Well, I hope I don't make this too long, but sometimes I just get carried away. one of the "against the mainstream" topics hanging around some of the discussions is "young earth creationism", the idea that the earth is a mere 10,000 or so years old. It is a preposterous notion, and the attempts to make it look "scientific" are, for the most part, no less preposterous. I will leave off from discussing geology & the age of the earth specifically, as outside the scope of this board. However, young earth creationists don't just think that the earth is a mere 10,000 or so years old, but that the entire universe is equally young. That does bring in astrophysics, and that's where I want to go.

I will try to present a brief outline of the astrophysical & cosmological determinations of the ages of objects in the universe. It's necessarily short, just to keep from overwhelming the board, but will hopefully carry enough references to satisfy those interested in extracurricular reading.

Stellar Evolution

The basis for deriving the ages of the sun & stars, is the theory of stellar evolution. Unlike biological evolution, where individuals don't "evolve" but populations do, stellar evolution actually refers to the life cycle of individual stars.

I don't propose to write an exhaustive survey of stellar evolution here and now, there are a few million pages of material available on this very broad topic. Suffice to say that stellar evolution amounts to the extraordinarily complicated application of extraordinarily simple physics to the problem of how the structure & appearance of a star will change with time.

Very basically, all main sequence stars are stabilized by the process of fusing hydrogen into helium, and the rate at which they do this depends on the central temperature of the star. The hotter the temperature, the faster hydrogen "burns" into helium. The core temperature is dependent on the mass, so more massive stars get hotter inside, use up their fuel more quickly, and live shorter lifetimes.

By throwing all the ingredients into a computerized recipe, we can calculate what the surface of a star would look like, depending on it's internal structure. We can allow the model to progress through time, and compare the changing surface appearance as a function of time with visible stars (of which there are a lot), and hence derive the age of a star given enough knowledge (color, brightness, mass, spectrum, etc.). It's even easier to compute the age of a cluster, via its color-magnitude diagram (CMD, also known as the Hertzsprung Russell diagram).

That's all I'll say about that for now, if you want to know more, hit the books. For general readers, the books by James Kaler are the best, and surprisingly informative (Stars, Extreme Stars, and Stars and their Spectra are my favorites). For big, tough, physics dudes (and dudettes), who want only the real stuff, there are plenty of books for you too. My recommendations would be Stellar Interiors - Physical Principles, Structure and Evolution, C.J. Hansen & S.W. Kawaler, Springer (A&A Library) 1994, and Advanced Stellar Astrophysics, W.K. Rose, Cambridge University Press, 1998. And don't forget the timeless classics, the books that define the science of stellar evolution; The Internal Constitution of the Stars, Sir A.S. Eddington, 1926; An Introduction to the Study of Stellar Structure, S. Chandrasekhar, University of Chicago Press, 1939, and Structure and Evolution of the Stars, Martin Schwarzschild, Princeton University Press, 1958. Maybe I go overboard with the books, but creationists forever like to complain about how "unscientific" is everything they don't believe. So tell them to go read a book.

Age of the Sun

The one star we can see up close & personal is the sun. We know more about it than any other star. And, thanks to the relatively recent science of helioseismology (which I won't get into either), we know a lot about it's internal structure. From that we can determine the age of the sun with greater precision than any other star, by application of stellar evolution theory to our observations of the sun's appearance and internal structure. The current best estimate of the age of the sun is 4.66±0.11 billion years (Helioseismology and the solar age, W.A. Dziembowski et al., Astronomy and Astrophysics 343(3): 990-996, March 1999; Are standard solar models reliable?, J.N. Bahcall et al., Physical Review Letters 78(2): 171-174, January 13 1997)

Age of the Galactic Disk

The sun is but one of the many stars that make up the disk region of the Milky Way. Since the sun is obviously made up of material already cycled through at least on previous generation of stars, we expect that the oldest disk stars should be rather older than our own sun. We can place limits on the age of the Galactic disk by deriving the ages of well observed individual stars, from the CMD for open clusters in the disk, or by using models of how long white dwarf stars take to sit there and cool off.

Studies of the Galactic disk conform with expectations. Liu & Chaboyer find the oldest field stars in the Galactic disk to be 9.7±0.6 billion years old. The oldest white dwarfs in the Galactic disk are of comparable age, 8±1.5 billion years according to Leggett et al., and a compatible 9.5 billion years, according to Oswalt et al. (A lower limit of 9.5 Gyr on the age of the Galactic disk from the oldest white dwarf stars, T.D. Oswalt et al., Nature 382(6593): 692-694, August 22, 1996; The cool white dwarf luminosity function and the age of the galactic disk, S.K. Leggett SK, M.T. Ruiz & P. Bergeron, Astrophysical Journal 497(1): 294-302, Part 1, April 10 1998; The relative age of the thin and thick galactic disks, W.M. Liu & B. Chaboyer, Astrophysical Journal 544(2): 818-829, Part 1, December 1 2000).

Globular Cluster Ages

Globular clusters should harbor the oldest stars in the Galaxy. Observation bears this out. Studies of globular cluster ages via their CMD consistently turn out ages in excess of 10 billion years. The recent success of applying the white dwarf cooling models to globular clusters (difficult because the clusters are very distant and the white dwarfs very dim) returns similar values.

