For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse.—Romans 1:20
Paul says we can see observe God's power and nature just by looking around at the things He created. Though Paul did not know it existed, I think he would have used the Grand Canyon as Exhibit A for his argument. Few can approach that vast and rugged expanse without coming to the realization that something greater than ourselves exists. The mind that imagined such a thing and the hand that carved it puts our own knowledge and power to shame. It is a sight that must put doubt into the mind of the most callous atheist. If God does not exist, the Grand Canyon mocks our pride and ambitions.
Even a cursory glance at the rock formations of the Grand Canyon reveals that it is quite ancient. Geologists estimate the Colorado River has been carving out the canyon via erosion for at least 5 million years. The topmost layers of rock the river cut through were laid down hundreds of millions of years ago and the rock at the base of the canyon dates back a billion years. With no knowledge of geology at all, it stretches credulity to imagine the Grand Canyon being formed in a few thousand years. God's fingerprints are all over His creation and He seems to have taken the time to do things right.
"Where were you when I laid the foundation of the earth?
Tell me, if you have understanding.
Who determined its measurements—surely you know!
Or who stretched the line upon it?
On what were its bases sunk,
or who laid its cornerstone,
when the morning stars sang together
and all the sons of God shouted for joy?"—Job 38:4-7
The fact is none of us were there when God created the universe and we all need to interpret the evidence He left for us. The evidence found in nature suggests a very long period of creation and the evidence found in Genesis suggests a very short period of creation. Genesis was written to a people surrounded by cultures that believed the natural world was eternal and spawned gods. Chaos and strife fill the mythology of the time as gods contended the world, people, and each other. By contrast, the God of Genesis is Himself eternal. Nothing can successfully contend with Him since He holds all power and created all things. The six days of creation clearly show Him to be a force for order in sky, sea, and land. On the seventh day, He rested to show, with the number of completeness, that His work of creation was over.
Without question God could have created everything in a literal week. But just as the universe turns out to be mind-boggling larger than the ancient people thought, it should not be a surprise that it is also immensely older than anyone can comprehend. From our perspective, the act of creation must have occurred over long ages, but to the One who speaks light into existence, shaping the Grand Canyon was the work of moments.