# Thread: What is "Space Time"

1. Let me try and explain my thinking, I think I know what "Space" is, that's what the universe is expanding into. I think I know what "Time" is???? or from my point of view it's Cause and effect, one event following another, and we have divided the obit of the Earth around the Sun to come up with Years months days etc. And I think I understand the basic concept of "relativity" like the analogy with two mirrors facing each other and a beam of light bouncing up and down between them and if they where on a train or space ship moving along to me the "Observer" it would appear as if the light was having to travel diagonally between the mirrors there by describing a longer path and there-fore would be traveling further and so would appear to going slower, or if you was moving away from the Town Hall Clock,, it would appear to be going slower because of the time it had taken the light to reach me the "observer" so "Time" is relative to the speed of the observer. (Perhaps not described exactly correctly) But let me ask this, Why is there "Space Time" Surely "TIME" is only needed by the observer. Out there in space there is no need for "TIME" the universe surely doesn't need to Know the time. YES one event follows another, but surely that just "ENTROPY" at work, things going from a very organized state to a more and more disorganized state. So why have the term "Space Time" surely you only need "TIME" if you are the observer. YES I can see the basic concept of how a huge "White Dwarf" with a massive Mass would distort space because of the huge gravitational forces. But why would it bend "TIME" you would have to be there in that region of space for "TIME" to exist,,,,,,,, surely there needs to be an "OBSERVER" (I don't know whether im making my point properly) Or how about this,,, Yes the universe needs ,,, Gravitational forces to work, Yes the universe needs the laws of thermodynamics to work, Yes the universe needs the strong and weak forces to hold atoms together so it can work,, Yes the universe needs entropy to work, yes the universe needs electro magnetic forces to work, (and many more) but they are fundamental forces that are basically the FABRIC of "SPACE" or the FABRIC of the universe, So where does "TIME" come into IT. I can not see how "TIME" is a fundamental force that the universe needs to make it work. The only reason it would need "TIME" is if it needed to "OBSERVE" itself. Well that opens a can of worms for sure because if you say the universe needs "TIME" because the universe is the OBSERVER then your implying the universe has intelligence. So to me thinking like that,,, you could say its 00.00 hundred hours everywhere, be it here on Earth or in the Crab nebular, Yes light may take millions of years to get here from distant galaxies but surely we are just seeing that Galaxies "NOW" So to me there is only "NOW" and its relative to where you are, so there is no going back in time or forward in time, if I travel at warp 9.9 for 2 weeks.then where ever I was it would be 00.00 hundred hours and my "NOW" the same as on Earth. Now to me my thinking and reason seems quite logical,,, "TIME" can not be a fundamental part of the universes fabric because time is only needed be an Observer to try and make sense of his surroundings. But then my reasoning goes to pot ,,, when some bright spark synchronizers two atomic clocks and flies one around the Earth a couple of times and they end up different or out of synch. But the simply reason behind that experiment would that "ENTROPY" happens more or quicker ,,,, the faster you go,,, so entropy has had some effect on one of the clocks. So in that case is "TIME" actually "ENTROPY" and instead of "SPACE TIME" we should have "SPACE ENTROPY" am I just getting the two mixed up and back to front. ,,,,,,,,,, Sorry my explanation / question is so long and drawn out, Where am I going WRONG,,,,, ???????? What am I missing ?????? thank you for your time and any comments or pointers ,,, Alan

2.

3. We have a number of threads on the topic of time.
Read some of those and then see what you think.

4. Space is just a name for the spatial distance between things. It forms the basis of what we normally think of as normal three-dimensional geometry.

Time is just a name for the temporal interval between things.

In relativity, time is treated as a dimension along with the three of space: hence space-time. This gives us a four-dimensional geometry which describes the universe in a unified way. Mass causes (or is) changes in this space-time geometry which is what we perceive as gravity. It is not enough to consider a large mass just curving space, it has to curve space time (for reasons that I don't think I can easily summarise...)

