How would two massive bodies effect eachothers gravity?

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Discussion Overview

The discussion explores the gravitational interactions between two massive bodies, specifically considering a scenario where one massive planet orbits another closely. Participants examine the implications of such proximity on gravitational forces and the potential for survival on the surface of one planet due to the gravitational effects of the other.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant proposes a scenario where a person lives on a massive planet (A) orbiting another massive planet (B) and questions whether the gravitational pull of planet B could counteract the gravity of planet A at a point between them.
  • Another participant confirms that there are points where the gravitational forces of two planets can cancel each other out, noting that both planets would rotate around their common center of mass.
  • A different participant draws an analogy to the Moon's effect on Earth's tides, explaining how gravitational differences can create observable effects, albeit on a smaller scale.
  • A further inquiry is made regarding the difference in gravitational force experienced at the closest and furthest points on planet A from planet B, questioning the size required for such differences to be noticeable.

Areas of Agreement / Disagreement

Participants express various viewpoints on the gravitational interactions, with some agreeing on the existence of cancellation points while others raise questions about the magnitude of gravitational differences. The discussion remains unresolved regarding the specific conditions under which these effects would be significant.

Contextual Notes

There are limitations regarding the assumptions made about the sizes and masses of the planets, as well as the lack of detailed mathematical analysis on the gravitational differences at varying distances.

Algaib
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Scenario: Let's say I lived on planet A (which was massive), which orbited planet B (which was also massive) so closely that upon looking up into the sky, planet B would fill most of what we would normaly see as being blue sky.

Living on such a massive planet has some probolems; e.g being crushed by massive gravity.

Question: Would the gravity of planet B work in the opposite direction to planet A, thus allowing me to survive on the surface at the point directly inbetween both planets without being crushed?
 
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Yes,k even without relativity, there exist points at which the gravitational forces of two planets cancel. (Strictly speaking the two planets would both be rotating around their common center of mass.)
 
Yes, to a much smaller degree, that's how the Moon causes tides on Earth. The Moon's gravity pulls one side of the Earth a bit more than it pulls the centre of the Earth, and the opposite side a bit less, and those differences cause the high tides.
 
How much difference in gravity would there therefore be between the closest point on planet A to planet B, and the furtherst point on planet A from planet B. (Lets say the planets are the size of our sun, or more). If none that would be noticable, then how large must the planets be for you to feel the difference?[PLAIN]http://www.theabominablesnowman.co.uk/planets.html
 
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