# Would greater electricity affect a gravitational field created by an electromagnet?

1. Aug 2, 2011

### 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.

2. Aug 2, 2011

### LostConjugate

Re: would greater electricity affect a gravitational field created by an electromagne

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

3. Aug 2, 2011

### chrisbaird

Re: would greater electricity affect a gravitational field created by an electromagne

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.

4. Aug 2, 2011

### LostConjugate

Re: would greater electricity affect a gravitational field created by an electromagne

Increasing current increases energy which is equivalent to mass.

5. Aug 2, 2011

### Bloodthunder

Re: would greater electricity affect a gravitational field created by an electromagne

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

6. Aug 2, 2011

### LostConjugate

Re: would greater electricity affect a gravitational field created by an electromagne

It increases the energy density.

7. Aug 2, 2011

### QuantumPion

Re: would greater electricity affect a gravitational field created by an electromagne

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

8. Aug 2, 2011

### Ryan_m_b

Staff Emeritus
Re: would greater electricity affect a gravitational field created by an electromagne

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.

9. Aug 2, 2011

### LostConjugate

Re: would greater electricity affect a gravitational field created by an electromagne

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

10. Aug 2, 2011

### Ryan_m_b

Staff Emeritus
Re: would greater electricity affect a gravitational field created by an electromagne

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.

11. Aug 2, 2011

### Bloodthunder

Re: would greater electricity affect a gravitational field created by an electromagne

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.

12. Aug 3, 2011

### Ryan_m_b

Staff Emeritus
Re: would greater electricity affect a gravitational field created by an electromagne

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

13. Aug 3, 2011

### Bloodthunder

Re: would greater electricity affect a gravitational field created by an electromagne

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.

14. Aug 3, 2011

### Ryan_m_b

Staff Emeritus
Re: would greater electricity affect a gravitational field created by an electromagne

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?

15. Aug 3, 2011

### LostConjugate

Re: would greater electricity affect a gravitational field created by an electromagne

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

16. Aug 3, 2011

### Bloodthunder

Re: would greater electricity affect a gravitational field created by an electromagne

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.

17. Aug 3, 2011

### LostConjugate

Re: would greater electricity affect a gravitational field created by an electromagne

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

18. Aug 3, 2011

### Ryan_m_b

Staff Emeritus
Re: would greater electricity affect a gravitational field created by an electromagne

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

19. Aug 3, 2011

### uart

Re: would greater electricity affect a gravitational field created by an electromagne

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?

20. Aug 3, 2011

### daveb

Re: would greater electricity affect a gravitational field created by an electromagne

That is correct. Solar sails work through momentum transfer.