A few familar examples follow. The best derived age for the globular cluster 47 Tucanae is 13±2.5 billion years (The white dwarf distance to the globular cluster 47 Tucanae and its age, M. Zoccali et al., Astrophysical Journal 553(2): 733-743, Part 1, June 8 2001). A best fit age for M92 is 14.5 Billion Years (A distance-independent age for the globular cluster M92, F. Grundahl et al., Astronomical Journal 120(4): 1884-1891, October 2000). And Omega Centauri can be no younger than 10.06 billion years (Theoretical uncertainties in the subgiant mass-age relation and the absolute age of omega Centauri, B. Chaboyer & L.M. Krauss, Astrophysical Journal 567(1): L45-L48, Part 2, March 1 2002; Cluster ages experiment: The age and distance of the globular cluster omega Centauri determined from observations of the eclipsing binary OGLEGC 17, I.B. Thompson et al., Astronomical Journal 121(6): 3089-3099, June 2001).

And it's not just a few (although a few will do). D.H. McNamara observed 16 globular clusters, with an average age of 11.3 billion years (The ages of globular clusters, D.H. McNamara, publications of the Astronomical Society of the Pacific 13(781): 335-343, March 2001).

And it's not just Milky Way globulars. We can make CMD's for globulars around other galaxies. Beasley et al. observed 131 globular clusters around the giant elliptical NGC 4472, and derived ages for two populations of globulars, metal poor (14.5±4 billion years), and metal rich (13.8±6 billion years) (Ages and metallicities of globular clusters in NGC 4472, M.A. Beasley et al., Monthly Notices of the Royal Astronomical Society 318(4): 1249-1263, November 11 2000).

End notes

There. I could have cited far more papers than that, the literature is awash with age determinations. All based on phyics applied to stars. I won't bother with cosmology, except to say that totally independent ages for the universe, derived from the acoustic spectrum of the CMB, run in the range of 13-15 billion years. That's compatible with the more precise globular cluster ages, even though totally independent in derivation.

So why have I carried on so? I just want to make the point that "young earth" or "young universe" creationism is strongly counterindicated by some very strong physics. It's not enough to demand that biology be tossed out the window, along with geology and the physics of radiometric dating. It also requires that astrophysics & astronomy are totally false.

That goes way beyond "against the main stream" to something more akin to "against all knowledge".

I figure, if anyone wants to hang around and debate the age of the universe, they should be obliged to explain why astrophysical ages are all wrong.

Good Night.

What you're missing is that the YEC don't even believe in physics, so using physics to prove the extreme age of the universe is pointless.

Nice post, though. [img]/phpBB/images/smiles/icon_smile.gif[/img]

Of course, a YEC might explain all this away by saying that God created the universe with the appearance of age. This is technically possible for God to do, but it likely takes us out of the arena of Science and into theology: Would God do such a thing?

I keep trying to tell everyone, from personal experience, that the only way to convince a YEC that their belief in a young Earth / universe is wrong is to speak their language! Explain to them how the literal six "twenty-four hour" time slots in Gen. 1 (for that is what they cling to) is a complete misinterpretation - make them question the interpretation of what is written without threatening or challenging their belief in a creator. Then they will be open and willing to listen to what you have to say. Try it! (And if it doesn't seem to be working, refer them to me, and I'll straighten them out for you. [img]/phpBB/images/smiles/icon_wink.gif[/img] )

__________________
"As I lay beneath the Southern Cross, the stars tell more than I could" . . . David Meece

The problem is that many YECs refuse to admit any non-literal interpretations of the Bible (except when waving away certain inconsistencies). They seem to fear a "slippery slope" wherein if you say, "this part of Genesis is metaphorical", soon you're flatly denying everything else in it.

Personally, I think that's a rather brittle version of faith. You then have to twist every empirical finding to fit this literalist framework, and you wind up pledging to fit the truth to your belief. For example, if you join the ICR (Institute for Creation Research), you have to sign a statement that the Bible is literally inerrant, and then you have to make all of your "research" fit that.

Reminds me of how the Soviets hammered plant genetics into fitting the good Marxist mold. That little adventure only cost them several million deaths from starvation.

I worked with an engineer who subscribed to the "Omphalos" (appearance of age) idea, i.e., that everything was created X thousand years ago with the precise initial conditions to match the appearance of the ~15Gy old universe. He was a smart guy, and he didn't say it was scientific. I don't really have a problem with that, as long as it's not pushed in a science class.


<font size=-1>[ This Message was edited by: sts60 on 2002-06-27 08:25 ]</font>

Not only that, but they also refuse to admit other literal interpretations for the numerous Biblical creation accounts! (old-earth being one of many)

Well, I learned. (Hurray for me!) It helps to realize the account is a poem - and scientific thinking and describing of events didn't exist until the late Middle Ages / early Rennaissance era, so it doesn't make a whole lot of sense to interpret it that way. Of course, then again, it did take me about a full semester to come around. [img]/phpBB/images/smiles/icon_rolleyes.gif[/img] Hoo, boy.

__________________
"As I lay beneath the Southern Cross, the stars tell more than I could" . . . David Meece

Here is how I resolve this:

How do I know that everything was not created 1 second ago? Maybe all my memories of my life were created on that same second. Maybe all the light and sound reaching me was created in transit in that same second.

If that is true, than who can blame me for being fooled into believing that I really did live all those years?

So if God created a universe 10,000 years ago that appears to be billions of years old, then can he blame me for believing it to be billions of years old?

So, I'll believe what I see and if it is illusion, so be it.
--Tommy
http://www.tommyraz.com

Good luck my friend.

My less lofty goal is just to keep other people from being drawn in to the supposed 'logic'.

