It is fine on paper to insist on a standard second, s = 1 sec, but in practice a standard second is difficult to define. However if time is the flow of space and space has mass, m. We might consider:
\( t={ C }_{ o }.\cfrac { dm }{ dt }\) a flow of space through an unit Area A and over time, a volume of space, mass m and \({ C }_{ o }\) is a constant of proportionality independent of time.
Solving this
\(\int { tdt } ={ C }_{ o }\int { dm }\)
\(\frac { 1 }{ 2 } { t }^{ 2 }={ C }_{ o }m\)
and so,
\(t=\sqrt { 2{ C }_{ o }m }\) where m is the mass of space.
This allows us to move onto the concept of Gravity.