basis of which all physics knowledge flows.

Therefor if your design/concept/hypothesis requires you to violate the laws of thermodynamics then it's by definition impossible.

Wormholes, FTL etc all violate the second law of thermodynamics which requires entropy to always increase as these concepts allow entropy to reverse.

Therefor time travel is impossible and will NEVER be impossible.

>>10816697
Causality can be broken according to certain interpretations of quantum mechanics such as the Many Words interpretation with interacting worlds or basically anything that can handle superposition of two states. I.e if you kill your grandfather in one universe both of you are alive and in another both of you are dead.

>>10816697
>Therefor time travel is impossible and will NEVER be impossible.
Anon... ¬_¬

>>10816689
sneed

Find exotic matter and we'll talk.
Make an assumptions that it exist like make an assumption that you can time travel any other way
And also timetravel to future is definitely possible

Did you not watch the show?

Why would you want to time travel?

>>10816689
>Is time-travel possible?
Yes. I am currently traveling into the future at a rate of one second per second.
It's pretty cool here. There are computers you can carry in your pocked connected to a vast web of electronic information.

>>10817222
OP is CERN brainlet too stupid to invent his own timemachine and force us to do this

>>10816689
If I said 'yes'.
How hard would you be willing to pursue it?
Would you be willing to give me an arm and a leg?

>>10816689
nope

>>10816689
I think it is possible, I also suspect the apparent causal contradictions are products of errors in our thinking more than anything else. An analogy: If we were in a game, it would be perfectly possible to load a saved game of an earlier point and play from there, this is because the causal continuuity isn't contained just in the game but outside of it, in the world of the player. Perhaps information is similarly encoded outside of our own causal continuuity. This is just one scenario allowing one to reverse time while preserving causality. By separating the two, you begin the see that time travel isn't inherently impossible.

Unfortunately, this means that it would in theory be possible to unmake the world in its present state, prevent billions from ever being born and so on. It would be a potentially devastating invention, and just because something is dangerous doesn't mean that it's impossible. No laws of nature intervened to prevent us developing the atomic bomb.

>>10817284
The kind of time travel you seem to be talking about would reverse our memories as well so we'd have no idea we traveled to the past. So it would be empirically equivalent to there being no time travel. That's why it isn't the type of time travel people usually speculate about.

But you also seem to touch the issue of whether there even exists "past" where we could go, or is it really gone forever. Relativity of simultaneity seems to suggest that past somehow does keep "existing".

>>10817301
>reverse our memories as well so we'd have no idea we traveled to the past.
Not necessarily, our memories could just as well be encoded outside of our time too. But I admit that's not a strong argument
>That's why it isn't the type of time travel people usually speculate about.
I think it's a powerful notion though. If you accept that the universe is probailistic, and I do, the option to give yourself or someone else, or indeed everyone another hand is tantalizing. It's possible that in the new world-line entirely different choices would be made.

I think that not only is it possible, but that the consequences of its discovery will be devastating.

>>10816689
Just wait until 2044

T. Actual time Traveller

US declares war on Iran a day before Christmas

>>10818313
On the off-chance you're not just memeing, how does it work? Is the Many Worlds interpretation correct or is causality preserved somehow in another way?

>>10816697
Physics as a whole models reality. Thermodynamics is just a model and it may be an incomplete description of reality. Nice try Kurisu. You're daddy is better than you.

>>10818313
I'll go along with your larp. How does it work?

>>10819113
>>10819217
>expecting someone to explain a time machine in the space of a 4chan post
t. not him

>>10819214
The second law isn't from observation, its from mathematics. Its true everywhere. If there are other worlds, it will also be true there.

>>10819274
yeah sure it takes billions of pages to explain whether there are different timelines or not

>>10818313
Last guy like you named Titor was wrong

>>10819295
Science is the use of repeated observation and testing to understand the numerical ordering of the world. By no means does a result that is based in math somehow supersede observation, since building (or finding, or whatever word for the philosophy of math you care to spout) math that matches what we see is the point, and we can then derive more math that also seems to fit, but it's still not perfectly complete. Another thing is that the second law only applies so strictly to closed systems. Your body "violates" it in the same way by decreasing the local entropy. I'm glad you're one hundred percent sure that our universe is a totally closed system, but you will be hard pressed to find evidence for that.

>>10819528
>"I'm glad you're one hundred percent sure that our universe is a totally closed system, but you will be hard pressed to find evidence for that."
Based.

>>10819274
Surely he can give us a simple explanation even if it isn't thorough.

