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Author Topic: How do you calculate the gravity of electrons and protons?  (Read 499 times)

Offline jeffreyH

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Consider this thought experiment. We have two clouds of particles equidistant from a central object. This meaning that the centres of gravity of each cloud is equidistant. One cloud is composed entirely of electrons and the other of protons. The mass me of the electron cloud equals the mass mp of the proton cloud. The question is would the gravitational fields be equal and cancel where the central object is?
« Last Edit: 23/05/2016 09:57:22 by evan_au »


 

Offline PmbPhy

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Re: What is the answer to this question?
« Reply #1 on: 22/05/2016 14:58:17 »
Consider this thought experiment. We have two clouds of particles equidistant from a central object. This meaning that the centres of gravity of each cloud is equidistant. One cloud is composed entirely of electrons and the other of protons. The mass me of the electron cloud equals the mass mp of the proton cloud. The question is would the gravitational fields be equal and cancel where the central object is?
You're mixing a classical theory, i.e. gravity, with quantum objects, i.e. electrons and protons. Don't expect the answer to be flawless. If the distributions of each system is spherical then they'd cancel at the midpoint.

Why do you ask? What do you think might suggest otherwise?
 
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Offline chiralSPO

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Re: What is the answer to this question?
« Reply #2 on: 22/05/2016 15:24:17 »
The way the questions is worded is ambiguous in several ways. It sounds as if the clouds do not overlap spatially (though this is not explicitly stated), and that each cloud is composed only of electrons or protons--implying that each cloud is charged. Also, it is not clear whether these clouds are free to expand, or (somehow) with fixed volume...

Because protons are 1836 times as massive as electrons, the electron cloud of equal mass will have 1836 times greater charge. If the clouds are somehow confined then that means that either the clouds are different sizes due to the difference in self-repulsion, or there is greater potential energy stored in the electron cloud. The charge density wouldn't have to be very large for the gravity due to the stored energy to be much more than due to the mass of the system.

Therefore, if we assume the two clouds have the same volume, shape, and mass, the electron cloud will have a greater gravitational field than the proton cloud.
« Last Edit: 22/05/2016 15:26:38 by chiralSPO »
 
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Offline jeffreyH

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Re: What is the answer to this question?
« Reply #3 on: 22/05/2016 15:29:04 »
I knew this one was going to cause trouble. Simply due to the charge imbalance. I was asking because I wanted informed opinions. I didn't expect a specific answer.
 

Offline jeffreyH

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Re: What is the answer to this question?
« Reply #4 on: 22/05/2016 15:39:56 »
The way the questions is worded is ambiguous in several ways. It sounds as if the clouds do not overlap spatially (though this is not explicitly stated), and that each cloud is composed only of electrons or protons--implying that each cloud is charged. Also, it is not clear whether these clouds are free to expand, or (somehow) with fixed volume...

Because protons are 1836 times as massive as electrons, the electron cloud of equal mass will have 1836 times greater charge. If the clouds are somehow confined then that means that either the clouds are different sizes due to the difference in self-repulsion, or there is greater potential energy stored in the electron cloud. The charge density wouldn't have to be very large for the gravity due to the stored energy to be much more than due to the mass of the system.

Therefore, if we assume the two clouds have the same volume, shape, and mass, the electron cloud will have a greater gravitational field than the proton cloud.

Your last paragraph is very interesting. I will think about it and get back to you.
 

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Re: What is the answer to this question?
« Reply #4 on: 22/05/2016 15:39:56 »

 

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