Think Critically

Just Because I Say So Don't Make it So.

How Old is the Earth?

So the Earth is very old, right? How do you know? Look at some images of the Grand Canyon like the one above. All the layers of rock are laid down one after the other. Not much doubt about that. Top layer cannot be laid down until all the others below it.

How long did each layer take to be laid down? Millions of years right? How do you know?

https://pubs.usgs.gov/of/2005/1309/

UNIFORMITARIANISM

One method to estimate the age of each layer uses "uniformitarianism" which basically says :

  1. Let's experiment to see how quickly sediment collects around the world. So you measure the sediment collection in a stream, a lake etc. If you get x inches in y years then you declare that you can get x/y = R inches per year. If you assume this is constant over the distant past then you can estimate the time required to lay down H inches by computing H/R = Time.

  2. So if you measure the height (H) of each layer in the Grand Canyon (or anywhere) you can estimate how long it took to build the layer.

  3. SIMPLE! Right?

  4. So the calculations indicate the Grand Canyon is millions of years old.

But is it true that rates of geological change have been relatively constant? What about catastrophes?

Famous Catastrophes

Mt. Saint Helens

So how could this bend without breaking? The deep "old" layers must be millions of years old. Surely they are hard by the time the rock is bent. Why didn't they crack?

Is it possible there is something not so simple in the forces that bend rock?

Is it possible the top layer was deposited in some way that did not involve sedimentation?

Is it possible the layers are not as old as you think?

If you assume rates of deposition in the past are the same as we see today, then sure it takes a long time to deposit the layers.

But if there was one or more catastrophic events that deposited the layers, maybe they were laid down quickly.

You Think About It!