What do we call the dimension measured with time?

  • Context: Undergrad 
  • Thread starter Thread starter notsureanymore
  • Start date Start date
  • Tags Tags
    Dimension Time
Click For Summary

Discussion Overview

The discussion revolves around the nature of time as a dimension and its relationship with other dimensions, particularly in the context of gravity and relativistic effects. Participants explore the implications of time being affected by gravity and how this contrasts with classical dimensions of space.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • One participant argues that time is a measuring tool, suggesting that it is affected by physical forces like gravity, which raises questions about the nature of dimensions.
  • Another participant counters that the fourth dimension encompasses both space and time, and that both can be warped under extreme conditions, such as near a black hole.
  • A question is posed about whether a box would retain its original height when subjected to extreme gravitational forces, indicating confusion about the effects of gravity on dimensions.
  • Special relativity is mentioned, with a participant explaining that both spatial and temporal dimensions can change based on the observer's frame of reference.
  • One participant expresses curiosity about the experience of falling into a black hole, questioning whether they would perceive any change while an outside observer would see them crushed.
  • Another participant suggests that the dimension measured by time could be referred to as "duration."
  • There is a reiteration that both space and time are subject to distortion, not just time alone.

Areas of Agreement / Disagreement

Participants express differing views on the nature of time and its relationship to space and gravity. There is no consensus on whether time is merely a measuring tool or a fundamental dimension that interacts with space.

Contextual Notes

Participants reference concepts from general relativity and special relativity, indicating that their understanding may depend on interpretations of these theories. There are unresolved questions about the implications of these theories on the nature of dimensions.

notsureanymore
I am told time is a dimension, indeed the 4th dimension

but then I am also told time is effected by other things such as gravity

These two seem to be at odds with each other.

the three classical dimensions are length breadth and width. yet no one I know of argues that gravity or any other force can effect them. they are indeed simply a means of measuring a physical property.

If the physical property of an item changes say the force of gravity causes a box to compress in the height dimension. its height is said to have changed. not the dimension we call height.

if the ruler is effected by gravity such that both the ruler and the box are compressed. no-one argues that the dimension of height has been warped.

So given the above it tells me that a dimension is unchangeable, it is a concept and has no physical attributes that can be effected.
The common belief today is that gravity effects time in such a way as the strength of the field is relative to the 'speed of time'.

This to me says that 'time' is a measuring tool, a ruler. and as a tool it is effected by normal physical means.

So if time is the tool we use to measure a 'dimension' what do we call that dimension?
 
Physics news on Phys.org
You're mistaken. The fourth dimension accounts for space and time. The three physical dimensions, can be warped under great gravitational and acceleration scenarios. Take a black hole for example. That can warp space, and time.

However, to account to the last part of what you said... Time is a hard thing to explain. What is the past, future, present, and why things in the past can be "erased", and even if the "past" existed, are all things that take quite a bit of explaining and trying to understand. Braine Green does quite an adequete job explaining the whole situation, if you wish to take a look at The Fabric of the Cosmos.
 
So in a black hole a 1 metre tall box crushed to 1 millimetre in height is still a 1 metre tall box?
 
notsureanymore,

In special relativity, both space and time dimensions can change, depending upon who's looking. If a spaceship flies past you at high speed, you'll not only see the spaceship as if it were squashed (change in spatial dimension), shortened in the direction of motion, you'll also see the people inside it moving slowly (change in the temporal dimension).

- Warren
 
notsureanymore said:
I am told time is a dimension, indeed the 4th dimension

but then I am also told time is effected by other things such as gravity

These two seem to be at odds with each other.

the three classical dimensions are length breadth and width. yet no one I know of argues that gravity or any other force can effect them. they are indeed simply a means of measuring a physical property.
No. General Relativity shows that gravity is a warp in spacetime. It also shows that there is less difference than we usually think between the three dimensions of space and the dimension of time: this is clear from the Lorentz transform. Take a look on Wikipedia. You will find that the Galilean transform (which you are used to thinking in terms of because of your life experience) changes space, but not time; however, the Lorentz transform (which we know to be more correct because of the failure of the Michelson-Morley experiment) changes both space and time, and in fact changes them into one another. Look at the equations and you will see what I mean. The interpretation of this is that spacetime is all one thing. So it is by no means surprising that if gravity warps space as GRT claims, then it warps time as well.
 
Ok I have to ask this question then, Sorry if it seems inane

If I was to fly into a black hole. as I descended into the black hole would I be crushed or would it appear to the outside observer that I am crushed, but to me I would not notice the change at all?
 
notsureanymore said:
Ok I have to ask this question then, Sorry if it seems inane

If I was to fly into a black hole. as I descended into the black hole would I be crushed or would it appear to the outside observer that I am crushed, but to me I would not notice the change at all?

You would be torn apart by tidal forces but it would appear to a distant observer that it took an infinitely long time to do so.
 
notsureanymore said:
the three classical dimensions are length breadth and width.
So if time is the tool we use to measure a 'dimension' what do we call that dimension?
That would be "duration".
 
Chroot had the answer space (3 dimensions) is relative. I have to stop thinking in layman ways.

time *and* SPACE does distort, not just time.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
5K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 20 ·
Replies
20
Views
4K
  • · Replies 48 ·
2
Replies
48
Views
5K
  • · Replies 143 ·
5
Replies
143
Views
12K
  • · Replies 0 ·
Replies
0
Views
4K
  • · Replies 16 ·
Replies
16
Views
3K
  • · Replies 6 ·
Replies
6
Views
3K
Replies
8
Views
3K
  • · Replies 71 ·
3
Replies
71
Views
6K