How can we know how old fossils are?

[polymath257]

Ok but even radioactive decay, can you honestly explain that? If we don't know for sure the atmospheric conditions could that of affected the process of aging for the rocks? different climates and such, if not just let me know, I'm not a fucking geologist, just very curious.

Nuclear reactions are not affected by atmospheric conditions. They aren't affected by climate. They aren't affected by chemistry. That's one of the amazing things about them: to affect them requires energies corresponding to nuclear bombs.

So unless you have nuclear bombs going off, the rates of radioactive decay aren't going to be changing.

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So is there any temperature in which the rocks couldn't survive throughout human history? Does the fact we have aged the rocks and shows the earth's age make you question, well what if there were rocks before them but the temperature was as hot as whatever it needs to be that it didn't survive, IDK that temp, just saying. Is this making sense?

Sure, the rocks can be melted. That is where lava comes from, after all.

But once the rocks have solidified, they have a crystal structure that we can look at and determine whether they have been modified. And the rates of radioactivity aren't going to be affected by things like melting, or climate. Even if you had an atom on the surface of the sun, the rate of radioactive decay would not change much (less than 1% and less than that for the ones used for dating).

[Rhondazvous]

Rhonda -

C14 dating isn't used for rocks as it's half life is far too short.  Other methods like Argon-Argon are used.

Rifht. It's used for dating the fossils (organic marerial) in rock? The next question is what is meant by decay? I'd think this is different from the physical wear and tear of water on rocks. I think I'll leave t hat question to those who know more than I do.

[no one]

I use the Fossilatronic 666. I never leave home without it.

[Nay_Sayer]

*Taps a robust stack of papers that took all night to ready and prepare to even them*

*Deeply inhales ready to give a 3-hour dissertation on how we age fossils, erosion, and the Precambrian explosion*

*Looks up to see the op has already been banned*

*takes science glasses off*


..... I hate you all.

[BrianSoddingBoru4]

Rhonda -

C14 dating isn't used for rocks as it's half life is far too short.  Other methods like Argon-Argon are used.

Rifht. It's used for dating the fossils (organic marerial) in rock? The next question is what is meant by decay? I'd think this is different from the physical wear and tear of water on rocks. I think I'll leave t hat question to those who know more than I do.

It refers to the decay of the radioactive elements within the rock. All elements, to a greater or lesser extent, lose mass in the form of (usually) alpha particle and electrons.  The rates at which this happen are stable and can be used as a sort of clock to determine how much of the element was originally present in the rock.

It's a tiny, TINY, (but measurable) change in mass.

Boru

[Gawdzilla Sama]

Rhonda -

C14 dating isn't used for rocks as it's half life is far too short.  Other methods like Argon-Argon are used.

Rifht. It's used for dating the fossils (organic marerial) in rock? The next question is what is meant by decay? I'd think this is different from the physical wear and tear of water on rocks. I think I'll leave t hat question to those who know more than I do.

There is no organic material in dinosaur fossils. They've been replaced by minerals.

[brewer]

Title: I ask Ken Ham.

Damn, missed most the the action for a taco break.

[polymath257]

Rhonda -

C14 dating isn't used for rocks as it's half life is far too short.  Other methods like Argon-Argon are used.

Rifht. It's used for dating the fossils (organic marerial) in rock? The next question is what is meant by decay? I'd think this is different from the physical wear and tear of water on rocks. I think I'll leave t hat question to those who know more than I do.

Decay, in this context, means that the nuclei of some of the atoms are unstable and will spontaneously change into another type of atom while emitting an alpha particle (two neutrons and two protons) or an electron.

This spontaneous change happens at a regular rate that is determined by the characteristics of the nucleus.

But all nuclei are surrounded by a cloud of electrons that, at ordinary temperatures (say, below that of the surface of the sun) shield the nucleus from outside influences. This is helped by the fact that the nucleus is *very* small. If an atom were as big across as a football field, the nucleus would be smaller than a tenth of an inch across. So those electrons are a pretty good shield.

Physical wear and tear removes whole atoms but leaves the nuclei the same. Similarly, chemical reactions affect the electrons but not the nucleus.

That is why radioactive dating can be done: to influence the rate of decay of the nucleus takes very high temperatures of other conditions that will kill off any living thing. Such conditions haven't existed on the Earth since it was formed (yes, they would have left traces if they had occurred).

So, to date a rock requires knowing the radioactive nuclei that were in the rock originally (this can be determined by the crystal structure) and what sort of atoms the change is into (the daughter nuclei). it is then, basically a count of how many daughter nuclei there are and how many 'parent' nuclei have decayed. Since the rate of decay is known (it can be measured today), the age is then straightforward to determine.

