Smaller and smaller into infinity?

Can size shrink down into infinity? Is there some physical minimum size that cannot be broken down further? If so, why can’t that just be cut in half, and so on?

Not just mathematically, I mean with the matter of our universe.

Well, there’s the Planck length. According to some theories that’s the smallest meaningful distance.

That is correct. As to why it is the value it is, it is similar to the speed of light in a vacuum (and those two values are related). No one knows why they are what they are but they are universal constants resulting from something deeper about the nature of the universe that isn’t yet known. Figuring that out would be a giant breakthrough in theoretical physics.

The Planck length is still somewhat a product of theory, isn’t it? That is, what is the size of the smallest indivisible particle? I would think it’s much larger than a Planck length. Not sure if the OP is asking about the size of matter or space.

I read the question as size but there is an answer for matter as well. The smallest unit of chemical matter is the atom but there are subatomic particles including protons, electrons, and neutrons. Those can still be subdivided further however and are made up of quarks, gluon, and leptons. You quickly get into quantum mechanics in the later subdivisions however where conventional ideas about energy and matter as well as time break down. The Planck length is still relevant there somehow and is a universal constant underlying it all.

There is no theory which predicts that there is some absolute smallest possible size. There are some hypothoses and models which predict such, and in some of them, that smallest possible size might be the Planck length. But none of those models has any observational or experimental support, and they are therefore by definition not theories.

I see. The more I read about the Plank length, the less I understand.

Although I prefer to believe there is an atom in my nose that houses a world where disco is making a comeback.

Exactly, and they worship you as a deity that they love with all their hearts. One day, you break out too much black pepper and their world is done man.

There really isn’t anything to understand about it. You get the Planck length by banging together a few physical constants in a particular way, and some folks have made some semi-educated guesses that something interesting might happen at that length scale, but nobody knows of any particular significance of those constants banged together in that way.

The Planck length is equivalent to one pixel in the simulation. After all, even Intergalactic Supercomputers don’t have infinite resolution.


There’s always author Larry Niven’s short story “Convergent Series”…

You yourself already are a world: why are we so certain that our cells have no freedom of choice, no internal life, no perceptions? White cells that follow the Bushido warrior ethic, red cell Salarymen? The “little man” that runs your brain is actually a large government of many voters, each living in a small community and dealing with neighbors and the constant flow of delivery vehicles.

If the neighbors are playing loud music, probably ALL of them are, and it ends up all mashed together and mistaken for “thermal noise.” So go and record the IR absorption spectra of a tiny patch of living material, then time-resolve those pure frequencies at femtoseconds.

Then see if it has a beat.

Scanning Electron Microscope Gnarles Barkley

Eh, they get it wrong: air at scale of dust mites has low Reynolds number, behaves like syrup or even putty, so rock music would needs be entirely electromagnetic.

Did someone put LSD in my soda? I’m pretty sure I didn’t just read that.
Wow. Can I have some more?

Dude, like, there’s this hippie commune in my kidneys and stuff. You gotta try some of this lettuce.

Useful only to subatomic pirates.

God bless the Dope. Someone asks a perfectly sensible question touching on physics, mathematics and philosophy, and it gets hijacked by a couple of spaced out Sith Lords.

I find your lack of faith… oh wow… look at my haaannndd

Because the thing doing the cutting would, by definition, already be smaller.


Matey, we be plunderin’ many electrons today. Arr! We be the strong force o’ the seas.

Do subatomic pirates make their victims walk the Planck?