So geologists have assumed these radioactive decay rates have been constant for billions of years.
However, this is an enormous extrapolation of seven orders of magnitude back through immense spans of unobserved time without any concrete proof that such an extrapolation is credible.
The rate of uranium decay must have been at least 250,000 times faster than today’s measured rate! As this article has illustrated, rocks may have inherited parent and daughter isotopes from their sources, or they may have been contaminated when they moved through other rocks to their current locations.
Or inflowing water may have mixed isotopes into the rocks.
We find places on the North Rim where volcanoes erupted after the Canyon was formed, sending lavas cascading over the walls and down into the Canyon.
Obviously, these eruptions took place very recently, after the Canyon’s layers were deposited ().
For the other radioactive “clocks,” it is assumed that by analyzing multiple samples of a rock body, or unit, today it is possible to determine how much of the daughter isotopes (lead, strontium, or neodymium) were present when the rock formed (via the so-called isochron technique, which is still based on unproven assumptions 2 and 3).No geologist was present when the rocks were formed to see their contents, and no geologist was present to measure how fast the radioactive “clock” has been running through the millions of years that supposedly passed after the rock was formed.No geologists were present when most rocks formed, so they cannot test whether the original rocks already contained daughter isotopes alongside their parent radioisotopes.Yet this view is based on a misunderstanding of how radiometric dating works.Part 1 (in the previous issue) explained how scientists observe unstable atoms changing into stable atoms in the present.This source already had both rubidium and strontium.