How old is the earth? Genesis genealogies and the scientific record

The passages

And Adam lived an hundred and thirty years, and begat a son in his own likeness, after his image; and called his name Seth.

Genesis 5:3

And all the days that Adam lived were nine hundred and thirty years: and he died.

Genesis 5:5

For in six days the LORD made heaven and earth, the sea, and all that in them is, and rested the seventh day.

Exodus 20:11

The problem

If the ages in Genesis 5 and 11 are added up as written, and combined with the chronology of later books, Adam lived roughly six thousand years ago. In 1650 James Ussher worked out a date of 4004 BC for the creation. Modern geology, using the decay of radioactive elements in rock and meteorites, puts the age of the earth at about 4.54 billion years, and cosmology puts the universe at about 13.8 billion. Many independent methods agree: ice cores, tree rings, lake sediments, the fossil record, the cooling of the oceanic crust.

What believers and scholars say

Young earth. Some Christians accept the plain reading and argue that the scientific dating is wrong or built on faulty assumptions, for example about decay rates or the conditions of the early earth. They typically propose that a global flood reshaped the geological record. Most professional scientists reject these claims, including most Christian scientists.

Gaps in the genealogies. Green argued in 1890 that Hebrew "begat" and "son of" can skip generations, so the genealogies cannot be added up. If so, the age of humanity is open. This is widely accepted, though the large numbers of years in Genesis 5 and 11 do look like a deliberate count.

Old earth readings of "day". The Hebrew yom can mean a period, so some read the six days as ages. Others read them as a literary frame. Walton argues that the days describe the setting up of a cosmic temple and make no claim about the age of the material world.

Evolutionary creation. Many mainline and Catholic Christians hold that God created through natural processes over billions of years and that Genesis tells who made the world and why, not how.

Where this leaves it

The plain sum of the genealogies and the measured age of the earth are far apart, and no one disputes that. The disagreement is over which gives way: the science, the reading of the text, or the idea that the text is giving a chronology at all. Different churches have taken each of those three roads.