Would Earth fly off into space if the Sun disappeared?

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  • Thread starter Thread starter Julius Ceasar
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Discussion Overview

The discussion revolves around a hypothetical scenario in general relativity (GR) concerning the immediate effects on Earth if the Sun were to disappear suddenly. Participants explore the implications of such an event on Earth's orbit, considering both the theoretical constraints of GR and the propagation of gravitational effects.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants suggest that if the Sun hypothetically disappeared, Earth would not immediately fly off into space but would instead experience a delay in gravitational effects due to the finite speed of light, approximately eight minutes.
  • Others argue that the scenario of the Sun disappearing violates the principles of GR, as it cannot happen instantaneously, and thus no predictions can be made about such an event.
  • A participant likens the situation to letting a string slip, questioning how the gravitational pull would change over time.
  • Some responses clarify that any changes in the Sun's mass or position would affect Earth only after a delay, while others emphasize that the question itself is fundamentally flawed within the framework of GR.
  • There is a discussion about whether the concept of "local mass changes" is appropriate, with some suggesting it could lead to misunderstandings about mass distribution versus mass amount.
  • One participant proposes that using Newtonian gravity could allow for a sensible interpretation of the question, suggesting that gravitational effects would change immediately without delay.
  • Another participant counters that the interpretation of the question must align with GR, which does not support the idea of instantaneous changes in gravitational effects.

Areas of Agreement / Disagreement

Participants generally disagree on the interpretation of the hypothetical scenario and its implications within GR. While some acknowledge the eight-minute delay in gravitational effects, others maintain that the question itself is invalid under GR, leading to unresolved tensions in the discussion.

Contextual Notes

Participants note that the scenario of the Sun disappearing is mathematically inconsistent with GR, which complicates the discussion. The conversation also touches on the need for clarity regarding the definitions of mass changes and gravitational effects.

  • #31
It all good Oro i am now aware the question is impossible in GR and will work on it. It was a high school level question so perhaps tone it down sunshine.
 
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  • #32
Julius Ceasar said:
It all good Oro i am now aware the question is impossible in GR and will work on it. It was a high school level question so perhaps tone it down sunshine.
Regardless of level, do you want to learn something or just be told a story? This is the difference between science and popular science. Whereas learning science will tell you how the theories actually work and generally requires you to make more effort outside your comfort zone, popular science will tell you a story about science that comes with a million caveats you have no chance to catch as a layman. This is all good if you understand that and it is what you want. However, there are countless examples of people coming to these forums with the impression that they know science based on popularised accounts.
 
  • #33
I can appreciate that.
 
  • #34
An object like the sun cannot go out of existence. But if it does (If the sun converted all its mass into energy in a second and all the energy is ejected from its poles perpendicular to Earth's orbit plane), it'll take 8:34 min to recognize, optical as well as gravitational since nothing is faster than the speed of light.

I do not see why there have been so many posts, and even less why this thread became personal.

Thread closed.
 
Last edited:

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