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Carbon Dating Gets an Update
ananyo writes "Climate records from a Japanese lake are set to improve the accuracy of carbon dating, which could help to shed light on archaeological mysteries such as why Neanderthals became extinct. Carbon dating is used to work out the age of organic material. But the technique assumes that the amount of carbon-14 in the atmosphere was constant — any variation would speed up or slow down the clock. Since the 1960s, scientists have started accounting for the variations by calibrating the clock against the known ages of tree rings. The problem is that tree rings provide a direct record that only goes as far back as about 14,000 years. Now, using sediment from bed of Lake Suigetsu, west of Tokyo, researchers have pushed the calibration limit back much further. Two distinct sediment layers have formed in the lake every summer and winter over tens of thousands of years. The researchers collected roughly 70-meter core samples from the lake and painstakingly counted the layers to come up with a direct record stretching back 52,000 years. The re-calibrated clock could help to narrow the window of key events in human history. Take the extinction of Neanderthals, which occurred in western Europe less than 30,000 years ago. Archaeologists disagree over the effects changing climate and competition from recently arriving humans had on the Neanderthals' demise. The more accurate carbon clock should yield better dates for any overlap of humans and Neanderthals, as well as for determining how climate changes influenced the extinction of Neanderthals."
The problem is that tree rings provide a direct record that only goes as far back as about 14,000 years.
What's the problem? That's 7,984 years before the beginning of time.
Sheesh, evil *and* a jerk. -- Jade
...they dominate U.S. politics!
In another 10,000 years they will be able to find at least two more radioactive sediment layers to refine their calculations.
:]
Holy crap. "Painstakingly" doesn't even begin to cover counting 52,000 stripes in a core sample.
Aren't you curious what God was up to before genesis? I mean, if God has existed forever, and the universe is just 6000 years old, then what the hell was he doing all the rest of that time? Off making other universes? Were they successful or not? How much baggage does God have? Are the angels the result of those previous geneses? If not, when were the angels created? And the cherubs, oh why won't anyone think of the cherubs?!
The theological implications of this new science are infinite and staggering.
Science is all about firing a drunk pig out of a cannon just to see what happens.
Maybe if you knew what a half life was you wouldn't find it so confusing?
Carbon dating to me seems to be used to further scientific data, in order to achieve the results they want. Captain Obvious says it is very inaccurate, and no matter what they have done or try, to advance Carbon dating techniques it already as that stigma of doubt because it is impossible to get within a few hundred years, let alone decades. Not saying that another technique cannot be used or something new won't come along but I do not buying into the Carbon Dating reports..
I not against Carbon dating or the results, but I om not going to bet my life on it either.
The half life of carbon-14 is only about 5000 years. So either other, unstable isotopes have been degrading into carbon-14:
in which case you should have science to back up those rates of isotopic altercations- or your science is bunkum.
You must be thinking about carbon-5. Carbon-14 is guaranteed for 14,000 years.
Sheesh, evil *and* a jerk. -- Jade
The half life of carbon-14 is only about 5000 years. So either other, unstable isotopes have been degrading into carbon-14:
in which case you should have science to back up those rates of isotopic altercations- or your science is bunkum.
You must be thinking about carbon-5. Carbon-14 is guaranteed for 14,000 years.
http://en.wikipedia.org/wiki/Carbon-14
I think you need to read wikipedia again.
Wouldn't the amount of C-14 have been the same for humans and Neanderthals at any given time? Therefore while we may be unclear exactly when they went extinct (presuming Bigfoot is not a surviving branch of Neanderthals), we should have a pretty good idea in the overlap. Unless they use different dating methods for different events, this really shouldn't change the general picture.
I'm amazed that they found a clear seasonal pattern in a lake going back 52,000 years. Lakes are short lived structures, geologically speaking and 52,000 years is quite far into the last ice age. I guess the lake somehow managed to avoid being glaciated and managed to avoid being washed away by the melt waters. Impressive! I haven't located an ice age map of Japan so I don't know how much, if any, of Japan was actually covered by ice. It is far enough North but the ice sheet was not uniform. (Parts of Alaska were ice free)
Which doesn't include you, obviously.
