How is there a limit to the space between atoms?

Question

I recently learned what it really means when people say space is constantly expanding. At first I thought it just meant more matter is getting created on the outer areas of the universe or something. But it’s moreso space in the spacial sense is expanding between everything, like a balloon being inflated. This opened up a realm of stuff I hadn’t thought about, with my brain struggling to comprehend how there is finite ‘space’ in that sense. Like how does existence itself have a limit to size? For distance as a concept to exist, the space between atoms has to be finite, and doesn’t break down infinitely. But my brain can’t comprehend this, similar to how it can’t comprehend there being nothing before the big bang. It obviously can’t be infinite because there’d be no existsnce as we know it, but how can it be finite and exist at all?

I guess the question is, how is there a limit to the space between atoms?

In: 127

Answer 1

what is expanding is space itself, not the distance between atoms. on a small scale, atoms are bound together by what is known as the electromagnetic and “strong” force. on a large scale, structures (people, planets, stars, galaxies, etc.) are considerably affected by each other’s gravity and are not going anywhere or expanding.

for example, the milky way galaxy we live in is not getting any bigger, nor is anything inside going anywhere from each other. gravity holds everything together. however, a galaxy that’s a billion light-years away isn’t affected by gravity from the milky way and is free to flow away with the expansion of space.

if you take your example of the universe as a balloon, imagine that you draw dots on the balloon representing the galaxies. when you inflate it, imagine the dots itself aren’t getting any bigger (they actually do on a balloon but you get the idea), but the space between dots are.

so why don’t the structure that makes up space rip apart due to such enormous expansion? we don’t technically know for sure if it won’t. some say it will rip apart one day in the future in an event called the “Big Rip”. others say space is not made out of anything, and it’s more of a concept of how far away things are relative to each other than a physical thing. there are many opinions and arguments on this, but they’re not much better than hypotheses at this point.