How far back can carbon dating measure

I'm not pushing some creationist angle here, they just like to pick nice "round" numbers. No, I'll take scientific observations any day of the week, it's just that so much of science must, as a discipline, base their observations on the painstaking recording of observable physical data. When no observer is present, can we comfortably assume anything about the physical state of the universe at a time when no recorded physical data is available? To merely observe the physics of atomic structures in the "here and now" and then state that "it's always been like this", seems somewhat presumptive.

The statement was that you can't use C dating for accuracy of over , years. However there are lots of other methods for radiometric dating available. Physical data like rock layers? Like types of rocks?

How Does Radiocarbon Dating Work? - Instant Egghead #28

Like the speed of light? Do you have a testable theory as to why this would not be the case? Science can provide rationale for the dating stated. Doubting simply so you can wag your finger and say "Nuh uh" isn't having an open mind -- it's simply being contrary. Originally posted by zeotherm: Radiometric dating they have a whole slew of dating mechanisms Excellent, thankyou. Yes, science bases its theories and concepts around concrete facts.

Even if there was some sort of Watcher race that stood in front of me and said that he was alive 10 billion years ago and bore witness to the birth of my planet, I would still insist on evidence. As a scientist, word of mouth means absolute nothing to me. Scientific statements need to be backed up by actual data. Well, I think you are putting the cart before the horse. Forget your miffed dismissal of the current thought on the history of the universe. You postulate that the laws of physics may not be constant. The next step, using the scientific method, would be to come up with an experiment that would elicit a recordable change.

In this specific case, try to manipulate the environment around a radioactive element to effect a change in the half-life constant. Now take that to the next step, to effect such a change you would need to effect the Weak Force directly within an atom or group of atoms. So a revised, and more scientific, of your OP would be: Can the Weak Force within an atom be effected? Are half-life constants truely constant? I have no idea what the answer is off the top of my head, but my intelligent guess says that this topic has already been researched and literature exists on it.


  • How Does Carbon Dating Work?
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  • What is Carbon (14C) Dating? Carbon Dating Definition.

It was no doubt an important question when dating first took off. I find ranty non-scientific curt dismissals of theories with this sort of attitude half baked and highly aggravating.

Carbon dating, rate of decay, how far can we go?

It's like a little kid turning their nose up their parent cause they think they know better. Originally posted by BuckG: Grrr Very much so. It's even more aggravating when you look at the attitude that it tends to come with: Therefore, I am actually considering more than you are , which makes me better than you mere "scientists". I don't care if I have no idea how you could be wrong, I am smarter merely by suggesting you are mistaken.

Fair enough, instead of opinionating, we'll just stick with the data from here on out. As it should be. Therefore, I am actually considering more than you are, which makes me better than you mere "scientists". As Hat Monster already pointed out, if these things were only slightly different from what they are now, the universe would be a vastly different place.

There was a special on PBS about the universe, particles, strign theory, etc that covered this topic quite well. Basically, by making even a small change in any fundamental particle, the whole puzzle gets tossed out the window. A good number of the subatomic particles we know about were calculated mathematically before they were ever discovered via observation. Heck, this is exactly why we are building the LHC. I don't think it was The Elegant Universe, but it could have been.

Thanks to relativity or, even without it, for a paragraph or two, just observing that there is a speed of light of such-and-so velocity , we can observe the heavens and realize that observing the heavens is also viewing a time machine. Astrophysics is not my discipline, to say the least, but even though a lot of what we look at it very large, many important things we observe are all still driven by physics. If the basic constants of the universe weren't, in fact, constant, we'd observe effects out there in deep space or maybe not so deep space that would be inexplicable.

Radiocarbon dating

If we add relativity to the mix, we have even less reason to expect to see this and, in fact we don't. Because time is relative.

No two particles who might have come into existence long after the big bang have any idea of what "time" it "really is". So, they don't know when to behave according to different laws of phyiscs than those we observe today. It isn't because today is so magical, then, but rather because it isn't "today" everywhere in the universe that allows us to conclude that what physicists claim are constants in terms of particle physics and so on are as they say they are.

And, actual observations back that up. This is all the more remarkable given that we can observe at energy levels and wavelengths that are beyond our ability to directly see. I suppose we can never know the unknowable, or prove the unprovable. All we can do is measure things.

If the measurements prove useful, and allow us to manipulate matter for our own good, so much the better. It's all we have, and anything else is mere conjecture. There's lots of big things out there we're now pretty sure that many galaxies have black holes and the core, quazars, pulsars, and a host of other things that exhibit very gross physical phenomena of various sort that, with work, we can observe here today. We can observe them, moreover, at several distances from us, and these distances are relative to us large in years.

I don't know how you work these things out given relativity, but it is exceedingly likely that they are large in time relative to each other as well which, in several individual instances, is capable of "good enough proof for this discussion" no doubt, such as being in radically different directions from us. Yet, the astrophysicists who examine all of this stuff tell us the same laws of physics applies everywhere and therefore every when they look.

