Simultaneity question – is sequence absolute?

rede96

Thanks for that. I was just doing some reading to understand this a bit more and came accross a different formula:

The space-time interval ds is defined by

ds^2 = -(cdt)^2 + dl^2

This obviously gives the negative interval. Is there any significance to this?

PAllen

Yes, the sign if ds^2 determines whether a path is spacelike or timelike. Using your conventionn for ds^2 (there is another), for a timelike path you integrate -ds^2, for a spacelike path integrate ds^2. The resulting intervals are called proper time and proper length.