Would Greater Electricity Affect a Gravitational Field?

[Randomguy96]

So I'm sitting here, reading about different ways to create gravitational fields as well as messing around with random thoughts and ideas, and this question comes to mind: Would greater electricity affect a gravitational field created by an electromagnet? Anyone who knows? I'd really like to know, seeing as how i can't figure out myself, even if my own guess would be yes.

 

[LostConjugate]

More Amps? Yes, gravity is proportional to energy density, so the more energy you have in some volume the stronger the gravitational force is.

 

[chrisbaird]

Mass creates gravitational fields, not electric charge. Increasing the electric current through an electromagnet will increase the magnetic field, but do nothing to the gravitational field. To increase the gravitational field produced by an object, you would increase its mass. The force of gravity and the electromagnetic force are independent according to our current understanding.

 

[LostConjugate]

Mass creates gravitational fields, not electric charge. Increasing the electric current through an electromagnet will increase the magnetic field, but do nothing to the gravitational field. To increase the gravitational field produced by an object, you would increase its mass. The force of gravity and the electromagnetic force are independent according to our current understanding.

Increasing current increases energy which is equivalent to mass.

https://www.physicsforums.com/showthread.php?t=515899

 

[Bloodthunder]

Increasing current increases energy which is equivalent to mass.

https://www.physicsforums.com/showthread.php?t=515899

Increasing a current does not increase mass of wire. Otherwise, superconductors would be nearly infinite in mass.

 

[LostConjugate]

Increasing a current does not increase mass of wire. Otherwise, superconductors would be nearly infinite in mass.

It increases the energy density.

 

[QuantumPion]

Increasing a current does not increase mass of wire. Otherwise, superconductors would be nearly infinite in mass.

Superconductors do not have infinite current, they have zero resistance.

 

[Ryan_m_b]

So I'm sitting here, reading about different ways to create gravitational fields as well as messing around with random thoughts and ideas, and this question comes to mind: Would greater electricity affect a gravitational field created by an electromagnet? Anyone who knows? I'd really like to know, seeing as how i can't figure out myself, even if my own guess would be yes.

Increasing current increases energy which is equivalent to mass.

https://www.physicsforums.com/showthread.php?t=515899

The implication here clearly being that if you want to increase the gravitational attraction of a wire it would be simpler just to add the required mass.

 

[LostConjugate]

The implication here clearly being that if you want to increase the gravitational attraction of a wire it would be simpler just to add the required mass.

Creating mass is not so simple, but if you have some lying around sure.

 

[Ryan_m_b]

Creating mass is not so simple, but if you have some lying around sure.

I didn't mean creating mass, I meant adding mass. I.e. if the OP want's his wire to have X gravitational well then it's going to be far easier to just get mass from elsewhere and wrap it around the wire than trying to increase the energy density.

 

[Bloodthunder]

Superconductors do not have infinite current, they have zero resistance.

Yes, I know. Critical current and all that, which is really high. Yet you don't see the weight of wire increasing.

And I still don't get what energy density of the wire has to do with anything.

 

[Ryan_m_b]

Yes, I know. Critical current and all that, which is really high. Yet you don't see the weight of wire increasing.

And I still don't get what energy density of the wire has to do with anything.

Because e=mc2, mass and energy have the same gravitational effect.

 

[Bloodthunder]

Well, for one, you need ~90 TJ of energy to increase the mass by just 1 gram. Also, you can't just make mass appear just like that. Pair production occurs occasionally, yes, but the anti-matter, being in such close proximity to everything else, would just hit some other matter to become energy again. And energy itself has no mass to speak of, and hence provides nothing to the gravitational field.

 

[Ryan_m_b]

Well, for one, you need ~90 TJ of energy to increase the mass by just 1 gram. Also, you can't just make mass appear just like that. Pair production occurs occasionally, yes, but the anti-matter, being in such close proximity to everything else, would just hit some other matter to become energy again. And energy itself has no mass to speak of, and hence provides nothing to the gravitational field.

Who were you responding to here?, no one is suggesting creating mass. Something does not have to have mass to have a gravitational field, photons are a good example of this.

