These techniques, unlike carbon dating, mostly use the relative concentrations of parent and daughter products in radioactive decay chains.
Clearly, such huge time periods cannot be fitted into the Bible without compromising what the Bible says about the goodness of God and the origin of sin, death and suffering—the reason Jesus came into the world (See Six Days? He said, This only makes sense with a time-line beginning with the creation week thousands of years ago.
It makes no sense at all if man appeared at the end of billions of years.
The strength of the Earth's magnetic field affects the amount of cosmic rays entering the atmosphere.
A stronger magnetic field deflects more cosmic rays away from the Earth.
These techniques are applied to igneous rocks, and are normally seen as giving the time since solidification.