>>10816697
(((einstein, von neumann, heisenberg))) yea i’m thinking it’s possible

>>10818313
While the US-Iran war is inevitable it won't be happening in 2019. Tensions are the lowest they have been in 20 years time.

>>10819623
Those 3 guys are the literal founders of modern science.

Einstein: Physics and electromagnetism
Von Neumann: Computers, AI, Game Theory and Mathematics
Heisenberg: Quantum Mechanics, Statistical physics and matter-wave duality

If you don't respect at least one of them then you don't belong on /sci/. You can't forge mathematics you brainlet so fuck off with your schizo conspiracy theories.

>>10819644
Von Neumann is also arguably the single most intelligent human being to ever live.

>>10819644
woah WOAH please watch your language my wifes son is perusing the board

>>10816689
If it was possible, why hasn't anyone travelled back in time to prevent this shitty thread from occuring?

>>10816689
Study how to simulate consciousness and then you can simulate time travel to an extent that will feel just as real as reality

>>10819674
Good answer.

>>10819674
if you can build a cohesive understanding of history back to prehistory and blend it with sociological/psychological understanding you can then perform directed inference.

>>10819698
though if you’re trying to r. view cosmic events you need to take your preparative study a bit deeper

>>10816689
>time-travel
>wormholes
>exotic matter
>folds
>space-time
> matter with negative mass
>time dilation
>https://en.wikipedia.org/wiki/Time_travel#Wormholes
>energy-expensive FTL travel
Bingo!

There is no time to travel to. There is only the current state of the universe. This state changes constantly step by step, one elemental interaction at a time. Time doesn't flow and there is no time outside of the order of events.

Can't prove any of this though, but it makes the most sense and is the simplest explanation.

>>10819838
>This state changes constantly step by step, one elemental interaction at a time. Time doesn't flow and there is no time outside of the order of events.

You can even express this mathematically by saying

1: Entropy must always increase
2: Between T=1 and T=2 the only difference in the universe is that entropy increased
Conclusion: Arrow of time will always go forwards because entropy needs to always increase meaning there is no such thing as going back in time just like there is no such thing as reversing entropy.

>>10816689
I don't see it working, the other side is just the mirrorverse where time will travel backwards, yes, but at the same rate it moves forward here. Also our matter would be destroyed near instantaneously, solve that then maybe.

>>10819838
>doesn't understand relativity

>>10819630
I don’t think war with Iran will occur. If everyone knows in 1993 WTC got a gold vault below ground. And due to structural damage since building the vault may have damaged the integrity of the structure they had to demolish the building. It was posted in newspapers as the law states. Then who is the terrorist here? Not only that but taking the Dodge-Plymouth building in DC and turning it into a compound called the Pentagon. Everyone knows nobody says it but plays along. Who is harboring terrorists?

>>10819845

Entropy increasing is simply statistics. It's not a "real law" by any means. Entropy can decrease and you can observe this if you want. For this reason it cannot be used as an arrow of time.

There's also no need for an arrow if time is not something real that flows or does anything. If universe simply changes state in succession (instantly even) there's no need for a direction. There's just change. That's mostly determined by laws of probability.

>>10816689
as I understand its only possible in multiverse theory, that is traveling (back) in time means you are actually traveling to another universe VERY similar to our own which has a different time frame, that way there is no time traveler paradoxes.

>>10819847
haha... I just figured it out. get fucked /sci/

no, it's not possible for massive objects to travel through time from what we know at the current state

>>10819853
Entropy needing to increase is an extrapolation from the laws of thermodynamics and yes it is a real law. Total entropy must always increase.

The arrow of time is just a function of the total entropy in the universe constantly increasing.

>>10816689
No it's not posssible for massive objects to travel through time from what we know at the moment

>>10819851
The idea is that perhaps time travel doesn’t exist from a physical perspective but does from a psychological one.

>>10819849
Teach me senpai.

There's nothing preventing observed time from being relative even if time doesn't exist. Time is just a collection of actions. Some amount of cesium-transitions is considered a second. Sometimes those transitions seem to happen slower or faster relative to some other clock. This doesn't mean that time moves at different speeds, just that those motions or measured actions require more elemental actions to occur.

>>10819838
That would have been the most reasonable assumption before relativity. But now we know there is no objective "current state of the universe".

https://en.wikipedia.org/wiki/Relativity_of_simultaneity

>>10819863
way to think inside the bucket

>>10819698
Are you implying something?

