I was told in Physics class that we live in a universe where energy can be converted from one form to another form(s) but the equation never exactly balances, there is always some small amount of energy "lost" as heat in every attempted conversion.

My question is, what differences would we see in a universe where perfect balanced conversion from one form of energy into another (including into heat, if that is what you want) was the rule? I.e., everything the same as in the universe today except no "waste" heat produced during energy conversion.

Would Earth still be possible? Would life as we know it still be possible? Other than the Universe not ending in a diffuse state of "heat death", would anything important be different? What would the impact be of that tiny little bit of energy always getting captured in the desired form instead of getting released into the Universe as unusable heat?

Hello Crissy,

I am a Physics teacher in Brazil,and I have found your question very interesting. Also, it is not simply hard for me to try an answer. I also believe to be a difficult question to be posed. Let me try, and forgive me for my bad english.

First of all, it seems strange for us to question what would the universe be like if our beliefs and theories are proven wrong. This is a philosophycal question. Since no one can PROVE you that our belief is right, I believe the answer to your question could simply be that the universe not would have been different if a scientific belief is proven to be wrong. A science phislosopher, Karl Popper, as far as I understand, sustained that a scientific theory was a a kind of a guess, which allways could be proven wrong, and I think he was right.

Returning to your question, I think it could be somehow made more precise. Books on Thermodynamics explain that, in some cases, heat can be completely converted into work, and the converse is also possible. However, the so called Second Law of Thermodynamics (Kelvin and Planck version) states pecisely that there is no possibility of heat being transformed completely into work IN A CYCLIC PROCESS, in which a "working substance" (for instance, the water in a steam motor) is made to return to its initial state. The law imposes no limit to work transformed into heat. A perhaps more general form of the Second Law of Thermodynamics is the law of entropy: global entropy (entropy of the working substance plus that of its environment) must not decrease. Roughly speaking, the entropy of a body is proportional to the number of "internal" molecular states (precisely, to the logarithm of the number of states)in which this body can be for a certain amount of material, energy, volume, and other possible quantities defining its "external appearance".

How would things be if the Second Law is proven wrong? Not also we could build cyclic machines (motors) that would completely convert heat into work (the so called perpetual motion machines of the second kind). The distincion between past and future would vanish, perhaps, for the gobal entropy would not change. But perhaps, as I said before, the world would be just the same, and our scientific beliefs woud just be different.

Best Regards,
Eduardo F. Henriques.

if heat could be transformed into another sort of energy then that would be pretty cool cuz we could finally get a 100% energy spare.. then perhaps there wont be nessesary to use oil for transportation and machinery use.. perhaps another sort of energy that can be re-transformed into another after used.. interesting question.. P.S (i don't think it would affect the universe in any kind)

Thank you for your answers! I asked this question in another Physics group where it generated more discussion. You can view it here.

Although is very correct the said by Eduardo from Brazil about second law, reversibility anad cyclic processes and perpetual motion, guess that using "internal" molecularto define roughly entropy can also give rise to misunderstanding, I think he wanted to say somthing like "internal" (or molecular), since the way was initially put could be understood by many as having t do with extra degrees of freedom (vibrational-rotational in molecules) that usually are not taken into account for entropy. Also, about "global entropy" doesn't satisfy my view at all. I just can remember have read the idea of our view of flow of time in the known book of Hawking, and Im not sure if he really believed in some kind of reversing of time if entropy in Universe be decreasing as a result of contraction. The view of some physicists is that second law would be so necessary as to have to do with Universe expansion, and I think it could have also to do with a cosmological constant (or acceleration of Universe), but (as put in somewhere by Eduardo) also could need a little different definition of entopy to take into account gravitational (or quantum gravitational) effects, but guess this is less esotherical than relate entropy with psychology.