Planck density

Planck density

The Planck density is the unit of density, denoted by ρP, in the system of natural units known as Planck units.

: ho_P = frac{m_P}{l_P^3} = frac{c^5}{hbar G^2} ≈ 5.1 × 1096 kg/m3

where:

:"mP" is the Planck mass:"lP" is the Planck length:"c" is the speed of light in a vacuum:hbar is Dirac's constant:"G" is the gravitational constant

This is a unit which is very large, about equivalent to 1023 solar masses squeezed into the space of a single atomic nucleus. At one unit of Planck time after the Big Bang, the mass density of the universe is thought to have been approximately one unit of Planck density.


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