# Why macro model bad for atomic world?

## Main Question or Discussion Point

why the universe is a bad model to describe the atomic world?

sun=nucleus
planets=atoms
they orbits
they spin like subatomic particles
they have magneticfield

I mean anything you get from the atomic world, you have it in the macro world.

## Answers and Replies

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vanesch
Staff Emeritus
Gold Member
why the universe is a bad model to describe the atomic world?

sun=nucleus
planets=atoms
they orbits
they spin like subatomic particles
they have magneticfield

I mean anything you get from the atomic world, you have it in the macro world.
The answer is simple and illustrative: because, when you assume that, and you do calculations that way, you don't find the properties that you measure in the laboratory.

Electrons are both particles and waves. As waves, they do not have well-defined elliptical paths like planets. Each electron is spread out, filling its entire orbital region.

Andy Resnick
Well, as you point out, the solar system was indeed originally used as a conceptual model for atoms. But the predictions do not correlate with reality. This means that the model is deficient. Once the model is adjusted to make predictions that agree with experiments, you will find that the model for an atom bears little resemblence to the solar system.

The answer is simple and illustrative: because, when you assume that, and you do calculations that way, you don't find the properties that you measure in the laboratory.
You're right, but maybe we didn't corelated right when we go from macro to micro? Maybe there is some constant when we go from 1 world to another, maybe space and time is on a log scale and not smooth interval like we assume, or maybe we didn't realized the equation is certain dimension (therefore we need certain number of independant solution). Example: Gravity is 34 orders weaker than electromagnetism and electromagnetism is 100+ weaker than strong force. There is no way to use Newton equation to account for strong force. I tried to amplify the equation through constant, but it change the macro world as well. When I play around with matlab and put all the weird equation in (by adding more term to the equation), I could partially achieve a graph that resemble macro in large distance and micro in close distance, yet it is a continuous function. I know that by constructing and adding waves together, you can get any graph, even a sharp edge drop.

For fun: F=gm1m2/r^2 + k/r^n , you can play around with k and r to basically spike the graph at any distance when close to the nucleus. Imagine adding more terms to manipulate the graph. My point is maybe there are terms tagging along that we overlook.

[/QUOTE]Electrons are both particles and waves. As waves, they do not have well-defined elliptical paths like planets. Each electron is spread out, filling its entire orbital region.[/QUOTE]

I have a good argument on this one. As far as I know, we do slits experiment to determine it's a wavelike. Imagine you shooting planets through the slits. We already establish it can be particle. Well, what if those planet also spin hella fast (much faster than earth spin). Slight touching each other or even the slit itself will cause a crazy path. Imagine a few billion Avagadro's number of planets going through together, in chaos probably emerge order.
About electron spread out filling the region, do you mean as the electron cloud? I do not know how and what experiment determine this but if time/space is a on log scale, an observer with galactic size won't keep up with planets rotation just like we can't keep up with electron.

Redbelly98
Staff Emeritus
Homework Helper
why the universe is a bad model to describe the atomic world?

sun=nucleus
planets=atoms
they orbits
they spin like subatomic particles
they have magneticfield

I mean anything you get from the atomic world, you have it in the macro world.
I think you mean planets=electrons, at least you have said so elsewhere.

There are some key differences between the two systems:

Planets attract each other, and do so weakly (by their gravity).
Electrons strongly repel each other.

Planets come in a variety of sizes and compositions (i.e. gaseous vs. rocky), and have different levels of magnetic field.
Electrons are all identical.

Planets may have satellites and rings. Electrons do not.

I think you mean planets=electrons, at least you have said so elsewhere.

There are some key differences between the two systems:

Planets attract each other, and do so weakly (by their gravity).
Electrons strongly repel each other.

Planets come in a variety of sizes and compositions (i.e. gaseous vs. rocky), and have different levels of magnetic field.
Electrons are all identical.

Planets may have satellites and rings. Electrons do not.
thx for the electron-planet correction
Some good point you made. "Electrons strongly repel each other". Let say we have another identicle earth come in contact with our earth (put the solar system away, just 1on1 now). You'll say that they'll attrack to each other by gravity. Sure, but now let's spin both earth faster and faster. The magnetic field is now generate stronger and stronger . At certain spin speed...the earth repel each other. I remember electron go in bond pair in bonding, and 1 have to be up spin and 1 have to be down spin.
Your second point needs specification. We do experiment not base on 1 electron, but on avagadro's number of electrons. I think they use charge to mass experiment to determine the mass. Even if a possibility of 1 electron doesn't have charge, or the charge is weak, or the mass is slight different (which is undetectable anyway), we can't detect it from a stream of electrons. Even if half of the electron in the universe doesnt' have charge or slightly charged, it still distribute evenly as a medium and no way we can detect them as a whole unless we examine 1 by 1. I want to ask if u can tell the different between a non spin proton and a neutron?

why the universe is a bad model to describe the atomic world?

sun=nucleus
planets=atoms
they orbits
they spin like subatomic particles
they have magneticfield

I mean anything you get from the atomic world, you have it in the macro world.
You do not "get" a nucleus with electrons orbiting each other in atomic physics. That is only the classical picture. The quantum mechanical one is described by electron wavefunctions, which is a good thing because classically the electron would radiate (electromagnetically) and their orbits would decay within like a fraction of a second!

Also the "spin" of an electron is an intrinsic property that is not the same as classical spin.

To reproduce the predictions of quantum mechanics, you also need to take into account the fact that energy only comes in discrete quanta (E=hf). Also, there is the uncertainty principle, indeterminism, etc.

You're re-inventing the wheel. Physicists went through the same struggle in the early 20th century.

i'm shaping the wheel square. lol I'm surprise when I first see this webpage. There are section on quantum, reletivity, classic, atomic, high energy... It just crazy. Now we have internet and easy access resources, more ideas keep coming. Not sure if it's good or bad.