>>10819623
kek

>>10818313
This anon's prediction just got orders of magnitude more likely. Check the news.

>>10819877
post a link... I'm not going to check all of the damn news.
>>10818313
what's it like being me in the future?

>>10819863
If you are correct that entropy can never decrease, then tell me what prevents all the balls from moving to compartment A just by random chance.

>>10819886
it's probabilistic.. them being equally divided is just a more likely outcome.

>>10819859
It's possible for a single timeline to be consistent and involve time travel to the past. So before you go on your trip to the past you'd already know that you can't kill your grandfather before he met your grandmother, for example. Even if you tried, by the virtue of your own existence you know that you would somehow fail. Just like if you went to the past, observed your grandfather in some life threatening situation from which survival would seem unlikely - you'd know that he'll survive, even if you have no clue how. You can still be a part of a causal chain of event that happened in the past, it's just that in that case you always were a part of that. What makes it weird is the order in which you'd subjectively experience things, considering the fact that objectively it all "already happened" before you even began your trip to the past.

>>10819887
and when looking at a large system, say many dice rolls, or many systems of such you had posted things tend to favour entropy. you're not going to roll a 1 1,000,000,000 times in a row.

>>10819890
The Novikov self-consistency principle and compossibles aren't particularly satisfying answers, though. They're generally regarded as copouts even though they're logically possible.

>>10819887
I know that but the other guy doesn't. There's no arrow of time, it's just statistics.

>>10819892
And why exactly can't you roll a 1 1,000,000,000 times in a row? Of course you can. It's just not probable.

>>10819895
What's the problem with it though? Because it conflicts with free will?

>>10819872
It looks to me information is simply transferred from separate events at different times to different observers (when their coordinate systems differ). Doesn't mean that there isn't some universal coordinate system.

>>10819907
Because it's spectacularly unlikely, it seems very unlikely that the universe would be formed just-so to prevent you interfering with the past in such a way, that a string of coincidences should somehow occur to prevent you killing your grandfather or something like that. It also implies that in the original master timeline (If we assume the "you were always there" idea) you spontaneously emerge ex nihilo with memories of a future that as yet doesn't exist. Stephen Hawking's chronology protection conjecture seems a far more serious candidate because rather than invoke bizarre coincidences it, as far as I know, simply suggests that the laws of Physics are arranged such that any attempt to build a time machine will result in the destruction of that machine. No coincidences necessary.

While I don't personally know shit about physics, I can't help but feel that the "order of events" is the simplest explanation of reality and most likely correct. I do get told a lot that my view is not correct but the thing is that the reason for dismissal seems to vary a lot and sometimes the counter-arguments are just plain stupid, so I don't feel like giving up just yet.

Since some actual physicists have had the same idea and presented it publicly as a valid option, I wonder if all the people opposed to the idea simply don't get it or something.

Here's one news item I can find that is essentially what I'm proposing:
https://phys.org/news/2011-04-scientists-spacetime-dimension.html

I'm also told that Rovelli has a similar view of time. He probably knows relativity in some degree also.

>>10819900
probability of 4.3368x10^(-778151251) it's safe to say it's impossible

>>10816689
>I’m currently interested in the concept of time-travel
>exotic matter (i.e matter with negative mass)
>more here: wikipedia link
Could you type any more like you just had this entire thing prescribed to you by a popsci video or I guess in this case an anime

>>10819936
Still doesn't cut it. Possible is possible, however unlikely.

>>10819969
written in decimal it would fill the entire board with threads max posted with zeros before ever getting to the 4.

>>10819969
>>10819981
infact after doing the math I think we could fill every board on 4chan, with max posted threads with nothing but 0's trying to write out that number in decimal and still never reach the 4

>>10819924
>It also implies that in the original master timeline (If we assume the "you were always there" idea) you spontaneously emerge ex nihilo with memories of a future that as yet doesn't exist.

This is not a serious objection. This kind of time travel would obviously imply that future "already exists", just like a physical location you're going to is still out there even if you haven't arrived there yet. And it presumably wouldn't be "spontaneously ex nihilio", but from a wormhole or something like that.

>it's spectacularly unlikely, it seems very unlikely that the universe would be formed just-so to prevent you interfering with the past in such a way, that a string of coincidences should somehow occur to prevent you killing your grandfather or something like that.