I think you need to look at the comment that was replying to again. It is either such a profoundly wrong understanding of half-life, or extremely poorly stated, and many probably don't think that warrants a serious reply... not that making a good comment stops people from making jokes either. Nonetheless, giving the benefit of the doubt and guessing the original poster doesn't understand how there can be C14 when most of it should have decayed away and stayed away without a source, the Wikipedia article right at the beginning describes the source and this story here on Slashdot is exactly about the science that backs up those rates.
The problem isn't just that C-14 isn't a constant over time.. It's varies over different parts of the planet. How does there lake account for that?
Maybe if you knew what a half life was you wouldn't find it so confusing?
His comment doesn't show that he doesn't understand the concept of a half life.
I'ts a superficialy reasonable question - if we know that C14 is decaying then it must of come from somewhere.
But his error is to assume the only place it could have come from is the decay of something else.
In fact it's generated by cosmic rays hitting Nitrogen, a beta particle (electron) is captured by N14 giving C14.
Watch this Heartland Institute video
That carbon dating has always been as accurate as you can afford. You decide the date that you need in order to confirm your thesis, send your sample to as many labs or as many times as your budget allows, then pick the closest answer from the essentially random set of results.
Anyone on the inside of the inside care to confirm or refute that?
If you were blocking sigs, you wouldn't have to read this.
Excuse me while I register a domain name...
Damn, already taken.
systemd is Roko's Basilisk.
The last magnetic reversal of the poles was 780,000 years ago, 720,000 years before carbon 14 dating is useful. I doubt it has any effect.
If only we had objects with known dates, this wouldn't be a problem, as you could compare directly. The best would, of course, be some kind of annual layers, so you could count how old they are. Oh, if only there was some method or another that worked that way.
Besides, I don't really think an event that last took place 780,000 years ago is going to affect a dating method where only traces too small to be measured exist after 100,000 years.
Neanderthals extinction reason is very simple they were too yummy.
...strudents are slacking here. Get back to your work. Recount!
Yes, that is why it is so convenient when they find coins with stamped dates like "70 BC" on archeological sites!
The Internationally agreed Radiocarbon calibration curve (IntCal) - co-ordinated from Belfast University - takes info from ice-cores, lake sediment cores, tree-rings, corals, etc from the Southern and Northern hemispheres (there's an offset between them) puts them together (this work is done by statisticians using specially developed methods rather than other scientists using off-the-shelf techniques) and although some scientists would rather that only their work was used (as they can then claim whatever 'accuracy' they wish to claim) independent verification of lab practices is extremely useful in the work. The most recent published work dates back to 50,000 years BP ('before present' where 'present' is 1950) and the next set of curves (IntCal 12) - being worked on at the moment will take it back further. Abstract for IntCal 09 - http://eprints.whiterose.ac.uk/10694/
Whooooooosh!!!!!
Not correct, absorbing an electron would not change the atomic number. N14 absorbs a thermal neutron, and C14 decays by beta decay. K capture emits a neutrino.
Fugue for Aaron Swartz
Usually when I see a post moderated as informative, it leads me to believe it may contain information of some kind. I think this would be better characterized as insightful.
If anyone does't understand what the parent is talking about, the half-life of Carbon 14 is 5,730±40 years. That means that 52,000 years is a little more than 9 half-lives. By taking 1/2 and raising it to the power of 9, we can conclude that about 0.2% of the original carbon 14 will remain in the oldest layers of sediment.
As for the question of where the Carbon 14 is coming from, we know that it's formed by cosmic radiation striking the atmosphere, and that the amount in the atmosphere varies slightly from year to year. As this article has explained, the purpose of this research is to get a better idea of how much Carbon 14 was in the atmosphere every year so that we can get a better idea of how old a piece organic matter might be based on it's isotopic ratio (the fraction of the carbon that is Carbon 14).
Since the decay of fission products produces thermal neutrons, some of these can be absorbed by the very common N14 to become C14. Above ground atomic tests produced a spike of C14, for example.
