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The Anthropic Principle Under Fire


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#86 modest

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Posted 13 February 2010 - 08:47 PM

My debate with modest was about this sentence:
"...Besides that, we also suppose that any alteration in one of the fundamental constants would make the possibility of life impracticable,
although no one has shown it yet. ..."


I said depend on *how much* this changing is made. If the changing is very tinny I thing it is no problem.


When the universe was 1 nanosecond old the density was:

447,225,917,218,507,401,284,016.0 gm/cc

had the universe been:

447,225,917,218,507,401,284,016.2 gm/cc

or greater, it would already have collapsed back into a singularity. Quoting Ned WRight's cosmology tutorial,

Thus the density 1 ns after the Big Bang was set to an accuracy of better than 1 part in 2235 sextillion.

Cosmology Tutorial - Part 3

I believe there is a reason these parameters appear so finely tuned. I think it will eventually be explained, perhaps with a theory of everything that has no such free parameters. But, we don't know yet. These are open questions in cosmology. And you are not solving them by supposing that changing the fundamental constants might still create a universe hospitable to intelligent life. That is just ignoring the problem.

~modest

#87 jocaxx

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Posted 15 February 2010 - 08:37 AM

When the universe was 1 nanosecond old the density was:

447,225,917,218,507,401,284,016.0 gm/cc

had the universe been:

447,225,917,218,507,401,284,016.2 gm/cc

or greater, it would already have collapsed back into a singularity. Quoting Ned WRight's cosmology tutorial,



I do not think so.
what about the dark energy?
what about dark matter?

This things is still unknown then I think this calculus are missing this two importants elements .



447,225,917,218,507,401,284,016.2 gm/cc

or greater, it would already have collapsed back into a singularity. Quoting Ned WRight's cosmology tutorial,


If the universe had 447,225,917,218,507,401,284,016.2 gm/cc
*also* the same thing could be said If the universe had 447,225,917,218,507,401,284,016.0 gm/cc
we do *not* had a singularity.

Besides it we still could have infinite possibility between 0 and 0.2.
For you it is "tinny" the difference between this density, because it is a human value
because I can say if the diference was not 0,2 but 0,000000000000000000000000000000000000000000000002
it s a *realy* tinny diferencem and 0,2 is to large. only human value.

#88 modest

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Posted 15 February 2010 - 01:08 PM

I do not think so.


You provide no reason do doubt the source I quoted.

what about the dark energy?
what about dark matter?


Dark energy is included in the Friedmann equation as the cosmological constant: the [math]\Omega_{\Lambda}[/math] term. Dark matter is included in the [math]\Omega_M[/math] term. In the context of a Friedmann–Lemaître universe they do nothing to solve the flatness/oldness problem I outlined in my last post.

This things is still unknown


The effect of both are known.

then I think this calculus are missing this two importants elements .


Calculus is a branch of mathematics dealing with limits, derivatives and integrals.

Neither dark energy nor dark matter are missing from relativistic physics or missing from the standard Lamda-CDM cosmological model. Purple unicorns are missing from cosmological models, but if you think they would solve the flatness/oldness problem then you must demonstrate how they do that.

If the universe had 447,225,917,218,507,401,284,016.2 gm/cc
*also* the same thing could be said If the universe had 447,225,917,218,507,401,284,016.0 gm/cc
we do *not* had a singularity.

Besides it we still could have infinite possibility between 0 and 0.2.
For you it is "tinny" the difference between this density, because it is a human value
because I can say if the diference was not 0,2 but 0,000000000000000000000000000000000000000000000002
it s a *realy* tinny diferencem and 0,2 is to large. only human value.


You have already had the logic of that argument corrected. Here is the problem as it is typically described:

In the early universe [math]\Omega[/math] is the ratio of the energy density to the critical density at that time. In the Lambda-CDM cosmology favoured by astronomers, the early universe is dominated by radiation, then by matter. In this case, if [math]\Omega[/math] is much greater than 1, the universe quickly recollapses in a Big crunch. If [math]\Omega[/math] is much less than one, the universe expands so quickly that matter cannot collapse under gravity to form galaxies or stars. If the current value of [math]\Omega[/math] is extrapolated back to the Planck time the value of [math]\Omega[/math] is such that [math]\Omega = 1 \pm 10^{-60}[/math]. That this value is so close to the critical value when it could take on any value at all is regarded as a highly improbable coincidence.

