[evan_au]

an object coming from space towards earth planet will just hit it and stuck on its surface

Another aspect of this discussion....

As far as we know, an electron is an elementary particle - it has no interior structure, and no incompressible minimum size.
- The electron is a radically different particle than the proton, and it doesn't interact with the proton (except by the electromagnetic force, which they both feel).
- So it's actually quite possible for an electron to exist inside a proton or pass through a proton with no adverse effects - without "hitting" or "sticking" - and without staying there.

On the other hand, the Earth and a Meteorite are not fundamental particles - they are both made of the same stuff (atoms), which interact strongly with each other. The atoms are extended objects which can't pass through each other without severe disruption. They will "hit" and get "stuck on its surface".

An interesting application of this lack of interaction between electron and proton is measuring the radius of the proton's electric charge.
- In Hydrogen, there is a small chance that an electron will be inside the proton
- It is possible to hit Hydrogen with a laser beam of the right frequency, and measure the energy required to boost the electron's energy into another orbital which does not enter the proton.
- There is another particle, the Muon, which is somewhat like an electron, only it is 207 times the mass of the electron.
- The Muon orbital radius around the proton is 207 times smaller than the electron, so it is very likely to be found inside the proton.
- It is possible to hit this "Muonium" with a laser beam, and measure the energy required to boost the Muon's energy into another orbital which does not enter the proton.

It is one of the unsolved problems in physics that the inferred radius of the proton is different depending on whether you measure it with Electrons or Muons.

See: https://en.wikipedia.org/wiki/Muon#Use_in_measurement_of_the_proton_charge_radius

[jeffreyH]

In considering extended objects we can turn to Newton's second law which can predict the motion of the centre of mass of an object even if it is rotating. All wee need to know are the force vectors applied to the object. If we consider both the proton and electron as extended objects at the microscopic scale then the force vectors are derived from the electromagnetic and weak force interactions. The masses of the muon and electron, being different, will have distinctly different centres of mass which will result in different proton radius measurements as they move through the fields.

[Yahya (OP)]

you can think of science as a description for how that intelligence directs the physical world.

I like this expression . I think so , but I thought this intelligence won't be achieved by a planetary model. may be I should post this thread hundred years ago.

[alancalverd]

It's all down to indeterminacy. There is a limit to the precision with which the momentum and position of a particle can be determined dp.dx = h/2(pi) where dp and dx are the indeterminacies of mometum and position respectively, h is Planck's constant (an experimental value) and (pi) is the number we usually represent with a Greek symbol that I can't insert because the forum software is screwed up!

Now the nucleus is very small, so if an electron were to be inside the nucleus,  we would know exactly where it was so dx would vanish and dp would be enormous. Since p is the product of mass and velocity, and mass is fixed, that would mean that if an electron approached the nucleus its velocity would increase enormously, so it couldn't stay there very long.

At the other extreme, the electrostatic attraction between an electron and a nucleus means that you are more likely to find electrons near nuclei than a long way from them.

Thus we can construct a picture of the probability of finding an electron, as a function of distance from a nucleus. In the simplest case of hydrogen, that looks like a fuzzy spherical shell with a maximum density at about 5.2 x 10^-11 m from the nucleus. The equations get more complicated as you add more protons and electrons, but the orbitals shown in reply #12 above are solutions to the equations in 3 dimensions (the rest of that post is mostly nonsense - for instance orbitals are NOT orbits!) and are confirmed by experiment.