Is matter mostly empty space?

In summary, the most abundant element in the universe is hydrogen, which is composed of a nucleus orbited by an electron. The volume of a hydrogen atom is mostly empty space, with the single proton in the nucleus having a volume much smaller than the electron's. This apparent difference in volume and solidity is due to the motion of the electron in its orbit around the nucleus. The pauli exclusion principle and quantum effects also play a role in the amount of empty space in an atom. If all the empty space in a cubic meter of iron was removed, it would become a white dwarf, occupying about 8 cm3, but would no longer be considered iron due to the collapse of the electron shells.
  • #1
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The most abundant element in the universe is hydrogen. The hydrogen atom, like all atoms, is composed of a nucleus orbited by a(n) electron(s). The most likely orbit of the electron in a hydrogen atom, according to the Bohr model, is about 5.3 X 10-11 meters. The volume of the hydrogen atom then is about 6.24 X 10-31 cubic meters. The single proton that makes up the nucleus of the hydrogen atom has a volume of about 4.19 X 10-42 cubic meters. Hydrogen's single electron's volume is approximately 9.2 X 10-44 cubic meters. If we compare the sum of the volumes of the electron and the proton to the volume of the entire hydrogen atom, the proportion of that atom that is empty space is 99.999999999314%!

If my analysis is basically correct, it appears at first glance that matter is obviously not much different from space. Yet, we all know that matter is much different from space. The apparent difference is a result of the motion of the electrons in their orbits about the nucleus. The volume and solidity of matter is a product of motion.

Jagella
 
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  • #3
Interesting! I wonder how the result for hydrogen compares with iron? If a cubic meter of iron was reduced to a speck of solid matter (all space eliminated), would this speck be visible to the naked eye or would I need a microscope to see it?
 
  • #4
Jagella said:
The most abundant element in the universe is hydrogen. The hydrogen atom, like all atoms, is composed of a nucleus orbited by a(n) electron(s). The most likely orbit of the electron in a hydrogen atom, according to the Bohr model, is about 5.3 X 10-11 meters. The volume of the hydrogen atom then is about 6.24 X 10-31 cubic meters. The single proton that makes up the nucleus of the hydrogen atom has a volume of about 4.19 X 10-42 cubic meters. Hydrogen's single electron's volume is approximately 9.2 X 10-44 cubic meters. If we compare the sum of the volumes of the electron and the proton to the volume of the entire hydrogen atom, the proportion of that atom that is empty space is 99.999999999314%!

If my analysis is basically correct, it appears at first glance that matter is obviously not much different from space. Yet, we all know that matter is much different from space. The apparent difference is a result of the motion of the electrons in their orbits about the nucleus. The volume and solidity of matter is a product of motion.

Jagella

is there a question here somewhere?

I'm not sure it's a product of motion ... I always thought it's because of the CHARGE
 
  • #5
Oldfart said:
Interesting! I wonder how the result for hydrogen compares with iron? If a cubic meter of iron was reduced to a speck of solid matter (all space eliminated), would this speck be visible to the naked eye or would I need a microscope to see it?

That's the thing though, you cannot remove all the empty space. The closest thing I can think of would be in a Neutron star. It would cease to even be iron if you could remove the space in your block!

I'm not sure it's a product of motion ... I always thought it's because of the CHARGE

While the charge is what keeps the electron bound to the nucleus, it is actually much more complicated. The electron can only be in specific energy levels around the nucleus due to quantum effects. In addition, the pauli exclusion principle tells us that two electrons (and all fermions to be precise) cannot have the same quantum numbers and occupy the same spot in space at the same time. Since the orbitals have distinct distances from the nucleus the result is a very large amount of "empty space". Although I'm not 100% sure it is entirely empty, as the electron wave form occupies the entire orbital I think. I don't know if that is just a math thing or if it actually happening. In any case I would personally say that the direct cause of all this empty space is the pauli exclusion principle. (Or rather the effect it is describing)
 
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  • #6
Oldfart said:
Interesting! I wonder how the result for hydrogen compares with iron? If a cubic meter of iron was reduced to a speck of solid matter (all space eliminated), would this speck be visible to the naked eye or would I need a microscope to see it?
1 m3 of iron has a mass of 7.874 t. Removing all the empty space would convert it to white-dwarf-type degenerate matter, whose density is approximately 1 t/cm3 (see http://en.wikipedia.org/wiki/White_dwarf#Composition_and_structure"); so the iron would be easily visible, occupying about 8 cm3.
Of course, you could not call it iron any more (in the usual sense). The nuclei would retain their nature and separate identities, but they would no longer be iron atoms because of the collapse of the electron shells.
 
