On the Anthropic principle

dickbill · 2003-05-10 16:03:47

I post this because I have thought a long time about this issue and I want to share with you my interest for the topic. It certainly applies to Mars, as I will show you later.
Anthropic, by the way with A, refers to anthropos, related to man and does not refer to the Entropic principles of thermodynamic.
First, a definition of what it is:

The physical constants, which describe the physical laws, like the gravitational constant G, the Planck's constant h etc, are not derived from fundamental laws and therefore these constants cannot be predicted. They are what they are, we can mesure them, but we cannot predict them from our current models of cosmoslogy.
Now, here is the interesting thing pertaining to the anthropic principle: Because these constant could have different values, the physicists have tried to simulate virtual worlds with arbitrarily different values for them. This could not have been possible without the help of computers since the calculus are very complex, but, in short, and as you might expect, different values for the or physical constant gives rise to very different kind of universes.

There is a very interesting web site at "imagine the universe"
The question, from a professional physicist, describes pretty well what is the anthropic principle:

Could the laws of physics be different in another universe?
The answer was:
" There are a handful of constants that shape physics. The three main fundamental constants that we measure but at this point cannot be determined are:
c - this is the speed of light, it is important in electricity, magnetism and the conversion of matter to energy.
h - this is Planck's constant, it is important in atomic and nuclear physics
G - this is the universe gravitational constant, it holds planets in their orbits and determines the large scale structure of the universe.
We have no theory of why the values of c, h, and G are what they are. This begs the question of why they have the values they do, and what the universe might have looked like were they (and other constants like the mass of an electron) different. It turns out you can't change these values much without making life-as-we-know-it impossible. Such consideration has led to several variations of "Anthropic Principle."
... (they continue) ...
Since spacetime and matter-energy come to us together courtesy of the Big Bang and are in some fundamental sense inseparable, we can assume that G, h, and c could not be changed without re-engineering the birth of the
universe which, if you buy the theories that point to near-critical density of matter-energy in the universe, all indicate that space, time, matter, and energy as we know them are inseparable from the three fundamental constants that characterize them. Although we cannot, at this point, alter these constants, one might wonder about how our universe would be different if these values were changed. "

From Jeff Silvis and Mark Kowitt
For Ask a High-Energy Astronomer
Imagine the Universe!
NASA/GSFC
http://imagine.gsfc.nasa.gov/docs/ask_a … ology.html

I hope the link is still active. I guess you get the point now. In short, these constants are what what they are, because if they were different, we could not talk about it, because life, or in general complexity, could not have arised in the universe.

Any comments at this point ?

nirgal · 2003-05-10 16:44:46

I've heard about this before, fascinating topic. The strong anthropic principle argues that since a universe like ours (suitable for life) is extremely unlikely (because there is an indefinite number of alternatives) all these alternative universe actually exist...and of course we live in the one which allowed us to evolve in the first place.
However, I don't see how such a theory could ever be proven either right or wrong but it's fun to speculate.

dickbill · 2003-05-10 17:08:21

I've heard about another explanation, I would have to retrieve the site, I just remember that according to its author, an life-possible universe was actually not so unlikely or said otherwise, that a range of different values for the constants allowed life, or at least complexity, to arise in such an universe.
This makes the economy to invoke the multi-universe theory.

dickbill · 2003-05-11 09:00:28

Let me give some examples of anthropic considerations. Imagine a cosmos with a very low gravitational constant G, such as the gravitational attraction is much weaker than in our universe, then the stars, galaxy and other astronomic bodies would never form, instead, in such an universe with low G, the cosmos would consist of a huge cloud of hydrogen gaz electrostatically linked, rather than gravitationally linked. Then, complexity at the chemistry level would not be possible without the atoms formed by nucleosynthesis inside the stars core, since there is no stars in that universe.
In the reverse scenario, G too strong, the cosmos could be an homogenous mass of huge density, or maybe a black hole. Again, no complexity is possible.
We can also imagine a universe where the electrostatic force, influenced by C the speed of light, is so weak that no molecules can form, here again, no chemistry, no complexity, no life possible.

There are many other examples but the anthropic principle points out that the cosmolgical constants, h,c and G seem to have the values that allows complexity and life to arise in our universe. It could be on purpose or by pure chance, nobody knows yet. I don't think there is a clear explanation for that fact.

