How big is the observable universe?

In an attempt to understand my place in the cosmos, I wanted to create a pithy analogy that would sum up the vastness of everything in a concise image. Preliminary research went well. I learned that the observable universe has a volume of 4 x 1080 m3, Earth has a volume of 1.083 x 1021 m3, the Atlantic Ocean is 3.104 x 1017 m3 and, going the other way, a grain of sand is 1 x 10-13 m3*.

These numbers didn’t feel intuituve to me. I wanted to find out how equivalent Earth versus the universe is compared to a grain of sand, or a molecule, versus the sea. That might be sufficient if I had a real notion of how large Earth is… which I probably don’t. I bungled the maths and ended up with a variety of numbers that were all too big to understand. Giving up for now, I decided to read a translation of Nagarjuna’s ‘Examination of Conditions’ and failed to understand any of that either. I suppose I was looking to be humbled in a way that made me feel clever.

*All according to Wolfram Alpha.