Changes

''See also [[Counterexamples to an Old Earth]]''.

''See also [[Counterexamples to an Old Earth]]''.

'''Radiometric dating''' is a method of determining the age of an artifact by implausibly assuming that decay rates have been constant (see below for the flaws in that assumption) and measuring the amount of radioactive decay that has occurred.<ref>[http://pubs.usgs.gov/gip/geotime/radiometric.html Radiometric Time Scale] USGS</ref> Radiometric dating is mostly used to determine the age of rocks, though a particular form of radiometric dating&mdash;called [[Radiocarbon dating]]&mdash;can date wood, cloth, skeletons, and other organic material.

'''Radiometric dating''' is a method of determining the age of an artifact by assuming that on average decay rates have been constant (see below for the flaws in that assumption) and measuring the amount of radioactive decay that has occurred.<ref>[http://pubs.usgs.gov/gip/geotime/radiometric.html Radiometric Time Scale] USGS</ref> Radiometric dating is mostly used to determine the age of rocks, though a particular form of radiometric dating&mdash;called [[Radiocarbon dating]]&mdash;can date wood, cloth, skeletons, and other organic material.

Because radiometric dating fails to satisfy standards of testability and [[falsifiability]], claims based on radiometric dating may fail to qualify under the ''[[Daubert]]'' standard for court-admissible scientific evidence.  It is more accurate for shorter time periods (e.g., hundreds of years) during which control variables are less likely to change.

Because radiometric dating fails to satisfy standards of testability and [[falsifiability]], claims based on radiometric dating may fail to qualify under the ''[[Daubert]]'' standard for court-admissible scientific evidence.  It is more accurate for shorter time periods (e.g., hundreds of years) during which control variables are less likely to change.

=== Initial quantities ===

=== Initial quantities ===

One key assumption is that the initial quantity of the parent element can be determined.  With uranium-lead dating, for example, you must be able to determine how much uranium was in the sample to start with.  One assumption that can be made is that all the lead in the sample was once uranium, but if there was lead there to start with, this assumption is not valid, and any date based on that assumption will be incorrect (too old).

One key assumption is that the initial quantity of the parent element can be determined.  With uranium-lead dating, for example, the process assumes the original proportion of uranium in the sample.  One assumption that can be made is that all the lead in the sample was once uranium, but if there was lead there to start with, this assumption is not valid, and any date based on that assumption will be incorrect (too old).

In the case of carbon dating, it is not the initial quantity that is important, but the initial ratio of C¹⁴ to C¹², but the same principle otherwise applies.

In the case of carbon dating, it is not the initial quantity that is important, but the initial ratio of C¹⁴ to C¹², but the same principle otherwise applies.

=== Rate of decay ===

=== Rate of decay ===

Another assumption is that the rate of decay is constant.

Another assumption is that the rate of decay is constant over long periods of time.

There is no reason to expect that the rate of decay of a radioactive material is largely constant,<ref>At least one example of a change in the rate has been observed in laboratory experiments.  See Walker, 2000.</ref> and it was almost certainly not constant near the creation or beginning of the universe.

There is no reason to expect that the rate of decay of a radioactive material is largely constant,<ref>At least one example of a change in the rate has been observed in laboratory experiments.  See Walker, 2000.</ref> and it was almost certainly not constant near the creation or beginning of the universe.

The process of decay is as follows.  Atoms consist of a heavy central core called the [[nucleus]] surrounded by clouds of lightweight particles (electrons), called [[electron shell]]s. The energy locked in the nucleus is enormous, but cannot be released easily. The phenomenon we know as heat is simply the jiggling around of atoms and their components, so in principle a high enough temperature could cause the components of the core to break out. However, the temperature required to do this is in in the millions of degrees, so this cannot be achieved by any natural process that we know about. The second way that a nucleus could be disrupted is by particles striking it. However, the nucleus has a strong positive charge and the electron shells have a strong negative charge. Any incoming negative charge would be deflected by the electron shell and any positive charge that penetrated the electron shells would be deflected by the positive charge of the nucleus itself.

The process of decay is as follows.  Atoms consist of a heavy central core called the [[nucleus]] surrounded by clouds of lightweight particles (electrons), called [[electron shell]]s. The energy locked in the nucleus is enormous, but cannot be released easily. The phenomenon we know as heat is simply the jiggling around of atoms and their components, so in principle a high enough temperature could cause the components of the core to break out. However, the temperature required to do this is in in the millions of degrees, so this cannot be achieved by any natural process that we know about. The second way that a nucleus could be disrupted is by particles striking it. However, the nucleus has a strong positive charge and the electron shells have a strong negative charge. Any incoming negative charge would be deflected by the electron shell and any positive charge that penetrated the electron shells would be deflected by the positive charge of the nucleus itself.