5. Dear Dywyddyr,,,, Can I thank you for your reply ,,,, it obviously says a lot about you as a person.

6. Did it say that I'd just cooked my tea and wanted to give you some pointers but didn't have time to write a full reply?

7. Originally Posted by aplinewalker
Dear Dywyddyr,,,, Can I thank you for your reply ,,,, it obviously says a lot about you as a person.
It says something about you, as well.
Always take care when pointing out what you think is a flaw in someone else, you may find that it reveals one of your own.

You went wrong on many parts of your armchair speculations and while it can be helpful for someone to hold your hand and guide you through it--- some very basic reading and research would removed the necessity of any of it.

8. Thanks for your comments "Strange" Yes I get time as the 4th dimensions, but that still seems to me like a way for the "Observer" (us) to try and describe our surroundings, perhaps I would understand better if I came from Northamptonshire instead of Yorkshire.

9. Originally Posted by aplinewalker
Thanks for your comments "Strange" Yes I get time as the 4th dimensions, but that still seems to me like a way for the "Observer" (us) to try and describe our surroundings
Is "space" merely a "way for the observer to describe our surroundings"?

10. Why do you think time is something special to the observer and not space?

Space existed before we were around and so did time.

Time is what stops everything happening at once. Space is what stops everything happening at the same place.

Space is what rulers measure. Time is what clocks measure.

(I have never been to Northamptonshire: I just had to Google it to see where it is!)

11. My introduction also said a lot about me and my limited education dose that make it wrong for me to try and get my head around things.

12. Time is what stops everything happening at once. Ok yes but surely entropy stops everything happening at the same time,,,

13. Surely entropy is just one of the (many) things that change over time? Are you suggesting that entropy is somehow more fundamental than time? But we can change the entropy of a system, we can't change time.

By the way, I haven't read through your first post in detail. It is too much like hard work. Paragraphs might help.

14. Originally Posted by aplinewalker
Time is what stops everything happening at once. Ok yes but surely entropy stops everything happening at the same time,,,
Time is the dimension in which entropy occurs.

15. Space time is when astronauts wear a wrist watch on their arm and travel in space.

16. Originally Posted by Dywyddyr
Time is the dimension in which entropy occurs.
Aren't the spacial dimensions also needed to properly model diffusion?

17. Originally Posted by Neverfly
Always take care when pointing out what you think is a flaw in someone else, you may find that it reveals one of your own.
This is very true, in a general sense.

18. Originally Posted by Markus Hanke
This is very true, in a general sense.
Ah, but the true hypocrisy is in me being the one to say it...

19. Its my first time on here and even though my spelling and grammar are very poor I did try putting in Paragraphs but it wouldn't let me. Yes I presume entropy is changing all the time, but entropy must cover "Everything" surely entropy isn't just "ONE" of the things that are changing,,,, (Am I suggesting that entropy is somehow more fundamental than time ) I don't know what I am suggesting, but surely we can change entropy all be it in a very small way, if we put mount Everest in a blender reduced it to basic elements and blasted the lot into space then wouldn't we have helped entropy because it would have taken billions of years for entropy to do the same thing. So perhaps you have more chance of speeding up entropy than changing time.

20. Alpinewalker, can you take a moment to think out your O.P. in linear thought and try presenting it again?
The O.P. was rather rambling- It is as if you were typing as fast as thoughts were popping into your head. Try typing it out on notepad or Word... then let it sit a while. Come back and read it and see if it really conveys your thoughts. Make any corrections necessary and aim for brevity.

A question cannot be answered if the question is not understood.

21. I think this is where im getting confused ,,, yes I can see "Time" as the 4th dimension etc. but why isn't entropy the 4th dimensions. Entropy is surely the universes physical and observable result of one event following another, entropy only flows in one direction, basically counting out the age of the universe and if an observer came alone and wanted to measure things then surely you would measure the physical and observable changes, which we call entropy ,,,, so it would be x amount of entropies since the big bang. Surely entropy is the universes clock and a fundamental part of its fabric,,,,, "TIME" is just a human invention designed to help us measure and make sense of things its only jurisdiction is in our minds,,, where as "entropy" has jurisdiction everywhere.

