How far does space-time bend out in space?

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Discussion Overview

The discussion revolves around the extent to which Earth's gravity can curve space-time and whether this curvature can be detected at the edge of the universe. Participants explore concepts related to gravitational effects, time dilation, and the implications of mass on space-time curvature.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions how far Earth's gravity can theoretically curve space-time and whether this effect extends to the edge of the universe.
  • Another participant introduces the Schwarzschild solution, noting that while curvature approaches zero at infinity, it never actually reaches zero.
  • A participant raises a hypothetical scenario involving two spheres of different sizes but the same density, questioning if gravitational effects and time dilation would be proportional to their masses.
  • There is a clarification regarding the distance at which curvature approaches zero, with a participant confirming it is at infinity.
  • One participant expresses uncertainty about the proportionality of gravitational effects and time dilation, suggesting that these questions may require more expertise in the Schwarzschild metric.

Areas of Agreement / Disagreement

Participants express curiosity and explore various aspects of gravitational effects and space-time curvature, but there is no consensus on the extent of these effects or the proportionality of gravity-related phenomena.

Contextual Notes

Participants acknowledge limitations in their understanding and the complexity of the questions posed, particularly regarding the Schwarzschild metric and its implications for gravitational effects.

johann1301
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When looking at Earth's ability to curve space-time; how far does these curves go? can they theoretically be registered at the edge of the universe?(just an infinite small amount of course).?

i suppose i could just ask if Earth's gravity stretches everywhere in the universe? or.. is there a place in the universe where there is no gravity?
 
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johann1301 said:
When looking at Earth's ability to curve space-time; how far does these curves go? can they theoretically be registered at the edge of the universe?(just an infinite small amount of course).?

i suppose i could just ask if Earth's gravity stretches everywhere in the universe? or.. is there a place in the universe where there is no gravity?
You guessed it. The closest thing we have to a direct answer to your question is the Schwarzschild solution. It describes a universe that's completely empty except for a single non-rotating, spherically symmetric distribution of mass with zero electric charge. In that solution, no part of spacetime is exactly flat. Curvature goes to zero as the distance from this object goes to infinity, but it never actually reaches zero.

Edit: I have corrected the mistake that Passionflower quoted in #4.
 
Last edited:
Thank you for a good answer!

I also wonder;

lets say:
1. There are two spheres that both have the same density as earth.
2. One sphere is twice the size as the other.
3. The bigger sphere would then have twice the mass.

would the effects of gravity in the big one be twice as big as the effects of the smaller one? for example; would time go half as fast in the bigger sphere?(relative to the other sphere of course) (time dilation) I guess I am asking if every effect of gravity is completely proportional?

Hope the question made some sense;)
 
Fredrik said:
Curvature goes to zero as the distance from this object goes to zero, but it never actually reaches zero.
You mean as it goes to infinity?
 
Passionflower said:
You mean as it goes to infinity?
:smile:

Yes, of course.

johann1301 said:
Thank you for a good answer!

I also wonder;

lets say:
1. There are two spheres that both have the same density as earth.
2. One sphere is twice the size as the other.
3. The bigger sphere would then have twice the mass.

would the effects of gravity in the big one be twice as big as the effects of the smaller one? for example; would time go half as fast in the bigger sphere?(relative to the other sphere of course) (time dilation) I guess I am asking if every effect of gravity is completely proportional?

Hope the question made some sense;)
Those are questions that would take me some time to answer, so I'll leave them for someone else. I'm sure there's someone who has worked with the Schwarzschild metric recently, who can answer in a tenth of the time it would take me.
 
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