Fugue for Aaron Swartz
Yes, the half-life of carbon-14 is only about 5000 years. After 5000 years that means half the original C-14 remains. After 10000 years, 1/4 the original C-14 remains. After 15000 years, 1/8th. After 20000 years, 1/16th. After 25000 years, 1/32nd. After 30000 years, 1/64th, and so on. Typically, with radiometric dating techniques you can keep on measuring the parent (radioactive/decaying) isotope to daughter (product) isotope until about 10 half-lives have gone by. After that, so little of the original parent radioactive isotope is left, and it is so easy to contaminate the sample with a wiff of modern material, it is tricky to go any further. If you use a really large sample and particularly precise techniques, sometimes you can stretch that a little. For C-14 dating that means the nominal range is about 50000 years. You can stretch a little beyond that if you are careful (I think the max is ~100000 years).
Because the Earth is very old, it's logical to wonder why all C-14 isn't decayed by now. The simple answer to that is: it is being constantly created by cosmic rays penetrating into the atmosphere and generating C-14 from N-14. It is an equilibrium process of generating C-14 and then letting it decay. More importantly, the rate of its generation does vary a bit, and that's what this study (and a lot of other previous studies) have been calibrating. The difference between using the modern-day atmospheric C-14 concentration (technically, the amount of C-14 in the atmosphere before we screwed it up with nuclear weapon testing) and the recalibrated values is about 10-20%, due to the variation in C-14 concentration in the atmosphere over the last 50k years or so.
So, I'm not quite sure what your problem with C-14 dating is, but I think you need to re-evaluate some of the basics of the method. I recommend the wikipedia page as a start.
Reading one of the articles ( http://researchcommons.waikato.ac.nz/bitstream/handle/10289/3622/Hogg%20Intcal09%20and%20Marine09.pdf ) seems to make it clear that the Lake Suigetsu project is a player, but only one of many, in the project to develop a better INTCAL chronology. It may be obvious to some, but any single dataset is not particularly useful until it is corroborated with many others. The Suigetsu project has been at work for several years and, although there has been some revision made to their baseline data, it hardly seems like headline news.
OTOH, it's always great to hear what scientists have been up to, regardless of the field.
This comment was written with the intention to opt out of advertising.
Two problems.
PHEM - party like it's 1997-2003!
I'm in! Should I bring flowers and candy?
The conversion of Nitrogen to C14 is caused by a neutron http://en.wikipedia.org/wiki/C14_dating. Being not charged, it tends to be rather insensitive to magnetic fields.
Chance that you're religious: above average.
Bert
Cosmic rays consist of vast majority of charged particles though. The neutrons involved in the production of carbon 14 are pretty much all from charged particles hitting higher in the atmosphere and creating a shower of secondary particles. So a reversal could potentially change carbon-14 levels due to change in cosmic ray fluxes, although the impact of such a short (in terms of geological time) exposure to new C14 might be a rather minor cumulative effect in dating depending on exactly how much change in production it causes.
But the issue is moot, because the last reversal happened about 780ka ago, an order of magnitude longer ago than the time period used for carbon dating.
Not correct, absorbing an electron would not change the atomic number. N14 absorbs a thermal neutron, and C14 decays by beta decay. K capture emits a neutrino.
If N14 absorbed a neutron, it would become N15. Beta capture means one of the protons in the N14 becomes a neutron, reducing the atomic number by 1 and making C14.
Uh, you do know that C14 decays to N14 by emitting a beta particle don't you?
No, the angels were "Version 1.0". After he realized he'd left off a few important bits, like genitals, he created man.
Of course angels have "important bits". Otherwise, how would the sons of God have knocked up the daughters of men (Genesis 6:4), creating the Nephilim and giving God the excuse for the great server wipe of 1656 A.M.?
Don't you know almost every G.I.R.L. on a geek board is a guy in real life? ;-)
if God has existed forever, and the universe is just 6000 years old, then what the hell was he doing all the rest of that time?
Reconciling the six creative days of Genesis 1 with the billions of years of the scientific record is perfectly possible because the creative days in Genesis 1 are not exactly literal. A day is like a thousand years to God (Psalm 90:4, 2 Peter 3:8). Consider that the seventh "day" of God's rest never had its "evening and [...] morning", implying that it is ongoing, and the discussion of God's rest in Hebrews 4 bears this out. We've hashed out day-age theory before on Slashdot.
