echidna

Now you're quite sure they took you ?

Hey, great posts BTW.

[ April 15, 2002: Message edited by: echidna ]</p>

KeithHarwood

They found out where and when they were held. They wanted to go, I had to do the driving. I paid, of course.

Thanks.

Tricia

sorry guys, school, softball, book reports, essay contests ( ) finally caught up with me and I have been tied up for the last coupla days.

Ok. I'm not so sure the earth is billions and billions of years old. Are there any of you whol believe Earth is in the hundred thousands tops?

~Tricia

Daggah

The earth is roughly 4.55 billion years old, Lil. That's whether you accept it or not. That's what ALL of the evidence points to.

KeithHarwood

Here is a little creation myth.

You are made of star-dust.

About 15,000,000,000 years ago the whole universe was tightly packed in a very tiny spec of light. If you want to say "God said let there be light" this is a good time to say it, because that's about all there was. But it was light of such power that it could create matter, and of such power that the matter was almost immeediately destroyed again. However, the universe was expanding and cooling down because of the expansion, and when it was three minutes old the last bits of matter that were created couldn't be destroyed. Those left-over bits were were the nuclei of atoms. There were nuclei of hydrogen (about three quarters), helium (about one quarter) and lithium (just a dash, for flavour).

Nothing much happened for the next three hundred thousand years. All the matter in the universe was a sort of luminous fog, like you see in a neon tube (it's called a plasma). But then the universe had cooled down a lot more and the nuclei could capture electrons to become fully-fledged atoms and the universe turned from foggy plasma into transparent gas. Then a new player started to become important. That player was gravity.

Under the influence of gravity the gas started to clump together and in doing so formed stars. These stars didn't have planets, because there was nothing to make planets out of. You need iron and nickel and silicon and stuff like that. Solids.

Do you now how stars work? Deep down inside, where the pressures are very high they turn hydrogen into helium. For every four atoms of hydrogen they get one atom of helium. (Actually I should say nuclei, because we are back to plasma here.) But one helium weighs just a bit less than four hydrogens and the missing bit of mass turns up as energy and this energy percolates through the outer layers of the star to make it shine. (We call this process hydrogen burning, even though it is nothing like the burning you do in the chemistry lab, where you burn hydrogen in oxygen to get water. In the chemical burning the orginal atoms are still there. In stars the atoms are changed from one kind to another.)

After a while the hydrogen at the centre of the star gets used up and the star gets a helium core with a shell of burning hydrogen around it. This makes the star brighter (because the volume where the hydrogen burning is taking place is bigger) and cooler (because the shell makes the outer layers of the star move outwards so that it gets rid of the heat more easily).

For most stars this is all that happens. The helium core becomes bigger, the burning shell moves outwards and eventually the shell is so far out from the centre of the star that the pressure is no longer enough to keep it burning and the star goes out. (Lots of interesting thing happen as well, but they aren't part of the story.)

For big stars however, rather bigger than our own sun, something else happens before the star goes out. The temperature and pressure at the centre of the helium core is enough to make the helium burn. Three helium atoms come together to make a carbon atom and, again, there is a little bit of mass left over turned into energy to percolate to the outside and make the star shine.

Eventually you get a core of carbon and for really big stars the carbon core starts to burn to form even heavier elements and the inside of the star begins to look like an onion with shells where different atoms are burning. Really big stars shine so brightly that they don't last for very long, perhaps a few million years, but as they build up heavier and heavier elements the little bit of mass left over is less and less so that in the last few stages it's a matter of hours between a core forming and the core starting to burn.

Eventually the biggest stars build up a core of iron atoms and within seconds that core starts to burn, trying to convert iron into even heavier elements. The star is in big trouble now, because there isn't any mass left over. In fact, the star has to supply extra energy, which it can't do, so it collapses very rapidly and very violently in an enormous explosion which rips the outer layers of the star off and sends them scattering all over the place at great speed.

So when the universe was a few million years old the first of the original stars started exploding and, where the universe had been just hydrogen and helium, now it was mixed with all the new elements from the insides of these exploding stars. And new stars formed from this mixture, so that they had a little bit of heavier elements from the start, the big ones of these exploded and put more heavier elements in the mixture.

This went on for 10,000,000,000 years until some corners of the universe were quite smoggy with the dust formed from these heavy elements and in one such corner a big cloud of gas and dust contracted under its own gravity to form a brand new star and some of the dust collected in a disk around it. And the disk clumped up under its gravity and the clumps collected into planets.

About 1,000,000,000 years later some molecules made out of that dust had learned the trick of turning other molecules of dust into molecules like themselves. (No one knows exactly how they did this.) And over the next 3,000,000,000 years the different molecules got better and better at doing this until they had got all the machinery they needed to form themselves into little globs that could swim around in water and collect sunlight to make energy for themselves and to collect other globs to eat and generally have a ball. Another 500,000,000 years and the blobs learnt how to work together to make life even more fun. Once at that stage things were really on a roll, the bunches of globs got better and better at doing what they did until one of those bunches of globs was named Tricia.

So you see, Tricia, every atom of your body (except possibly some of the hydrogen) was once inside a star and you are made of stardust.

Now I've told you not to take anything on faith and that goes double for this little myth. So . .