Are there technical issues to resolve? Of course. For example, carbon-14 has a relatively fast rate of decay, so it can only be used for fairly recent things (the last 50,000 years or so---which can be extended to 100,000 years with a loss of accuracy). So no dinosaur bones will be dated by C14 dating: all you will pick up is the background amount of C14 and not that from the dinos. Also, things that live in the deep sea tend to have already decayed carbon around, so cannot be dated by this method.

As another example, in Potassium-Argon dating, the daughter nucleus is a gas (argon). If the rock is too porous, this gas can leak out and give an incorrectly *young* age for the rock.

[Anomalocaris]

Thnk about this, water they say causes decay of rocks, well how do we know that there weren't great floods that altered how old we think those rocks are? We also don't know for a fact the atmospheric conditions throuhgout history, so even though we can determine how rocks age in the present in our lifetime, we can know that something turns into something over 10 years persea, how can we know it changed to this degree over millions and millions of years not knowing the atmospher? Also if rain causes rock decay and water does, then that alters how old we think it is, in another words, if the water makes it older than it isn't really older. Does this make you think maybe science isn't all that accurate and those supposed evolutionary bones may not be old at all but different creatures just popping up around the same time? How can geology explain this?

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Does rock decay and weathering disprove rock dating and other forms b/c it's decaying from atmosphere and not natural and how can we know which is which?

You brought up some valid points.  There's nothing wrong with asking how scientists do things. If they have something other than divine revelation to back them up, they will welcome questions.

I may be wrong, but you seem to be proffering Noah's flood as an explanation for the apparent aged look of the rocks of the earth.  I'm no scientist, but I know they dom more than just look at a rock and decide that it looks old. Water may account for  wear and tear. However, it has nil effect on the decay of carbon 14  atomsin rocks that scientists use to date them. Your argument would hold water (pun excusable) if scientists were just looking at how old rock looks. Carbon 14 are carbon that have 14 neutrons.  

You must have at least a rudimentary understanding of carbon dating before you decide scientists don't know what they're talking about.

Actually, carbon 14 has 8 neutrons.   All carbon atoms have 6 protons.   It is the presence of exactly 6 positively charged protons in the nucleus that is responsible for defining the electron configuration of the neutral carbon atom and from that the chemical properties of carbon atom.   It is those specific chemical properties that make carbon carbon.

Different varieties of carbon atoms all have essentially the same chemical property, but their atomic nuclei have different masses.   All atomic nuclei consist of some mixture of positively charge protons and neutral neutrons of very similar mass. All carbons have 6 protons, but those with mass 14 (ie carbon 14) have 14-6=8 neutrons, while the much more common (and non-radioactive) carbon 12 have 12-6=6 neutrons.

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Rifht. It's used for dating the fossils (organic marerial) in rock? The next question is what is meant by decay? I'd think this is different from the physical wear and tear of water on rocks. I think I'll leave t hat question to those who know more than I do.

There is no organic material in dinosaur fossils. They've been replaced by minerals.

Intriguingly, that does not appear to always be true.   Organic material has been recovered from Cambrian marine fossils preserved in very fine grained sedimentary rocks.   Many of the fossils of soft bodied animal forms, as well as some hard shelled arthropods, were preserved as impressions in very fine grained marine sedimentary rocks.  Many of these fossils have dark colored discoloration around them.  It has been shown these discoloration are actually a very thin layer of carbon from the original soft tissues of the animals that oozed out of as the animal’s body was compacted by the sedimentary process.

So organic material definitely can and do survive fossilization.   But much more stunning is fact that actual original soft tissue appeared to have survived inside some fossilized dinosaur bones.    Some tyrannosaur femurs were found to have only fossilized part of the way through the bone.  The interior of the bone was not only not mineralized, there were even what appeared to be extremely well preserved soft bone marrow tissue as well as blood vessels with blood cells inside in vasculated parts of the bone.  Unfortunately this was only recognized part of the way through the conservation process, by which time the conservation process, while preserving the texture and form of the soft tissue remains, destroyed any possibility of DNA recovery. 

However, there was never any possibility of carbon 14 dating because the dinosaur bones were simply too old for any meaningful analysis of carbon 14 to decay daughter element analysis.

[madog]

Thnk about this, water they say causes decay of rocks, well how do we know that there weren't great floods that altered how old we think those rocks are? We also don't know for a fact the atmospheric conditions throuhgout history, so even though we can determine how rocks age in the present in our lifetime, we can know that something turns into something over 10 years persea, how can we know it changed to this degree over millions and millions of years not knowing the atmospher? Also if rain causes rock decay and water does, then that alters how old we think it is, in another words, if the water makes it older than it isn't really older. Does this make you think maybe science isn't all that accurate and those supposed evolutionary bones may not be old at all but different creatures just popping up around the same time? How can geology explain this?

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Does rock decay and weathering disprove rock dating and other forms b/c it's decaying from atmosphere and not natural and how can we know which is which?

If you look at the bottom, its self explanatory  .....  the first date is how old it is and the 'sell by date' is the time it should be used by? next?