Question about distance units in relativity

In summary, the units of x, y, and z are necessarily 3x10^8 meters when considering the proper time equation ΔΤ2 = Δt2 - Δx2 - Δy2 - Δz2 with c = 1 and t in seconds. This is due to the unit of length being 1 light-second, which is equivalent to c = 1. Alternative systems of "natural units" exist, such as setting pi = 1, but setting c = 1 is the most common.
  • #1
PerpStudent
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When one considers (proper time) ΔΤ2 = Δt2 - Δx2 - Δy2 - Δz2, with c = 1, if t is in seconds, are the units of x,y and z necessarily 3x108 meters?
 
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  • #2
PerpStudent said:
When one considers (proper time) ΔΤ2 = Δt2 - Δx2 - Δy2 - Δz2, with c = 1, if t is in seconds, are the units of x,y and z necessarily 3x108 meters?
Yes. The unit of length is 1 light-second which makes c = 1.
 
  • #3
Yes. You may find http://en.wikipedia.org/wiki/Natural_units interesting - there are several alternative systems of "natural units", but setting c=1 is most common. (There are also semi-joke "supernatural" units where pi=1, useful for interpretive dance physics, a.k.a "hand-waving".)
 

What is the distance unit used in relativity?

In relativity, the most commonly used distance unit is the meter (m). However, other units such as the light-year (ly) or astronomical unit (AU) may also be used for larger distances.

Why is the speed of light used to measure distance in relativity?

In relativity, the speed of light is used as a fundamental constant because it is the same for all observers, regardless of their relative motion. This allows for consistent measurements of distance and time in different reference frames.

How does relativity account for the measurement of distance in moving objects?

According to relativity, distance is not absolute and can be affected by the relative motion of an observer. This is accounted for by the concept of length contraction, where an object appears shorter when viewed from a moving reference frame.

Are there any other distance units used in relativity besides the meter?

In addition to the meter, other distance units such as the light-year (ly) or astronomical unit (AU) may also be used in relativity for larger distances. However, the meter is the most commonly used unit in relativity calculations.

How does the concept of spacetime affect the measurement of distance in relativity?

In relativity, distance is not only measured in space but also in time. The concept of spacetime allows for the measurement of distance in terms of both space and time, and how they are affected by the relative motion of observers.

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