# The Naked Scientists Forum

### Author Topic: If the earth stopped rotating would it's mass decrease?  (Read 10572 times)

#### Bill S

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##### If the earth stopped rotating would it's mass decrease?
« Reply #25 on: 06/03/2011 00:55:44 »
If the matter in the atom in its ground state, and in its excited state is the same, but the mass is greater in the excited state; i.e. when energy is added; is that not the same as saying that mass = matter + energy?

#### lightarrow

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##### If the earth stopped rotating would it's mass decrease?
« Reply #26 on: 06/03/2011 12:58:26 »
If the matter in the atom in its ground state, and in its excited state is the same, but the mass is greater in the excited state; i.e. when energy is added; is that not the same as saying that mass = matter + energy?
1. You can't sum two completely different things. Can you sum lenght and colour, for example? How much is 1metre + 1 red colour?
2. even if with "matter" here you intend the mass of the atom in its fundamental state, your "equation" would be valid only in very specific cases as this one, it wouldn't have general validity. For example, how could you explain the mass difference between two excited states? You couldn't say that the lower energy state is mass of the "matter" because it's an excited state. Furthermore, you can't say that the mass of a composite system is the sum of the masses of its particles, because this is false (mass is not additive).
"matter" is a concept not useful in physics, unless we can neglect every form of internal energy variations, with respect to invariant mass. For example, in chemistry or thermodynamics you usually can do that approximation.
« Last Edit: 06/03/2011 13:04:20 by lightarrow »

#### simplified

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##### If the earth stopped rotating would it's mass decrease?
« Reply #27 on: 07/03/2011 04:59:51 »
Quote from: lightarrow
mass is not matter.

Mass is matter + energy. Right?
No. "Matter" is not a very precisely defined term, it essentially means "particles" as protons, neutrons, electrons. If you have, for example, a single hydrogen atom in its fundamental state, it's the same "matter" that the atom in an excited state (it's still one proton and one electron; all the properties of the proton and the electron are the same). But the mass is different, because the excited atom as a greater mass.
And so energy of Earth rotation is generator of gravity relatively of Sun.Then photon is generator of gravity relatively of universe. Therefore a photon loses energy,therefore universe does not expand in reality. [:X]
« Last Edit: 08/03/2011 14:47:52 by simplified »

#### lightarrow

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##### If the earth stopped rotating would it's mass decrease?
« Reply #28 on: 07/03/2011 12:55:40 »
And so energy of Earth rotation is generator of gravity relatively of Sun.Then photon is generator of gravity relatively of universe. Therefore a photon lose energy,therefore universe does not expand in reality. [:X]

#### simplified

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##### If the earth stopped rotating would it's mass decrease?
« Reply #29 on: 08/03/2011 15:26:45 »
I think a radiation of gravity takes energy of the radiator.If energy can radiate gravity in some interaction with mass,then photon can radiate gravity in some interaction with universe.

#### lightarrow

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##### If the earth stopped rotating would it's mass decrease?
« Reply #30 on: 08/03/2011 19:28:48 »

#### Bill S

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##### If the earth stopped rotating would it's mass decrease?
« Reply #31 on: 09/03/2011 22:23:54 »
Quote from: lightarrow

This one I understand, completely.

#### lightarrow

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##### If the earth stopped rotating would it's mass decrease?
« Reply #32 on: 10/03/2011 12:47:22 »
Thank you Bill, I felt a bit lost...

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##### If the earth stopped rotating would it's mass decrease?
« Reply #32 on: 10/03/2011 12:47:22 »