The process of figuring out a rock's age often falls to the scientific techniques of radiometric dating, the most famous of which is radiocarbon dating. This process focuses on the ratio between the number of carbon-14 and carbon-12 isotopes in any once-living being: that ratio indicates how long it's been since that being was alive. But carbon is not the only element that can be dated—a whole host of others exist. In uranium-lead dating, for instance, the radioactive decay of uranium into lead proceeds at a reliable rate.

Based on the very old zircon rock from Australia we know that the Earth is at least 4.374 billion years old. But it could certainly be older. Scientists tend to agree that our little planet is around 4.54 billion years old—give or take a few hundred million.

forbes.com:

Do you believe that the Earth is 4.5 billion years old according to science, or 6000 years old according to the Bible? originally appeared on Quora: the place to gain and share knowledge, empowering people to learn from others and better understand the world.

The Earth solidified 4.54 billion years ago, plus or minus 1%. That’s a fact, and if your belief is not aligned to this fact, then you are what we call “wrong.”

This age is arrived at by several cross-checking lines of evidence, but the great antiquity of the Earth has been apparent for much of human history. True, scientific progress repeatedly found our home to be much older than previously suspected, but the widespread view that the planet is only a few thousand years old is relatively new, and has no basis in either fact or scripture.

The 6,000 year age was arrived at by James Ussher, a 17th century Irish Archbishop who counted up estimates of the ages of Abraham’s family listed in the Old Testament and calculated that the creation began (on the Julian calendar) on Saturday, October 22, 4004 BC, at 6 pm. Really.

Usher made a lot of assumptions, chose to ignore inconsistencies within even those scriptural sources known at that time, and was unaware of certain, now obvious translation issues, importantly including the way the Babylonians counted, but that’s beside the point. As William Henry Green wrote, “The Scriptures furnish no data for a chronological computation prior to the life of Abraham; and the Mosaic records do not fix and were not intended to fix the precise date either of the Flood or of the creation of the world.”

In other words, even if Ussher’s calculation were correct (it isn’t) it would only tell us when Abraham lived, not when the world was made.

But even this doesn’t matter, for as Thomas Paine reminded us, the only revelation we can really trust is the creation itself. When nature disagrees with scripture, scripture must necessarily be wrong.

Nature tells us Ussher was off by six orders of magnitude.

The Earth formed a persistent solid surface 4.54 billion years ago. Life appeared no less than 3.8 billion years ago... Neanderthals appeared in Europe about a quarter million years ago. If they were alive today, they could probably run for congress (that’s not an insult). They might even do better than those now in Congress (that is). Various groups of humans started domesticating crops and animals between 16,000 and 8,000 years ago, which is why most young Earth wackados now argue for an Earth around 10,000 years old instead of Ussher’s increasingly ridiculous 6,000.

But here’s the thing, the dendrochronologic record—last I checked—now goes back 12,000 years in some parts of the world. You don’t trust radiometric dating? Fine. Buy a magnifying class and a box of Twinkies and visit a dendro lab. Tree rings form a unique fingerprint as trees across a region are exposed to similar conditions. For this reason, overlapping ring patterns from living, dead, and fossilized trees can be lined up to build continuous series stretching back through thousands and thousands of years. 12,000 and counting. No fancy science required.

And at a certain point, the dendro dates line up with ocean core dates and pack ice dates, both of which go back hundreds of thousands of years—but that might take a little scientific know how. Easier are simple geologic strata:

This is the Grand Canyon: Those lines are sedimentation lines that form 40 major layers spanning 2 billion years of deposition. Okay, you might need a degree in geology to tell desert sand deposition from silt and to follow the series around the West to account for disconformities, but even a casual, unbiased evaluation will convince you utterly of two things: 1) The canyon was laid down by erosion through ancient sediments, not cut by any flood, and 2) those sediments were laid down over many, many, many millions of years.

And that’s just scratching the surface, so to speak. Even the Pope knows the Earth is 4.54 billion years old. When you accept it and start studying the data, you’ll discover something important...