entropy and its implications on "design"

[mikech]

first off, i'm an agnostic. i also don't have much of a science background. but there's something i'd like to ask the scientists out there about entropy and the logical consequences of this law of physics.

so, years ago in my college intro physics class i learned that entropy will always increase, that the universe is moving from a more "ordered" to an ever-more "disordered" state, until one day the "heat death of the universe" is reached. so how did WE get here? i understand that if energy is wielded in a way so that the entropy in one system increases, the entropy in another can be decreased, like forcing all the air in a room into a small corner, or assembling a bicycle, but then wouldn't that imply some sort of design? that a designer (some external organizing input) used energy to decrease entropy in this little corner of the universe which allowed such complexity and order to arise? how could a closed system, on its own, randomly organize (how's that for an oxymoron) and form life?

even though i'm not a theist, i'd like to hear atheists explain this to me.

The solution to this puzzle comes from realising that energy and entropy are mathematically equivalent. That is, you can force order onto a previously less ordered body by the input of energy (the work done pushing all the molecules into place, if you like). The fact that entropy increases means that you will always have to put in more energy than the value of the increase in order.

The solution to the "how did we get here" puzzle is that the earth isnt a closed system. Every day the earth is bombarded with energy from the sun. This energy is converted into order through micro-organisms, plants, solar panels, etc. Atheists can explain where we are now using the theory of evolution (provided there has been enough time for the higher life forms to evolve).

Basically the sun's energy powers the earth (and there is always "leakage" or inefficient use of that energy) and that input of energy is why the order on our planet is increasing rather than decreasing

[mikech]

i understand we get energy from the sun. there are also billions of other stars out there, many with planetary systems, how likely has life arisen on those?

How likely it is that life has arisen somewhere else seems impossible to answer to me. I certainly cant see anything special about our planet so my hunch is that it's probably occurred many times elsewhere through the universe. Nonetheless, it is nothing more than a hunch.

The atheist position seems to rely on a spontaneous generation of life at some point through the action of physical laws. To calculate how likely it is that life has arisen elsewhere depends very much on the chance of this spontaneous creation - I've never seen any credible estimate as to how likely this is (though many non-credible claims ranging from zero to one hundred percent)

[mikech]

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ranging from zero to one hundred percent

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gee, that helps! [img]/images/graemlins/grin.gif[/img]

can't this experiment be conducted? create an environment much like the earth a billion years ago or whenever, supply the environment with energy, and see if the inorganic elements somehow "come alive." science is all about being able to duplicate results by experiments, no?

[Superfluous Man]

Google the names Urey and Miller. You might find that enlightening.

They have done this (or tried to)

They made some primordial "goop" that they theorised were similar to conditions on primordial earth. They then ran thousands of volts of electricity through it at intervals and found some organic chemical compounds had been made that were minor building blocks for life...

But what does that say? Maybe their goop was wrong. Maybe it's easy to make building blocks but what does it take to make the first strand of RNA?

Science is all about repeatable experiments sure, but what we know about early life on earth is pretty limited - hard to recreate a meaningful experiment. Another problem, of course, is who is to say that how things are here is the only way life can exist?

All in all it isnt really an area we can discuss scientifically in my opinion (at least with our current understanding of the universe and its laws)

[benkahuna]

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How likely it is that life has arisen somewhere else seems impossible to answer to me.

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You don't need to answer it because Drake already did.


Description

The Drake Equation was developed by Frank Drake in 1961 as a way to focus on the factors which determine how many intelligent, communicating civilizations there are in our galaxy. The Drake Equation is:
N = N* fp ne fl fi fc fL

The equation can really be looked at as a number of questions:

N* represents the number of stars in the Milky Way Galaxy

Question: How many stars are in the Milky Way Galaxy?
Answer: Current estimates are 100 billion.

fp is the fraction of stars that have planets around them

Question: What percentage of stars have planetary systems?
Answer: Current estimates range from 20% to 50%.

ne is the number of planets per star that are capable of sustaining life

Question: For each star that does have a planetary system, how many planets are capable of sustaining life?
Answer: Current estimates range from 1 to 5.

fl is the fraction of planets in ne where life evolves

Question: On what percentage of the planets that are capable of sustaining life does life actually evolve?
Answer: Current estimates range from 100% (where life can evolve it will) down to close to 0%.

