Methods Of Dating Rock & Fossils

[CaliforniaSun]

Completely false. The accuracy is only good as long as this present nature existed. If the basic formula was different in the amount of C14 that existed or etc etc etc etc etc etc etc then all dates are OFF. The calibrations are also off. For example if a nature change (in laws) happened say 4400 years ago, and trees used to grow fully in a month or so, then a full grown tree with say, 300 rings, would only represent a month. In the present time, they represent a year per ring more or less. In calibrating dates using rings, a year is what is used. Therefore as I said it is only good in this state.

I think it only works on Thursday.

 

[Michael]

Completely false. The accuracy is only good as long as this present nature existed. If the basic formula was different in the amount of C14 that existed or etc etc etc etc etc etc etc then all dates are OFF. The calibrations are also off.

Let's start by noting that the term "false" in your first sentence applies to YOUR beliefs about possible CHANGES in the atmosphere, and their effect on the technique, not my description of the technique.

For example if a nature change (in laws) happened say 4400 years ago, and trees used to grow fully in a month or so, then a full grown tree with say, 300 rings, would only represent a month. In the present time, they represent a year per ring more or less. In calibrating dates using rings, a year is what is used. Therefore as I said it is only good in this state.

First of all, while the changes you proposed might affect ring tree counts (assuming it's even physically possible to grow a tree in a month), it would have little or no effect at all on the amount of C14 it contained, and no effect on the dating technique.

The only thing that would/could affect the C14 dating technique is a CHANGE in the amount of C14 in the atmosphere at some point in time. To my knowledge, no such evidence exists. In fact we have ice core samples going back hundreds of thousands of years that detect no such changes in our atmosphere during the past 50K years, and that's the only time frame that can be measured using the C14 technique.

IMO that particular technique is MORE reliable than some of the radiometric methods related to longer decaying isotopes because of the timeframes involved, and the fact that solar flare activity can and has been shown to have some effect on those decay rates. The sun's output could in fact have 'some' influence on those numbers, but even still it would be a "limited" effect IMO.

 

[RocksInMyHead]

I find this topic to be my interest and have lots of question regarding it. My first question is about radioisotopes dating. When people discuss about ratios say uranium and lead in order to know how much was initially in the sample. What exactly are they referring to?

Not sure if I understand what you're asking. Do you want to know about how initial values are calculated? Or why uranium and lead in particular? Or is it something else?

 

[Elendur]

Completely false. The accuracy is only good as long as this present nature existed. If the basic formula was different in the amount of C14 that existed or etc etc etc etc etc etc etc then all dates are OFF. The calibrations are also off. For example if a nature change (in laws) happened say 4400 years ago, and trees used to grow fully in a month or so, then a full grown tree with say, 300 rings, would only represent a month. In the present time, they represent a year per ring more or less. In calibrating dates using rings, a year is what is used. Therefore as I said it is only good in this state.

You have no idea what those rings are, do you?
The rings are a good approximation for years because the darker areas represent slower growth (during seasons with less light, nutrients and/or water) and the brighter areas represent faster growth (during seasons with more light, nutrients and/or water).

The most apparent seasons are winter, spring, summer and autumn.

If the trees grew in a month they would have one wide ring to represent that growth.

 

[pgp_protector]

You have no idea what those rings are, do you?
The rings are a good approximation for years because the darker areas represent slower growth (during seasons with less light, nutrients and/or water) and the brighter areas represent faster growth (during seasons with more light, nutrients and/or water).

The most apparent seasons are winter, spring, summer and autumn.

If the trees grew in a month they would have one wide ring to represent that growth.

Not if God wanted it to look older (or maybe it's the devil putting rings in it now)

 

[Elendur]

Not if God wanted it to look older (or maybe it's the devil putting rings in it now)

True, but that's nowhere near what he wrote. What he wrote demonstrates a lack of understanding of the mechanics behind it all.

I think Noah would have recorded the weather if it had changed dramatically several hundreds or thousands of times during that month.

Noah: 5:16 "Guess what, temperature varies from -20C to +20C every five minutes, huh isn't that strange?"


Edit: I'm just guessing that's you anticipating his response, this was my response to his anticipated response

 

[hisgrace26]

They are "typically" (not always) talking about how long it takes for a PURE sample of say uranium to decay into the various elements they find in their sample today. The uncertainty factor comes from ASSUMING that the same sample was a PURE sample at sometime in the past.

In carbon dating, it's a bit different. Living things tend to concentrate a KIND (a particular isotope) of carbon that decays over time (C14). They can then tell long it's been since that living thing was alive, but it's only accurate to about 45-55 thousand years, due to the decay rate of of C14. After about 45K years, all (once) living things returned to pretty much a 'background state" of C14/C13 content and will remain that way indefinitely.