This argument I'm conflicted about. I'm not sure if it's a failure of our intuition - it's really hard to think in the eternalist framework of time without free will, with symmetry between past and future - or would the laws of physics need to be preposterously more complicated than otherwise to make this kind of time travel work. But think about acquiring a recording of the past, where a person is trying to prevent an event that you know occurred for sure. You know that this person is very motivated about preventing this event. Judging from the record alone, it seems pretty likely that he'll succeed. Yet as you are watching it "from the future" - after the event which he is trying to prevent has already happened - you know that he'll fail. You have no idea how. Does his failure require "bizarre" coincidences? Does it need laws of physics that are specifically designed for him to fail?

>Stephen Hawking's chronology protection conjecture seems a far more serious candidate

Oh you'll have no argument from me that the most likely solution is that time travel to the past is simply impossible.

>>10820031
>This is not a serious objection. This kind of time travel would obviously imply that future "already exists", just like a physical location you're going to is still out there even if you haven't arrived there yet. And it presumably wouldn't be "spontaneously ex nihilio", but from a wormhole or something like that.
You'e not seeing what I'm saying. In order to accept your position, then you'd need to take an eternalist point of view wherein all points in history are equally "real" and exist simultaneously. But it appears that the future has not popped into being ex nihilo, it's a thermodynamic progression from the present moment. If I accept your argument I'm probably tacitly accepting the proposition that our normal causal chain is an illusion.
>Does his failure require "bizarre" coincidences? Does it need laws of physics that are specifically designed for him to fail?
You're committing a kind of category error here. It's one thing to suggest that someone in the past may be prevented from preventing something you know to have happened by coincidence, it's another thing entirely for it to be logically necessary for such coincidences to occur. It's an enormously inelegant distortion of the Laws of nature.

>>10819644
>Mann
>Stein
>Berg
Why do you like kikes so much?

>>10819528
>Another thing is that the second law only applies so strictly to closed systems.
It applies to ISOLATED systems, you brainlet
> I'm glad you're one hundred percent sure that our universe is a totally closed system
Im 100% sure its an isolated system because the definition of Universe is 'all there is'.

>>10819936
By the same logic, no combination of 1,000,000,000 dice rolls is possible.

>>10816689
The mainstream concept of "time" is highly illogical.

The concepts of "past" and "future" are just that, concepts, of a metaphysical nature, but are erroneously used as if they are physical in nature, and can therefore be used to describe the entirety of physical reality moving in a particular direction, therefore turning "past" into a physical container that stores what has been, and the future into a container of what will be.

This is all completely a construct of our minds, one deeply ingrained in us, espeically as the words we use are entirely based upon past, present and future tenses.

So to answer the question, no, time-travel is not possible, because "time" is not physical in the first place.

>>10816689
Forward or reverse?

>>10816697
All the top phycisists before are nothing compared to today's physicists. Some of them are working on time travel right now at Oakridge National Laboratory. We're talking like beyond Nobel level people.

>>10816689

>>10820685
This is not wanted, so they clamp and vaccinate.

>>10820223
Closed systems in classical mechanics are isolated systems which is why I mixed them up, but you're correct. That said, if time travel is possible it simply means that the universe isn't an isolated system in the way you're thinking it must be. Why can the universe not include what will be, or what was, along with what is?

You're time traveling right now, fucker.

>>10820660
Isn't entropy a physical process?

>>10816689
Within the present frame of physics time travel isn't possible because it violates thermodynamics, and practically speaking ideas like exotic matter with negative mass don't mean anything presently outside of an esoteric interpretation of mathematical models used in theoretical physics.
In short, it is reasonable to assume it is impossible given our present understanding.

>>10820957
If time travel is possible, all those laws and mathematical models that prevent it are wrong.

>>10821007
>If time travel is possible, all those laws and mathematical models that prevent it are wrong.
If the universe were a bubble in the glass of a multiversial Roman Coke...
You follow? You're assuming that it's possible. I'm saying we have no firm ground for that assumption.

>>10821093
No, I do not follow.

>>10816689
This game created more autists than anything on earth. Time travel is not a thing no matter how convincing a work of fiction makes it seem.

>>10821136
>No, I do not follow.
You're speculating, engaging in what-ifs. Anything substantial?

>>10821158
No, I'm not. You are.

>>10816689
Yes
>t. currently traveling forward in time at one second per second

>>10816689
puremathlet here
Can anyone summarize the list of physics postulates that time travel would violate? If time travel is a theoretical prediction of relativity that contradicts these postulates, isn't there a big logical consistency issue?

into the future

best way to amplify gravity? or slow down time?

can we ever build a gravity amplifier?

emergent gravity postulates gravity is just teh universe slowing down because of information density (it takes the computer longer to process) so things fall towards eachother in 4D spess time... so would a super powerful quantum computer be the best way to slow down time?

what about using a bunch of superconductors to twist a super dense plasma or electron degenerate matter?

