Question

hey frnds...i have a ques. related to the bigbang ..we all know that the evolution of our universe is accompanied with increase in entropy..if we reverse the time common sense says that entropy decreases...i thought that that would be correct...at the bigbang itself our universe should be extremely smooth...but stephen hawking in his "the brief history of time" says even when time arrow is reversed entropy increases with contraction of the universe in chapter "the arrow of time" pg-158to159......but he also says the early universe was smooth ...how is this possible?

Answer 1

Good question, normally all theories suggest a change in entropy from low to high. The universe at the big bang started out in a low entropy state and is increasing in entropy as it ages. With Hawkins perhaps boils down to what he is referring to when he uses the word "entropy"?

Answer 2

Does this help?
http://library.thinkquest.org/06aug/02088/hawking.htm

Answer 3

However, by the time the rate of expansion of the universe falls below critical speed and the universe's own matter begins to pull in on itself, all the stars will have burnt out, galaxies will have collapsed, and protons and neutrons will have decayed into radiation and photons; basically, the ultimate state of disorder (or very close to ultimate). When the universe begins to contract and the cosmological arrow reverses direction, there will be no solid direction for the thermodynamic arrow to point in, since entropy could not increase much more. Furthermore, the psychological arrow would be entirely insignificant in this state of the universe; at ultimate entropy, life could not possibly exist.
PLEASE @miss.sarahconrad i dont understand this please explain this alone thank you very much