Astronomy:Chaplygin gas

Chaplygin gas, which occurs in certain theories of cosmology, is a hypothetical substance that satisfies an exotic equation of state in the form [math]\displaystyle{ p = -A/\rho^\alpha }[/math], where [math]\displaystyle{ p }[/math] is the pressure, [math]\displaystyle{ \rho }[/math] is the density, with [math]\displaystyle{ \alpha = 1 }[/math] and [math]\displaystyle{ A }[/math] a positive constant. The substance is named after Sergey Chaplygin.

In some models, generalized Chaplygin gas is considered, where [math]\displaystyle{ \alpha }[/math] is a parameter, which can take on values [math]\displaystyle{ 0 \lt \alpha \le 1 }[/math].

See also

• Dark fluid