Discussion in 'Physics & Math' started by Saint, Dec 10, 2021.
That’s a very good insight into just a few words. Thank you
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Ask a question at physics forums about whether time exists, or is real, and you'll get accused of promoting metaphysics.
The question isn't relevant to physics: either a thing is physical or it isn't. An alternative universe where time runs backwards is physical, but does it exist? The question isn't relevant, whether this alternative universe has some observable properties is, though.
Put another way, the alternative, backwards-time universe has to influence the one we know and observe in some, er, physical way--there has to be information available to observers so they can interpret it.
I also think what Richard Feynman was really saying about energy--which has a conjugate variable, called time--was along the lines of discrete information, in his analogy of a number of children's blocks.
The blocks of course, although Feynman doesn't say so explicitly, represent an encoding. "block information" is analogous to units of energy in his lecture on the subject. He also says something like, "in physics nobody knows what energy is".
Except we do know it can be counted in physical units, and so we don't need to ask about whether it exists or is real. It can be encoded in physical blocks called Joules.
There is a strong connection between energy and information. Energy is always encoded in the same units, whereas information has many more degrees of freedom for whatever encoding is chosen, by humans when they want anthropocentric information units (as in modern computers), or when we observe nature and whatever encoding it has.
Does time exist?
I'll tell you shortly.
I have to adjust the simulation for a few moments.
Oh yes, I think it exists. My most recent thread wants to tackle the time problem by first keeping it explicitly in there, while we treat gravity on a semi classical model, since full quantization of gravity has led to horrible divergence issues including the loss of time from diffeomorphism invariance.
Just a convenience? I wager it is more important than that since it's presence in GR allows space to be curved.
Does time exist in the future?
Future is an illusion no? If there is, it is a present moment seemingly eternal. However, the duration of one present moment to another need not mean time is necessarily static, though is a popular interpretation. If a future exists now, then time as we know it would be intrinsically static. It means all time has already passed and we are stuck in an amber, where change is meaningless and illusory.
Information can be encoded into entropy as energy quite easily, but it is not always coded by the units of energy. In fact, dimensionless objects in physics is a more natural way to describe information by entropy, since only physical objects are described by dimensionless equations.
What are you asking, if 10:00 PM tomorrow exists now? No, it does not.
Do you think 10 PM tomorrow will come and go? Yes, it certainly will.
Say 10 PM tomorrow is 27 hours from now.
27 hours is a duration of time, whether clocks are around to measure that time or not.
27 hours of duration does not need to be measured to elapse. If the entire universe vanished in 10 hours from now, and there was nothing but space, 27 hours of duration will continue to elapse.
Mass has no effect on duration. The duration of time of 27 hours will elapse, there is nothing that can stop that from happening, just like there is no way to stop an infinite line in space from extending infinitely.
Distance and time are INEVITABLE!
So, are you saying that time will emerge along with the passing of a chronological existence of something?
So you propose that time existed before the beginning of time?
How about a "timeless nothingness" where "passage of a chronology" does not exist?
That's an oxymoron how can something exist before itself? By assumption time has a beginning, it has to be synonymous with its end with no inbetween in that version. I am by the way not saying I agree with that interpretation of time only starting a conversation.
There was no beginning of time. Time did not start, it is inevitable. Just like space has no beginning and no end. It is infinite in every direction. You can't stop distance. There is no way, no concept of preventing more distance.
There is also no concept of time having a beginning. There is always a time before. You can't say time started at 500 billion years ago, because there is a 750 billion years ago from now.
Time is like this: <------------------------------------------------------------------------------now------------------------------------------------------------------------------------>
There is no beginning and no end to time, and there is no beginning and no end to distance. They are INEVITABLE!
Who says time is infinite? I know the idea certainly, but I'd like qualitive figure?
I do. Anyone who claims time started is blowing smoke up your butt!
You can certainly claim time started for an object, say the manufacture date of your car. So the car was born in say Jan 2015. So if you want to know the AGE of the car now, the car is 2015-2022, or the duration of 7 years.
Same applies to the universe. You can certainly claim the universe was "manufactured" 13.8 billion years ago, but that is the AGE of the object the universe. Yes, the universe is an object, like a galaxy is an object.
Time always existed before the universe was "manufactured" just like time always existed before the car was manufactured.
This is analogous to saying the big bang happened more in time than it did space. The idea is plausible, but weird.
If I had to say anything, infinity doesn't exist, not even for time. If relativity is true, then space and time are one object and neither is more fundamental than the other. Since space almost certainly has a finite past, it cannot infinitely extend backwards, unless by an exotic model. The water becomes muddy if the future cone doesn't really exist because there is no bound on the present moment unless something halts this forward impetus of entropy in one direction of time.
Yes, but this universe started 13.7 billion ago. We have absolutely no proof of any space or time before then.
You say spacetime is infinite.
I say only a timeless nothingness can be infinite.
Everything else has a beginning and time emerges with duration of existence.
Saying the Universe started 13.7 billion years ago just means the universe is 13.7 billion years old. That does NOT equate to the start of TIME. It simply means the AGE of the universe is 13.7 billion years old.
Just because the universe started 13.7 billion years ago does not mean that was the start of time. There was a 15 billion years ago, a 100 billion years ago, and a trillion years ago. A trillion years ago was not the start of time, neither was 100 trillion years ago, or 10,000 trillion years ago.
What you are saying is that because my car is 10 years old, and it started life in 2010, that time started 10 years ago. Don't you see your error in saying that?
If you have no proof of any space or time BEFORE the universe started, then you have NO PROOF of anything before the universe. Having NO PROOF means you can make NO STATEMENT claiming "time started." You want to make that statement then prove it, which you already claimed you can't, because you have no proof. So stop making claims that you can't prove! My claim is the default until it can be shown otherwise. We know time exists, that is a default. To claim it had a beginning requires proof, of which you have NONE!
You can't even talk about BEFORE, because BEFORE means a time prior to, which you claim there is none. It doesn't add up!
I never said "spacetime", that is not a word I use. I use the term "space," which is 3D distance (volume), and I use the word "time", which is duration. Space and time are INEVITABLE, they have no beginning and they have no end. They NEVER STARTED and they will NEVER END. There is no way to end them, and there is no way to start them.
Distance is infinite. Time is infinite. Infinite simply means "continuation."
If you think distance is infinite from the point you are right now, then you are claiming that distance is time, if traveling at the speed of light. If light traveled from your point along a line away from you, it would never reach an "end" distance, and it would travel continuously at the speed of light for infinity, which means it will continuously travel, forever, and not reach an end. It will travel for 500 trillion years and not even be close to an end, because there is no end to distance and time, they are infinite because they are inevitable! There is NO CONCEPT of either of them being anything other than infinite. If you have a concept of them being finite then let's hear how either one of them is finite! Let's hear the concept!
No! My car had a beginning and it had a point in time for its beginning. There was time before its beginning. The universe is no different! It had a beginning and that was a POINT IN TIME. It's like saying 12:30, that is a point in time. of course there was a 12:29 BEFORE that point in time.
You think because objects have a date of birth that that is the start of time. That is not time, that is a point in time that the object was created! That has nothing to do with duration other than being it's start point! It's like distance, there is a starting point for a 100 meters, and there is an ending point for 100 meters. Do you want to say that space is only 100 meters long because there is a start and end point to 100 meters??
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