fi is the fraction of fl where intelligent life evolves

Question: On the planets where life does evolve, what percentage evolves intelligent life?
Answer: Estimates range from 100% (intelligence is such a survival advantage that it will certainly evolve) down to near 0%.

fc is the fraction of fi that communicate

Question: What percentage of intelligent races have the means and the desire to communicate?
Answer: 10% to 20%

fL is fraction of the planet's life during which the communicating civilizations live

Question: For each civilization that does communicate, for what fraction of the planet's life does the civilization survive?
Answer: This is the toughest of the questions. If we take Earth as an example, the expected lifetime of our Sun and the Earth is roughly 10 billion years. So far we've been communicating with radio waves for less than 100 years. How long will our civilization survive? Will we destroy ourselves in a few years like some predict or will we overcome our problems and survive for millennia? If we were destroyed tomorrow the answer to this question would be 1/100,000,000th. If we survive for 10,000 years the answer will be 1/1,000,000th.

When all of these variables are multiplied together when come up with:

N, the number of communicating civilizations in the galaxy.

The real value of the Drake Equation is not in the answer itself, but the questions that are prompted when attempting to come up with an answer. Obviously there is a tremendous amount of guess work involved when filling in the variables. As we learn more from astronomy, biology, and other sciences, we'll be able to better estimate the answers to the above questions.

I guess this is what I meant by impossible to answer, at least for the forseeable future. Questions like "What is the probability that intelligence develops on a planet where life evolves?" require such an enormous amount of observation to answer that the whole thing rapidly degenerates into pseudoscience.

There is indeed a profound question regarding the thermodynamic state of the universe, and its relation to entropy. Ironically, though, ID'ers seem not to be aware of it, and instead use incorrect arguments about the "entropy of life."

The facts are these: "Phase space" is a way to express the state of any system. The state of a system corresponds to a point in phase space -- the location of this point in phase space tells you, for example, the velocities and position of every particle in the system being studied.

In thermodynamics, we take all the states that look approximately like one another (they are described by the same "temperature" and other macroscopic variables) and note that all these "similar" states occupy some region of phase space. Phase space is thus divided up into many regions, each region describing a seperate thermodynamic state.

The entropy of a particular thermodynamic state is the log of the volume of the region in phase space it occupies.

With that background, one can do a quick calculation. Using the Bekenstein-Hawking entropy formula for the entropy of a black hole (a high-entropy state), one can approximate the total phase space volume of the universe by putting all the matter in the universe into a single black hole. This gives a phase space volume (in any reasonable system of units) of about 10^10^123. This is a simply enormous number -- it represents the number of possible states of our universe.

Then, one can look at the current thermodynamic state of the universe, and estimate its current entropy based on the big sources like the black holes at the centers of galaxies, the cosmic background radiation, etc. and determine the volume of phase space that corresponds to our current state. One obtains an estimate of something like 10^10^101.

Now, this is interesting, because 10^10^101 is absolute chicken feed compared to 10^10^123. In fact, divide the latter by the former to find how "generic" our universe is, and one finds that to get a universe that looks anything at all like our universe, one must specify the state to one part in 10^10^123 (i.e. 10^10^123/10^10^101 = 10^10^123).

Now, this is rather incredible, because statistical mechanics is based on the notion that there is no "preferred" region of phase space -- they are all equally probable. This means that ordinary statistical mechanics predicts a universe like ours (that is, one in which all the matter is not down black holes, which would apparently be far more probable) with a probability of 1 in 10^10^123.

As everyone is probably aware (and someone is sure to bring up), there is a thing called the "anthropic argument" which says "the universe appears special because we require a special universe to be alive in order to observe it." Interestingly, this does absolutely nothing to diminish the above argument -- a universe dominated by black holes, except for a single galaxy to support life occupies a far, far, far, far greater region of phase space than our universe does, and thus is far, far more probable than the universe that we observe.

So anyway -- yes. There are some profound puzzles regarding entropy and the thermodynamic state of the universe. Our universe appears to be fantastically special (in the most genuine sense of the word), given our understanding of statistical mechanics.

There is an online lecture (by Roger Penrose) on this stuff here: http://www.princeton.edu/WebMedia/lectures/
Lecture 3 of his series deals with entropy and cosmology.