Time as a dimension, can spatial length be applied to it?

In summary, the conversation discusses the possibility of using the formula "planck length/c=planck time" to convert time into a spatial distance and how this can be used to measure the distance of objects through time. However, it is noted that at the Planck scale, the concepts of size and distance break down. The conversation also touches on the equivalence of time and distance and the complications that arise when considering gravity in the context of relativity.
  • #1
mcjosep
35
0
Could you use the formula "planck length/c=planck time" to convert time into a spatial distance? Using that to tell how far something is through time.
 
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  • #2
mcjosep said:
Could you use the formula "planck length/c=planck time" to convert time into a spatial distance? Using that to tell how far something is through time.

Sure. I don't see why not.
 
  • #4
The equivalence of time and distance is much simpler then that. 1 second = 0.3 gigameters (Approximately)
Using that equivalence you can say that all objects travel at the same rate, C, at least as far as special relativity is concerned, I suspect GR changes that.
If a clock is not moving through space, it is moving through time at 1 second / second, or 0.3 Gm/s. If it is moving through space at ,for example, .1 Gm/s then you can compute the time dilation as a simple right triangle problem with space as one leg, time as the perpendicular leg, and the hypotenuse as a constant. The space side in my example is .1 Gm, the Hypotenuse is 0.3 Gm, so the time side, which is perpendicular to the space side must be about .283 Gm. So for every second, or .3 Gm the stationary observer's clock measures, the traveling clock measures about .943 seconds, or .283 Gm.

I suspect GR changes and complicates this somewhat. I don't understand GR well enough to say, but I'd suspect that time and space may not always be perpendicular, moreover, the triangle I just described may have to be constructed in non-euclidean space.
 
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  • #5
mrspeedybob said:
Using that equivalence you can say that all objects travel at the same rate, C,

only for massless objects, like the photon
mrspeedybob said:
time and space may not always be perpendicular,
they are never 'perpendicular'
 
  • #6
alw34 said:
only for massless objects, like the photon
What's mass got to do with it?
I think you must have misunderstood what I wrote. If you can explain why you think mass is relevant I might be able to re-explain myself more clearly.

alw34 said:
they are never 'perpendicular'
In the real universe, that may be true. I'm assuming flat space-time for simplicity's sake.
 
  • #7
For those of us who are into computers and high-speed electronics, 1ns corresponds to 0.3m in vacuum and about 0.2m along a cable. That is why layout becomes very critical at Gigahertz clock speeds.
 
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  • #8
mcjosep said:
Could you use the formula "planck length/c=planck time" to convert time into a spatial distance? Using that to tell how far something is through time.
Yes. Or you can use any units you like. For instance you can say that a typical human is about 7E17 m long in time compared to about 2 m long in height. The conversion factor is c in whatever units you use.
 
  • #9
alw34 said:
they are never 'perpendicular'
He is talking about four-vectors, ##(ct,x,y,z)##. Where ##(1,0,0,0)\cdot(0,1,0,0)=0## indicates that time is perpendicular to space, although "orthogonal" may be a better word.
 
  • #10
So could you say I am gravitationally attracted to something in a different time than right now and calculate that attraction by using this conversion formula and saying that length is the my radius to that object?
 
  • #11
mcjosep said:
So could you say I am gravitationally attracted to something in a different time than right now and calculate that attraction by using this conversion formula and saying that length is the my radius to that object?
No.

I know you want more of an answer then that, but the instant you start considering gravity in the context of relativity, things get HUGELY more complicated. GR is way beyond my math skills.
 
  • #12
mcjosep said:
So could you say I am gravitationally attracted to something in a different time than right now and calculate that attraction by using this conversion formula and saying that length is the my radius to that object?
It is not clear from your question, but I assume that you are thinking of "calculate that attraction" being Newton's law of gravitation. Unfortunately, Newtonian gravity is not compatible with relativity, so that won't work. Instead you would need to calculate gravity using the Einstein field equations.
 

Related to Time as a dimension, can spatial length be applied to it?

1. What is the concept of "time as a dimension"?

Time is often referred to as the fourth dimension alongside the three dimensions of space (length, width, and height). This concept suggests that just like space, time can be measured and represented as a coordinate in a four-dimensional space-time continuum.

2. How does time differ from other dimensions like length or width?

Unlike the three spatial dimensions, time is one-dimensional and only moves in one direction - forward. While space can be measured in units such as meters or feet, time is measured in units such as seconds or years.

3. Can spatial length be applied to time?

No, spatial length cannot be applied to time as they are fundamentally different concepts. While length refers to the physical distance between two points in space, time refers to the duration or interval between two events.

4. How is time used as a dimension in scientific theories?

Time is a crucial component in many scientific theories, including Einstein's theory of relativity and the concept of space-time in physics. Time as a dimension allows for a better understanding of the relationship between space, matter, and energy.

5. Is time the only dimension that moves at a constant rate?

No, time is not the only dimension that moves at a constant rate. While time moves forward at a constant pace, the other three spatial dimensions can change based on factors such as gravity and motion. For example, time may feel slower for someone experiencing stronger gravitational forces.

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