Well, just so this thread doesn't remain as merely a bunch of non-Creationists talking to each other and patting themselves on the back, I'll jump in. I generally ignore this type of thread, because I know it's really a waste of my time since no-one who is already committed to a non-Biblical stance on the universe is likely to listen to a Biblical stance, but this thread is so boringly monotonous as yet that it needs a bit of the opposing viewpoint to pep it up.

First, Tim, thanx for classifying stellar evolution as a theory. So many people forget that little detail, or the actual definition of the word theory. Anyway, as support for your theory, you'll be happy to give two or three examples of stars that have evolved exactly according to that theory, with documentation, won't you? Thought not.

Stellar evolution looks at all the different types of stars that we see, and hypothesises that there must be some overarching explanation for why this one is a red giant and that one is a yellow near-dwarf. The theory 'explains' that there is a progression from one to the other, with all the other variations either along the way or as minor offshoots from the 'main sequence'. Yet we have exactly zero evidence that any star has ever changed states along this so-called sequence. The red giant stars that we see today have always been red giant stars for as far back as we have observational accounts; likewise, the sun is exactly the same today as the earliest descriptions of it we have. It's never gotten larger nor smaller, brighter nor dimmer, redder nor greener. Ditto for all the other varieties.

Yes, we have stars that do change: we call them novas and supernovas. But these changes are all we see, we do not have any evidence that any star has ever followed the 'main sequence' or any standardly-accepted offshoot thereof. The idea that there must be some sort of explanation that derives one stellar type from another is strictly an imaginative creation that isn't called for by the known facts.

And Nebularain, while there are certainly a lot of liberal and/or secular interpreters who support your contention about the interpretation of 'yom' in Genesis 1, it remains that only by begging the question can they support that argument. There is no proof, or even realistic argument, that 'yom' there means anything other than a 24-hour day. The liberal interpretation came about solely to try to find Biblical support for modern evolutionary theories; since the Bible doesn't support evolution in any form, the words have to be twisted in order to make it appear to do so. Hence, the creation of the "Age-Day" theory for those who want to have their cake and eat it, too.

Xriso, you'll be able to clarify that remark about "numerous Biblical creation accounts," I'm sure? There's only one account in the Bible of creation, Genesis 1. I realise that there are plenty of people who try to make hay over the supposed inconsistencies between the "two accounts" in Genesis 1 and 2, without realising (or perhaps, ignoring) that Genesis 2 isn't an account of creation but of God's dealings with the first human couple. The only creation detail in Genesis 2 is the specific creation of Eve, which was glossed over in Genesis 1 as being included in the overall creation of mankind.

And Traztx, is God to be blamed because mankind invents theories that require billions of years to work out, when the evidence of the stars themselves in no way requires such theories? God created the stars as they are; men look up at them and, desiring to deny God, make up a story about how the stars must have been formed through a multi-billion-year process. But other than the so-called end results of that process, there is no evidence of the process itself. And the end results--the stars, the planets, the nebulae, etc.--don't require that one particular process to be here. So blaming God for the "appearance" of billions of years, when it was men who created the perception of a need for billions of years in the first place, is rather naive.

Okay, I'm done. You may commence firing.

The (When I consider thy heavens, the work of thy fingers, the moon and the stars, which thou hast ordained) Curtmudgeon

Curtmudgeon, if you dismiss stellar evolution you must dismiss pretty much all of physics because the foundation of stellar physics is basically F=ma.

Stars do not change fast as you point out, therefore forces in stars balance. The forces are (mostly) gravity and internal pressure. The energy for the internal pressure comes from thermonuclear reactions (this is the fundamental step. And the evidence for nucleosynthesis in the Sun is now overwhelming). Thermonuclear reactions change the chemical composition. The change of chemical composition in the core makes the star evolve.

Sure this model is not directly testable in a lab. Sure different type of stars may be completly unrelated. But the evidence is not just the different stars you see with some arbitrary link invented to make it look good. Stellar models explain and reproduce well stellar pulsations, the abundance correlations, stellar winds, explosive events, cooling curves of white dwarfs, for example, across many varieties of stars without fudging the physics. This theory does surprisingly well given its simplicity.

Stellar evolution can be discounted like everything else in the world but it is firmly established in very basic science.

<font size=-1>[ This Message was edited by: frenchy on 2002-06-27 16:30 ]</font>

Curtmudgeon: if one continuous observation were required, we wouldn't be able to know that giant redwood trees grow from redwood seedlings. I don't recall who (was it To Seek?) who said that no one has ever really seen a tree grow.

Silas

Pow pow pow!!!

So are saying you choose to ignore the preponderance of scientific evidence that does not agree with the literal translation of the Bible in favor of the literal translation that is supported by no* scientific evidence?

*No is my word choice, but substituting 'very little' or 'some' would not change the meaning of my question.

<font size=-1>[ This Message was edited by: beskeptical on 2002-06-27 16:53 ]</font>

Thanks for the contrarian viewpoint, The (it's only interpretation if I call it interpretation) Curtmudgeon.

By the way, how do you know your parents were really your parents? That's just a theory... and you weren't there to observe the process take place, were you?

Just teasing...

A question for Dr. Tim...

Has anyone ever estimated how much of the Sun (or rather, the nebula that produced the Solar System) was primordial material, how much was contributed by 1st-generation stars, how much by 2nd-generation stars, and so on? Or is there any distinction between first- and subsequent-generation material?

Not that it matters much; I'm just curious.

