2006-06-13 12:40:50 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Biology
*NOT CARBON DATING!* Why do people all make the same mistake?? This is a common misconception (happily encouraged by creationists).
Carbon dating (or radiocarbon dating) is just one of *many* forms of radiometric dating ... but only useful up to about 60,000 years ago and thus is practically useless for most fossils.
And radiometric dating is just one of *many* forms of dating fossils and rocks.
Besides radiometric dating, other methods of dating fossils are dendrochronology (matching tree rings in wooden artifacts), paleomagnetic dating (the reversals in the earth's magnetic field), ice cores, varves (counting layers of sedimentary deposits), superposition, stratigraphy, etc. etc. All of these are good for dating overlapping time ranges ... and where the ranges overlap they confirm and calibrate each other. (My first link under Sources gives a great overview of many of these different methods.)
Carbon dating is used for dating once-living tissue like bones or wood (*not* fossils) and is very accurate, but only to about 50,000 to 60,000 years ago ... much younger than most fossils. Why? Because carbon-14 decays with a very short half-life of only 5,730 years (which is why it is so accurate). For dating older things like fossils, we use isotopes of radioactive materials that decay with a much longer half-life. Each technique is named after an atom that decays at a known rate (half-life) into another atom. For example, potassium-argon dating measures the decay of potassium-40 to argon-40 with a half life of 1.26 *billion* years (!). There are literally dozens of other methods, and again, because they overlap, they all confirm and calibrate each other.
2006-06-13 13:11:52 · answer #1 · answered by secretsauce 7 · 0⤊ 0⤋
The short answer is "carbon dating". The long answer is about how every living thing has a lot of carbon in it while it is alive. Some of this carbon exists randomly as an unstable isotope known as carbon-14. When the organism dies the carbon-14 in the bones decays back to stable carbon-12 or 13. This decay takes a very long time and but happens at a steady, predictable rate which can be used to measure how long ago something died based on how much carbon-14 is left.
2006-06-13 12:46:12 · answer #2 · answered by Charles T. Spencer III 2 · 0⤊ 0⤋
The actually can't determine the absolute age, carbon dating only gives them a broad range of years. Usually that range is good enough, but an exact year is currently impossible.
2006-06-13 12:44:13 · answer #3 · answered by Bobby D 3 · 0⤊ 0⤋
Carbon dating, but I think there is now a more accurate method used. I forget, ask your dumbass science teacher and then tell them that, "thats what happens when Alex Trebeck has a picture of a giraffe up his *** during an earthquake"
2006-06-13 12:44:16 · answer #4 · answered by Rock Skull 2 · 0⤊ 0⤋
scientist determine the age of fossils based on evidenceof other discoveries. they also detirmine what a fossil is by looking at the characteristics of modern animals.
dude, this is an elementary question, where have you been this was taught in seventh grade, i should know i'm in seventh grade!!!!!!!!!!!!!!!!!!! ha :)
2006-06-13 12:47:20 · answer #5 · answered by alexzandra 2 · 0⤊ 0⤋
i just learned this..they use carbon dating..which determines about to the decade of how old it is..carbon dating uses a special type of carbon to determine how old it is...but it isnt exact down down to the month and year...
2006-06-13 12:44:13 · answer #6 · answered by Anonymous · 0⤊ 0⤋
carbon dating
2006-06-13 12:42:21 · answer #7 · answered by Shopaholic Chick 6 · 0⤊ 0⤋
through carbon dating.
2006-06-13 12:42:55 · answer #8 · answered by jo 2 · 0⤊ 0⤋
they DETERMINATOR the fossils by...do you know who this is? the governor of california!!!!!!!!!!!!!!!!!
2006-06-13 12:44:17 · answer #9 · answered by Anonymous · 0⤊ 0⤋