Chaplygin Gas , Energy Conditions and Cosmology

It is explored that if dominant component of content of the future universe behaves as Chaplygin gas, voilation of other energy conditions (null energy condition, weak energy condition and dominant energy condition) can be avoided if " strong energy condition " is obeyed. In the investigations, here, two cases arise. In one case, universe expands with acceleration leading to finite energy density and pressure in the asymptotic limit. In the other case, accelerated expansion continues upto its maximum followed by contraction to finite-time singularity in future with divergent energy density and vanishing pressure. contraction of the universe. 1 A number of observations, including Ia Sne data [1], cosmic microwave background anisotropy [2] and the most recent one, WAMP (Wilkinson