Think about this: take a human, tie each arm with a rope to a car and speed up the cars. The person would die dismembered because his arms would be plucked from his body.

My question is if it's possible to do the same with gravity. For example: take a human, put in each side a massive object (e.g: black hole, or a sun) and wait. What will happend? (don't take in note vaccum, heat or radiation...)

The thing that I am tring to ask is if gravity is possisble to cancel with two gravity wells or is that is just an illusion (the object doesn't move because two vectos are doing the same amount of force in opossite directions). I mean:

  • Both gravity wells will cancel each other. So the human won't nottice nothing. Or;
  • Gravity wells won't cancel. Both wells would pull the human so he will be splited in two (and die dismembered).

In case the first is true, would "specials things" caused by gravity (like slowdown time, warp the space and other kind things that I don't know) still happen or they will be cancel?

  • $\begingroup$ You don't even need two gravity wells: look up 'Roche limit' $\endgroup$ – tfb Jan 30 '18 at 21:37
  • $\begingroup$ @tfb. 1) I am not sure but I thing Roche limit can only be applied in object which use their own gravity to stay together (e.g: planet). But a person doesn't use gravity, it use the strenght of the materials which is made. 2) I am not talking about how to broke an object, I want to know if the effects produced by gravity (like the pull) can be cancel with another one in the opossite direction or in real both effect are applied at the same time. $\endgroup$ – Ender Look Jan 30 '18 at 21:42
  • $\begingroup$ Yes, the Roche limit applies to gravitationally-bound objects. Objects bound by stronger forces would need to get closer, but they too will be disrupted: a good example of this is the 'spaghettification' which occurs near the horizons of (sufficiently small) black holes. $\endgroup$ – tfb Jan 30 '18 at 21:45

While it's certainly possible for gravity alone (and even from just one source) to rip a person to shreds (the term to look up is spagettification) you have I feel a possible misconception or two going on in your question.

The issue is what's the difference in force between one side of the person and the other. It doesn't matter how big the forces are due to the objects, it's the difference between that force on that one extremity of the human experiences compared to the other extremity.

Well people are relativity small compared to most objects producing significant gravitational fields (like planets), so for most purposes, the difference in force you experience is going to be minute.

When you have a very intense gravitational field (like very, very close to a black hole) you can have huge differences between the force on one extremity and another, even though the distance is small.

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  • $\begingroup$ shear and torsional forces by extreme warping of spacetime? I can't imagine tensile forces would be possible in a single massive body. Or do dimensions need to be re-thought? $\endgroup$ – docscience Jan 30 '18 at 23:11
  • $\begingroup$ Your answer is interesting but it isn't an answer to my question. Do you know about Lagrangian points? I don't know much of them but I have understand (I just read a bit in wikipedia) that they are points where 2 gravity wells (Earth & Sun, Earth & Moon) "cancel" each other making zones where you can have an stationary satellite without problems. I want to know if that satellites inside that point are in real experimenting two pulling forces or not (so e.g. if they were in the langranes point of 2 black holes the pull of both will broke the satellive even when he is inside the "non-G zone"). $\endgroup$ – Ender Look Jan 31 '18 at 2:05
  • $\begingroup$ You did not mention Lagrangian points in your question. They are not points where forces are zero, but where forces are such that the net force would maintain the object in the same position relative to the other objects (which would normally be moving themselves due their own mutual attraction). Black holes are, in this sense, just normal gravitational objects and the specific forces at a Lagrangian point would depend on the precise details of individual cases). $\endgroup$ – StephenG Jan 31 '18 at 2:35
  • $\begingroup$ Oh, I have misunderstanded the concept of Lagrangian Points :), thanks thanks for the explanation. $\endgroup$ – Ender Look Jan 31 '18 at 16:04

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