MarsGuy2012 · 2003-05-11 23:39:46

Since this seems to show that life and intelligence are rare in the universe or rather that this universe with life is a rare universe, it makes me think that it was not all by chance. Every new discovery confirms my belief that there is a creator.

dicktice · 2003-05-12 15:08:38

He/she/it would have to be a creator outside the universe, for "whom" lightspeed, for example, wouldn't be a hinderance to the creation process, relativity-wise. Imagine the impossibility of an indiginous creative intelligence whose neuron-equivalences were linked, say, by the electromagnetic spectrum....

dickbill · 2003-05-13 12:33:58

I generally believe that you cannot prove the existence of good by any single mathematical or physical argument like the anthropic principle "alone'. There are a couple of book using meta-physique or esoterico-quantum metaphysique to prove God's existence. This is more a philsophical concept than scientific but the anthropic coincidences are purely scientific facts, I hope that everybody is convinced about that. At best, it would prove the existence of multi universes, not God.

dickbill · 2003-05-17 19:37:34

Here is a new version, cleaner shorter, and easyer to follow, I hope. When I have time I will reformat the tables below.

I?d like to present a case of anthropic coincidence. it?s interesting in my opinion, because it could applies to Mars as well, as you will see.

Originally, I was interested to ?quantify? the likelihood for life to happen in a planetary body or satellite, provided that the other parameters, such as c, h and G, the ?big? cosmological constants are suitable for life to happen in the universe. So, in that universe, we already have stars, galaxies, atoms and molecules. And we have planets and stars like the sun. And around that sun there are a couple of planetary bodies. I wanted a parameter, like an ?indice of suitability? for life. Call it i.

So, what are the important parameters that make life possible at the surface of a planetary body ?

One of it is Liquid water, meaning the temperature at the surface of the planet has to be adequat. The atmospheric pressure is one variable that I already ignore at this point. These temperatures could be found on any body at the right distance from the star. So, in fact, what is important is the distance star-planetary body.

Not just the temperature, but also the composition of the planetary body is important. Obviously, the composition depends greatly of the kind of planetary body we are talking about. Gaseous planets like Jupiter or Saturn are planetary bodies full of light elements like hydrogen and methane. Telluric planets like venus, earth, mars, contain less of these light elements and more of heavy compounds like metals and carbon. Consequently, the mass of the planetary body, alone, is not a so good indicator of its composition. The size matters too. The mass plus the size of the planet are important because small planetesimals wouldn't have enough gravitational attraction to retain an atmosphere or just to retain themselves in a single piece. So, I would say the mass AND the size, (which then define the density of the body) are the good variables. But these variables also define the gravity at the surface of the planetary body. Thanks to Newton, the gravitational attraction, g , at the surface of this planet, is directly derived from its mass and radius, because of the Newton's law. The relation is g=Gm/r^2 , (the sign ^ means power) where G is the gravitational constant, m the planet mass and r its radius. As you know, It is g=9.8 m/s^2 for earth.

The dimensional analysis is used when problems are very complex. For the non specialists, in dimensional analysis, you ask what are the important parameters in the problem and you combine them to make dimensionless combination. Here, the dimension are just the units of the parameters, like m/s for a speed, kg for a mass etc. A dimensionless variable is just a number without unit.

The problem now is: if I, the ?indice of suitability of life?, is a function of the distance d and the gravitational attraction g, written I= f(d,g) , how to combine these variables to make a new dimensionless variable ?.

Empirically, there is a way to do it.
By using the third law of Kepler which said that T, the period of orbital revolution of the body around the star is linked to d, the distance between the star and the planetary body (or system).
The third law of Kepler says:
T^2= Kd^3
the squared of the duration of the orbital period T, is proportional to the third power of the distance d. K is just a factor of proportionality.
For earth, d=1 (1 AstronomicalUnit=150 million km) and so T=1 (1 unit of revolution/time= 1 year).
For Mars d=1.52 UA, so T= (1.52^3)^1/2= 1.87 year (real is 1.881UA).
So, for what matters, T is interchangeable with d in th i function.
So, I can replace d in I = f (d,g) by I = f (T,g)
This time, the dimensions of the variables are time in seconds for T and m/(s^2) for the acceleration g, or meter per second per second. So globally, there is two dimension left: time and distance.
We are almost there. T and g are completely independent variables, which is an important request in the Pi theorem but obviously they are not dimensionless.
But if you multiply T by g, you reduce the dimension of the product to a speed in m/s because seconds (s) multiplied by meters per seconds per seconds (m/s^2) become meters per seconds (m/s), which is the dimension of a speed.
Then, I think it is safe to divide the product T.g by an invariant speed to obtain a fully dimensionless combination. What invariant speed ? well, I would choose the most invariant of all speed? call this speed s, since s is a speed, s dimension is m/s.

