Imagine you’re dead. You’re floating up through the clouds, heading for the pearly gates, and you turn for one last look at this green-and-blue planet and whatever you did with your time here. What’s going to be on your mind? If you’re reading this, you can’t give me a factual answer to that question. So guess. People will be on your mind, right? You might feel love, or grief. Or surprise [“Wait, I’m dead? Like, dead dead?”].

They say a waterfall is created when the softer under-rock erodes faster than the upper layer. As the soft rock is swept away, the hard rock is left unsupported. Eventually, it falls under its own weight combined with the weight of the water, and the waterfall moves upstream. Once the harder rock is all broken away, there won’t be a waterfall anymore. Just rapids at first, then a swift-flowing stream, then a gentle river. I