Why time is a scalar is also neither a scalar or vector

[Sigma]

Quick reminder = a scalar is just magnitude (size) only. It does not have a direction.

Ok, so what about time? Time is in a positive direction as described as the arrow of time, so does that not make it a scalar - well, yes it does. But..

According to Einstein's special theory of relativity, time is neither a scalar or vector but it is actually a component of 4D.

However, in order for a physical quantity to be a vector, you must be able to draw a triangle or parallelogram.

So, us physicist describe time as a scalar. Done. It dopey, but, hey its physics she is absurd in nature.

[Theodric_Ironfist]

Depends what you mean by “time”.

If using time as a coordinate in the 4th dimension such as in relativity, then time would be a vector that points from the coordinate (t, x, y, z) to the coordinate (t + dt, x, y, z).

However for 99% of the time, when we use time we are using the magnitude, so it doesn’t really make sense to call it a vector if it’s never really used as a vector.