What is the lowest possible temperature
on the Celsius scale? On the Kelvin scale?

Celsius . . . negative 273.15 degrees

Kelvin . . . . zero of them

  the unit of the measure =

explanation:

  the property that is quantified by the energy needed per of material to raise the temperature by one.

  si unit of energy = joule (j)

  si unit of temperature = kelvin (k)

  si unit of mass of material = kilogram (kg)

the property that is quantified by the energy needed per of material to raise the temperature by one is called specific heat.

the unit of specific heat is

3. dark matter

empty space could also be a simple vacuum