I got this formula for calculating the distance between spacetime intervals at Wikipedia:(adsbygoogle = window.adsbygoogle || []).push({});

ds^2 = c^2dt^2 - dx^2 - dy^2 - dz^2

Now first I thought the d was supposed to be the Greek delta which my physics teacher uses to indicate a difference of the following variable, instead of just a simple value, but when looking at other sites, I saw they also used the d. So my question is, is this the same as the delta?

Secondly, I was wondering if someone could explain this formula to me. I understand what it says (if the d is indeed what I thought it was - the delta), but not why this is the formula.

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# Spacetime interval formula - what's the d?

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