22. point taken,

23. Originally Posted by aplinewalker
I think this is where im getting confused ,,, yes I can see "Time" as the 4th dimension etc. but why isn't entropy the 4th dimensions.
What about this. If you need to meet somebody then you will need to specify where. This requires 3 dimensions (latitude, longitude and altitude, for example. Or x, y and z). But you also need to say when you will meet. A fourth dimension.

There are people who speculate that time (or at least the fact we perceive time moving forwards) is due to entropy. BUt that seems more like philosophy than science to me.

24. Strange YES YES YES, brilliantly put, Yes ok I know we use Time as the 4th dimension, otherwise we would be late to work, and could never arrange to meet someone. Your last sentence (There are people who speculate that time (or at least the fact we perceive time moving forwards) is due to entropy. BUt that seems more like philosophy than science to me.) well that says more or less what I tried to say in my previous message. you finish by saying "That SEEMS like philosophy... which suggests that you have no proof, (or the scientific community at large) has no proof ,,,, so if someone speculated that what we perceive as "Time" is actually Just Entropy how would you prove that the 4th dimension of "Time" existed, as a physical and fundamental force.

25. Originally Posted by aplinewalker
so if someone speculated that what we perceive as "Time" is actually Just Entropy how would you prove that the 4th dimension of "Time" existed, as a physical and fundamental force.
You can't "prove" anything in science. However, the fact that our best theories use space-time as the basis suggest that treating time as a dimension is a reasonable thing to do.

26. You can't "prove" anything in science.???? I presume your talking in a 100% literal sense when you say that, because surely scientific experiments presumably show an ever increasing certainty and plausibility the more refined (or repeated) the experiment becomes, to the point where there must by some burden of proof, so surely science must have "Proved" something over the years so that "Theories" have some foundation. (OR put another way) if your saying science can't "prove" anything, does that mean these "Best" theories of space-time have no burden of proof behind them.

27. All scientific theories await evidence that can invalidate them. Science doesn't deal in "facts", it simply proposes models that can explain our observations and these models only stand until a better model comes along.

There is no such thing as a scientifically proven fact - there are only models that have yet to be disproved. The longer a model stands up to scrutiny and accurately describes our observations, the more it is accepted, but it is never proven absolutely.

28. Thanks for your comment. I thought there must be certain things that are,, or have been accepted as proven.

29. Alpinewalker, can you take a moment to think out your O.P. in linear thought and try presenting it again. OK I have tried to take on board your comments like (Time is the dimension in which entropy occurs.) (Space existed before we were around and so did time.)

(Time is what stops everything happening at once.) (Space is what stops everything happening at the same place.) etc. and they all seem very logical. but can I ask this,,,,???? "Is "Time" a fundamental physical force"

30. Time is no more a force than is distance.
It's a dimension.

31. Time is no more a force than is distance. It's a dimension
. So if "time" is not a force then it can have no effect on any event taking place. but someone said "Time is what stops everything happening at once" surely then if time is not a physical force, then it can have no control over events,,, So how would it stop everything happening at once. would I be anywhere near being right if I said "Entropy which I presume would be classed as having a physical force, is what actually stops everything happening at once. and "Time" is almost a bystander.

32. Originally Posted by aplinewalker
So if "time" is not a force then it can have no effect on any event taking place. but someone said "Time is what stops everything happening at once" surely then if time is not a physical force, then it can have no control over events,,, So how would it stop everything happening at once.
Ho hum...
It was also stated that "Space is what stops everything happening at the same place" - would you class space as a force?
If there were no time then everything would happen at once (because with no time events couldn't be spread out along the time axis and become separate events).

would I be anywhere near being right if I said "Entropy which I presume would be classed as having a physical force, is what actually stops everything happening at once. and "Time" is almost a bystander.
No.
Altogether wrong.
Entropy is not a force either. And entropy is NOT what "stops everything happening at once".
Entropy is less fundamental than time.
Entropy occurs IN (the dimension of) time.

