Why is time measured in ct in special relativity?

Question

mstoldegon · Answer

Because time is not constant but is "dilated" as a function of its speed (velocity) relative to that of the speed of light. Do you need the equation?

vincent-lyon.fr · Answer

Because, as it affects the way space is transformed, it is easier and mathematically simpler to take ct as a variable (dimensionally a length) rather than t.

Most equations in special relativity look simpler and more symmetrical if you use ct instead of t.

anonymous · Answer

An alternative approach is to leave time in time units, but change distance to distance/c, in other words, measure distance in a time unit, so time and space intervals are again measured in consistent units.
An example of this that you might be familiar with is the measurement of large distances in light years.

anonymous · Answer

time is written as ct simply because in special relativity it is conseidered that we have four" "dimensions" and since in ds2 is the invariant interval between to events ,therefore time t is multiplied by c to make it have the units of "distance"