# Heat Death, eh?

KillaMarcilla
Yo, d00ds, my Physics book mentions the concept of Heat Death (All the energy in the universe going to an unusable form) but says that it might not be valid if the universe is bounded in certain ways

Does that just mean that if the universe hits a Big Crunch, it won't experience Heat Death, or if it experiences Cold Death it can't hit Heat Death, or is it something more interesting?

IS there any way on any level to conceive of a (statistically reasonable) net decrease in entropy?

Edit: fixed typo

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maximus
Originally posted by KillaMarcilla
Yo, d00ds, my Physics book mentions the concept of Heat Death (All the energy in the universe going to an unusable form) but says that it might not be valid if the universe is bounded in certain ways

what do you mean by unusable form? are you talking about the possibility of an ever expanding universe?

IS there any way on any level to conceive of a (statistically reasonable) net increase in entropy?

as of now, everything is on a net increase. maybe you meant net DECREASE.

KillaMarcilla
yeah, that's what I meant

So do you know anything, Maximus?

maximus
i'm still unclear about what "Hot Death" is or what you mean by unusable energy. also, what is the situation in which this hot death will take place? the big cruch collapse or the other, continually expanding scenerio. i can make a guess that you mean the eternal expansion becuase that's the situation in which entropy will eventually increase to a state where even stars will be unable to make thermonuclear reactions (be rendered "useless" i suppose) and the distribution of the energy of the universe will become too uniform.

but in a more direct answer to your last question: no. in both scenerios (collapse and no) the net entropy value will increase to a maximum.

Staff Emeritus
Gold Member
Heat death refers to the situation where, in an open universe, everything reaches the same temperature. When this happens, thermodynamics states that there will no longer be any way to move energy around -- and since all biology and technology depend on the heat reservoirs, biology and technology will cease to exist.

If the universe is closed, it will reach a big crunch (probably) far earlier than it will suffer heat death.

- Warren