With all due respect to Silas, this doesn't invalidate The Curt's point. The seedling-to-redwood link is strengthened by such observations as "There was a seedling right here and now the seedling's gone and there's a redwood in the same place." I believe The Curtmudgeon is referring to this type of observed change, not "one continuous observation."

After all, when you look in a desk drawer and see a pile of paper-clips of different sizes, do you conclude the little ones must grow into big ones?

__________________
SeanF

"Ask to understand, but don't challenge unless you have the knowledge."--NEOWatcher

The contents of this post are ©2009 by SeanF and may not be copied or retransmitted in any form without the express written consent of SeanF

My opinion: I wouldn't blame God for anything man invents. If man invents a theory that corresponds to data, then blame the data. If the theory did not correspond to data, then the theorist is at fault due to error or some other intention other than seeking the truth (fame? control?). If two theories explain the same data, then also look at why one was chosen over another.

I don't see how such a story would in itself be a denial of a divine creator. Multi-billion is really big, but still finite and does not explain the first cause. However, it would be a denial of other stories that other men wrote into the scripture. It would propose that such stories are false.

But there is a process going on and some of it can be observed. The process of nuclear fusion, for example. We can detect the energies and by-products from the sun that correspond to the energies and by-products of fusion in laboratory experiments. Sure some other process might produce the same data, but it is reasonable to suggest that fusion is occuring in the sun.

I agree. Unless there is a way to get to data that eliminates some possible processes, you don't really know which is the actual one that happened.

Agreed, except that I would change the phrase "created the perception" to "observed evidence".

-Tommy

Didn't PhD Creationist Relativists like Russell Humphreys ("Starlight & Time") and Gerald Schroeder ("Genesis & the Big Bang") show that a 10,000 year universe is not incompatible with a 10 billion year one, just as Relativity compels us all to accept Geocentricity to be an equally viable model of reality?!

(Note: My own theological belief is that the standard scientific explanation for the Universe is correct, but that the Universe was created by a Divine Being to follow those "rules")

I'm going to have to respecifully dissagree with you Curt. The accounts of Genesis 1 and Genesis 2 don't appear to mesh... at least not if taken literaly. For example, my copy of the Living Bible says

A literal interpretation of this passage indicates that no plant life existed until God made the Garden of Eden after Adam, which would contradict Genesis 1:26 in which God makes man on the 6th day.

A common school of thought amoung the Methodist denomination (or which I am a part) is that the two stories belonged to diffrent groups amoung the jews. The first story, with it's exacting cataloge of what was made where was told by the priesthood. THe second story which glosses over the details in favor of ease of telling was told "around the campfire" as it were... the story of the common man. The fact that the two groups told slightly diffrent versions does not invalidate the core belief of either (the God created the Earth and Heavens) although it does cause difficulty for literalist interpretations.

__________________
Carl Matherly

Offical Battlestar Galactica Apologist

Named Time Magazine's 2006 "Person of the Year"

Caryn asks:
"...Relativity compels us all to accept Geocentricity to be an equally viable model of reality?"
Chip:
The wise perception of a viable application rests with us, since we are the ones here today, doing the observing. So, no. The fact that relativity can be applied to geocentric ideas does not mean that those ideas are equal or closer to reality than on-going scientific research. On-going is a key phrase, since ancient legends and mythology is "dead" or frozen in the closed culture of their past. One could believe in even older legends and apply modern mathematics and a relativistic frame of reference to our position within Homer's "sideron ouranon" -- (a solid inverted bowl over the earth, with sparkling ether above the "cloud-bearing" air.) Or to Hesiod, who's concepts of astronomy originated with the gentle songs of the Heliconian Muses. There is much to appreciate in myth as a symbolic representation (as Joseph Campbell pointed out.) We can also perceive that if a tree falls in a forest, and there is no one there to hear it, it indeed makes a sound that no one hears.

The Curtmudgeon said (and applauded himself) that no one had ever observed stellar evolution.

I responded that no one has ever seen a Redwood seedling grow into a Redwood tree.

Both observations are true. Since it takes on the order of 200 years for a Redwood to grow to maturity, and since it takes some few billion years for a Main Sequence star to pass through its stages, no one has ever made such an observation.

The Curtmudgeon implied that this was a failure of some sort; I merely parodied it by direct analogy.

I *do* admire your counterexample about paperclips. That is a point of non-trivial profundity (although trivially dismissed in the immediate case.) For instance, we have reason to believe that the Hawaiian Island chain consists of volcanoes that rose and then gradually eroded. But the same argument, applied to other mountains, wouldn't work. Mt. Everest is *not* the result of a smaller mountain that grew over time.

All I can say is: if you read the history of the development of the H-R diagram and the mass-luminosity relationship, you will see that the pattern of deduction resembles the same pattern of deduction that allows us to claim, as a theory, that Redwoods grow from seedlings. The Curtmudgeon's somewhat pointless crowing that no one has ever seen it is the only thing that I was directly rebutting.

Silas

A few random observations:

1. While a geocentric coordinate system is in theory just as good as any other, in practice it is only useful for a restricted set of problems. As far as the geocentric model representing a *physical* reality, i.e., that the Earth is literally the center of the Universe, that's quite wrong. Claiming that relativity supports that viewpoint is well, Bad Physics.

2. Curt, please don't go telling me I seek to deny God because I look at what His handiwork tells us. The various versions of the Good Book came to us through the hands of men, but the Universe is, how should we say, Factory-Direct.

3. Stellar evolution takes a very long time, according to the theory. You cannot legitimately claim the theory is flawed because it doesn't produce transitions observable in a short time. That doesn't make sense.

