Tuesday, 30 June 2015

The creationist half life fallacy

Through various discussions with creationists I have heard two takes on nuclear decay half life, the one is purely deceitful and the other is ignorance. For this reason, I thought I would do a quick write up to explain half life in simple terms and lift the wool from some peoples eyes.

The core problem with radiometric dating is that most people do not understand half life of radioactive decay. To not be to technical, radioactive decay is when one type of atom changes into another type of atom by releasing some type of energy. For example, if there are 100 school children in a tight group and one runs away, then there are 99 children. These groups of 100 and 99 children would be atoms in our example, with the one child running away being the release of energy.

So what is half life? Half life is the time it takes for an amount of atoms to decrease to half its original amount. For example, if there are 100 houses and we destroy 50 houses over a time period of 1 year. Then the half life of house destruction would be 50 years.
This is where it all gets a little more complicated and counter intuitive. One would then expect that the next year of house destruction would leave 0 houses, in fact the number of houses left is 25!

How is this possible?
Its not that complicated really when we think of the term half life and what it is defined as (the  time it takes for an amount of atoms to decrease to half its original amount). If we take 100 houses, then after 1 year we have 50 houses. But now we have a new number of houses, and this number is 50. This means that after 1 more year we have halved 50 houses and that leaves 25 houses. Now with this new number of 25 years and we take one more year, we now have 12.5 houses.
Simulation of many identical atoms undergoing radioactive decay, starting with either four atoms (left) or 400 atoms (right). The number at the top indicates how many half-lives have elapsed. Note the law of large numbers: With more atoms, the overall decay is less random.

So, what about the other group that are deceitful you may ask. Simply put they argue (with zero evidence) that the half life of nuclear decay varies with time. Are these people ignorant? No, this is a lie and they know it. SCUM, that's all I have to say scum.