matter, energy, space, time and gravity

Dremmer

Are these five different things or are they just variations or properties of the same thing?

mfb

They are different things (which is the reason why they have different names).
Their interaction is the topic of physics.

Dremmer

Matter is the only one of these that we can perceive directly. We cannot perceive energy, gravity, space or time directly.

bahamagreen

We do not perceive matter directly, we perceive nothing directly.

manojr

Mathematical model that combines space and time is Spacetime that curves (gravity) in presence of matter (mass/energy).