There are a few questions that have perplexed humans for all of recorded history, ranging from the nature of matter to the origin of the Universe to whether there are limits to what is knowable in principle about all there is. One of the great questions that people have wondered about since ancient times — that we still wonder about today — is whether there’s a fundamental smallest scale to the Universe or not.
From the ancient paradoxa posed by Zeno to Heisenberg’s uncertainty principle, it might seem like there either could or couldn’t be a fundamentally smallest scale; maybe the uncertainty in measurement is just our uncertainty, and maybe isn’t inherent to the Universe at all. Or maybe it is fundamental, after all.
An outstanding exploration of the smallest possible scale from Sabine Hossenfelder; go read the whole thing!