2nd law of thermodynamics and progress

This blog post is part of my series delving into the belief in progress.  This particular post will be about the second law of thermodynamics and the claim that this law amounts to a final limit on progress.

The second law  (1) states that "All processes result in a reduction in the free energy of the universe.".  The ability to maintain islands of order against the trend towards disorder depends on using free energy.  Once free energy is all gone we will be unable to maintain civilisations and even life.  This decent into chaos is known as the heat death of the universe.

Many people have stated that the second law makes a heat death inevitable.  In fact there are two other physical principles that must also hold to imply the collapse of civilisation:

(2) The universe is finite in space or matter.

If this were not the case there could be a constant influx of new hydrogen into our region of the universe allowing the formation of new stars.  In such a universe there would be no heat death.

(3) There is a lower bound to how much energy is necessary to perform a given calculation.

Most of the useful things that civilisations do can be described in terms of computations in one medium or another.  If the amount of energy required to perform a computation decreases over time (which is possible without [3]) then civilisations may be able to stay ahead of the game redesigning themselves constantly to use less energy.  In such a universe a heat death might occur but it would not necessarily destroy all civilisations.

So in deciding whether civilisations can survive indefinitely or not we need to know how much credibility to give these two principles and how much we can trust the second law of thermodynamics.

Before getting into this we need an estimate of how long away the heat death of the universe is according to our current understanding of physics.  According to wikipedia stars will stop shining in roughly 100,000 billion years.  However, blacks holes are also sources of energy (via hawking radiation) and civilisations could probably eek out an existence on bodies orbiting super massive black holes.  Hawking radiation could be used as a source of useful energy.  There is no obvious reason in the known laws of physics that civilisation couldn't survive until approximately 10^40 years.  Hence, in order for the principles (1), (2) and (3) to form an absolute limit for progress we must be able to trust them to hold without significant error over a period of ten thousand billion billion billion billion years.

In reverse order let us look at these principles and judge their likelihood in this context:

(3) If there are only finitely many different types of particle then their behaviour may put an absolute limit to the amount of computation that can be performed in any given volume or for any given amount of energy.  It is conceivable that there are only a finite number of elementary particles possible, however, the history of physics includes at least two occasions where it was believed that we had discovered the fundamental constituents of matter only to be proved wrong.  It is not obvious that there are only a finite number of types of particles.  It may be the case that there is an infinite hierarchy of particles each harder than the last to produce.

(2) Current cosmology maintains that the universe is finite in extent.  However, there are major problems with the standard cosmological model.  We have mysterious entities such as dark matter, dark energy as well significant unexplained phenomena such as inflation and the uniformity of the universe.  Several new cosmological theories do not imply a finite universe and we are not yet in a position to form a reasonable estimate of how likely it is that the universe is finite.

(1) The second law of thermodynamics is one of the best justified principles in science.  Formulated in 1824 there has been no experimental data contradicting it since despite the best efforts of many.  Hoards of cranks over this period have claimed to have produced perpetual motion machines violating the second law but none of these claims has ever been independently verified.  It certainly would be a good bet that no one will find a violation of the second law in the 21st century.  It might even be reasonable to assert that we won't find a violation in the next millenia.  However, in order to justify the second law as an absolute bar to progress it must not only hold for a thousand, a million or a billion years but for 10^40 years. 

So in conclusion although the second law of thermodynamics would seem to pose an absolute barrier to progress it does not do so on its own.  Two other principles are needed neither of which we can be particularly sure of.  Furthermore the time spans under consideration are so vast that even the second law of thermodynamics may well breakdown.

As a cautionary example here I present the principle of parity conservation:

(4) If you take the entire universe and reflect it in a perfect mirror then the reflection will behave in exactly the same way as the original universe.

This was believed to be an absolute conservation law of the same type as the first law of thermodynamics.  However, in 1956 the decay of Cobalt-60 was shown to violate partiy conservation.  Since then several other conservation laws have been found to fail.

Comments

[Harry]