EDIT: I retract that, I may be under a big misunderstanding. Anyone know the proper answer to this and why?

 

[LostConjugate]

Who were you responding to here?, no one is suggesting creating mass. Something does not have to have mass to have a gravitational field, photons are a good example of this.

EDIT: I retract that, I may be under a big misunderstanding. Anyone know the proper answer to this and why?

Photons are a perfect example. They have mass proportional to their frequency (energy).

 

[Bloodthunder]

It is not proven that photons have any mass. While photons are affected by gravity, it is explained to be due to the curvature of space-time by massive objects (General Relativity). Another thing probably suggest photons by themselves do not have gravitational fields are that they do not attract and stick to each other. Instead, the 2 photons interact like waves that pass through each other without much effect.

I do understand that one uses the energy of a photon, convert it to mass, and then calculate the angle of deflection due to the massive object. However, this doesn't in anyway say that the photon produces any gravitational field of its own.

 

[LostConjugate]

It is not proven that photons have any mass.

It is not? Have you heard of a solar sail?

 

[Ryan_m_b]

It is not? Have you heard of a solar sail?

I thought that worked through the transfer of momentum? Not because photons have mass...

 

[uart]

Also, you can't just make mass appear just like that.

Ok then answer this hypothetical question. If I took 26 protons of mass 1.00727646681u (u = atomic mass units) and 30 neutrons of mass 1.008664916u and assembled them to make an iron nucleus, then how much would that iron nucleus weigh?

 

[daveb]

I thought that worked through the transfer of momentum? Not because photons have mass...

That is correct. Solar sails work through momentum transfer.

 

[daveb]

As for the OP, there are numerous threads about it here at PF. A search should come up with several of them.

 

[chrisbaird]

Photons are a perfect example. They have mass proportional to their frequency (energy).

Photons do not have mass and do not create gravitational fields. Photons have momentum but it is a field momentum p = hf/c as opposed to a mass momentum. Photons also have energy E = hf, but again it is a field energy and not a mass energy. Saying that "photons have energy, energy is the same as mass, mass creates gravity, therefore photons create gravity" is just sloppy logic that comes about from using terms loosely. Einstein's famous equation E = mc² is actually a special case of the more general expression:

E² = (pc)² + (mc²)²

which states that both mass and momentum give rise to energy. Photons have no mass, so this reduces down to E = pc. It is true that photons can be converted to particles with mass that generate gravitational fields, but that requires an event. It does not happen naturally at any significant rate.

 

[LostConjugate]

Photons do not have mass and do not create gravitational fields. Photons have momentum but it is a field momentum p = hf/c as opposed to a mass momentum. Photons also have energy E = hf, but again it is a field energy and not a mass energy. Saying that "photons have energy, energy is the same as mass, mass creates gravity, therefore photons create gravity" is just sloppy logic that comes about from using terms loosely. Einstein's famous equation E = mc² is actually a special case of the more general expression:

E² = (pc)² + (mc²)²

which states that both mass and momentum give rise to energy. Photons have no mass, so this reduces down to E = pc. It is true that photons can be converted to particles with mass that generate gravitational fields, but that requires an event. It does not happen naturally at any significant rate.

I have heard that photon's do not generate gravity. However since in general relativity you learn that gravity is proportional to the energy density matrix, wouldn't the energy density matrix of a photon be non-zero.

 

[IsometricPion]

I have heard that photon's do not generate gravity. However since in general relativity you learn that gravity is proportional to the energy density matrix, wouldn't the energy density matrix of a photon be non-zero.

The https://www.physicsforums.com/showthread.php?t=442266" provides a good discussion about the gravity of photons. Summary: classical electromagnetic waves gravitate (see posts #83, #84), in certain limits (e.g., high photon energies) a theory of quantum gravity would be needed to know whether photons gravitate the same way as other matter.

As for electric fields (produced by charged particles), the strong equivalence principle requires they gravitate (by conservation of momentum) (for experimental verification of this principle see sec. 3.6 of http://relativity.livingreviews.org/Articles/lrr-2006-3/" , section 3.7.3 provides an effect that explicitly depends on the electric field).