Why matter is mostly empty space? or not?

The movie says that matter is mostly empty space because atoms are more like a huge cloud of electrons(with no significant weight) with a small nucleus (which contains all the mass of the atom). A size comparison indicates an atom is to its nucleus like a football stadium is to a tennis ball.

A great example is given by Bill Bryson in his book, "A Short History of Nearly Everything." In it he gives the example that if a helium atom was the size of a cathedral the nucleus of the atom would be the size of a fly and it would weigh several times more than the cathedral.

That's why matter is mostly empty space.

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Depends on how you look at an atom. These days, it's not clearly defined, because the facts that have been observed about the behaviour of atoms, and their components like electrons and neutrons, seem to simultaneously present evidence that would support a couple of different and conflicting ways of envisaging an atom.

If you think of an atom as made up of specific pieces of matter, you can use a model that makes it look a lot like our solar system, with the nucleus being like the Sun, and the electrons being like the planets that orbit around it at specific distances. If you look at a model of the solar system, you can see that almost all of the space occupied by the orbits of the planets, and between the orbits of the planets, is empty at any one time in any particular point.

But there's also evidence in the way atoms behave to suggest that a valid way of envisaging an atom is with a (roughly) spherical core, again like our Sun, but with the electrons effectively each being like a spherical cloud of specific increasing sizes, each cloud made up of a specific charge of energy. So in that model, an atom is like a set of Russian dolls, made up of spheres within spheres, and so in a way it occupies most of the space from the outermost sphere to the innermost one.

That's why different people give a different answer to that question -- it depends on which model they're envisaging to describe the nature of an atom. And neither model tells the whole story.



You might very well think that. I couldn't possibly comment.

Matter is mostly space because Jesus said so.

Signed,
Joe Republican

An atom has two components, a teeny heavy nucleus and a huge, light cloud of electrons around it. The electrons repel each other very well, so it's the size of this cloud of electrons which determines the size of the atom.

The old way of figuring out how big the nucleus was, was to fire a bunch of protons through a thin film of metal and see how often they were deflected. Most of the time they weren't deflected at all, so they weren't hitting the nucleus of any atom on their way through the film of metal. The nucleus itself was clearly very tightly packed in the middle.

Back then, it was thought that the electrons had very well-defined positions, and for their cloud to take up all that space they must fly around at a great distance from the nucleus. Therefore the atom would have to be mostly empty space, between the electrons on the outskirts and the nucleus in the middle.

However we now know that the electrons are actually "smeared out" into shapes that are defined by some mathematics, and a lot of those electrons are actually really heavily concentrated in the middle of the atom. So there are electrons all the way from the outside of the atom right to the core, and in that sense there's no empty space at all! It's just that most of the space is occupied by something that isn't very dense.

The real trouble with thinking about this problem is that, on a subatomic, objects don't have a well-defined position, and size is hard to discuss too. For example you can bring two particles closer and closer together indefinitely if you push them hard enough, so they don't seem to have any size at all by some definitions, although they'll being to interact in strange ways when you're really putting them on top of each other. If you can't pin down where a particle is, and you have trouble saying how big it is, you can't really say where it isn't, and so it's hard to say what places are empty.

There is no matter or solidity in the universe. Every "particle" is merely made up of far smaller formations of "particles", repeated forever.

It is energy in a complex formation which we are able to perceive using our senses, and have decided to mis-name this as "solid matter". Like all of science, solid matter will eventually be proven wrong -- but that's the fun and interesting part of science.

Every time science discovers a new smaller entity, such as cells, molecules, atoms, nuetrons/protons, quarks, etc. they declare that they know the smallest building block of the universe.

It's really quite silly, and it's only there to let them sleep better at night thinking the universe isn't "empty". As our intrumentation increases so we can see what makes up quarks, and what makes up those sub-quark particles, and repeat that a few more scales downward, eventually science will have to accept that solidity doesn't exist.

It's the same on the other scale as well, going up. Satellites around stars, stars orbitting in a complex pattern around the "dense" galactic nucleus, galaxies orbitting around each other in galactic strands, etc. At every scale of the universe, it's the same thing. Space empty of solid matter, with complex energy formations.