His result was in close agreement with his estimate of the age of the earth.
The solar estimate was based on the idea that the energy supply for the solar radioactive flux is gravitational contraction.
Of course, the detected variation is no more than 0.2% of the published rates, but this paper is still quite interesting since such a correlation was never suspected before.
If magnetic fluxuations or other influencing forces are strong enough, radiometric decay rates could be much more significantly effected.
Many granites that contain polonium radiohalos appear from their geologic contexts to have been formed during the Flood, and therefore cannot have been primordial (that is, created) granites as Gentry has suggested ( Link ).
Most sedimentary rocks such as sandstone, limestone, and shale (which do contain fossils) are related to the radiometric time scale by bracketing them within time zones that are determined by dating appropriately selected igneous rocks in lava flows, or weathered from lava flows.
Other factors and basic assumptions must also be considered.
Of course, Kelvin formed his estimates of the age of the Sun without the knowledge of fusion as the true energy source of the Sun.
However, on the whole, he thought that these sources were not adequate to account for anything more than a small faction of the heat lost by the Earth.
In short, the assumption that decay rates are immune to outside influences isn't as solid as it once appeared to be.
However, if one does assume a constant decay rate, and if one starts with an originally pure sample of “parent element,” then the proportion of parent to daughter tells us the number of half-lives, which has been used to find the supposed age of igneous rocks. The conclusions of Renne and his team read as follows: Ar can be identified in volcanic sanidine, and while perhaps negligible in pre-Holocene rocks, it has important consequences for sample at the limit of the method’s applicability.
was published, the earth was "scientifically" determined to be 100 million years old. In 1947, science firmly established that the earth was 3.4 billion years old.
Finally in 1976, it was discovered that the earth is "really" 4.6 billion years old… The answer of 25 million years deduced by Kelvin was not received favorably by geologists.