How many galaxies are there in the observable universe? How many cells are there in the human body?

We know both of these numbers must be really big. But which is bigger?

No one has counted all the cells and all the galaxies one by one, so any number will be an estimate. But estimates are not just guesses.

Scientists actually have counted the number of cells in some multicellular organisms. A tiny transparent worm called Caenorhabditis elegans, a common laboratory animal, was the first multicellular organism to have its complete genome sequenced.