4. Science is a useful tool for providing natural explanations for the natural world. If you wish to believe certain supernatural explanations for the natural world due to your interpretation of the Bible, fine. I will stand up for your right to do so. But you are attempting to hammer a scientific explanation to fit a supernatural one, and brother... it ain't pretty [img]/phpBB/images/smiles/icon_razz.gif[/img]

I do, however, appreciate your urge to spice up the forum. You seem to have accomplished your mission! [img]/phpBB/images/smiles/icon_smile.gif[/img]

Caryn: Didn't PhD Creationist Relativists like Russell Humphreys ("Starlight & Time") and Gerald Schroeder ("Genesis & the Big Bang") show that a 10,000 year universe is not incompatible with a 10 billion year one, just as Relativity compels us all to accept Geocentricity to be an equally viable model of reality?!

Not so far as I can tell. Schroeder does not use literal days. He thinks that the word "day" in Genesis is meaningless. In his story, the first "day" starts 15.75 billion years ago, and runs to 7.75 billion years ago. The remaining "days" are successively shorter, the 6th being 500,000,000 years long. See "How to Make 6 Days Last 13 Billion Years".

Humphreys is a physicist, but not a "relativist", for what it's worth (his specialty is nuclear physics & engineering, though he should be able to teach himself relativity well enough). His thesis in "Starlight and Time" explicitly violates the laws of physics, by having the universe expand outwards from a black hole. He relies on this shortcoming, so as to give meaning to the phrase that God "stretched out the heavans" (or some such, I can't recallt the exact quote). As far as I am concerned, this is a fatal weakness, for it requires the presumption of direct devine intervention to explicitly violate the laws of physics. That might be perfectly consistent with a creationist notion of the miraculous, but I don't accept anything with built in miracles as "scientific", and neither do the vast majority of scientists.

Donnie: Has anyone ever estimated how much of the Sun (or rather, the nebula that produced the Solar System) was primordial material, how much was contributed by 1st-generation stars, how much by 2nd-generation stars, and so on? Or is there any distinction between first- and subsequent-generation material?

There is no distinction between first and subsequent generation material, so that distinction is impossible. What we do know is that the sun is a main sequence star that is fusing hydrogen into helium. Anything heavier than helium in the sun cannot have been made in the sun (mostly), but must have been processed through at least one previous generation of stars.

Now, I say "mostly" because the sun is hot enough to derive about 2% of its output energy from the "CNO bi-cycle", a catalytic cycle of fusion that can leave behind extra carbon, nitrogen & oxygen. But that effect is quite small, and it's a good bet that more than 99% of the C,N, & O that we see in the sun came from those earlier stars, and not the suns own CNO cycle.

See "Solar Fusion & Neutrinos".

Curtmudgeon: First, Tim, thanx for classifying stellar evolution as a theory. So many people forget that little detail, or the actual definition of the word theory. Anyway, as support for your theory, you'll be happy to give two or three examples of stars that have evolved exactly according to that theory, with documentation, won't you? Thought not.

Indeed, stellar evolution is a theory. However, are you really sure that you yourself are aware of what a "theory" really is? Do you know the difference between the words hypothesis and theory?

A "guess", as you might say, is an "hypothesis" in the jargon of science. It can be anything, and it can come from anywhere; it can be a suggestion from your kid, it can be suggested by reams of data, or it can be generated by too much coffee at 3AM. After all, it's just a guess.

But, suppose we test that guess and see if it's right? Suppose it passes that test, and we test it again? Suposse we test that "hypothesis" a zillion times, and each time the test result implies that the hypothesis is true. What happens then? Our hypothesis becomes a theory.

Yuppers, when scientists say "theory", they are talking about something which is accepted as either true, or very likely to be true, based on some kind of documented experience.

So I call stellar evolution a theory becasue it is based on strong, documented evidence, and well accepted basic physics. To dismiss the whole notion on some semantic displeasure over the word theory is disingenuous, and just plain naive.

Will I support my theory by giving an examole of a single star, seen to evolve throughout the whole life cycle? No, as we both know it's quite impossible. However, I will maintain that it is also quite irrelevant.

I will support the theory of stellar evolution through two pathways. First, just plain physics. I already gave reference to appropriate text books on the subject, where the physics and application thereof is given in detail. Now, to quote myself from the first post: "I figure, if anyone wants to hang around and debate the age of the universe, they should be obliged to explain why astrophysical ages are all wrong.". Now, if you are going to personally claim that the physical theory of stellar evolution is physically invalid, then you are personally responsible for describing the relevant physics, from valid sources (such as the books I cite), and explaining the mistakes. If you can't do that, yourself, personally, then you are in no position to argue that the theory is scientifically flawed.

The second pathway, which links astrophysical theory directly with observation is the Hertszprung Russell Diagram (HRD). The HRD is just a plot of color (x-axis) vs brightness (y-axis). If you look at every star you can find, and plot its color against its brightness, on an HRD, you do not get a random pattern of dots. You do get a highly non random pattern. If you follow my link above, and look at figure 1, you see that the pattern is organized into general reagions, such as the main sequence, the giant branches, and the white dwarfs.

An HRD for a cluster of stars is usually called a color-magnitude diagram (CMD). Figure 3 is a CMD for the globular cluster M5. The labeled regions are explained in the text.

If you make a model of a cluster, and run it through a stellar evolution calculation for X years, tou can create a synthetic model of what the CMD should look like, all derived from the basic physics of stellar evolution. Comparisons show a remarkable agreement between the general, and detailed shape and form, of both modeled & observed CMD's for the same cluster (figure 4 is just one example).

