reklaw67

It was recently argued toward me that the 2nd law of thermodynamics makes a cyclical universe highly unlikely. I admittedly am a layman on such issues but tried to research this after this was brought up.

I finally stumbled across the Palo Alto Institute for Advanced Study site.

There is a fairly extensive reading on the 2nd law of thermodynamics there that I found interesting. It seems the argument is that the 2nd law of thermodynamics is not a sound scientific law but rather more useful for the field of engineering.

Lacking the technical aptitude to make sense of much of it however I was wondering if anyone who does have this aptitude could take a look at this site and post your thoughts. I think you will find it pretty interesting.

Sorry to beg for help but I need it.

Link to site is:
<a href="http://www.paias.com/paias/home/Science/Entropy/entropy1.htm" target="_blank">http://www.paias.com/paias/home/Science/Entropy/entropy1.htm</a>

tronvillain

Well, it is a statistical law, but in that it generally describes the behavior of the universe I think that its standard formulation can be labelled "sound scientific law" in the same sense that F=ma can.

[ August 20, 2002: Message edited by: tronvillain ]</p>

ohwilleke

The Second Law of Thermodynamics may break down at very small scales in isolated instances, but it is an extremely robust and reliable scientific law with great practical applications and supported by vast evidence over many circumstances.

echidna

When it comes to universal origins and destinies, it’d be safe to say that most work today is speculative. The article would be correct if the 2LoT can be applied to the entire universe as a closed system.

I recall that one solution many years ago was that ultimately expansion of the universe would cease, & when contraction began, time would reverse! (Hawking ?) But subsequent cosmological measurements refute slowing & actually show the universe is accelerating.

Arguably Conservation of Energy might be another law which may be violated when one considers creation ex nihilo. Only by radically rethinking the law itself can one result in a zero energy sum. And as ohwilleke indicates, when it comes to quantum events, not enough is known to even understand the concept of entropy and time’s arrow in the quantum world.

reklaw67

I thank you for the replies.

Did anyone get a chance to check out the site. I'm looking to see what someone with a more advanced aptitude has to say about what is being said. Some of it is slightly technical to the layreader. (or at least to me) The author says the 2nd law is scientifically false and I'm wanting to know if anyone agrees with his arguments and can explain them a little more.

enigma555

I glanced over the site, and I'm not as impressed as they would like me to be (3rd year aerospace engineering student)

The only section I got into to any depth was the part about how heavier bodies (mid sized) fall faster than lighter bodies because the massive body (the planet e.g.) gets attracted to the mid sized object more than the small one. While this is technically true, the magnitude of the difference is so small it is literally unmeasurable. It is so small infact, that it can be completely ignored for any object made by man, whether it's a ball, a satellite, or a 100 story skyscraper. To put it in perspective, imagine the change in acceleration of a man lying down under a falling anvil 100' above his head and blowing at it to try to slow down the fall... I'd bet even money that his blowing has more effect than the acceleration of the earth due to the anvil's mass

To include it in the calculations would do absolutely nothing except give you a headache trying to keep track of all the new variables.

I'm not going to be taking my orbital dynamics course until next spring, but I'd be willing to wager that for planet sized objects (the only size which matter for this variety of nitpicking) that the website is using the wrong types of math. Although I didn't go through their calculations line by line (and I don't think I will have time... school starts in two weeks and I need to move), I haven't the foggiest idea why they were using a rectilinear coordinate system (XYZ) over a polar (radius, angle).

At a glance, I'm also pretty sure they swept things under the rug, themselves. Their equations only had a single cosine component for acceleration with three objects. This means that although the massive body is changing it's position toward the mid sized body more than the low sized body, they most likely swept that under the rug. Again, I didn't go through line for line. I just glanced, so I could be mistaken.

One more thing... anytime a web site boasts that "famous scientists" have contacted them to ask them to cease operations (or similar), they are lying. "Famous scientists" have far better things to be doing with their time than playing internet police with potentially pseudoscientific websites. After all, I am a completely unfamous future scientist and I don't have the time to do more than find glaring, obvious errors in websites, and that only happens either when someone asks if the website is genuine, or if an obviously bogus website is recommended to a student as a site to look at...

[ August 21, 2002: Message edited by: enigma555 ]</p>

bluefugue

According to Richard Dawkins, Sir Arthur Eddington (who I suppose was one of those imposing British scientist sorts?) wrote:

"If someone points out to you that your pet theory of the universe is in disagreement with Maxwell's equations -- then so much the worse for Maxwell's equations. If it is found to be contradicted by observation -- well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation."

Of course, Eddington wrote that back in 1928...

beausoleil

It seems to me to a mix of the blindingly obvious with the completely incomprehensible. I couldn't make any sense of the discussion of time reversal at all. Maxwell's demon doesn't seem to take account of Maxwell's demon's flashlight.

Baloo

The 2nd Law is, technically, incorrect. Imagine a partitioned container, where one half contains a mole of helium and the other a mole of Argon. The 2nd Law says that if one removes the partition, the gasses will mix and any subsequent state will be less ordered than the initial state. In reality, this is only true on a extremely short timeline (i.e. the 10^10 year-old age of the universe). However, with enough patience to watch the container for, say, 10^10^100 (that is, a 1 followed by more zeroes than there are particles in the universe) years, one would ultimately be rewarded with seeing the container reach a state of pure separation many, many times.

Basically, the law just boils down to the fact that lacking any outside influence, any system will spend most of its time in unordered states simply because there are more unordered states than ordered states. Kind of a "well, duh" statement, but the engineers do seem to like it...