How long did it take, exactly? Science measures. Anything else you take on faith, yes?
>>>> Not the least of which is how long it would take to deposit the layers of the grand canyon, have them compress, bend and fold and then have water wear down through a mile of solid rock.
I can’t measure anything exactly. The objective is a good estimate with an error range and to eliminate things that are not true.
For water to dig a hole 20 miles wide and a mile deep takes many many times longer than 6,000 years. It also takes thousands of years for a layer of sedimentary rock with bones in it to fossilize and compress. There are thousands of layers there. The rock in the area has uplifted by nearly two miles - that takes millions of years.
Clearly the canyon itself is on the order of a million years plus and the rock its wearing down through is hundreds of millions of years old. People who study that sort of thing say you can actually rock layers dating back more than a billions years. Its pretty staggering.