Even small details can be matched, or predicted, by stellar evolution theory. For instance, the well know astrophysicst Erika Böhm-Vitense predicted that there should be a small gap tucked away on the main sequence, where stars would be notably rare compared to the surrounding main sequence, because of the sudden onset of convection in a star's outer layers. It is known, oddly enough, as the Böhm-Vitense gap.

But is there really a Böhm-Vitense gap? It's small & hard to see, but it has been found (The Böhm-Vitense Gap: The Role of Turbulent Convection, F. Dantona et al., Astrophysical Journal 564(2): L93-L96, January 2002; Two Böhm-Vitense Gaps in the Main Sequence of the Hyades, J.H.J. de Bruijne et al., Astrophysical Journal 544(1): L65-L67, November 2000)

In short, the basic physical theory of stellar evolution is able to reproduce, in fine detail, the structure of an observed HRD (or CMD). Hence, we have good reason to assert that the theory really does represent how stars change with time.

Curtmudgeon: Yet we have exactly zero evidence that any star has ever changed states along this so-called sequence.

This too is not quite true. Probably the best example of real time stellar evolution is something known as Sakurai's object (V4334 Sgr). Stellar evolution theory requires the onset of helium fusion to be very sudden, and event called the helium flash. Spectroscopic studies show that Sakurai's Object (discovered, I might add, by an amateur astronomer), originally misidentified as a nova, is a star experiencing helium flash, the first yet recorded.

Most of the events in the life of a star are too slow to be easily observed in a lifetime, but the helium flash is one. Unlike a simple "nova", the observation of a helium flash is the observation of stellar evolution in progress, in real time. The helium flash represents the transition point, where a star at the tip of the red giant branch begins its descent to the horizontal branch. That trip is fast. If, in fact, Sakurai's Object really is a helium flash star, as suspected, then it will soon reappear as a horizontal branch star. There is a campaign on now to look for that event as well.

Curtmudgeon: The idea that there must be some sort of explanation that derives one stellar type from another is strictly an imaginative creation that isn't called for by the known facts.

Absolutely preposterous. The idea that there must be some sort of explanation that derives one stellar type from another is absolutely required by even the simplist notions of physics, and there is no way around that fundamental truth. We know that stars are powered by nuclear fusion, and we know that stars don't have an infinite supply of nuclear fuel, and we know that time passes. Stars must run out of fuel, and that is what pushes stellar evolution along, the transition from one fuel source to another.

On the other hand, the idea that stars must not change with time, is an idea that requires the ignorance of all laws of physics.

The bottom line here is that stellar evolution theory is indeed a very valid physical view of how stars "age" with time. People don't stay the same forever, and there is no good reason to think that stars should either. Stellar evolution theory recreates the observd detailed characteristics of stellar populations, and models the aging process for a star in accordance with the expectations of physics. The ages derived therefrom are derived with fidelity to reality, and not preconceived dogma. The universe is billions of years old, and so are the oldest stars it contains.

<font size=-1>[ This Message was edited by: Tim Thompson on 2002-06-27 22:40 ]</font>

Terminology is a big problem in communication. I'm just curious whether you would call plate tectonics a theory now that GPS can measure the plate movement and earthquakes mark the boundaries of the plates so well?

I understand the proper use of the term, but for some things I have quit using 'theory' and begun using 'fact' or 'fairly well proven' or something along that line to make a point more clear.

Medical science has gone to a continuum though it is in reference to smaller units of data rather than a more encompassing theory of a larger process.

There might not be enough data to accept or reject; data suggesting rejection; data suggesting acceptance; data strongly supporting or rejecting; and data that 'rules out' or 'rules in' a conclusion and so on.

I like the term overwhelming evidence myself.

There is no distinction between first and subsequent generation material... Anything heavier than helium in the sun cannot have been made in the sun (mostly), but must have been processed through at least one previous generation of stars. ... it's a good bet that more than 99% of the C,N, & O that we see in the sun came from those earlier stars...

Isn't that a contradiction?

I always thought that the "First Generation" of stars were those formed from the "primal hydrogen and helium" and would contain traces of lithium, but nothing beyond. These stars manufactured the heavier elements through various processes and expelled them in their end-time.

Later generation stars incorporated those elements in their compositions, so the sun would start with more of the "trans-helium" elements than First Generation stars.

Is my learning wrong, my memory failing faster than I thought or are we talking two different things?

__________________
Never attribute to malice what can be adequately explained by ignorance or stupidity.
Isaac Asimov

Jim,

I think you misunderstood my original question. Tim's answer makes sense to me (though he left out the actual answer... see below).

I asked how much of the Sun was primordial (i.e. H and He from the Big Bang) and how much was produced in first or subsequent generation stars. Tim's answer was that we can't tell material that was produced in first-generation stars from that produced in subsequent generations -- not that we can't tell primordial material from star-cooked stuff.

But Tim never quite got around to mentioning how much of the Sun (by mass) is non-primordial. Guess he wants me to look it up myself... [img]/phpBB/images/smiles/icon_smile.gif[/img]

Now, see how much more lively this topic is since I made my contribution? [img]/phpBB/images/smiles/icon_biggrin.gif[/img]

Just in case anyone missed my subtle positioning in the first post, I'll point out that my post was almost tongue-in-cheek--not that I don't believe it myself, because I do believe everything in my post, but rather that I deliberately posted it here knowing that it was going to be totally rejected. I wasn't so much looking for a real discussion (I don't think it's possible to get a real and fair discussion of such topics on a board that by its very nature takes a particular stand on the issue), as having some fun by deliberately making myself and my beliefs a target. I was bored that day--so sue me. [img]/phpBB/images/smiles/icon_lol.gif[/img]

Having said that, I will now go on to address a few specific points in the various "rebuttals". If I seem to ignore any of your favourite points, it's not because I cannot answer them so much as it is that I believe all that can be said has been said--my position is clear to you, your position is clear to me, and we all know we're not changing each other's minds.

