Entropy and Closed Systems

[Dragar]

Entropy is so often abused by creationists. The claim they make is usally something like this:

"The Second Law states that the entropy always goes up! That means the disorder of a system will always go up! But evolution states that systems (populations or individuals, I can never tell what their 'system' is defined as) become more organised! This contradicts the Second Law, so evolution is wrong."

So I'm going to show you a system where the entropy goes down.

Let's take a block of iron. And we heat it up, really, really hot.

Now, to begin with, this block of iron is isolated from the rest of the universe. But then I attach a tiny, tiny bit of wire from this stupidly hot block of iron, to another really huge block of iron - but at a much lower temperature.

A small amount of heat, dq, will leave the hot block of iron, and enter the cold block of iron. This is so small it is reversible so we can use the equation:

dS = dQ/T

where dS is a small change in the entropy, and dQ is a small change in the heat in the system. And T is the temperature.

What is the entropy change of the hot block of iron?

Well dQ is so small that T has not changed. dQ, you will also notice, is negative, as it has left the system - the heat has gone down. And that means dS - the change in the entropy - is also negative.

In other words, contrary to creationist assertions, the entropy of a system does not always increase.

If we were to consider the entropy change in the cold block of iron, we would find that the entropy change would be positive, and would at the very least cancel out the negative entropy change in the hot block of iron.

The entropy of a closed system tends to increase (statistically speaking), and that is what the second law actually says. A closed system is one that is thermally isolated - no energy enters or leaves the system.An example would be the combined hot block of iron and cold block of iron system I described above, and that is why we find the entropy of that closed system increases. Energy might go between the two blocks, but it doesn't leave (or enter) the system.

This is important. It is important because the Earth is not a closed system. Populations of animals are not closed systems. Individual animals are not closed systems.

They are not closed systems because animals are constantly losing and gaining energy to and from the environment. The environment is constantly radiating energy into space, and recieving energy again from the sun - a great big fusion reactor sat around eight light-minutes from us.

So, because none of these systems (the Earth, populations of animals or individual animals) are closed, none will necessarily tend to have an increase in entropy.

 

[JohnR7]

In other words, contrary to creationist assertions, the entropy of a system does not always increase.

So does that mean we can not depend on a carbon 14 test that depends on the decay rate being consistant? Anyways, let us take a look at what creation science really has to say about entropy:

Participant: How do you respond to the theory that the Big Bang that you're studying now is merely one of a series of Big Bangs? That the matter of the universe is constantly exploding, accelerating, decelerating, concentrating and re-exploding?​

Hugh Ross: I whizzed right past that in my talk, thinking no one would pick up on it, but you did. If the universe has sufficient mass, then it's expansion will stop. Two massive objects tend to attract one another. The universe contains enough galaxies and quasars and other material that the mutual attraction would eventually take the steam out of the expansion of the universe, forcing the universe into a subsequent period of collapse.

There have been those of the Hindu persuasion who first began to believe 3,000 years ago that when the universe collapses, it will go through a bounce. It will rebound into a second stage of expansion, collapse, expansion, collapse, etc.

Then we're back to infinite time. If there are an infinite number of bounces of the universe, then you can postulate that this just happens to be that lucky bounce of the cosmos in which conditions were just right for the formation of life.

The truth of the matter is that it's physically impossible for the universe to bounce. In 1983, Alan Guth and Mark Sher published a paper in the British Journal of Nature titled, “The impossibility of a Bouncing Universe”.

The reason it's impossible for the universe to bounce is because of its enormous entropy. It has a specific entropy of 1,000,000,000. That translates into a mechanical efficiency for the universe of 1/100,000,000 of a percent.

In terms of a bounce, if I have a ball in front of me, and I let if fall towards the carpeted floor, we can measure it's mechanical efficiency by how far it bounces off of the floor compared to the height from which I drop if. It's about 30% efficient.

The universe has a mechanical efficiency of 1/100,000,000 of a percent. Engineers in the audience will tell you that anytime an engine falls below a 1% mechanical efficiency, it will not oscillate. The universe falls 8 orders of magnitude short of that limit. Therefore, it's impossible.

This impossibility has not only been demonstrated in the classical physical sense, it's also been demonstrated under the conditions of quantum mechanics. Even if we're talking about a bounce in that period of time in which the universe is compressed smaller than a quantum entity, there too, it's impossible.

The universe could collapse, but we're still talking about only one creation event, only one beginning. Therefore, we pull the rug out from under Hinduism, Buddhism and New Age philosophy, because all of those religions preach that the universe reincarnates. The fact that astrophysicists have demonstrated the impossibility of reincarnation scientifically demonstrates the fallibility of Hinduism, Buddhism and New Age philosophy.

 

[Dragar]

John, why have you responded to my post by presenting a lather long quotation which has little to nothing to do with what I posted?

 

[JohnR7]

John, why have you responded to my post by presenting a lather long quotation which has little to nothing to do with what I posted?

Ok, lets look at what you said: "A small amount of heat, dq, will leave the hot block of iron, and enter the cold block of iron. This is so small it is reversible so we can use the equation" How can this be reversible? There is always a transfer from hot to cold, never from cold to hot. If you know how to stop or reverse this transfer of heat then let me know because I would like to save on my gas bill in the winter.

 

[Dragar]

How can this be reversible? There is always a transfer from hot to cold, never from cold to hot.

On average, this is true.

 

[c'mon sense]

Exactly, on average. To the observed shift from hot to cold an equal shift from cold to hot could be observed until an equilibrium is reached. This is THE law of the Universe.

 

[saibot]

You all should watch "Creatures that Defy Evolution". It's really cool.

 

[MartinM]

And this has what to do with thermodynamics, saibot?

 

[corvus_corax]

As the Naclist Hierophant (blessed be Mechanical Bliss), I feel the need to point out that the 2LoT clearly points out that salt cannot form under natural circumstances
"Everyone knows that the Second Law of Thermodynamics says that complexity does not increase. Putting two homogenous materials together to form one material that contains both is an increase in complexity. NaCl-ism violates a scientific LAW!"

So it was written, so let it be known

 

[c'mon sense]

Or from a single cell we arrive to a full grown human! What a nerve the Universe has to defy the *blessed* 2nd law of thermodynamics...

Of course, this happens at the expense of a range of other systems. Nothing for free, everything correctly priced in nature.

 

[Spherical Time]

So does that mean we can not depend on a carbon 14 test that depends on the decay rate being consistant? Anyways, let us take a look at what creation science really has to say about entropy:

Ignoring the long quote, what did Dragar post to make you think that the second law prevents decay rates from being consistent?

 

[madarab]

JohnR7, if you had any idea what you were talking about, you'd reach exactly the opposite conclusion. I'm not even sure that it's worth wasting the time to try to educate you as to why radioactive decay would remain consistant under the laws of thermodynamics. (Not that thermodynamics is really a particularly useful way to evaluate that kind of behavior.)