sophie

Bob K :

But time is a time interval (refer to your definition) which began at T=0 ; Why are you trying to confound laymen? At best you are confused yourself using various connotations of time. At worst the basis for your arguments are faulty.



Nonsense. No foundation for such a claim.


Possibly but very unlikely.


So how can you measure time intervals.

Nowhere357

Time measures "when" by measuing cyclical motion of matter in space. Thus time is dependant on terms of distance.

This imo is incorrect. To measure time we measure motion - the sun comes up, the sun goes down. The water drips, the pendulum swings, the atom oscillates.

I am a huge fan of Einstein, and I understand that his view of time has led to tremendous insights, but I believe that his view also has led to misperceptions. Time is not a dimension; because the past and future do not exist. All that exists is the now, which includes all the vectors that lead to change.

spacer1

BobK,
I don't see how this follows simply from establishing simultaneity.
If time has no relationship to matter/energy, then just what does time measure? You say one only need select a time interval (TI) of any duration and we can have time, but against what do you measure duration, if not the motion of matter/energy?
Wouldn't the selection of a TI impose a mathematical limitation on time?

jfryejr

Way to go Sophie...

Bobk, your entire post relates to adjusting time to some standard set on earth (or wherever). Consider what relativity theorizes about physical changes and reference frames at different velocities/gravity.

thestickman

WOW! That is exactly what I have been saying.
"ME:... that is akin to saying time doesn't exist.

Guess what? That's unprovable. "
...along with other posts.

-tsm

jfryejr

Time is a vector quantity and by definition (of vector) that makes it a dimension. Time is the dimension that our visual 3d world, and the other 9 or 25 dimensions depending on your flavor of string theory, moves along. Also, if time weren't a dimension, it would make it scalar and non-relativistic. I don't think scalar measurements, barring differences in perception, can be relative. Although, I see where you're coming from with the past and future not existing...

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jfryejr

quote:
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Originally posted by paul30
But the perception is itself an event, and the relations are always subject to doubt.
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Part of the problem with calling time merely a perception because we can't physically see it, is that it assumes we can see everything. I don't know if the following is good analogy, but...

A snake can only see in two dimensions. Let's say we have some really smart snakes. One of the snakes notices that when it pushes a ball, the ball gets smaller (as it would in two dimensions). Now, this snake becomes curious and decides to explore what is happening. He gets his friend and the two of them think of an experiment. One will face the ball and push it. The other will look on from a few feet away perpendicular to the event. As the snake pushes the ball, it notices that the ball gets smaller. His friend, perpendicular to him, notices the ball stays the same size. The two compare notes and develop this entirely new concept, depth. They aren't able to visualize the 3rd dimension because of their natural limitations, but their empirical evidence, simple as it may be, tells them it is there.

All of our empirical evidence points to time being altered by gravity and velocity. This implies that time, while relative, is not merely a matter of perception, as those relative differences equal real physical differences, not simply perceived physical differences.

Nowhere357

I have trouble reconciling the first statement with the last. I understand that time can be viewed as a vector quantity in a vector space (which is a mathematical construct); but to say that it is a real dimension implies that the past and future exist!

I don't understand string theory, but I'm resistent to the idea that string dimensions are any more than mathematical constructs. But then, I'm an idiot.

Time is definitely relativistic. I'm not sure why you say that if time is not a dimension, then it's scalar. I assume you mean, as opposed to continuous. But if time represents the movement of matter/energy, then we determine continuousness of time by considering the continuousness of matter/energy.

I think the concept of matter/energy contains the concept of movement and space. Time is a concept that relies, is based on, all of them. To talk about time is to talk about the movement of matter/energy through space, and nothing more.

Nice tour of flatland - I think I understand the insight. But again, applying the insight to the spatial dimensions plus time, implies that the past and future have existence.

