Posted: Jul 28, 2010 1:39 am
by Oldskeptic
AMR wrote:

I find that long-lived stars that could make life more likely will occur over a wide range of these parameters. For example, if we take the electron and proton masses to be equal to their values in our universe, an electromagnetic force strength having any value greater than its value in our universe will give a stellar lifetime of more than 680 million years. If we had an electron mass 100,000 times lower, the proton mass could be as much as 1,000 times lower to achieve the same minimum stellar lifetime. This is hardly fine-tuning. Many more constants are needed to fill in the details of our universe.

AMR wrote:
680 million years is hardly sufficient for singe-celled life to develop.

I have analyzed 100 universes in which the values of the four parameters were generated randomly from a range five orders of magnitude above to five orders of magnitude below their values in our universe, that is, over a total range of ten orders of magnitude (Stenger 1995, 2000). I have also examined the distribution of stellar lifetimes for these same 100 universes (Stenger 1995, 2000). While a few are low, most are probably high enough to allow time for stellar evolution and heavy element nucleosynthesis. Over half the universes have stars that live at least a billion years.

AMR wrote:
Curiously he doesn't name the parameters in this paper, if one of them is the ratio of gravity to electromagnetism ~1:1036 even five orders of magnitude may not be that significant and yet still he gets stars to shine just a billion years which would be insufficient for multi-cellular life to emerge, let alone a civilization.

One gross and fatal assumption is that only one kind of life, ours, is conceivable in every conceivable configuration of universes. However, a wide variation of constants of physics leads to universes that are long-lived enough for life to evolve, although human life need not exist in such universes. Although not required to negate the fine-tuning argument, which falls of its own weight, other universes besides our own are not ruled out by fundamental physics and cosmology. The theory of a multiverse composed of many universes with different laws and physical properties is actually more parsimonious, more consistent with Occam's razor, than a single universe.

AMR wrote:
I kid you not these were Stenger's best arguments from probably the most cited paper on the internet critical of fine tuning arguments -- and I agree with probably half of it. 1. No form of life could emerge out of hard vacuum which is what the universe would be within a margin of a few parts in 10120. 2. In 100 tries he could only get half his universes' stars to last a billion years which would be insufficient for the emergence and evolution of live and development of civilization.

This concerns the bold part above:

There is a problem with the cosmological constant, on one hand it is predicted to be very large, but on the other it is measured to be very small. And guess what this problem is called? It is called a “fine tuning problem”, but not for the reasons that you might think. Because in science dealing with hypotheses/theories there is a problem when any factor needs to be finely tuned to make the hypothesis/theory work. It is especially a problem when different hypotheses/theories need to fine tune their factor in different ways. As in the cosmological constant where quantum theory predicts its value to be high and cosmology concerning accelerating expansion of the universe measures it to be very low.

What this scientific fine tuning problem indicates is that the hypothesis/theory is either wrong or that there is something that someone hasn’t figured out yet. And since the standard model of quantum mechanics as a theory has the proven tract record of making astonishingly accurate predictions, and dark energy is an educated hypothesis I will go with QM for now.

Stenger has pointed out as have others that there are alternatives to the cosmological constant concerning expansion. There is not really an alternative to the standard model of QM.

So your constant repetition of the number 10^120 is not the magic bullet that you think it is. This number is smack dab in the middle of raging scientific debate and the verdict is not in.

Now for the rest:
You seem to think that the evolution of intelligent life depends on stars that live at least as long as ours has, and you are probably correct in one aspect given that the only intelligent life that we know of revolves around a sun like ours. But all life similar to ours no matter where it appears would be at least or more dependent on extremely large stars such as population III stars and super-giants that tend to go supernova, and spread heavy elements far and wide within 30,000,000 years of formation.

The thing is that all of the elements heavier than hydrogen and helium and lithium, and lighter than iron were created within extremely massive and short lived stars that went boom, and those elements heavier than iron were created in the concussion wave of the super-nova.

These massive early type III stars contained no elements as heavy as iron, in fact no heavy elements at all until they manufactured them. They are called metal-free stars, and because of the lack of heavy elements at the beginning they were very large and very hot, and went through their stellar evolution very quickly. Then they exploded and spread their components far and wide. Second generation stars formed from the debris, and the process continued with stars less large but still super-giants that formed more heavy elements and went boom with 30,000,000 years. These are the metal-poor stars; Type II.

The fact is that the more metal contained in a star the smaller it will be and temperatures will be lower. This leads to smaller stars like our sun lasting much longer, and never going super-nova.

680,000,00 years is a short lived star by comparison to stars like the one that we depend on, but it is longed lived for the types of stars that produce stars like ours and planets.

I would also like to point out that Stenger said “I have also examined the distribution of stellar lifetimes for these same 100 universes (Stenger 1995, 2000). While a few are low, most are probably high enough to allow time for stellar evolution and heavy element nucleosynthesis. Over half the universes have stars that live at least a billion years.”

A billion years seems to be his lower metric not a limit. And I am not clear on which type of stars he is talking about. If it is the early type III and later super-giants then a billion years is more than sufficient for any universe to form longer lived stars and with them planets where life could evolve.