Thread: Space cannot be infinite

I know this thread is a little bit old, but my high school math teacher ALWAYS talked about "the limit". Here's his example from what I can remember:

"If I stand x amount distance from the wall, and then decrease my distance by 50%, will I ever hit the wall?"
"No."
"But will I appear to be touching the wall eventually? The answer is yes. I may be physically touching the wall, however if we go down on an atomical level, I will never, ever, touch the wall."

Space is infinite.

Who's to say it is limited to one universe, and not a multiverse, anyway?

Originally Posted by Exhalent

Who's to say it is limited to one universe, and not a multiverse, anyway?

No one. But science can only affirm what has been observed. If other thinsg exist, but there can never be contact between those and us, it'll be as if they didn't exist. Aka Schrodinger's cat.

Originally Posted by billygan

... however if we go down on an atomical level, I will never, ever, touch the wall."

Why?

Yes, atoms do 'touch' when two objects touch.

The nuclei of atoms don't touch, but nobody ever said they did.

The electron clouds surrounding the nuclei - which are what give atoms volume - do touch, and they repel, because of the like negative charges. That's what touching is.

Originally Posted by Xei

Yes, atoms do 'touch' when two objects touch.

The nuclei of atoms don't touch, but nobody ever said they did.

The electron clouds surrounding the nuclei - which are what give atoms volume - do touch, and they repel, because of the like negative charges. That's what touching is.

Electron clouds are not physical. An electron cloud is nothing but a region where it is more likely to find an electron in a given situation. That said, electron clouds don't usually touch either (at least in normal circumstances) - the repulsive force becomes too strong before they do collide. But you're not to say nuclei don't touch - they did in Rutherford's experiment, like a century ago.

The point is, people often spread around this idea that objects never actually touch, when it isn't really true. Touching is only electrostatic repulsion anyway.

Electron clouds are arbitrary; they are volumes in which an electron has a certain probability of being found. Any electron clouds can touch if you allow the probability to be high enough (electrons can potentially be found infinitely far away from a nucleus).

About nuclei touching; actually it's kind of arbitrary on the subatomic level too. Nucleons aren't spheres at all, they are just sets of three coordinates (quarks). They are arbitrarily assigned a radius at which the strong and electrostatic forces cancel, but it doesn't really represent a physical boundary.

Originally Posted by Xei

The point is, people often spread around this idea that objects never actually touch, when it isn't really true. Touching is only electrostatic repulsion anyway.

Electron clouds are arbitrary; they are volumes in which an electron has a certain probability of being found. Any electron clouds can touch if you allow the probability to be high enough (electrons can potentially be found infinitely far away from a nucleus).

About nuclei touching; actually it's kind of arbitrary on the subatomic level too. Nucleons aren't spheres at all, they are just sets of three coordinates (quarks). They are arbitrarily assigned a radius at which the strong and electrostatic forces cancel, but it doesn't really represent a physical boundary.

Quarks aren't points. They are the smallest thing we know, and probably the smallest thing that we can observe, but not points.

There's no evidence that quarks have any dimensions. Same goes for leptons (leptons and quarks make up the entirety of matter).