So, that's why we don't have to worry about it all changing. Observation and ordinary logic tells us that there is no variability. So, while we might enjoy speculating about it, if it actually happened, we would be seeing the variability, because some of these effects that we can, in fact, see, would not be behaving according to today's laws either thousands or even millions of years ago, depending on what the scientists are looking at. Originally posted by ZeroZanzibar: What if the change itself also propagates at the speed of light?

The change could be trailing or preceding our ability to detect it in every case, due to the very same reason we are able to "look into the past" in the first place. The answer simply, the answer is "No and yes". You see, if you mess with the weak force, you automatically then have to mess with the electromagnetic force, since they're interrelated electroweak unification. Just altering the weak force by a tiny amount throws out everything. Which means you get no protons, no neutrons, no electrons, no atoms.

We see a relic of a tremendously hot surface, the Cosmic Microwave Background. Not only that, but the CMB is everywhere, so everywhere was once emitting the CMB at a phenomenal temperature a very long time ago. The CMB is normal photons, which means neither the weak force nor the electromagnetic force were any different in magnitude or sign that far back all across the universe. If they were, we wouldn't have had photons.

What is Radiocarbon Dating?

We do have photons, hence they were not. The weak force has not changed during the history of the solar system. Actually, the first answer is also "yes" - until "effected" becomes "affected" quote: More precisely, we can put limits on how much it could have changed - and it's pretty damn small. Sadly not, or at the very least, facing an utter lack of supporting evidence. Electron capture is a much more viable hypothesis than fudging around with a fundamental force.

Originally posted by bantha: This surface is what we see in the cosmic microwave background Hat mentioned earlier, and reconciles quite well with current particle theory without altering the electroweak force. The stable isotopes are carbon 12 and carbon Carbon 14 is continually being formed in the upper atmosphere by the effect of cosmic ray neutrons on nitrogen 14 atoms. It is rapidly oxidized in air to form carbon dioxide and enters the global carbon cycle.

Plants and animals assimilate carbon 14 from carbon dioxide throughout their lifetimes. When they die, they stop exchanging carbon with the biosphere and their carbon 14 content then starts to decrease at a rate determined by the law of radioactive decay.

Radiocarbon dating is essentially a method designed to measure residual radioactivity. By knowing how much carbon 14 is left in a sample, the age of the organism when it died can be known. It must be noted though that radiocarbon dating results indicate when the organism was alive but not when a material from that organism was used.

Carbon dating, rate of decay, how far can we go? - Ars Technica OpenForum

There are three principal techniques used to measure carbon 14 content of any given sample— gas proportional counting, liquid scintillation counting, and accelerator mass spectrometry. Gas proportional counting is a conventional radiometric dating technique that counts the beta particles emitted by a given sample. Beta particles are products of radiocarbon decay. In this method, the carbon sample is first converted to carbon dioxide gas before measurement in gas proportional counters takes place.

Liquid scintillation counting is another radiocarbon dating technique that was popular in the s. In this method, the sample is in liquid form and a scintillator is added. This scintillator produces a flash of light when it interacts with a beta particle. A vial with a sample is passed between two photomultipliers, and only when both devices register the flash of light that a count is made.

Accelerator mass spectrometry AMS is a modern radiocarbon dating method that is considered to be the more efficient way to measure radiocarbon content of a sample. In this method, the carbon 14 content is directly measured relative to the carbon 12 and carbon 13 present. I don't know the chemistry behind it, but as I understand it we know that simply because, based on the rate of decay of the Carbon isotope. Radiocarbon dating is based on the decay of carbon into carbon, the stable isotope. Carbon decays at a rate known as its half-life; by calculating the ratio of C to C in a sample and using the half-life formula you can figure out how old it is.

After a certain amount of time, 75,, years, the amount of C left in a sample is simply too small to measure since it has decayed into C, so that's how we know that you can't date anything that old using radiocarbon dating.

Carbon Dating

The half-life itself would have been determined by studying the rate of decay in samples over a set amount of time hours, days, weeks, etc. Radiocarbon calibration is more accurate than uncalibrated radiocarbon dating but both are fairly good. It does mean that going back tens of thousands of years, you might have an error of several hundred or even a few thousand years, which sounds like a lot but it means that you can say that something happened thousand years ago.

Going back that far, the year range isn't so terrible. With calibrated dates, you might have an error of less than a century. This can be very useful when we look at things that have happened in the last few thousand years, where you have a better idea of events and knowing whether one thing happened before or after another with good precision can be very useful. Radiocarbon calibration is based on dendrochronology tree-ring dating , which can produce a very precise record going back thousands of years in some places.

When the radiocarbon dates are calibrated to the tree-ring dates, you can account for and correct for atmospheric and local variation in carbon which is what causes a lot of the error with radiocarbon dates.