Encyclopaedic Dictionary of Astrophysics (S. K. Basu) 2007 p.103

And from wikipedia:

This tiny value is the crux of the flatness problem. If the initial density of the universe could take any value, it would seem extremely surprising to find it so 'finely tuned' to the critical value [math]\rho_c[/math]. Indeed, a very small departure of Ω from 1 in the early universe would have been magnified during billions of years of expansion to create a current density very far from critical. In the case of an overdensity ([math]\rho > \rho_c[/math]) this would lead to a universe so dense it would cease expanding and collapse into a Big Crunch (an opposite to the Big Bang in which all matter and energy falls back into an incredibly dense state) in a few years or less; in the case of an underdensity ([math]\rho < \rho_c[/math]) it would expand so quickly and become so sparse it would soon seem essentially empty, and gravity would not be strong enough by comparison to cause matter to collapse and form galaxies. In either case the universe would contain no complex structures such as galaxies, stars, planets and people.

Flatness problem - Wikipedia, the free encyclopedia

It is partly because of this problem that cosmologists propose, and many advocate, inflationary models of cosmology as a real solution to the very real problem described above. I personally wonder if freely coasting cosmology which does not have the problem above might have some validity to it.

You, on the other hand, say that [math]1 \pm 10^{-60}[/math] is an infinite set of real numbers implying that a randomly generated number between, let's say, 0 and 10 is likely to fall within [math]1 \pm 10^{-60}[/math]. That is not good reasoning.

It is highly improbable that a randomly generated density... it is, in fact, 10^61 times more likely that some other density between 0 and 10 outside the acceptable range would be randomly generated. That's about how many atoms there are in the visible universe. If every atom in the visible universe represented a different range of density at the Plank time between [math]\Omega = 0[/math] and [math]\Omega = 10[/math] then there would be one correct atom with an acceptable Omega representing [math]1 \pm 10^{-60}[/math]. It is highly unlikely that such an atom would be picked randomly... randomly picking one atom out of the billions of galaxies in the visible universe... the correct one... unlikely.

There are possible solutions to the flatness problem, but ignoring the problem doesn't solve it. Saying "if the changing [fundamental constant] is very tinny I think it is no problem." doesn't mean there is no problem. Saying that [math]1 \pm 10^{-60}[/math] is only a human value and may not be "tiny" doesn't solve the problem.

~modest

#89 jocaxx

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Posted 15 February 2010 - 03:13 PM

You provide no reason do doubt the source I quoted.


because (from wiki):
"The Friedmann equations are a set of equations in cosmology that govern the expansion of space in homogeneous and
isotropic models of the universe within the context of general relativity.
They were first derived by Alexander Friedmann in 1922[1] from Einstein's field equations of gravitation...
Notice, however, that the mainstream of Cosmological research endorses a homogeneous and isotropic Universe on scales larger than ~100 Mpc."


And when we talk about of the beginning of the big-bang we have to consider quantum effects and
the general relativity and quantum mechanics are incompatible.

Therefore is reckless and dangerous use only equations that are conceived to large space ( homogeneous and isotropic)
and use it in miscroscopic scale where quantum mechanics is more apropriate.

This is almost how to use gravitation equation to calculate the interaction between subparticle inside the atom: it has no effecr at all
the gravitation has no effect inside atomic nucleo.


So I think this equations is not apliacable to origin of the universe because it was very less than 100Mpc where it could be aplicable.





The effect of both are known.


Not in micro scale as I know.



There are possible solutions to the flatness problem, but ignoring the problem doesn't solve it. Saying "if the changing [fundamental constant] is very tinny I think it is no problem." doesn't mean there is no problem. Saying that 1 pm 10^{-60} is only a human value and may not be "tiny" doesn't solve the problem.


You are varying only the density and stay others parameters equal.
But in our case the others parameters also can change. Then the omega can be very diferent and we could still have planets and stars.

I think BobSpece1 is right when he said:
"We don't have remotely enough information about the possible range of values those fundamental constants referred to in the 'Anthropic' argument have, or what possible combinations of values would allow something we might recognise as 'life' to emerge. It is extremely unlikely that the laws of physics we have currently deduced precisely describe even our Universe, let alone all possible universes with similar laws but different constants - even small departures or omissions could lead to vastly different consequences.