Hi all . I am a fabrication engineer with only basic knowledge of heat etc. The survival of this species so far into the future as the writer suggests is in my view flawed and cannot happen. This generation and maybe two or three more will survive. Beyond that I see only wars with the stronger nations fighting for and capturing areas containing the valuable mineral resources such as metals, oil, water, etc. Iraqu oil has already been “acquired” by the US. and handed over to the multinational oil companies to profit from. The water in Palestine has been with the help of the US, ”acquired” by the Israelis, and ethnic cleansing is gathering pace with tragic results for Palestine and its people, and the surrounding areas with boiling resentment from all the refugees trapped in someone else’s land.
This is already happening now what will it be like in the future when the sea levels rise forcing an ever expanding world population into an ever decreasing land area. I predict Nuclear Weapons will be used on mass with this in mind in the near future, thus again polluting and causing widespread deaths by cancer etc. Then famine and diseases will wipe out the remaining population leaving only the basic forms of life, termites etc to survive, until the sun expires.
As for black holes surely the centre of a black hole must be very cold indeed as the atoms at the centre do not move at all due to there being no space to move about at all, and heat in anything is due to atomic movement within the element. The cold in deep space being several degrees above absolute zero, would surely tap any heat away from the surface of the mass (with no atmosphere) as it collects more matter from its own universe.
Worm holes, moles, smoles. What is that about, you get within a million miles or so of a Black Ball as I would rather call it, you and your craft are sucked in and obliterated and become part of other atoms smashing into the surface of this monster never to be released again in any form whatsoever? I think Mr Hawkins has a lot to answer for. I am keen on science but lets keep it real. There will be no survivable visits ( or plants being populated) to any of our nearest planets apart from the moon. We can’t even survive in a purpose built environment here on earth in the Arizona Desert let alone a few million miles away on another planet. We are stuck with this planet so we had better forget about going elsewhere and spend that money on the people here and now and not on Buck Rogers type pipe dreams.
There you go, give it to me with both barrels I have broad shoulders so don’t hold back but remember when shooting at me I have no intellectual armour only my secondary modern shell to ward off your barbs. Take are H..

[Barnaby Dawson]

Your comments make several separate points. I shall isolate them and respond to them one at a time:

1) Our species will not survive into the indefinite future.

It seems very likely that our species will either evolve or be replaced by another species or most likely hyper intelligent AI. However, that does not mean that civilisation will be destroyed or that progress will stop. We must be careful not to be too anthropomorphic.

2) Wars are getting worse.

As this post should make clear wars are getting less terrible in the long term. You give good reasons to think that warfare will get worse in the short term. There are too many unknowns to make longer term predictions in my view (in particular whether we will expand into space).

3) We will never leave the earth.

I think its inevitable that we'll leave the earth. My reasons are as follows:

a) There is a huge amount of energy available in the solar system (and hence a huge economic incentive).

b) Once out of Earth's gravity well travel in space is cheap (no friction, efficient momentum exchange systems).

c) Raw materials are available in the asteroid belts.

d) Once we have AI we will be able to move intelligences around the solar system at or close to the speed of light.

[Harry]

[There is a huge amount of energy available in the solar system (and hence a huge economic incentive).]
I return to my point that we can't even survive without outside help here on earth for any length of time in what would be a sealed environment for anything like the time needed to travel to our nearest planet. So even our closet planets are in the near future and as far as I can see in the far future unobtainable. It's good to be an optimist but maybe better to be a realist. The growing of food in space is as been proved is impossible, so how do we feed ourselves in space. Perhaps I do not have the vision, for this; maybe we won’t need food as we perceive it now. Perhaps we could survive on nano food or some such macro biological soup, but for how long. The nearest planet and the most friendly, (friendly being not too hot) is four years away at present speeds of travel, and not a thing there that will improve our existence even if they do get back, and they will have to get back to survive. So with this solid evidence of failure of survival here on earth with all the resources at our disposal your theory of space travel and every other statement to do with this subject I feel is flawed as without the development of craft that are safe, able to be lived in for years without resource supply whatsoever over this period of time, none of the points made stand up to debate at all.

I don’t think we will ever be able to travel at close to the speed of light. Why would anyone risk this is beyond my comprehension. When at present speeds of say 12 000 miles per hour, even a speck of paint will do serious damage to the craft, and a small stone or rock would obliterate the craft, should a craft ever be available to travel at these speeds. Sorry Mr D. I love your thoughts and optimism but I have so many reservations as to your future predictions, my main problem being is the wasted recourses and therefore lives here on earth whilst trying to obtain the unobtainable. Take care all, H..( Buzz Lightyear.)

[Barnaby Dawson]

I'll address your points in sequence:

1) We can't survive in space in a self contained manner.

We don't yet know how to do it. But we've hardly put any effort into trying yet. Give it a few hundreds of billions in funding and we'll figure it out. This really isn't a big impediment to our species colonising space. Sure it might delay things a few hundred years though.

2) The growing of food in space is impossible.

This is just false. Perhaps you meant "in a vacuum"? Growing food in space efficiently is a challenge but growing it at all requires only routine research.

3) The argument about moving around at the speed of light was meant to apply to information not matter. With an AI society minds could move around at light speed (once a slower move colony ship has arrived somewhere first of course). There would be little point moving matter of energy between starsystems so this isn't really any kind of problem anyway. I agree that moving matter around at near light speed would be silly.

4) Trying to conquer space is a waste of resources.

Firstly this blog post was never arguing otherwise. But seriously we've spent $500 billion on space travel which is less than on the Iraq war and the spin offs in communications technology are worth more than $500 billion over the last 30 years. If you want to reassign money for third world development you're much better off opposing pointless wars.

[Felix]

Hi Barnaby, I've finally found time to respond to this post. (you posted a comment with a link to it on my blog a while ago) Let me know what you think of this: http://themeatyard.blogspot.com/2009/09/belief-in-progress-and-how-it-relates.html