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  • #7
Silverhill said:
1 m3 of iron has a mass of 7.874 t. Removing all the empty space would convert it to white-dwarf-type degenerate matter, whose density is approximately 1 t/cm3 (see http://en.wikipedia.org/wiki/White_dwarf#Composition_and_structure"); so the iron would be easily visible, occupying about 8 cm3.
Of course, you could not call it iron any more (in the usual sense). The nuclei would retain their nature and separate identities, but they would no longer be iron atoms because of the collapse of the electron shells.

Just to point out, the matter in a white dwarf is not in a normal physical structure as in the iron bar. Most of the electrons are not bound to the nuclei and the whole thing is more of a plasma than a solid. But you are essentially correct in your explanation.
Edit: Heh, looks like you edited your post between when I read it and replied. (Either that or I just misread it) Yes, that is pretty much spot on as far as I can tell.
 
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  • #8
phinds said:
is there a question here somewhere?

Sure. Is it safe to say that matter is less a result of actual subatomic particles and more the consequence of its attendant physical phenomenon such as charge?

phinds said:
I'm not sure it's a product of motion ... I always thought it's because of the CHARGE

Please elaborate. Are you saying that the repulsion between particles of like charge and attraction between particles of opposite charge is what gives matter its apparent solidity? Is all that empty space in an atom obscured by charge in the atom?

Jagella
 
  • #9
Oldfart said:
Interesting! I wonder how the result for hydrogen compares with iron?

Try it out for yourself. Look up the diameters or radii for electrons, protons, and neutrons and how many of each make up the iron atom. Then, find the diameter or radius for the iron atom. Calculate the total volume for these particles and the whole atom using the formula 4/3 π r3. Finally divide the sum of the volumes for the particles into the volume of the iron atom. The result is the proportion of the iron atom's volume taken up by particles.

It may seem like a lot of work, but I've found it's a great way to learn about physics.

Jagella
 
  • #10
What I'm saying is that the reason we can't walk through walls is that our electrons are repulsed by the wall's electrons. There is no "apparent solidity" in my mind since you are quite correct that matter is almost entirely empty space. What there IS is the inability of macro objects to pass through each other and of course we DO perceive that as solidity.
 
  • #11
phinds said:
What I'm saying is that the reason we can't walk through walls is that our electrons are repulsed by the wall's electrons.

OK, I know this sounds stupid, but why doesn't this repulsion cause walls and everything else in the world that is comprised of atoms to fly apart?
 
  • #12
Molecules SHARE electrons among their atoms (look up "molecular bonding") rather than having them cause any repulsion. Now, how the MOLECULES hook together I'll have to leave for someone who knows that stuff ...
 
  • #13
phinds said:
is there a question here somewhere?

I'm not sure it's a product of motion ... I always thought it's because of the CHARGE

And also because of its fermionic nature. http://arxiv.org/abs/math-ph/0401004
 
  • #14
Oldfart said:
phinds said:
What I'm saying is that the reason we can't walk through walls is that our electrons are repulsed by the wall's electrons.

OK, I know this sounds stupid, but why doesn't this repulsion cause walls and everything else in the world that is comprised of atoms to fly apart?

phinds said:
Molecules SHARE electrons among their atoms (look up "molecular bonding") rather than having them cause any repulsion. Now, how the MOLECULES hook together I'll have to leave for someone who knows that stuff ...

See here: http://en.wikipedia.org/wiki/Chemical_bond
 

1. What is matter?

Matter is anything that has mass and takes up space. This includes all the physical substances we encounter in our daily lives, such as solid objects, liquids, and gases.

2. Is matter mostly empty space?

Yes, matter is mostly empty space. At the atomic level, matter is made up of tiny particles called atoms. However, atoms are mostly empty space, with a small, dense nucleus at the center and electrons orbiting around it.

3. How much of matter is empty space?

It is estimated that around 99.9999999% of an atom is empty space. This means that only a tiny fraction of an atom's volume is occupied by its particles, such as protons, neutrons, and electrons.

4. Why does matter appear solid if it is mostly empty space?

The electrons in atoms are constantly moving and interacting with each other. This creates a force that holds the atoms together, giving matter its solid appearance and physical properties.

5. How does the concept of mostly empty space in matter affect our understanding of the world?

Understanding that matter is mostly empty space helps us to understand the behavior of particles at the atomic level. It also explains why objects can pass through each other without colliding and why matter can change states, such as from solid to liquid to gas.

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