Recall that atoms are the basic building blocks of matter.
Atoms are made up of much smaller particles called protons, neutrons, and electrons.
They have their work cut out for them, however, because radiocarbon (C-14) dating is one of the most reliable of all the radiometric dating methods.
Because the exact amount of time this accretion process took is not yet known, and the predictions from different accretion models range from a few million up to about 100 million years, the exact age of Earth is difficult to determine.
The age of the earth has been a topic of debate among Christians over the last two centuries.
Several Christian ministries promote the idea that the earth is less than 10,000 years old, which they say comes from the Bible.
Archbishop Ussher took the genealogies of Genesis, assuming they were complete, and calculated all the years to arrive at a date for the creation of the earth on Sunday, October 23, 4004 B. Of course, even assuming the method was valid, such an exact date is not possible from the genealogies of the Bible (Ussher assumed all the years the patriarchs lived were exactly 365.25 days long and that they all died the day before their next birthday).
There are a number of other assumptions implicit in the calculation.