Units of spatial coordinates in the proper time interval formula

[PerpStudent]

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?

 

[Mentz114]

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.

 

[EWH]

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".)