Monday, 19 January 2009

A light dusting

On Saturday Ryan had a discussion about the age of the Earth with a Creationist. This doesn't happen very often, and I was sorry to have missed it. Creationism is essentially an adherance to a literal interpretation of the bible's description of the formation of the Earth.

At some point, somebody sat down and counted any mention of periods of time in the old testament and added them together, coming up with a figure of some 6,000 years. I've heard variations on this, but 6-10 thousand years seems to be the norm. So - the thinking is that it took god seven days to make the Earth, and everything in it, and that was about 6,000 years ago.

This is contrary to SO much empirical evidence that it's barely worth going into it, but as a palaeontologist, fossils are a pretty good clue. Many Creationists argue that all the fossils to be found on Earth were deposited during the flood that put Noah and his ark into action. But that's silly.

In any case, the age of the Earth is a subject that has fascinated science for a l-o-n-g time. It's likely people have been thinking about how old the planet is for a lot longer than 6,000 years, at the very least. Dogs were domesticated more than 6,000 years ago. Decidedly human - Homo sapiens - fossils have been dated at over 100,000 years old, and it's thought the divergence from our closest relative would have occurred at around the 200,000 year mark.

There were a couple of documented musings on the age the Earth in the early 11th Century, and a good number of stabs at finding an age scattered through history - with some ingenious but inaccurate experiments - but it wasn't until the principle of radiometric dating was established that things began to come together. This is the measurement of time by studying the radioactive decay of elements from one form to another. Carbon dating is a form of this, though only accurate to about 40,000 years.

Current thinking puts the Earth at around 4.55 billion years old. Difficult to out this into context, as we don't really have an average lifespan to look to, but with a bit of luck we're not quite into the retirement years yet. At the very least it should last until I've managed to watch the fifth series of The Wire.

As a footnote, our visitor on Saturday provided his coup de grace to put poor scientist Ryan's risible fact-based arguments to the sword:

'When you see footage of the astronauts landing on the moon, the dust on the surface isn't deep enough for it to be any older than 6,000 years old.'

Well, as everybody knows, this is entirely due to diligent hoovering.

7 comments:

Maningo said...

Hi Mr Wood. There are errors in your brief essay. For example:

* The Bible says God created everything in six days (Exodus 20:11, 31:17) , not seven.

* It is not possible to add up 6,000 years from periods of time mentioned in the Bible. (Of course from the data in the Bible you can get 4,000 years from Creation to Jesus. For a shortcut in your addition, use the 'Golden arches of time' verses.)

For a list of about 40 ancient and olden days calculations of the age of the earth, see the table in Old-earth or young-earth belief.

The most serious flaw in your essay is the idea you express that age can be measured. Age cannot be measured. See Immeasurable age.

Matt Dale said...

Hi Maningo,

You're right about the 6 days thing. But really, that's pretty immaterial.

4,000 years - ok. I've never actually tried adding up the periods of time, and I'm not going to. It's such a flawed approach that even if I were interested, it would be pointless. The most common age I've been told by those with these beliefs is 6,000, though. And again, I don't think a difference of 2,000 years is significant when in comparison with ages produced with other methods.

And your last point. Age can be measured. I'll be 37 this year. I will have been alive for 37 years. 37 orbits of the Earth around the sun. Not a flawless measurement of time, as evinced by the extra second in 2008, but pretty good.

I don't profess to be an expert in anything, but I do have a great deal of training in geology. It's my view that the weight of evidence against a 'young Earth' is so substantial that it's a little futile arguing against it. In any case - you are perfectly entitled to your opinion. And I mine.

Thanks for your comments, though.
m

Maningo said...

Matt the immeasurability of age is a matter of fact, not opinion. You could not have measured your age because there is no instrument that measures age. Of course with a calendar and accurate knowledge / historical records of someone's date of birth, it is an easy matter to calculate their age.

When it comes to rocks, it is isotope ratios that are measured, not age. To generate an 'age' from isotope ratios, assumptions must be made re initial isotope levels, constancy of decay rate, etc., and some of the foundational assumptions used are extraordinarily unreasonable, while others have actually been disproven. For example some decay rates have been speeded up a billion-fold in the laboratory, disproving the idea that radiodecay rates are constant under all conditions.

Several bodies of igneous rock that were observed to form in modern times, e.g. recent Mt Ngauruhoe lava flows have been 'dated' by radiometric methods to millions of years. If the results can be wrong by many orders of magnitude when radiometric methods are used on rocks of known age, there is little reason to trust them on rocks of unknown age.

Matt Dale said...

One of the starting principles of science is the assumption of emergence - that it is essential to be open to new information and ideas. It is to the detriment of almost all religions that they are not.

Your first point is a little pedantic, but as it leads to a more weighty issue, I'll let it go.

I completely agree that the age of the Earth as estimated by the current best-fit theory is likely to be inaccurate. It is not likely to be as inaccurate as you would like it to be.

It is entirely within the nature of science to hold to a working hypothesis within the bounds of our knowledge. Not true of religion, which is based on faith, and spurns a requirement of proof as treacherous.