Some have attempted to estimate the total size of plausible 'islands of life possibility' within the multi-dimensional mathematical space defined by the fundamental 'constants', and it suggests that the possibilities are much greater than if we restrict ourselves to just varying one figure at a time. It would be like exploring only the edges of a cube in the case of three constants, rather than the whole volume, which is literally infinitely larger.

So the Anthropic Principle is not a goo"


When you speek about omega (density) there are still a lot of another constant to exploere, density is only one of arest of this multidimensional cube.

#90 modest

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Posted 15 February 2010 - 07:51 PM

Notice, however, that the mainstream of Cosmological research endorses a homogeneous and isotropic Universe on scales larger than ~100 Mpc."[/i]

...So I think this equations is not apliacable to origin of the universe because it was very less than 100Mpc where it could be aplicable.

Either wiki's quote has confused you, or your point is confused. The current universe is approximated well as homogeneous at scales [math]\geq[/math] ~100 Mpc and the visible universe is hundreds of times that size and therefore approximated well by a FRW universe. The further back in time you look the more homogeneous the universe was making the universe more accurately modeled with FRW cosmology when it was smaller and younger.

The quote is talking about the local inhomogeneities in the universe today, making FRW a bad approximation of, for example, a 100-million lightyear (30 Mpc) spherical portion of today's universe. When the whole visible universe was 100-million lightyears in diameter more than 13 billion years ago—shortly after the surface of last scattering when CMB radiation was released—a sphere of that size was extraordinarily homogeneous making the universe at that size and age better approximated by FRW than is the visible universe today.

Since your constant objections to my straightforward point has pulled us away from that point I'll again post the comment that I took issue with:

Besides that, we also suppose that any alteration in one of the fundamental constants would make the possibility of life impracticable, although no one has shown it yet.

I've now shown two examples where an "alteration in one of the fundamental constants would make the possibility of life impracticable". I'm satisfied that I've defended my refutation so I'm going to bow out of the thread now.

~modest

#91 alexander

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Posted 15 February 2010 - 10:34 PM

See this words "to fit".
This the essency of the Anthropic Principle that criationits love.
Generate UC *to fit* according some characteristics like life *require* some intelligence for the generator of the UC.
Dou you agree??
Its my point with Pyro.
"We" have to consider some intelligent generator to choice these UC in order to life is possible.
because this I am against this model.
There is no necessity of god or inteligent generator of UC because our universe is not speciall at all!
Only for us it is special not for the universo or anything else.

I don't just see the words, i recall writing them, but you took them the wrong way. And no, i don't believe in genies with magic wands...

There is no necessity of an intelligent being to have universes, fall/fit within a certain curve, even with equiprobable (random) UC generation, they will do it by themselves. The probability curve for getting an actual working universe from a set of UCs (completely random UCs) is most likely a bell shape, which is what Pyro was trying to say, i think. And there you have order in chaos...

You also have clearly not gotten my point on simulation, but you must get back on topic...

#92 jocaxx

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Posted 16 February 2010 - 03:12 PM

The further back in time you look the more homogeneous the universe was making the universe more
accurately modeled with FRW cosmology when it was smaller and younger.


Then you are seeing that the Friedman equation is not exact in all the cases.
it depends on of the homogeneity and isotropy.
And the universe is not homogene neither isotropic even in the beggining:
there is symetry broken and there are not anti-mater and matter equally.
Besides it, relativity is not a good theory to study the beginning of the big-bang where there are important quantumn effects.

Therefore I dont agree that the friedman equations could be used to scan the big-bang.

Perhaps the more adequate theory for this is the Quantum Gravity ( Wiki :
"Quantum gravity (QG) is the field of theoretical physics attempting to unify quantum mechanics with general relativity in a self-consistent manner, or more precisely, to formulate a self-consistent theory which reduces to ordinary quantum mechanics in the limit of weak gravity (potentials much less than c2) and which reduces to Einsteinian general relativity in the limit of large actions (action much larger than reduced Planck's constant). "
)


There is no necessity of an intelligent being to have universes, fall/fit within a certain curve, even with equiprobable (random) UC generation, they will do it by themselves. The probability curve for getting an actual working universe from a set of UCs (completely random UCs) is most likely a bell shape, which is what Pyro was trying to say, i think. And there you have order in chaos...