How do we know that the universe was a tiny dot?
In the 1920's an astronomer named Hubble discovered that all the galaxies were flying away from each other as if in a vast explosion. When he plotted their paths backwards they all came together in one place. In the eighty years since then lots of other astronomers have plotted lots more galaxies backwards, with much greater precision and they all come together in one spot at the one time.

How do we know that the primordial composition of the universe (after the first three minutes) was 3/4 H and 1/4 He? Well, that was worked out from the measured masses of the nuclei by the end of the 1940's, then in the 1970's astronomers found they could see the primordial gasses themselves. The universe isn't neatly packed with galaxies. They come in clumps with vast spaces between. There are some very bright, very distant objects called quasars and light from some of them comes to us through these empty spaces. When we look at that light we see very fine dark lines which show the presence of huge, cold masses of gas which have never been inside a star. And those gasses are 3/4 H and 1/4 He.

How do we know about the universe going from foggy to transparent? We can see it happening. The further away something is the longer it takes the light to reach us so that we can see it. So if you look at something a long way away you see it as it was when the light left it, not as it is when you see it. If we look at the empty sky in any direction we see the last bits of light that were emitted when the universe was a fog but not absorbed before it became transparent.

How do we know about those atoms burning inside a star; we can't go there and we can't get masses of atoms under those pressures. No, but we can do it one atom at a time. We can take a few atoms and give them enormous energies and shoot them at a target of other atoms, and look at what happens. I knew people who were investigating the carbon burning by firing carbon atoms on carbon targets, not that it happened, they already knew that, but the intricate details that showed told us about the internal structures of the nuclei. (My job was making the targets.)

We can see stars being born and stars dying. We can see what is left after a really big star explodes, it's called a neutron star and there are lots of them about so we know lots of stars exploded in the past. Most of these neutron stars are in those places where the cosmics dust is thickest, which is what we would expect if exploding stars provided the material to make the dust. Most of the exploding stars we see are a long way away, but one went off nearby in 1987 (which, if my arithmetic is correct, was the year you were born) and now that most of the fireworks are over we can see the neutron star that was left behind.

And so on for the rest of it (except the bit about molecules that could reproduce themselves) there is an enormous amount of evidence gathered directly from nature that things happened the way I have said. The important thing to know, though, is that no one made up that myth. The evidence came first and the story made to fit the evidence. And when more evidence comes along, we'll change the story to fit the new evidence.

Oolon Colluphid

Just to say, great post Keith! <img src="graemlins/notworthy.gif" border="0" alt="[Not Worthy]" />

Personally I find such a version of events far more inspiring than any ancient myth... and it has the advantage of being checkable!

To Tricia: Why do you let go of the 6000-ish date of the bible, yet not accept the scientific version? Why a few hundred thousand? If the bible isn't spot-on literal, then what does it matter, to belief in it, if instead the real date is billions?

Best wishes, Oolon

faded_Glory

Let me guess....hundreds of thousands of years is not enough for evolution to go from single-celled organisms to humans.

Billions of years is enough.



fG

Thanatos

Evolution is a philosophy, a religion - whatever word you want to use. Don't play word games to avoid the subject.

Prove to me that evolution is not a religion. I haven't found anything on this forum that does!

Clutch

Coupla comments:

First, Michael Ruse. I get the feeling from his recent writings that he's become more interested in headlines and conference invitations than in the secure but poorly-paying respect of those who are grateful that *somebody* will take the time to make sure the cretins don't destroy the teaching of biology and science methodology. (Whether this coincides with his move from Canada to central Florida is an interesting question.) Moreover, I would dispute the earlier description of Ruse as a highly respected philosopher of science. He is, I think, respected among philosophers for the reason just mentioned -- everyone wants to see someone explain patiently why creationism is buffoonery, but it takes time that would otherwise be spent on research. So, thanks, Mike! But if thinking of *contributions* to the philosophy of science, I submit that Ruse's name would spring to nobody's mind.

Second, this "evolution as religion" business. I don't have the quote near to hand, but Wittgenstein said something like, "If you wrap different pieces of furniture in enough paper, they will all look the same". I'm normally opposed to the quoting of Wittgenstein as if it were a crushing point in itself, but in this case I think it's the right thought. Debase the notion of a religion sufficiently to make belief in common ancestry count, and you eviscerate the concept altogether. My hockey team is a religion, as is my discount warehouse shopping centre membership, the set of people who obey traffic laws, and the group of people who watch Law and Order reruns if and only if it's an episode with Claire as the ADA. So Darwinism is a religion? &lt;*YAWN*&gt;

Mageth

Thanatos:

Evolution (common ancestry/tree of life/descent with modification) is about as close to a "fact" as we can get, IMO. The mechanisms of evolution (natural selection, etc) are generally considered theories.

Thus I hold evolution as a fact, and support various current theories of the mechanisms of evolution as explanatory, consistent with the evidence, and generally probable.

Where in Sam Hill is the religion in that? I don't worship Darwin, hold any particular theory as sacrosanct, or do anything else "religious" in the name of Evolution.

Before trying to prove to you why evolution's not a religion (which it is not), tell us why do you think it is, so we know what fallacies to address.