# Carbon dating **URL:** \ **Category:** Factual Questions\ **Created:** [June 18, 1999, 1:10pm UTC](https://boards.straightdope.com/t/carbon-dating/1295 "1999-06-18T13:10:00Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [June 18, 1999, 1:10pm UTC](https://boards.straightdope.com/t/carbon-dating/1295/1 "1999-06-18T13:10:00Z")
i heard a rumour the other day that carbon dating was hopelessly unreliable and was confused, is this true or just another unfounded attempt at discrediting science? moari fulla ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [June 18, 1999, 1:13pm UTC](https://boards.straightdope.com/t/carbon-dating/1295/2 "1999-06-18T13:13:00Z")
It is actually very reliable but it depends on how old the object is. It is acurate to ± 500(I think) years which seems terrible but when you have a dinosaur bone that’s 200 million years thats not to bad (of course if you try to date something that you threw away last week it proabable won’t work. ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [June 18, 1999, 3:50pm UTC](https://boards.straightdope.com/t/carbon-dating/1295/3 "1999-06-18T15:50:00Z")
> [@](#): > > but when you have a dinosaur bone In this case, Potassium-Argon dating is used… I’m wondering if the person who told you about carbon dating being inaccurate is a religious zealot who believes in the authenticity of the “Shroud of Turin.” * * * “[He] beat his fist down upon the table and hurt his hand and became so further enraged… that he beat his fist down upon the table even harder and hurt his hand some more.” – Joseph Heller’s Catch-22 ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [June 18, 1999, 4:05pm UTC](https://boards.straightdope.com/t/carbon-dating/1295/4 "1999-06-18T16:05:00Z")
Carbon dating is accurate, but you have to buy into certain premises to believe it. In the upper atmosphere, a certain amount of Nitrogen is converted into carbon-14, a radioactive isotope of carbon with a very long half-life. Some of this carbon then becomes intermingled into every living thing on earth through breathing and eating. When that thing dies, the carbon-14 begins decaying to regular carbon-12. By measuring the concentrations of carbon-14 in a bone, and comparing it to concentrations in living things today, scientists can guess how long ago that animal lived. The premises you have to accept are that living things have always had the same percentage of carbon-14 as they do today, and that the particular animal had an average amount which decayed at an average rate. * * * That’s the way that it is on this bitch of an earth." – Pozzo, _Waiting For Godot_ ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [June 18, 1999, 4:08pm UTC](https://boards.straightdope.com/t/carbon-dating/1295/5 "1999-06-18T16:08:00Z")
Carbon dating is an extremely accurate way to tell when a plant died. It is useful to about 50,000 years ago. The correlation of isotope ratios with the dendrochronological record has allowed dating to +/- 5 years for archeological sites. Bad results can be obtained if the correct procedures are not followed. For instance, it has been shown that C12/C14 ratios for organisms which do not gain their carbon from atmospheric CO2 cannot be dated by this method. But when used correctly, carbon dating is the most reliable tool for determining the age of artifacts. ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [June 18, 1999, 9:53pm UTC](https://boards.straightdope.com/t/carbon-dating/1295/6 "1999-06-18T21:53:00Z")
I dated a carbon once, I took her out for a movie and softdrink, and she … oh, wait. Sorry. ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [June 19, 1999, 12:22am UTC](https://boards.straightdope.com/t/carbon-dating/1295/7 "1999-06-19T00:22:00Z")
Radiocarbon dating has been verified in just about every way you can think of. One of the most precise ways is through dendrochronology. Lumber, wooden carvings, trees, tree fossils, and so on are compared thusly: during certain years, tree growth rings show tell-tale signs of having been formed during a year of a significant volcanic eruption. Each volcanic eruption spews a specific mix of certain chemicals into the atmosphere, and large ones can spread their signatures over a good chunk of the globe. By comparing tree ring signatures, completely accurate comparative calendars can be constructed. (You thought your job was tedious.) Dendrochronology has dated various stuff as far back as 2000 BCE the last time I checked, and radiocarbon dating of these wood samples proves that radiocarbon dating is dead on. (within plus-or-minus 3 percent.) Of course, radiocarbon dating is only one tool used to date an item. Comparing artistic styles, inscriptions, considering where and in what layer an item is found, whether the item is mentioned in contemporary literature . . .there are lots of different data that are figured into dating any archaeological or paleontological find. As long as you have a good sample to work with, and your equipment is functioning correctly, you can bet the farm on radiocarbon dates.