If I understand what you say, you wrote jut the opposite that modest wrote.

He says the probability to get life is very too tinny and you are saying the opposite: a lot of constants would lead to life.

and I ..... think the opposite you two !! rsrsr :lol:

#93 alexander

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Posted 16 February 2010 - 05:03 PM

I recall saying that it doesn't matter whether or not a universe has intelligent life.

Some constants will not yield a universe of any interest at all though, on one end of the extreme cases the universe will collapse onto itself within nanoseconds of creation, other times within days or years; on the flip side some universes will expand so rapidly that the atoms will be so wide spread that they will never form anything, thus at both ends of the spectrum we have cases in which universes will exist as singularities, or will be so vast that nothing in them, other then the initial particles that will eventually radiate out. So hence the bell curve of universes based on universe constants that will actually be interesting as a universe, because universe made of a singularity or a universe that has nothing in it is not something interesting to look at.

As far as what you are saying about modest, our views are on different points...

#94 modest

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Posted 17 February 2010 - 04:28 PM

As far as what you are saying about modest, our views are on different points...


Uh-huh.

I easily agree with you and Pyro. If you sum six random variables the result is a normal distribution—a bell curve. In Jocaxx's first post he assumes equal probability follows from his assumptions where it clearly does not. But, I don't think Jocaxx is amenable to having his logic corrected. :shrug:

~modest

#95 alexander

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Posted 17 February 2010 - 09:03 PM

yeah, i am agreeing with you and pyro, if you apply/relate the 6 variables, the probablity curve of getting a universe with respect to a ratio/relation of the variables fits a normal distribution curve. I dont know how jocaxx thinks we are arguing on different sides with you... you and Pyro are absolutely logically correct... I know i said i was not trying to take sides, but, well, here i am...

#96 jocaxx

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Posted 19 February 2010 - 11:44 AM

I do not know if I understand very well what you are saying ,
but I undertand the following:

Modest believe that any different change in the constants UC would lead the universe to a singularity our something that leave the universe to something life is impossible;


Alexander believe the opposite: A lot of universe will have chacateristics that could have life.
Because this he says if "we" plot "Life chacteristics" vs "Uc constants" we will have a bell curve where our universe is in the central point.

I believe that each different set of UC constant random generated will produce a different universe. And so, if the UCs aredifferente then the universes are different too and therefore we could conclude that if the UCs are linear distributed their respective universe are equiprobable since the Ucs are equiprobable too.

#97 alexander

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Posted 19 February 2010 - 01:14 PM

you are mistaking what i am saying...

if you plot uc, which determine a universe actually existing and interacting in any way (i.e. not a singularity, or so large that particles don't really even interact and die out) with respect to time. You would get a normal distribution curve

if you plot uc with respect to the probability of the universe containing anything (again so it is not a singularity or a universe in which particles never formed, or a universe in which particles died out too quickly or a universe that is so vast that they will never interact). You will get a normal distribution.
Also note that in this last scenario, universes made of hydrogen would mostly fit somewhere within the curve, and a lot fewer cases would fit within the extremes of the bell curve, i am guessing that the probability for not getting a working universe is lower then that of a probability of getting a universe of a decent size that would contain some sort of objects, systems, clusters, whatever, but some, undoubtedly would. I don't think you are as likely to get a universe which will not work at all as you are to get some weird universe... but, contrary to what you are saying, i think that not all uc will produce a universe...

#98 jocaxx

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Posted 19 February 2010 - 01:33 PM

There are a *lot* of kind of universe inside the hyper-cube where each arest is one of the UCs constants.

If someone see a little region inside this hyper-cube around of our universe , this may seem very "unproductive" but is very difficult to know what kind of the universe could be produced when the UCs were really different of our UC constants;

Anyway,
I think "good"/"interesting" universe depends on the "taste" of the observer. To someone the hydrogen universe is pretty better than the our because in there , there is no pain !
And for the universe does not matter what kind of the characteristics of the universe the UCs will produce. For the universe that has no mind it does not matter at all. All universes are "good" as any other.

And if each set of different UC produce a differente universe and this UC-set was randomly distributed then the universe generated are equiprobable.