Sixth Post
Pitfalls of RadioCARBON Dating
Hey, y’all!
Pax Christi!
And a grace-filled Byzantine Calendar Feast of St. Leontius, Martyr and Gregorian Calendar Feast of St. Ephrem, Deacon, Confessor, and Doctor of the Church!
A subdivision of radioactive dating is radioCARBON [emphasis mine] dating.
It is unique because it claims to measure the age of materials that contain the organic element of carbon, i.e. usually the remains of once-living organisms or of past human activity (textiles, ashes, etc.), and is thus widely used in archeology and in dating dead organisms. Since all living creatures incorporate carbon into their bodies (plant, animal, or human), it makes sense to use it for radioactive dating bc it has a radioactive isotope.
The general premise behind radiocarbon dating is the same as for all other radioactive dating, as explained in the Fifth Post: a radioactive parent element with a known half-life radioactively decays into a daughter element, then the proportion between the two is measured to see how much of the original parent element decayed and, based on its half-life, an age is come up with.
However, in the case of carbon, which has three isotopes (see Fifth Post for a review 🤔), C-12, C-13, & C-14, with the C-14 being radioactive, having a half-life of 5700 years, there's a two-fold problem:
--C-14 turns into nitrogen (N-14), a gas when it decays. Gases don't hang around unless REALLY constrained by a crystal's molecular lattice. (Even then, they can generally diffuse out over time based on temperature differences across the crystal, etc.) And…
— Dead or burned organic matter is usually not crystalline (except for things like apatite crystals on bones, etc.: Do your homework! 🤭), so nitrogen would readily escape.
SO, the way to measure C-14 age is by looking at the proportion of C-14 to C-12 at measurement time and comparing it to what the proportion would've been at the start. The more missing C-14, the older the item. (After nearly ten half-lives, there is so little C-14 left, that measuring beyond 50,000 years is considered useless.)
Sounds pretty useful. However, there are plenty of pitfalls:
— all the shaky assumptions listed in the Fifth Post, for starters.
— C-14 is produced out of N-14 in the atmosphere by cosmic ray bombardment. The rate of that bombardment varies depending on multiple factors, including the variable strength of Earth's magnetic field, which affects cosmic ray entry, and the variable rate at which the cosmic rays themselves come in from space. (Homework, anyone? 🙄) So, given the variability of N-14 production through time, how do we know the actual initial C-14/C-12 proportion?
— C-14 is roughly seventeen percent heavier than C-12: Do different tissues in an organism absorb it more than others? (Homework time!! 🤗) Different parts of an organism would then yield different dates!
--Do researchers consider the carbon source for an organism? A living tree, amid airport runways, for example, was recently carbon dated at about ten thousand years! It was absorbing carbon dioxide from jet exhaust, which uses C-14-poor (thus dating old) fossil fuel. (Homework! 🫠)
A procedure used in the Natural Sciences to gather data, to yield true data, needs to be founded on reliable assumptions.
Our Mother of Perpetual Help, aid us!
Ademar