I agree with this, and your note that this means time is associated with actual physical differences. But the movement of matter/energy through space is affected by gravity and velocity (which btw reduce to the movement of matter/energy in space) - so the effects on time caused by gravity and velocity can be explained by referring to the effects on the movement of matter/energy through space.

We think of reality as matter/energy in space/time. Is there anything else? Sometimes I add "patterns of" to the front, but I'm not sure that's necessary. Anyway, I think each of the words is defined in terms of the others. But we can bottle up matter or energy or space; I don't see how bottling up time has meaning. Hence my fussing over the idea that time is fundamental in the same way as the others.

Here's a question: we know reality is m/e in s/t. If we remove the m, e, and s, then what is left? What is it made of?

jfryejr

A vector is a measurement with a magnitude and a direction (time, velocity, acceleration). A scalar is a measurement with magnitude and no direction (length, width, mass, temperature). Being a vector has absolutely nothing to do with being a dimension. A scalar can apply relativistically, as with length and mass. I have no idea why I wrote what I did. The issue isn't with you reconciling my statements, the issue is that my statement was completely and utterly wrong.

I think we're arguing about the definition of dimension and not so much about the property of time. I'm at work now, so I'll write more later...just wanted to print a hurried retraction in response to your post. My statement was one hell of a brain fart.

jfryejr

I finally understand what you mean by this. If you take dimension to be the "physical" dimensions of something, like the length/width/depth of a box, and call that three dimensional, it's correct but not the definition I would use for 4D space time.

I have the ability to move in 3 dimensions. I can move up/down, left/right, and forward/backward. I am forced to move forward through time by the 2nd Law of Thermodynamics. When I move in any direction (or dimension), I'm not leaving a copy of myself behind. The space where I was is no longer occupied, much like the M/E arrangement at a time that has passed is no longer there. So, in other words, I'm a 3 dimensional object moving through 4 dimensions. Time gives me the ability to move in the other three dimensions.


To begin with, I'm the worst kind of pseudoscientist when it comes to string theory. I only understand what little I've read because I haven't read anything with an equation! So, I definitely wouldn't say you're an idiot for not understanding string theory, I would just say that you're not a genius (and neither am I).

The concepts makes sense, however, although I don't understand N-dimensional mathematics. There was a Nature article about particles being 5 dimensional, the size and nature of the particle being determined by what kind of "shadow" was cast by its string on our 4D universe. If you have a subscription (or access), I can post a link. If not, PM me and I can work something out. It's more of a review of an article so it's written in layman's terms. It helped me visualize how other dimensions could exist.

Part of this I responded to earlier by refining my definition (actually my connotation) of dimension. I would also like to say that we can't actually see the 3 dimensions our eyes tell us are there. We can see objects that occupy 3 dimensions, which is the empirical evidence that tells us they are there. The analogy was more about empiricizing (sp?-or is it even a word?) our understanding, even though they couldn't perceive it directly, it was there.

As far as time goes, simply watch something grow or decay. We can't see this dimension either, but we can see its effects. As for other dimensions, I'll readily admit I'm taking the physicists' word for them, but it is generally agreed upon from what I've read, which is definitely not exhaustive of the literature, that there are more dimensions than we can readily perceive. These have effect in particle formation itself..?? *Note the question marks...

I don't think we can exclude time from the bottle, either. I think time is as fundamental as M/E. I don't think you can have one without the other. Warping space warps time, mass warps space/time, space/time tell mass how to move. The relationships are fundamental to the laws of our universe (at least as we know them). Length can be defined as time and time as length. That's part of the beauty (and trouble) of a constant speed of light. It gives you a measuring stick to which all other things are relative.

I don't think one makes sense without the other. With no space to move in, there's no time. With no M/E, there's no space/time. I *think* Einstein's General Theory predicts a finite universe, which means space has a boundary. No matter how hard I try, I cannot conceive of something "not there" (like empty space is), being not there.

I hope that last sentence made sense, I can't think of a better way to phrase it.