This challenge is mainly headed by Creationism which teaches a young-earth (YE) theory.

Most people accept the current old-earth (OE) age estimate of around 4.6 billion years.

This age is obtained from radiometric dating and is assumed by evolutionists to provide a sufficiently long time-frame for Darwinian evolution.

One early approach was based upon ocean salinity [John Joly, 1800's].

This assumed the ocean was initially pure water and that it's salinity was derived from continental erosion.

One problem with earth dating is that the original earth surface is assumed to have eroded long ago.

But assuming the earth was formed at the time of the rest of our solar system, then recovered moon rock and meteorites can also be used to estimate the age of the earth.

Radioactive parent (P) atoms decay to stable daughter (D) atoms e.g.

the carbon isotope C-14 decays to nitrogen-14 and the uranium isotope U-235 decays to the lead isotope Pb-207.

The earth precesses (wobbles like a spinning top) around the sun in a series of cycles.

These cycles affect sunlight and hence long-term can form layers in rock.

These estimates give 4.4-4.5 billion years for moon rock, and 4.54 billion years for iron metreorites.