33. Originally Posted by aplinewalker
o if "time" is not a force then it can have no effect on any event taking place. but someone said "Time is what stops everything happening at once" surely then if time is not a physical force, then it can have no control over events,,, So how would it stop everything happening at once.
It is a kind of jokey metaphor. It might be more accurate to say "time is what enables things not to happen all at once". But also slightly clumsier. Events happen at different times because time exists. With no time, everything would have to happen at once. Do you begin to get the point?

Note that all these messages are numbered and posted at different times. That is the definition of time.

34. Thanks for your patients, and yes I know the "definition" of time, having got up for work about 10.750 times. but can I give this analogy and tell me where my supposed logic is falling head over heels. A motor car needs many things to make it work, and for it to work it must follow all the laws of nature/physics,,, so the laws of thermodynamics are at work in the engine as chemical energy is turned into kinetic/mechanical energy, electromagnetic magnetic laws and forces are needed to make the alternator work, the car needs to obey gravitational laws so it stops on the road. etc.etc. BUT the car does not need a speedometer, or clock for it to work, a speedometer and clock would be totally superfluous, The car would work perfectly well without either. The only reason to add a speedo or clock is for the benefit of an "OBSERVER" ( so the driver can check his speed and time ) the car has no need for a speedo or clock. Now put a rockets on a billon cars fill them with hydrogen, arrange them in a sphere, in space, all pointing out and throw in a big bang, and they would happily expand outwards following the laws of physics (You never know with enough of them they might coalesce into planets of scrap) but surely they just need the empty 3 dimensional space, the expanding Mass would have no need surely to know what time it was, or how much time had elapsed, would not the law of entropy just make each event follow on from the last. And likewise wouldn't the mass of the universe just expand outwards into 3 dimensional space, why does it need TIME, and if time is not a physical force then what roll can it play, If time is not physical then how can it have any course and effect on the universe. Sorry its a ramble again don't know how you guys can be so succinct >>>>> OK but now you get to make me look like a prat,,, I should have got interested in gardening instead.

35. Your car needs timing for the spark plugs (or the inverters driving the motors if it is electric).

In all your examples you need time to define/measure the movement/speed/expansion/change. If there was no time, how could space expand? It would be frozen, unchanging.

36. Originally Posted by aplinewalker
but surely they just need the empty 3 dimensional space, the expanding Mass would have no need surely to know what time it was, or how much time had elapsed
If there is no time there is no motion.

would not the law of entropy just make each event follow on from the last.
Entropy is a consequence.

And likewise wouldn't the mass of the universe just expand outwards into 3 dimensional space, why does it need TIME, and if time is not a physical force then what roll can it play, If time is not physical then how can it have any course and effect on the universe.
You keep coming back to this and persist in ignoring our questions: is distance a force? Is distance physical?
Movement is the change of position over time. No time: no motion.

37. and persist in ignoring our questions: is distance a force? Is distance physical?
You make it sound as if I have purposefully ignored the question a dozen times, Im sorry I didn't take it as a direct question, perhaps I didn't answer because I was unsure,,
is distance a force?
Is distance physical?

38. Originally Posted by aplinewalker
is distance a force?
Then why do you persist in claiming time "should" be?

Is distance physical?
Really?
Can you give me a bottle of 1 metre?

To me if an explosion happens in a empty space then it would expand outwards into the empty space, to me if its got the energy to expand then it wouldn't need any other,,, force/law/element/or thing to do so
If there's no time then it can't move.
Any motion involves being here, now and there, then.
If now and then don't exist then there's no possibility of moving from here to there.

39. Originally Posted by aplinewalker
and persist in ignoring our questions: is distance a force? Is distance physical?
You make it sound as if I have purposefully ignored the question a dozen times, Im sorry I didn't take it as a direct question, perhaps I didn't answer because I was unsure,,
is distance a force?