When performing radioactive dating scientists measure the
When performing radioactive dating scientists measure the - Dirty girls chat
The radioactive decay of ‘parent’ isotopes of uranium, thorium, potassium, and rubidium to ‘daughter’ isotopes of lead, argon and strontium respectively is analogous to our hourglass ‘clock’, including these three assumptions.However, in the case of these radioactive ‘clocks’ these three assumptions can be shown to be not only unprovable, but invalid, rendering these ‘clocks’ virtually useless.
So we have seen that none of these three basic assumptions which are foundational to all the radioactive dating techniques can be proved.So geochronologists have assumed that the uranium, thorium and lead isotopic composition of particular meteorites is equivalent to the initial composition of these isotopes when the earth came into existence.This is assumed because it is supposed that these meteorites represent fragments from another planet in the solar system similar to our earth that disintegrated very early in the history of the solar system.magazine has been continuously published since 1978, we are publishing some of the articles from the archives for historical interest, such as this.For teaching and sharing purposes, readers are advised to supplement these historic articles with more up-to-date ones available by searching Snelling Some types (technically known as ‘isotopes’) of ‘parent’ elements such as uranium, thorium, potassium and rubidium are said to be radioactive because the nuclei of the atoms are unstable, resulting in readjustments between the ‘particles’ (primarily neutrons and protons) in the nuclei with time.The final assumption is, of course, that the radioactive decay rates have remained constant.
However, once again, this assumption can in no way be proved, because there were no human observers present right throughout the earth’s history to be constantly measuring the radioactive decay rates and to have recorded them.Now this ‘clock’ works because the initial conditions are known—that is, all the sand grains are in the top glass bowl and none are in the bottom one.If there is already some sand in the bottom glass bowl, then unless this amount is known the hourglass ‘clock’ cannot ‘tell’ the time.Or, some uranium might have been deposited by groundwaters into the sample, thus making it appear younger than what it really is.Indeed, geochronologists often plot the chemical analyses of the isotopes, expressed as isotope ratios, on graphs, and these often show that the parent-daughter systems have not been closed, but open.To achieve stability, some ‘particles’ are ejected from the atoms, and these moving ‘particles’ constitute the radioactivity measured by Geiger counters and the like.