Orbital effect of a sudden change to G

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Discussion Overview

The discussion centers on the hypothetical scenario of a sudden change in the gravitational constant (G) and its effects on Earth's orbital radius. Participants explore the implications of such a change within the context of gravitational physics, considering both theoretical and practical aspects of orbital mechanics.

Discussion Character

  • Exploratory, Debate/contested, Conceptual clarification

Main Points Raised

  • One participant questions whether the Earth's orbital radius would adjust to maintain the equality of gravitational forces if G were to change suddenly.
  • Another participant argues that the question is fundamentally flawed, suggesting that it is impossible to predict outcomes when disregarding established physical laws.
  • A different perspective introduces a scenario where a minuscule asteroid merges with the Sun, prompting a discussion on whether this mass change would affect Earth's orbit, specifically questioning if there would be a change in orbital radius or period.
  • Some participants challenge the notion of an asteroid having no gravitational influence on Earth until it impacts the Sun, emphasizing the continuity of gravitational effects in such scenarios.

Areas of Agreement / Disagreement

Participants express disagreement regarding the validity of the initial question and the implications of a sudden change in G. There is no consensus on how to approach the problem or the effects of mass changes on Earth's orbit.

Contextual Notes

Participants highlight limitations in the assumptions made about gravitational interactions and the nature of physical laws in hypothetical scenarios.

enotstrebor
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If the gravitational constant suddenly changed, would the Earth change its orbital radius r' such that the new G'M'/r'^2 equals todays GM/r^2. If not how?
 
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There is no way to answer the question "if I dispense with the laws of physics, what do the laws of physics say will happen."
 
Vanadium 50 said:
There is no way to answer the question "if I dispense with the laws of physics, what do the laws of physics say will happen."

Another version which I think does not dispense with the laws of physics.

An asteroid 1.0*10^-15 the mass of the sun's mass joins with the sun (giving the sun's new mass M'). The asteroid's path into the sun does not disturb the orbit of earth.
Considering only the effect of the suns mass change (I know there are other effects), is there an orbital radius change such that M'G/r'^2 is equal to the old M_sun/r^2. If not, no matter how negligible the effect, what is the gravitational effect of the mass change to Earth's orbit (e.g. change in P?).
 
You can't have an asteroid magically have no gravitational pull on the Earth until it hits the sun, and then magically have it's gravity restarted. There is no way to answer the question "if I dispense with the laws of physics, what do the laws of physics say will happen."
 

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