However - my point remains that it is ridiculously at odds with any amount of observable facts that the Earth could be only a few thousand years old.

Maningo said...

The observable facts are the same for evolutionist and creationist alike. After all, we all live in the same world with the exact same fossils, rocks, isotope ratios, starlight, DNA, etc. The difference is in the interpretation of the facts.

Due to different axioms (i.e. worldview / bias / presuppositions) evolutionists and creationists interpret the scientific data differently.

All people, including secular scientists, hold to particular axioms, and axioms are by definition faith-held beliefs. One of the axioms of secular science is naturalism, the idea that all things can be explained by natural processes. So, the evolutionary worldview is just as dependent on foundational faith-held beliefs as the biblical creationist worldview.

Basically, the secular logic goes: We exist; Everything came about via natural means; Therefore we must have evolved. The scientific facts are then all incorporated into that framework of understanding.

For some observable facts that are extraordinarily difficult to reconcile with the idea of millions of years, see Young Age Evidences.

Matt Dale said...

Of course observable facts are the same for all. Whether people choose to observe them is clearly an issue.

Scientists approach a subject with an open mind, with no agenda. Those looking with religious constraints tend to see what they want to see, ignore what does not fit with what they want to believe, or find unsupportable excuses.

Axioms are not truly a basis for much of science. They are not proved or demonstrated, and most of science's founding principles can be and are demonstrated. Your argument that evolution is first accepted as fact and evidence forced into the template is far from correct. That's not the way science works.

To accuse science of having shaky foundations of assumption whilst standing on a religious platform is hypocritical in the extreme. Basing a world view on a book written a long time ago, based on some first hand, some second hand and some third hand accounts, many seemingly contradictory, seems very strange to me. Written when the understanding of the world was very, very different. And then let's not forget how many times it has been compiled, translated and edited over a long period of time by many different hands with many different agendas.

Leaving aside all other strands of religion - of which there are and have been countless - Christianity alone has thousands of varied branches, each with their own interpretation of the bible.

As an atheist and a scientist I can still see how a religious person can justify their faith in a modern world, should they want to. Justifying a Young Earth is an entirely different thing.

Steven Horrobin said...

The references used by Maningo draw exclusively from niche committed creationist websites. There is no significant debate whatever about the general validity of the many different methods of radiometric dating, which depend upon divergent principles, and which are mutually confirming. But the idea that there is no way whatever to determine age, such that it is "immeasurable" is a laughable nonsense. Such a position can only be held by someone who needs desperate means to defend an indefensible hypothesis, as do young earth creationists.

There are dozens of entirely independent methods of geochronological dating methods. Ice cores, for example, give a very accurate record of patterns of seasonal change, which demonstrate absolutely that the earth's age exceeds 740,000 years. But these are sat on top of geophysical structures which themselves show quite ordinary patterns of geomorphic variation, requiring vast stretches of time. For example, (not necessarily in that latter case) sedimentary rock layers, composed of oceanic sediment, kilometres thick. A very nice example of this, though under somewhat more recent glaciation (in some cases still older than the young earther's idiotic <10000), is the stratigraphy of the himalayas, which in places shows an unbroken chiefly sedimentary record 12km thick. And no, this wasn't caused by the flood. It lies in perfect accord with the evolutionary account of the emergence of species, and confirms absolutely the standard chronology of the Phanerozoic. The idea that the flood caused this, as put about by ignorant creationists, is impossible given the order found, and the variation among layers, nicely discrete in themselves in composition with regard to the progression of the fossil record. Which is of course confirmed by radiometric dating. This dating however is unnecessary to establish the great antiquity of this record, for perfectly obvious reasons.

If the flood had raised the himalayas, it would have required a thermodynamic release sufficient to turn the Earth's surface into a molten mass, blowing the atmosphere into space. Oh, and what of plate tectonics? What of the indisputable connection between the geophysical structures of north america and Europe, and South America and Africa? What of the fossil, geomagnetic, and radiomagnetic record of the expansion of the sea-floor between these continents? Doubt this expansion? Bzzzz.... it is presently observed on a year-by-year basis. You can go visit the divide itself at the Thingvallir, in Iceland. Attempt to speed it up, and you face a thermodynamic nightmare? Try to calculate the effect of the energy required to move these continents thousands of miles apart in a few thousand years...

But if you don't like that, and I'm not about to list the dozens of other indisputable methods of measuring age, then how about this: the speed of light. Your ridiculous charge concerning the alleged variability of one method of radiometric dating, says nothing about the speed of light, which, in like for like media (so, space) is invariant. We know indisputably that there are galaxies and quasars whose distance from us is in the billions of light years, but which we can observe, which means that the stars are that old. The whole young earth nonsense derives from an abject effort to defend the first few lines of a storybook of repeatedly demonstrated falsehood, which states that the stars were created after the earth (tee hee!), which means that if you want to defend this absurdity, you have not only the horrible embarrassment of having to explain THAT, but also you need to deny more or less the whole of modern physics.

A book length treatment could be written on the vast numbers of other means of clearly measuring great age! Immeasurable? Ridiculous!