How do they know what the half-lives is? I've read somewhere that even the extremely slow half-lives can be measure accurately. How are they known?

 

[CaliforniaSun]

How do they know what the half-lives is? I've read somewhere that even the extremely slow half-lives can be measure accurately. How are they known?

Because every time they have measured every elemental decay, it's always the same, irrespective of continent, country, language, gender or political bend. The ONLY place you'll see dissent, is from cdesign proponentsists, who wouldn't know what an isotope if it bit them in the shin.

 

[RocksInMyHead]

How do they know what the half-lives is? I've read somewhere that even the extremely slow half-lives can be measure accurately. How are they known?

Decay is a continuous process. If you have a large enough quantity of parent material (a gram or two is usually enough) and you observe it over a length of time, you can determine the decay rate.

 

[Michael]

How do they know what the half-lives is?

They typically "measure" samples in the lab in relatively precise ways.

I've read somewhere that even the extremely slow half-lives can be measure accurately. How are they known?

It typically involves taking a known sample of something and measuring the isotope content of that sample. They then let it sit there for a relatively long period of time, and they remeasure the sample again. They can then use that information to extrapolate backwards, even relatively LONG half-lives.

In terms of "accuracy", there was a recent set of studies that suggest that solar output can have a direct influence on the decay rates of various radioactive elements. That bit of knowledge was unknown until recently. It's still unclear how much effect that might have on long term decay rates, but there are some variables that were unknown until recently.

The strange case of solar flares and radioactive elements

 

[Michael]

Because every time they have measured every elemental decay, it's always the same, irrespective of continent, country, language, gender or political bend. The ONLY place you'll see dissent, is from cdesign proponentsists, who wouldn't know what an isotope if it bit them in the shin.

FYI, that's actually not entirely accurate. I agree they are relatively stable and accurate processes, but folks at Stanford have noticed changes in decay rates that are based on solar output variations.

The strange case of solar flares and radioactive elements

 

[RocksInMyHead]

In terms of "accuracy", there was a recent set of studies that suggest that solar output can have a direct influence on the decay rates of various radioactive elements. That bit of knowledge was unknown until recently. It's still unclear how much effect that might have on long term decay rates, but there are some variables that were unknown until recently.

The strange case of solar flares and radioactive elements

This is something that appears to apply only to elements with short half-lives (elements used as biological tracers, for example), and not to longer half-lives. This makes sense, because it's a cyclic process, and the effects are very small, so it averages out over time.

 

[CaliforniaSun]

FYI, that's actually not entirely accurate. I agree they are relatively stable and accurate processes, but folks at Stanford have noticed changes in decay rates that are based on solar output variations.

The strange case of solar flares and radioactive elements

Interesting article. Seems to be cyclical, on certain isotopes (e.g. Mn) and only slightly alters decay rate of some of the atoms, but not all.

 

[Michael]

This is something that appears to apply only to elements with short half-lives (elements used as biological tracers, for example), and not to longer half-lives. This makes sense, because it's a cyclic process, and the effects are very small, so it averages out over time.

I think you hit the nail on the head with the idea that it "averages out of over time". Whatever changes might be solar output related are likely to be averaged out over time anyway since the sun's cycle is about every 11 years, and most of these half life samples have been studied for many decades at this point. I don't think it's likely to have a "serious" long term effect on the AVERAGE, but it's noteworthy that there are things that actually CAN influence this number that we really didn't know anything about until the last few years.

 

[Michael]

Interesting article. Seems to be cyclical, on certain isotopes (e.g. Mn) and only slightly alters decay rate of some of the atoms, but not all.

I thought it was intriguing as well, particularly since I'm also interested in solar physics. It really does make me think that gravity and the strong force may be related to the EM field. I guess that's the holy grail of physics, and sometimes nature/God just likes to tease us a little.

 

[CaliforniaSun]

I thought it was intriguing as well, particularly since I'm also interested in solar physics. It really does make me think that gravity and the strong force may be related to the EM field. I guess that's the holy grail of physics, and sometimes nature/God just likes to tease us a little.

Agreed. Science rocks!

 

[Michael]

Agreed. Science rocks!

I love science too. It's fascinating how science is always changing the way we perceive reality.

 

[Jazer]

I think it only works on Thursday.

Thur is not good for me, can we maybe do it on Friday?

 

[RickG]

FYI, that's actually not entirely accurate. I agree they are relatively stable and accurate processes, but folks at Stanford have noticed changes in decay rates that are based on solar output variations.

The strange case of solar flares and radioactive elements

They are oscillations, not an actual change in decay rate. They are also very small and are not of any of the radionuclides used in radiometric dating.

 

[thaumaturgy]

FYI, that link is no good.

When I click on it it works.

Oh well, google it. SOrry!