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/sci/ - Science & Math

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3312818 No.3312818 [Reply] [Original]

Can someone explain to me why time has a direction?

>> No.3312830

Because clock hands point a certain direction depending on the TIME, dipshit.

>> No.3312827

>implying it has a direction.

>> No.3312835

>>3312834
why?

>> No.3312834

The net entropy of the universe must always increase.

>> No.3312838

http://en.wikipedia.org/wiki/Arrow_of_time

>> No.3312840

>>3312835
That's the only way any work (the physics definition of the word), can be done.

>> No.3312845

As a function of wha?

AS A FUNCTION OF TIME!
QED DUNKASS
BOOM!

>> No.3312848

Time is entropy.

In one direction, Entropy increases. In another, it decreases.

From our point of view, time flows in the direction of increasing entropy.

>> No.3313295

Entropy is just the amount of lost energy right? How does that translate into the propelling of time?

>> No.3313540
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3313540

>>3313295
>>3313295
>>3313295
>>3313295
>>3313295
>>3313295
ANSWER THIS MAN YOU MOTHERFUCKERS

>> No.3313557

Unless you had a 2-d or 1-d looping worldline, time can't go anywhere but forward because you cannot go back. The only way this could change would be in a universe where you started walking away from point A but you always came back to point A, as if in a circle/along the outside of a cylinder.

Even then you aren't going backward, you are moving forward yet arriving in the past in a loop, and time still moves forward.

>> No.3313564

>>3313295
entropy is not exactly lost energy (its units are Joules/Kelvin). it is more of a measure of how the energy in a system is distributed and is created when a system is out of equilibrium and is brought to equilibrium.

it translates to time because the it dictates how energy must be transferred (in terms of heat, this is always cold to hot). not sure if other time dependent phenomenon like newtonian mechanics are controlled by entropy however...

>> No.3313570
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3313570

Lines? uhh...Time does not travel in lines...It travels in circles...This is why clocks are round...

>> No.3313572

>>3313570
Lol troll

>> No.3313600

Because when the big bang banged it sent everything moving away from the bang across every dimension, including time.

>> No.3313610

Man, i hear the wrong definition of entropy spouted out so many times, and pseudo-scientists screaming the word as if it were the new Satan.

Temperature measures the energy stored within the random particle motions within a system. Entropy is a measure of how probable a system is to have a given state. Namely, you start with the assumption that every state has equal probability. Then you figure out how many states there are. Finally you determine how many different ways there are to wind up with essentially the same state.

One way of determining a state is deciding how many quanta of energy each particle has. These amount to random (I.E. "Thermal") motions, which, for a per particle average, is proportional to temperature. Thus entropy has a temperature dependence.

Also, saying entropy has units is not exactly true. It has units, but only because Boltzmann's constant is thrown into it after all the actual information is determined because someone decided it needed units, not because the factors used for the calculation resulted in so any units left over.

Another note: It is possible to do work without increasing entropy. It just needs to be done at extremely slow rates, under very definite conditions.

>> No.3313617

>>3312818

Maybe space-time doesn't have a direction?

>> No.3313630

>>3313295
Lost useable energy. It doesn't propel time. It's just one of the ways that we can tell the "forward" direction from the "backward" direction. Things evolve into stable solutions. The big bang was an unstable solution, so the universe and everything in it has to evolve through states until a stable solution is found, which is the heat death of the universe. If the stable and unstable ends of the universe were reversed, we'd probably experience time proceeding the other way, since the gain in stability is what lets us accumulate knowledge. That is there is nothing intrinsic in the dimension of time itself that gives it directionality, but rather that the conditions at one end are more stable than the conditions at the other end. Just thinking out loud.

>> No.3313636

BECAUSE SOMEONE FROM ANOTHER DIMENSION WILLS IT

>> No.3313646

>>3313630
Not OP
That was enlightening, thanks.

