Posted 13 April 2005 - 05:32 PM
Hi everyone, sorry to jump into a relatively old thread, bringing it back from death and all...
I think the problem with the second law of thermodynamics debate stems from equivocation. Sometimes this might be intentional, but most of the time its unintentional.
Now SLOT, or 2LoT is often defined, by YECs as
"The entropy of a system will always increase"
"The disorder of a system will always increase"
Or such things. Now, first there is an error by emission here. The 2LoT talks about a tendency. That's quite important here, but its not vital.
Lets define some terms.
Literally: Heat movements. A branch of physics that deals with laws of heat transfer.
Its already been defined before. But remember that entropy is an energy which means its measured using Joules.
This is not about how tidy and lively something is. It refers to how concentrated energy is in a given system.
This is about how diffuse energy is a system.
The transfer of energy from one physical system to another.
A simple example of what 2LoT implies
So, if I put a hot coal in a thermodynamically isolated system, the heat energy from that hot coal will transfer to the rest of the system. Eventually our system here will reach a uniform temperature. 2LoT says that energy transfers occur from hot to cold. Since there is no hot nor cold there are no more energy transfers.
In thermodynamics we started off with low entropy (order) because we had a concentration of energy. In the end, no concentration of energy existed, the energy was fully spread out, so now we have high entropy. Or disorder.
OK, that's straightforward, but what happens when we add work into the affair?
Work and 2LoT
2LoT tells us, by inference, that no 'machine' (a system that does work) can be 100% efficient. Some energy is always lost, as heat. Now imagine a system that gets hold of that heat, and uses it to do more work? It can be done, but that work is not 100% efficient either. One can keep building more systems that grab on to the lost heat, but in the end, there is some amount of heat that isn't enough to be able overcome the force (eg friction) to do any work. That heat is lost and is called 'entropy'.
People have tried to make perpetual motion machines, but they stopped once 2LoT became accepted, because perpetual motion machines cannot occur and obey the second law...some energy is always lost.
OK, where am I going here? Lets look at our system. We shall simplify it. It is a Star and a Planet. The Sun and Earth as we call them. The Sun is a huge concentration of energy, the Earth, also, has energy but not like the sun has...the sun is a million times the size of the earth, and is a big nuclear explosion. I think its safe to say, the sun is HUGE energy. Its a good job that not all of that energy reaches earth, or we'd be toast. Anyway according to thermodynamics the sun should be transferring energy to the parts of the system that have less energy (are colder). This is happening, 2LoT has not been violated yet.
OK, now the energy that is being dissipated by the sun, can be put to work. Not all of it, but most of it. A plant that exists on Earth, can take that energy and convert it to chemical energy. It uses this chemical energy to divide its cells. This division of cells allows the plant to grow. It also allows it to create special reproductive cells so it can make more plants.
So, the energy from the sun is being made to do work. This work is not 100% efficient. Some of the energy from the sun is wasted in this endevour...to eventually boil away into space as per 2LoT which says that the ordered (concentration of energy) earth should be distributing that energy (radiating it off into space) to become more disordered (less concentrated).
A bad example of evolution, but it doesn't violate any known laws
Poor earth, half of it is getting rid of its heat energy and becoming more entropic, the other half is getting loads more bloody energy from the sun over there. So the earth is nearly always the same temperature, it has about the same level of energy on it.
Our plant is busy using that energy to do work, and is contributing its entropy to the great and powerful Thermo-taxman. All is good. Now...the plant does some strange work...it creates a reproductive cell with a beneficial mutation (and an extra chromosome)...it took more work create that cell, than normal! No worries, there is plenty of chemical energy with which to do that work, but it does make a little bit more entropy as well. Surely not! That betrays the law of thermodynamics you say! Of course it doesn't, the plant does work to evolve, it gets the energy to do that work from the sun. The price we pay for evolution? A little more entropy in the universe a little more quickly.Evolution increases the entropy of the universe, just like any work does anywhere.
2LoT has not be violated at any point during our hypothetical journey. If it did, please tell me where.
Abiogenesis/Autogenesis and an example of a everyday violation of 2LoT
Now. The creation of life. Does that betray thermodynamics? Do we need a system in place to harness raw power? If a system doesn't exist, does it all just go to waste? Unworkable energy?
No. I can show you right now a localised system that requires no Intelligence driving it, where a high entropy state is transformed into a low entropy state, temporarily. That's right, if you are unfortunate to live somewhere as miserable as Britain I can almost guarantee that if you walk outside now you can observe the result of a seeming temporary violation of 2LoT. Go out...look up. See any clouds? How did they get there?
Look at a body of water. Its energy is evenly distributed. Its just sat there, not doing anything, no work is being done, there is no workable energy. OK. High Entropy state right? The sun shines on it...it warms up. The top water molecules suddenly have the energy to brake free of their watery bonds and turn into vapour. Weeee! The vapour starts to do work as it works against gravity to fly to the sky...with its friends, attending a party we call a cloud. What is a cloud? Its 3 water molecules: Two's company, three's a cloud. I kid. Anyway, this cloud is officially a concentration of Potential Energy. Where there was once a distribution of energy, there is now a localized concentration of energy. A temporary violation of 2LoT. No intervention by an intelligence was required to produce this temporary violation.
So, it can be seen that the sun can, and does everyday, cause localized seeming violations of thermodynamics.
Of course, no violation has really occurred because the cloud and water are not closed systems...and the work done is not 100% efficient, some of the work to do that produced unworkable energy that is now working its way through the universe on a mission to make everything the same uniform temperature.
How it all fits together
Now - since the sun can, and does, do this. It is therefore possible (though not proven) that the sun can cause complex molecules to form without violating thermodynamics. One day, a long time ago, the sun caused one of these complex molecules to form with another, and another. Eventually the collection of complex molecules was able use the sun's energy to create new complex molecules that simply copied the original.
One day after that, during this chemical copying process, an error occurred. This error led to a complex molecule not copying properly, and when it did a lot more work than normal (and made more entropy wee!) and ended up creating 4 collections of complex molecules (these collections we call cells). The funny thing is - when this group of cells tried to copy themselves, they found that the instruction error that led to this multicellular organism, copied itself over too. And so, lots of multicellular organisms came into being.
And so we see abiogenesis and evolution occurring without a violation of thermodynamics.
Now, unless anyone out there can tell me why my logic is flawed here, please stop using the 2LoT as if it destroys the Theory of Evolution. It doesn't. Thanks for reading.