>>10821312
Fast-forwarding to the future relative to some other frame of reference is a prediction of relativity (time dilation), a confirmed thing. The effect could in principle be as dramatic so that it would be in every way just like "time travel to the future" in fiction, though the energy and speed required would be absurd. Time travel to the past is not something general relativity predicts, but it also "does not forbid" it... if you make up stuff that we have absolutely no reason think that they exist, like matter with negative mass and wormholes.

>>10821364
how much energy?

>>10821364
I see
>like matter with negative mass and wormholes
Well, physicists have always had a peculiar way of interpreting the math in their models, so I wouldn't entirely rule it out
How do they define mass/energy again? If you go by a gravity model (a physical attribute affecting spacetime geometry), wouldn't something behaving like dark energy do the job?

>>10821373
>negative mass

could be bullshit..
>emergent gravity postulates gravity is just teh universe slowing down because of information density (it takes the computer longer to process) so things fall towards eachother in 4D spess time

that means there is no mechanism for "negative gravity" repelling something or speeding up time

and inflation might be gravity from universes outside our own

>>10816697
It wouldn't break any conservation laws if the conservation laws apply within the time dimension as well (i.e. you need to accelerate something into the future if you want to travel into past)

IMO

>>10821366
Depends how far to the future you want to go in how much of your time. But let's say you want your 5 minutes to equal everyone else's (who are not moving anywhere near the speed of light) day. If you want to achieve that effect by speed alone, you need to go at 99.9994% of the speed of light. You would need to accelerate the mass of whatever vehicle you were traveling on to that speed, you can just imagine the energies required considering that the speed of light is the velocity of massless particles in vacuum.

>>10821426
i know...

would it be easier to manipulate gravity somehow or go relativistic speeds?

>>10821428
Rotating black holes could be useful - Kip Thorne at first thought the Interstellar writer's idea of a planet that's a near black hole and because of that has such an extreme time dilation that 1 hour there equals 7 years on Earth was impossible (the planet would get sucked in the black hole he thought), but then after doing some calculations that in principle if the black hole was a spinning one and the angular momentum was strong enough, it could be simultaneously possible for the time dilation to be strong and the planet not get sucked into the black hole. So if there was such a black hole and we could travel there it might be easier.... but needless to say creating something like that artificially would again require preposterous energies, even if the effect wasn't quite that dramatic.

>>10821456
could we make a rotating black hole with fusion or antimatter bombs?

because the closest one is thousands of lightyears away

>>10821456
oops didnt read the whole thing well steven hawking said that if you used all the hydrogen in the ocean to make fusion bombs that might be enough to create a black hole?

you think thats true?

we can get hydrogen from jupiter or the sun

>>10820633
whoa

>>10820633
The case the anon is talking about is rolling the same number x amount of times, you have a far higher probability rolling for a number that wasn't your last roll x amount of times. Anon is wrong to say that it is impossible, but would be right to call it improbable or practically impossible.

An example for those not following: the odds of choosing any number out of ∞ is 1/∞ yet the probability that a number is chosen is 1 (a number has to be chosen, even if they are all equally likely/unlikely).

>>10821192

>>10821519
You claim it is not possible. I'm saying that such claim is not justified.

>>10821680
It's so small that it's measurably indistinguishable from impossible. Go ahead and roll a million dice for a single combination. I can guarantee you'll never see it in your lifetime. That's the equivalent of impossible.

create a mirror through quantum entanglement?

is it possible to snapshot the universe by collapsing to a mirror?

that guy who was posting that non claw function

>>10821462
>could we make a rotating black hole with fusion or antimatter bombs?
>because the closest one is thousands of lightyears away
Probably not. Remember that the energy in an antimatter explosion is simply a release of the mass it contains as energy and so it limited by that mass. Black holes are extremely massive, no getting around that basic fact.

>>10819969
>Still doesn't cut it. Possible is possible, however unlikely.
It's hard to tell if you're being argumentative but what we're talking about is a bell curve which gets increasingly narrow as the number of particles in the system increases, with the tail ends of the bell curve approaching zero. We interpret this like a limit at say it is impossible (zero probability) because there isn't enough time in the universe for it to probabilistically allow a single instance of entropy decrease in the parameters you describe.

>>10816689
YES
you just need a cute redhead tsundere as assistant