As a general point that several posters brought up or alluded to, I do not believe that stars "must not change with time," to use Tim's phrase, anymore than I believe that people or animals or trees or any other of God's creations must not change with time. I'm not the exact same as I was thirty or forty years ago; I'm pretty sure that neither is Tim nor Nebularain nor any of the rest of us here. But I am still the same person, I'm not Tim nor Silas nor Queen Elizabeth.

Sure, there's nuclear fusion going on in the Sun and other stars; I never said that there wasn't. I said that stars do not change form totally according to stellar evolution's theory of a main sequence uniting all different 'stages of a star's life' into a single continuity. Tim mentioned that fusion in stars burns fuel, and that stars must run out of fuel over time. Okay, I can even grant that--but Tim, they haven't used nearly as much fuel in the few thousand years that they've existed as your multi-billion-year theory requires. Running out of fuel isn't nearly the problem you make it out to be.

In other words, if the universe was truly billions of years old, then your point about stars running out of fuel is valid. But you cannot use the idea "stars run out of fuel" as proof that the universe is billions of years old or that stars must evolve over billions of years. The age of the universe is an assumption in the argument, not a consequent.

To put it another way, would you (that's a group 'you', not necessarily Tim or any specific poster) agree with me, based on your acceptance of stellar evolution as the most plausible explanation of stellar development, that any given star is unlikely to burn through its total fuel supply in 7000 years? (I note the point about the 'helium flash' in Sakurai's Object being a short-term or quick event, but Tim himself says "If, in fact, Sakurai's Object really is a helium flash star, as suspected" (yep, emphasis definitely mine), so it's pretty hard to use that as supporting 'evidence' for the theory.) So, to me, waving the 'fuel depletion' flag is begging the question--we agree that the process of fusion is using up a finite resource, but the time scale (based on the Bible) is such that it doesn't matter. It's not a problem unless stellar evolution is correct, so you can't raise it as an objection to Biblical literalism.

Silas, you're (deliberately or not, I don't know) misreading what I wrote. I never said that there was a need for "one continuous observation". I specifically mentioned "as far back as we have observational accounts" (note the plural). Take all the recorded observations by ancient astro(nom)/(log)ers from Sumeria, Egypt, China, Central America, etc., and all the early scientific observations from Ptolemy, Copernicus, Kepler, Galileo, Brahe, etc., and all the modern observations from all the current observatories. Take individual stars, and collate all the observations of each one from every available source. We still don't have a single instance of a star which is observed to be different today from when the first written observation comes down to us.

This isn't about what one person might or might not observe; it's about the totality of what observations have been recorded from us for as far back as people have bothered to make stellar observations and write them down in a manner that we can understand.

SeanF, thank you for picking up on my position (I don't assume that that means you agree with it, although of course I would hope so). Yes, finding a drawer full of different-sized paper clips is a good analogy for looking at the stars and seeing many different forms, colours and sizes. Thanx for the well-worded example.

Traztx, "If two theories explain the same data, then also look at why one was chosen over another"--have you actually read a history of science, especially one that focuses on the 18th and early 19th centuries? Because of the influence of the Encyclopaedists and the so-called Enlightenment, early science deliberately took the stance, "We cannot accept Genesis as an accurate account, therefore how do we go about explaining fossils and stars and strange fauna and such?" I know why the one theory was chosen over the other, and while I also know that the reaction here is going to be a cry of "Paranoia!" that doesn't by itself show it to be wrong. (On a nearly-related note, I was amused in a different BB recently to read someone's post that Christianity is a dying religion, especially 'fundamentalist' or literal Christianity, as if that was somehow refutation of Christianity's beliefs. But the Bible clearly says that the latter days will be marked by a complete falling away from God, even within the Church itself, so the fact--and I agree that it's a fact--that literal Bible-based Christianity is on the wane actually supports my literal Bible-based Christian beliefs. So there. [img]/phpBB/images/smiles/icon_razz.gif[/img] )

I will grant that at least part of the impetus for rejecting Genesis at that time was that it wasn't really Genesis that was being rejected, as it was a too-simplistic ideal reading that had been made of it. To many people of the time (and, unfortunately, all too many today, but not as many as are accused of it), accepting a 'Christian' world-view meant believing that the world not only had been created a few thousand years prior, but had been created exactly as it was perceived to be in the 18th/19th century. This, in fact, is not taught in Genesis; I delight in confusing anti-Biblicists by explaining that the Bible does support plate tectonics, although because physical geology isn't the point of the Bible it doesn't spell out tectonics as specifically as some would like (as I put it, the Bible supports plate tectonics without teaching plate tectonics). Yet this was never seen by Christian scientists (or nonChristian scientists, for that matter) until long after, simply because the Bible alludes to it in passing without making a big deal out of it. (Of course, the Biblical timeframe is totally out of sync with the secular interpretation of tectonics, but that's a different problem.)

