Does gravity cause electric resistance?

[haael]

Suppose we have a wire and we pass electric current through it. When placed horizontally in a gravity field, the wire has some resistance. Now what happens, when we place this wire vertically?

Suppose the electrons are flowing upwards. They have to counter gravity potential, so this should be visible as a voltage loss. On the other hand, when electrons fly downwards, they should gain some energy, so perhaps not resistance, but voltage is the proper description of this phenomenon.

Has this ever been measured? Maybe there are some special materials, i.e. semiconductors, where this effect is exceptionally large. This woud make a fine accelerometer.

[Barwick]

I don't know the answer to it, but it sounds plausible to me. It would require incredibly sensitive equipment, but I would think it's possible.

Though it might also be offset by the compression of the conductor when it's in the vertical alignment position. A 10 km long wire would be say 9,999 meters due to compression when it's vertical, leading to different transmission times due to the length, and also leading to reduced resistance due to the atoms being slightly closer together.

[cragar]

are you asking if the electric field interacts with the gravitational field.

[pallidin]

I agree with the "plausibility"
Electrons have mass, thus affected by gravity.
Though it's effect might be incredibly hard to measure in that circumstance, it seems right.

[haael]

Uh oh. I did some small research. It doesn't look good.

This effect is indeed extremely small - of the order of Planck scale. I was naively hoping to compare electron's charge and mass. The numbers that appear are close to 10^-31. When you have an electron in equilibrium in an electric field pushing it up and in a gravity field pulling down, then varying the gravitation compared to varying electric field gives numbers as small as the ratio of electron's charge to its mass in Planck units :).

Additionally, the measuring device would have to be cooled down below nanokelvins, since the thermal noise energy of electrons is many orders larger than their gravitational energy.

The only solution would be to find some much heavier charged particles, that are capable of transferring current. Maybe some heavy ions (uranium) could be injected into vacuum lamp and produce some measurable effect. Maybe we could use some chemical molecule that can survive ionisation.
Or maybe we can use semiconductors or something, where electrons gain mass and are affected by gravity.

It's still far in the future. I will not have such compact accelerometer, maybe my grandchildren will :).

[mrspeedybob]

If you are going to measure this at all there will have to be some sort of measuring device, like a meter, somewhere. This measuring device is going to have to be connected to both ends of your test wire, thus creating a loop. Any voltage that exists in the test wire will be canceled out by matching and opposing voltage in the test leads leading from the ends of your wire to the meter.

[sophiecentaur]

I have a feeling that the experiment with the greatest likelihood of success would be to use a long horizontal beam of very heavy (mercury?) ions with as low a velocity as one could get. One could calculate the deviation that you would get due to gravity - given the motivation.

[ZapperZ]

The ions in RHIC goes around many times around its ring. Has there been ANY indication of its mass being affected by gravity? If there isn't, then what hope is there that electrical current, where electrons are the charge carriers, would exhibit an effect to gravity?

Zz.

[sophiecentaur]

In 'the collider' the ions are travelling as fast as is possible. What you need is the reverse. They need to be going slowly so as to have enough time to observe them falling down. You would need to operate the equipment 'both ways up' to see the effect, if any.

[haael]

This measuring device is going to have to be connected to both ends of your test wire, thus creating a loop. Any voltage that exists in the test wire will be canceled out by matching and opposing voltage in the test leads leading from the ends of your wire to the meter.
Yes, I know. That's why I wanted to use two different materials, where charged particles have different masses. One way up, another way down - the difference should be possible to be measured, in principle.

I have a feeling that the experiment with the greatest likelihood of success would be to use a long horizontal beam of very heavy (mercury?) ions with as low a velocity as one could get.
Yes, but they still have to be cooled down, so they can fall in gravity field. Their thermal velocity should be smaller than the escape velocity from Earth, lol :).

If the ions are cold enough, we should observe slightly more ions on the bottom of the chamber. The charge would not be distributed uniformly, what can be measured.

---
To be clear once again: I want to measure gravity or acceleration using electricity alone, without having some macroscopic reference body on springs. The massive body in my setup are charged particles, the "springs" are electric force.

[sophiecentaur]

You could collimate the beam, surely??

[pallidin]

The ions in RHIC goes around many times around its ring. Has there been ANY indication of its mass being affected by gravity? If there isn't, then what hope is there that electrical current, where electrons are the charge carriers, would exhibit an effect to gravity?

Zz.

With all due respect, are you being sarcastic or making a point?
Your post, Zapper, is somewhat confusing.