I often think about these kinds of numbers when talking with my father-in-law, who's a marine geologist, and who regularly talks about time in millions of years

I often think about these kinds of numbers when talking with my father-in-law, who's a marine geologist, and who regularly talks about time in millions of years. I wonder if he has a real grasp of the scale of what that means, in the same way that I might understand hours / days / months / years / decades. The only way he can explain it to me is by metaphor, which is what this post does. It's sort-of-effective, but what it mainly does it prove to me how little I comprehend numbers like that. I find even centuries are a little difficult to wrap my head around.