What is less commonly known are any of the details of how the issue was settled: such as that the 4.5 billion year 'date' came from a single meteorite that was assumed to be the same age as the earth's core.And since this favored 'date' is the only one that's trumpeted by the media it is the only date that many assume to be correct.We can get absolute ages only if we have rocks from that surface.For others, all we are doing is getting a relative age, using things like the formation of craters and other features on a surface.
We can then use radioactive age dating in order to date the ages of the surfaces (when the rocks first formed, i.e. We also have meteorites from asteroids and can date them, too.
The biggest assumption is that, to first order, the number of asteroids and comets hitting the Earth and the Moon was the same as for Mercury, Venus, and Mars. The bottom line is that the more craters one sees, the older the surface is.
This can be interpreted in two ways: why it is important to know the age of a planet or how is age dating important in determining the age of a planet?
Many minerals, such as zircon, contain minute quantities of two forms of uranium, with atomic weights of 235 and 238.
Each decays at a constant rate into lead atoms with weights of 207 and 206, respectively.