Then T.g/s has the dimension of (s).(m/s^2)/(m/s) = (m/s)/(m/s) =1,
T.g/s is a pure dimensionless product.

So, the indice of suitability for life is I = T.g/s

Remark: T.g can be much superior to c, the speed of the light, because it's not a real physical speed, it' s a symbolist calculation.
Whatever is the value I for earth, this value will be considered as a marker for good physico-chemical conditions for life. I don?t deny there is a circular argument here.
To begin, lets calculate first T.g in meters per seconds, for a couple of planetoids.
It?s easy to calculate T.g in m/s, just multiply T with 31536000 seconds, the duration of one year in seconds. I took the values from an astronomy book from the eighties, it might not be up to date. Feel free to recalculate with more modern g and T values.

planetoid acceleration g in m/s^2 Sideral period t (year) g.T (m/s)

Mercury 3.6 0.24 2.72e7
Venus 8.5 0.615 1.65e8
Earth 9.82 1 3.09e8
Mars, yeah ! 3.76

dickbill · 2003-05-17 19:49:15

That was not finished... It is obvious that if "I" should be equal to 1 to be suitable for life, then there are different way to do it. A good way is to find Tg the closest possible to c or even equal to c, since I=Tg/c then obviously I=c/c=1.

This mean that we can have small (small g value) planetary body very far (high T value) , or big planetary (big g vale) bodies very close (small T value) to the star, to have a product Tg equal to c.
Indeed the Tg values for the satellites of distant planets are much closer to c than for their mother planets in the previous post. The best in the list below would be Rhea, with Tg=2.43e8 m/s. it gives i=0.81, better than Mars !
But that doesn’t make sense (a priori) because Rhea is a small piece of rock of 764 km of radius, orbiting Saturn. How life's conditions could be more suitable on Rhea than on Mars ?. But who knows, maybe it is, however that suggest to me that the I parameter, the indice of suitability for life, needs more parameters than d (distance star/planet) ,m (masse of the planet) and r (radius of this planet) to be accurate.

Also, note that I use the distance and period of revolution of these satellites relative to the sun. It's not their revolution period around their mother planet which matter for their insolation, but the distance to the sun which provides the heat and light, not the planet. So it doesn't matter that Titan is satellite of Saturn, regarding the solar energy received, I use Saturn's distance to the SUN for Titan. I feel there is a problem here as some energy is received from Saturn.

Europa    1.31    11.86    4.89e8
Io 1.79 11.86 6.72e8
Callisto    1.24    11.86 4.66e8
Ganymede 1.42    11.86 5.33e8

Titan    1.34    29.46 1.24e9
Dione    0.23    29.46 2.15e8
Rhea    0.26    29.46 2.43e8
Iapetus    0.205    29.46 1.9e8
Thetys    0.15    29.46 1.38e8

Titania    0.37 84.05 9.8e8

Nereide    0.046    164.78    2.38e8
Triton 0.78 164.78 4.02e9

But where is the anthropic principle here?

Here is my theory, from the anthropic principle's point of view, It' s not I=f(T,g), I= Tg/c = 1 or Tg=c the indicator of earth-like conditions, but the reverse: c=gT
Meaning that c, the cosmological constant for the celerity of light, which was set up at the very beginning of the universe, 13 billions years ago, was in fact, set up to copy a value I, fonction of the life, which will only exist 10 billion years later !
It’s like an arrow pointing a target 10 billions years in the future !

dickbill · 2003-05-23 17:12:20

after all these anthropic divagations, lets back to reality, back to Mars !

http://www.renderosity.com/viewed.....ist=Yes

(yeah, it's too red, I know...)

nirgal · 2003-08-09 20:19:12

Great pic!

space_psibrain · 2003-08-15 19:12:08

but what is truly reality?

Have you ever had a dream so real that you couldn't tell it from when you were awake?

*sorry, couldn't resist

Shaun Barrett · 2003-08-18 07:11:28

Dickbill, you certainly have put a lot of thought into this hypothesis of yours!