Also (still on Traztx's post), "I don't see how such a story would in itself be a denial of a divine creator"--it isn't, as long as all you're concerned with is any divine creator. But the Bible doesn't just say "God created the universe" and leave it at that. It also tells us something of how He did it, and it's the details that are in opposition to a theistic-evolutionary theory. You can believe evolution and a divine creator simultaneously; you just can't believe evolution and the Biblical description of God's creation simultaneously.

Matherly, I'd address your point except that it gets us completely away from cosmology and astronomical topics, and onto Biblical exegesis. I really do try to obey BA Phil's restrictions of allowable topics on this board (although, of course, I don't claim to be 100% successful). So I will quickly point you to Tekton Apologetics as a starter, as well as Answers in Genesis, and leave it at that. Both of those have bibliographies if you want to pursue it.

Sts60, "The various versions of the Good Book came to us through the hands of men, but the Universe is, how should we say, Factory-Direct" is an almost good point. First, you need to realise that despite what skeptics are always loudly proclaiming, the "various versions" don't amount to a real discrepancy in the Biblical text. We have many thousand more Biblical texts than of any other ancient work of comparable age, and we have many manuscripts much closer in time to the events they record than for any similar ancient writings. And the discrepancies come down to a few dozen scribal copying errors and one or two "big" questions like where does the Gospel of Mark really end? Many people recite that mantra of "various versions" and "hundreds of discrepancies" without having actually checked to see what those descrepancies actually are. (See, that's what I mean. I sidestep Matherly and then respond to Sts60 on a strictly Biblical topic. Sorry.)

But other than that, I can readily agree with you. As my pastor was fond of putting it, "God is the Author of two books. One is the Book of His Word, which we call The Bible, and the other is the Book of His Deeds, which we call The Universe. When we properly understand both, we see that there is no discrepancy between them." But like many, you confuse the issue of what exactly constitutes "the Universe," and what is merely man's interpretation of what he sees in the Universe. Stars are "universal" facts; stellar evolution is an interpretation.

"Stellar evolution takes a very long time, according to the theory. You cannot legitimately claim the theory is flawed because it doesn't produce transitions observable in a short time." Yep, what my good friend Steve (not himself a Biblical literalist, I should fairly point out) calls "a perfect theory"--there's no way to prove it either true or false. I say it doesn't happen; you say we just haven't been around long enough to see it happen. There's absolutely no way to evidentially distinguish the two sides.

"I do, however, appreciate your urge to spice up the forum. You seem to have accomplished your mission!" Good, because when it comes right down to it, that really was all I was trying to do here.

So I will close on that note, having won my acceptance for a job well done. [img]/phpBB/images/smiles/icon_biggrin.gif[/img] [img]/phpBB/images/smiles/icon_razz.gif[/img] [img]/phpBB/images/smiles/icon_lol.gif[/img]

The (we now return you to your normal upright and locked positions) Curtmudgeon

<font size=-1>[ This Message was edited by: The Curtmudgeon on 2002-06-28 17:25 ]</font>

[quote]
On 2002-06-27 15:39, The Curtmudgeon wrote:
Well, just so this thread doesn't remain as merely a bunch of non-Creationists talking to each other and patting themselves on the back, I'll jump in. I generally ignore this type of thread, because I know it's really a waste of my time since no-one who is already committed to a non-Biblical stance on the universe is likely to listen to a Biblical stance, but this thread is so boringly monotonous as yet that it needs a bit of the opposing viewpoint to pep it up....

Okay, I'm done. You may commence firing.
[quote]

Why do I smell troublemaker? (A troublemaker is someone who will throw out any comment, whether they beleive in what they are saying or not, just for the sheer pleasure of provoking a reaction out of someone. He does not care about the answer, he just enjoys watching people getting riled up. My brother does this all the time.) For this reason I will forego the firing and revert to the whacking-over-the-head.

FromThe New Strong's Exhaustive Concordance of the Bible:
Day - yowm: "a day (as the warm hours), whether lit. (from sunrise to sunset, or from one sunset to the next), or fig. (a space of time defined by an associated term), [often used adv.]: -age"

Can you prove that the figurative sense of the word "day" is not being used in Gen. 1? [WHACK!]

(There, I hope you took your pleasure out of my reaction. Pht-t-t-th!)

[Edited to add - oops! It looks like the Curtmudgeon got his reply post up before I did!]
_________________
"All that is gold does not glitter / Not all those who wander are lost..."

<font size=-1>[ This Message was edited by: nebularain on 2002-06-28 18:15 ]</font>

Will there still be followers after man has colonized other planets? Or will the "end of the world" be re-interpreted to mean the "end of all worlds"?

I guess the scripture can always be re-interpreted as needed, just as it has always been.

--Tommy

With all due respect, Matherly, one should not not use the Living Bible translation when arguing schematics. The Living Bible is one man's attempt to re-translate the Bible into more modern concepts and language so that it may be understood better. Not completely a bad idea, but there's room for error in how he interprets things.

The NIV translation of Gen. 2:5,6 states:

A common mistake we have in Biblical interpretation is that we look at the text through our 20th/21st century Western culture mindset. We need to look at the passage in terms of how the people of that time and culture viewed and expressed things. From what I've been able to research on such matters, it appears that "shrub of the field" and "plant of the field" are referring to cultivated plants, not all plants in general (it makes more sense within the context of the text - especially when you get to verse 8 where it mentions God specifically planting a particular garden in a particular location).

_________________
"All that is gold does not glitter / Not all those who wander are lost..."



<font size=-1>[ This Message was edited by: nebularain on 2002-06-28 19:04 ]</font>