>> No.3313709

>>3313610
>Another note: It is possible to do work without increasing entropy. It just needs to be done at extremely slow rates, under very definite conditions.

I will ask for a more detailed source of information on this matter, please.

>> No.3313710
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3313710

because cause and effect

>> No.3313719

entropy is a lie

meaning, entropy doesn't really define an arrow of time, so much as our implied understanding about the boundary values of the universe works.

meaning, imagine you were teleported to an unknown universe, which has X entropy. Then, it is overwhelmingly likely that the entropy will be higher in the future. It is also overwhelmingly likely that the entropy was higher in the past.

entropy doesn't have that much to do with time. just, we know that a high entropy system is far more likely than a low entropy one. in the toy universe, we observe that the amount of entropy when we get there is surprisingly low, so in all likelihood, this moment is the lowest amount of entropy.

in other words, if you walk into a poker game, look over my shoulder and see i have a straight flush, you would assume that both my previous hand, and my next hand will be worse.

in our universe, we've been around long enough to notice that, there's nothing really special about the moment in time we live in. so when we ask "why's entropy so low, it should be higher", the answer is always "it was even lower yesterday". this seems illogical, because this means that the further you go in the past, the more exceptional the universe becomes. but then we basically just say "well when the universe was created, it had ridiculously low entropy. we don't know why such an unlikely universe was created". it's a question about boundary conditions.

>> No.3313727

(cont)

a more interesting question, imo, is about our brains. we observe entropy increasing, which makes sense because we started out with a really low entropy universe. the opposite seems crazy though: imagine that, contrary to mathematical predictions, entropy always decreased, because the end of the universe just happened to have low entropy. this seems impossible.

So, is it possible that entropy causes us to experience the universe in the direction we do? in other words, the reason we remember the past but not the future, is it because the past has lower entropy, but the future has higher?

>> No.3313741

time doesn't have a direction. entropy has. and the unidirectional irreversible entropy evolution of a system is ''interpreted as time'' or ''arrow of time''.

>> No.3313746

>>3313570

RAARGH!

My name is Michael J. Caboose... AND I HATE BABIES!

>> No.3313770
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3313770

>>3313709

>> No.3313781

Turns out time only exists when near a strong force of gravity; ie: living on a planet.

If you go into a zero gravity environment such as space you will stop aging.

True story.

>> No.3313798
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3313798

>>3313770

You think quantum mechanics violates thermodynamics?

>> No.3313800

>>3313727
Entropy isn't a thing that can be reversed. Entropy is the other side of the coin called information. If you have no information to start with, you won't have entropy.
If we teleported in a maximum entropy universe, we will be instantly sucked out of any kind of organized energy we have, by the whole universe itself and nothing more will happen, ever again.

IF everythings relly went backwards (doesn't mean anything if you ask me) we'll most likely be adjusted in the "right direction" nd we couldn't even notice it. We would face the direction in wich entropy increases. So past and future wouldn't be any different for us.
?

>> No.3313844

>>3313781
Not sure if stupid or troll.

In any case, this is incorrect. The closer to the speed of light you are traveling, the slower you will age over a longer period of time.

Zero gravity affects things like bone density. Astronauts only age nanoseconds slower than the rest of us because they are traveling faster than us but not nearly close to the speed of light so there is no pronounced effect.

>> No.3313860

>>3313557
Wow this is really confusing..... Can you please explain this further?
I don't know much about physics and I can't digest this

>> No.3313873
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3313873

>>3313781
cool story bro

>> No.3313876

A lot of you are forgetting that time is relative to the observer.

>> No.3313891

>>3313876
>The great thing about highschool chicks is I keep getting older and they keep staying the same age.

>> No.3313895

>>3313891
/thread

>> No.3313898
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3313898

well there are two understandings of time

an illusion humans have created to comprehend and measure units of space

or just another aspect of physics.