Isnt there still alot of scientific controversy about local variations effecting the few samples (how widely was this system applies - one lake isnt enough staticstically even when multiple cores up the mass of material to average the results)
Especially at the far end of the spectrum (the 50000 year ago end)
If they are really 'splitting straws' they may have already reached the threshold of usefull ness for attempting judging samples of that age.
Are there that many other sites around the world (to that range) that they can coroborate THIS data set with ???
You're right (well not about the beta particle bit). I misunderstood the misunderstanding :)
Well, some of us are geologists who date rocks, you insensitive clod.
So, how do you turn N14 into C14? With a hammer?
So many levels of imaginary history here ...
How many Neanderthal fossils do we have? A handful.
How many have been discredited by darwinists? All of them.
Who is rigging the science journals to keep out differing view points? The people who believe global warming is real.
So basically imaginary people were made extinct by an imaginary problem.
There is an account of a lab dating a sample as being 200,000 years old but When they told the CoalMiner the sample came from he was very surprised.
also with any radioisotope dating you can get a rather large spread even in the same chunk of "stuff" (and with the same technique also) this is even Order of Magnitude level differences.
Any person using FTFY or editing my postings agrees to a US$50.00 charge
Hitting an N14 nucleus with a neutron would be the usual method in the atmosphere. Though you could hit C13 with a neutron too amongst other things, but there's a lot of N14 in the atmosphere so that path is the overwhelming mechanism.
Are you lost, little one?
Free Martian Whores!
If a day is an era, why are an evening and a morning even mentioned?
The use of "day" in Genesis 1 is an illustration, just as Jesus used illustrations in his ministry.
Following the 7th day, Adam fell into sin and was expelled from the Garden.
What makes you say "following the seventh day", as opposed to the seventh day being the present era?
Carbon dating is fine, but when they decide to marry, it's Adam and Eve, not Atom and eV!
N14 is 7 protons + 7 neutrons. Add a neutron to that and you've got N15 (7 protons + 8 neutrons).
To get to C14 from N14 you've got to turn a proton to a neutron. (Carbon has 6 protons. C13 has 6 protons and 7 neutrons, C14 has 6 protons and 8 neutrons).
Roughly speaking proton + electron <-> neutron, so
N14 + beta <-> C14
Obviously you could get from C13 to C14 by neutron capture, but that's not what we're talking about here.
or am I dumb?
What does this have to do with Jurassic park plausibility?
Not dumb, misinformed. It's
N14 + neutron -> C14 + proton
The decay of C14 to N14 is beta decay, but C14 production isn't the reverse of that - it's a thermal neutron knocking out a proton (well to over simplify).
We'd know for certain whether eating bacon cheeseburgers, sticking our willies up other men's bottoms or wearing a wool sweater with cotton trim is OK.
The Mosaic dietary law worked for its time, protecting the health of the Jews for over a millennium. Though many of the specifics were no longer needed by 33 CE due to improvements in general sanitation, the general principles on which God operates have not changed. True, the way the Judaizer controversy about circumcision was handled (Acts 15; Galatians 2:11-14) appears to repeal a lot of the old laws. But the way I see it, if a law follows from loving one's neighbor or is otherwise reiterated in the Greek Scriptures, it's still something God wants us to do. For example, the commandment to put a railing around the roof of your house so that people don't fall off (Deuteronomy 22:8) follows from "you must not murder", which follows from "love your neighbor as yourself." The commandment not to have gay sex (Leviticus 18:22) is reiterated by Paul (Romans 1:27). The laws about specific composition of clothing (no mixed fabrics, blue thread, tassels) are not; those were intended to establish a distinct Jewish culture. But what the leadership of Pharisaic Judaism did to the Son of God shows that Jews are no longer God's chosen people. As for bacon cheeseburgers, start with Peter's vision of a sheet with animals (Acts 10). This and the resolution of the circumcision problem show that the dietary laws are no longer needed to protect God's people, except for the part about eating or shooting up blood (Acts 15:29).
What bothers me about the article is that they pretend that the best data we had was 14000 years. In the 90's this lake was used to calculate back as far as 45000 years. See this article in Science from 1998.
Science 20 February 1998:
Vol. 279 no. 5354 pp. 1187-1190
DOI: 10.1126/science.279.5354.1187
http://www.sciencemag.org/content/279/5354/1187.abstract