Can a piece of space-time having 3 spacial dimensions and 1 dimension of time be viewed as a particle? Could this piece of space-time have properties of its own (mass, spin, charge) independent of the energy that it coexists with? How small would it be, and how much mass does a "volume time" of space time have? Like, say a $light second^3s$?. Also, since time can be measured forwards or backwards could you have a -$light second^3s$