And your conclusions seem to be saying that the universe was planned, billions of years in advance. Does this mean that you support the notion of a supreme being doing the planning?
I don't ask this question with any ulterior motives. I'm not a rabid atheist waiting to shoot you down if you tell us you're inclined to believe in God! Nor am I some fundamentalist religious nut ready to consign you to hellfire if you deny there's a God
As I've said elsewhere, I happen to believe there's more to this universe than nuts and bolts. I believe there has to be some reason for all this incredible beauty and intricacy, and for the rise of consciousness.
It seems that maybe you feel the same way, though you arrive at this conclusion from a different direction.

In any case, I'm impressed with the originality of your thoughts.

dickbill · 2003-08-18 08:59:19

And your conclusions seem to be saying that the universe was planned, billions of years in advance. Does this mean that you support the notion of a supreme being doing the planning?

Thank you Shaun for the compliments and your interest, yes, I have thought about that for a long time, its disturbing.
To answer your question, no I don't think that the "anthropic coincidences" PROVES that the Universe was "planned" at the very beginning, by God that is. MAybe the universe was planned by God, but I don't think one can prove God this way or by other mathematical reasonment.
What I suggest to explain this particular coincidence is that the value of c, speed of the light, might have been set up at the beginning of the universe to "fit" to another value (that I have called i, i= g.T/c, indice of suitability of life ). The problem with "i", is that this value makes sense and has reason to exist, only billions of years after the big bang, since "i" integrates values relevant for planets, which are not present at the big bang. That way, at least, it eliminates the need to explain the awfull unlikelly coincidence that i=1 (or close to 1) for a planet harboring life. Now, how did "c" knew in advance the value of 'i', I have no idea. I think that there is simply a physical/mathematical relation between i and c, that is still unknown at the present day.
But ultimately, this is just "another anthropic coincidence", that could be treated like any other anthropic coincidence : multi universes etc.

Note that "i" integrates the values for the mass, size, and distance to the sun (or their derivatives g and T), parameters, plus actually the speed of the life to make the value i dimensionless. But that's it, and it is obviously not sufficient because of the weird values obtained for small satellites of giant planets. So I wonder what other parameter should be included in "i". I would think that the presence of a satellite like earth/moon doublet is very important, then the task would be to find a representative physical value for that and recalculate i to make it dimensioneless again. I hope to post about that later.

alokmohan · 2003-09-16 04:26:00

It is too early to thnk of life in other unierses when we donot know our nextdoor neighbours MARTIANS.

dickbill · 2003-10-28 14:35:16

A recent article about the debate on the anthropic principle:

http://www.nytimes.com/2003....2&8hpib

Looking for God in the equations might be futile, but looking for natural explanation is the goal of science. Unexplained anthropic coincidences should not be ignored by scientists.

The best natural explanation to date: multi universes with all possible different physical laws.

dickbill · 2004-03-15 14:21:31

A link that explain in mathematical terms what is the "dimensional analysis", in this case applied to fluid mechanic.

[http://www.efm.leeds.ac.uk/CIVE/CIVE140 … alysis.htm]http://www.efm.leeds.ac.uk/CIVE....sis.htm

That was in a book of fluid mechanic that I discover that"non dimensional analysis" but it can be applied to other domains.

In the case of an indice of "suitability of life" (see former posts in this thread) I wonder what this indice represents in reality, a probability (or a function of it) ?, or an "amount of life" (the more suitable, the more life there is) ?
What could be an amount of life, does it mean that life is a mesurable quantity ?

So far, the official scientific position is "there is no life" there is only chemistry. Life is a chemical reaction that started 3.8 byears ago on earth (initial state), with many intermediate states more or less stable, and the fun is that we don't know what is the final state. The reaction is not over as long as evolution, contingencies and selection proceed.

lunarmark · 2004-03-16 05:38:30

Our notion of 'time' was created with the big bang and is only an effect we sense (like 'heat' or pain for example) time doesnt exist as a physical object (as far as we know) there is no 'time particle' There is no 'before the bigbang' - wether the universe we see is 'all there is' is a good question - but it is all simply 'the universe' but some of it is forever beyond our reach since we cant go faster than light. :bars2:

dickbill · 2004-03-16 08:03:38

Our notion of 'time' was created with the big bang and is only an effect we sense (like 'heat' or pain for example) time doesnt exist as a physical object (as far as we know)

I think Time is a physical object. Time is the most important variable in thermodynamic. You probably know the "arrow of time" of Stephen Hawking : time might not be the real physical variable, entropy, might be the real variable.

The arrow of time points in the direction of the increasing entropy.

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