Does electrical-magnetic fields curve spacetime?

[Dale]

If three masses are placed at the corners of an equilateral triangle, and the "force" on anyone corner can be determined using the "center of gravity" of the other two corners, does the "deepest point in the valley" occur at any individual mass - or the "center of gravity" of the system?

I went ahead and worked the math on this one. I hope you can read a topographical map, the contour plot was easier for me to understand than the 3D surface plot. The darker the color the "deeper" the potential at that contour in the "hill and valley" analogy. There are 3 equally-deep deepest points each located at the center of one of the darkest contours.

The white rings represent the surface of the spherical mass. Note that the center of the mass does not correspond to the deepest point in the "valley". Therefore each mass will experience a net force which will pull it towards this deepest point.

 

[Dale]

Firstly, can you insulate against magnetism?

Yes, it is done all the time in the construction of MRI suites. Usually iron is used.

 

[gonegahgah]

I find that drawing very good Dale and very easy to understand.

When you go inside a planet I have been told that the decrease in gravity occurs proportional to 1/r. Is that correct?

You have shown this as well via the almost petrie dish like shapes that are about the sizes of the masses and which centre close to the centre of those masses. That is correct isn't it?

 

[gonegahgah]

So if you had one of those floating picture frames and you put a sheet of iron between the upper arm and the top of the frame the frame would fall down too?

 

[Naty1]

Naty you talk of generic local spacetimes & of still only one space-time fabric in the same post.

I sometimes think of it this way: a coordinate grid, analogous to a graph paper in two dimensions...with different plots in different parts of the graph paper...like putting three or four different plots on a single page...in spacetime each "plot" (say mass) flows into the other, unlike plots on paper, so each local spacetime reflects a tiny piece of the universe within causal distance...in other words, forces like gravity and electromagnetic waves have a loooooong reach

 

[Dale]

I find that drawing very good Dale and very easy to understand.

When you go inside a planet I have been told that the decrease in gravity occurs proportional to 1/r. Is that correct?

You have shown this as well via the almost petrie dish like shapes that are about the sizes of the masses and which centre close to the centre of those masses. That is correct isn't it?

Yes, both of those are correct.

 

[Dale]

So if you had one of those floating picture frames and you put a sheet of iron between the upper arm and the top of the frame the frame would fall down too?

If it was thick enough and big enough. It often takes a lot of iron, e.g. for a 7 T MRI scanner it can take on the order of 700 tons of iron in order to reduce it from 7 T down to 5 Gauss.