I believe it's part of physics, in the sense that time is completely unanimous with gravity.

more gravity = faster time
less gravity = slower.

As far as time's direction i guess it would just have to be due to the physical principles of our universe.


If we do so happen to live in a multiverse that consists of other universes around ours, then perhaps there would be completely different physical compounds of the universe. such as no gravity at all, something completely different and irrelevant. and what we think of as time may be different as well, or there may be time but it just goes backwards.


The thing is, i'm starting to believe time is both something that's always within our conception of existence and also an entity affected by gravity.


>mfw i think i just rambled for that entire post

>> No.3313907

>>3313610
He speaks the truth. In high energy physics, temperatures are usually measured in J or eV (instead of T, we use kT).

The rest of you are just copy pasta'ing wiki, without being aware of Poincare Recurrence (though proving that our trajectory will remain in a compact set of phase space is not trivial).

>>3313781
lolfail

>>3313800
You forget the time scales on which entropy increases. If you're in a space suit, you can stick around as long as your suit doesn't fail.

>> No.3313910
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3313910

A universe with time flowing in more than one direction would be unstable.

>> No.3313926

>>3313910
Exactly.
It's nature's way of ensuring stability.

It simply IS.

>> No.3313945

>>3313910
how convenient, the only universe that can exist is the one we can predict.

>> No.3313957

>>3313945
You are a complete dipshit.

>> No.3313975

>>3313957
I Ascertain by your frustration, that your anal cavity has been wounded.

>butt hurt

>> No.3314000

>>3313975
You seem fascinated with my anus, faggot.

>> No.3314007
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3314007

>>3314000
You see fascinated by my fascination, transhumanist.

>> No.3314016

>>3314007
Let your freak flag fly!

>> No.3314023

>>3313630
First informative answer from philosophers

>> No.3314035

>>3313727
no

>> No.3314053

OP, there are a few books you should check out:

Time Travel in Einstein's Universe

Cycles of Time

The Secret Pulse of Time

>> No.3314735

entropy has to always increase. time go in the direction of increasing entropy.

>> No.3314814

>>3313910

http://www.physorg.com/news98468776.html

eh?

>> No.3314826

>>3313945
Anthro principle, bro
Take a gander at that shit

>> No.3314857

>>3312818
(Fucking magnets, how do they work? answered) Feynman 'Fun to Imagine' 4: Magnets (and 'Why?' questions...)
http://www.youtube.com/watch?v=wMFPe-DwULM

It is, because the evidence says so. I am unable to provide any better answer to your why question because there is nothing which I can use to explain the "arrow of time" with which you are more familiar than "the arrow of time".

>> No.3315180

Entropy DOESN'T always have to increase. Entropy can decrease within a system boundary but overall entropy will still increase in a real process.

Also, positrons can be thought of as electrons travelling backwards through time.

>> No.3315189

>>3315180
>Also, positrons can be thought of as electrons travelling backwards through time.
/And/ mirror-flipped.

Google CPT symmetry.

>> No.3315203

CUZ LIKE OF MASS N SHIT BRO N THESE DIMENSOINS N SHIT IT ONLY MAKES SENSE 4 THERE TO BE A LINEAR PATH

>> No.3315226

>Can someone explain to me why time has a direction?
because of Entropy and the expansion of the universe
everything else is reversible

>> No.3315231

>>3315189
>>3315180

Then why is there a preferential matter to antimatter content to the universe?

>> No.3315232

>>3315231
I suggest wiki. I assume some of the prevalent hypotheses are on there. I don't know them offhand. It has to do with CPT symmetry, and some reactions which violate the CT symmetry, probably.

>> No.3315241

>>3315232
Yeah yeah yeah, I know. I was just jumping in and saying that an electron is more than just a positron moving in the opposite direction in time. Reality is more subtle than that.

And actually the difference is not well understood at all.

>> No.3315320

I posit that the momentum of matter is a vector in time.