The Pork Chop Solution: Pondering My Place in Space

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Discussion Overview

The discussion explores the hypothetical scenario of an individual conceptualizing themselves as an asteroid in space, reflecting on the effects of gravity and mass on their existence. It touches on themes of gravitational forces, the nature of space, and the implications of general relativity versus Newtonian physics.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant describes a vivid metaphor of being an asteroid in space, contemplating the gravitational forces acting upon them.
  • Another participant suggests that the strength of the individual's body and their weak gravitational force would prevent them from being pulled apart by tidal forces.
  • A follow-up comment questions the scenario if the individual were "empty space," implying a lack of resistance to gravitational forces.
  • Further discussion introduces Newtonian theory, stating that within a uniform sphere of matter, no net gravitational force would act on the individual.
  • Another participant contrasts this with general relativity, noting that the situation becomes complex and depends on the universe's deceleration parameter and the presence of a cosmological constant.
  • One participant offers to provide links to previous discussions involving tensor algebra related to these concepts.

Areas of Agreement / Disagreement

Participants express differing views on the effects of gravity and mass in the scenario, with some agreeing on the basic principles of gravitational forces while others introduce complexities from general relativity. The discussion remains unresolved regarding the implications of being "empty space" and the conditions under which gravitational forces would act.

Contextual Notes

The discussion includes assumptions about gravitational forces and the nature of mass, with references to Newtonian and general relativity frameworks. There is an acknowledgment of mathematical complexities that are not fully explored in the conversation.

Chronos
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I was BBQ-ing yesterday. I ate eight pork chops [they were small] and lapsed into a sated, torpid slumber. Suddenly, I was a lonely asteroid drifting in deep space, with nothing but diffuse filaments of primordial hydrogen and helium molecules to keep me company [I was recoil kicked out of my mother galaxy about 8 Gy ago.]. It suddenly occurred to me I was being gently pulled in all directions by the gravity of the near infinite number of massive bodies isotropically surrounding me in the universe. Were it not not for the attractive properties of my own feeble mass, I would be stretching... Any thoughts?
 
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I imagine 2 things would hold you together. The strength of your body and the very weak gravitational force created by your mass should each be sufficient to prevent the very weak cumulative tidal forces from pulling you apart.
 
Agreed, but what if I'm empty space devoid of any appreciable resistance to this force?
 
Chronos said:
Agreed, but what if I'm empty space devoid of any appreciable resistance to this force?
Good question, gravity gravitates, i guess the only thing keeping you from "imploding" is the hubble.
 
In Newtonian theory, there is no force anywyere inside a sphere of uniform matter. So you wouldn't be pulled apart.

In GR things get a lot more complicated, and the previous statement is not necessarily true. From some other threads, including one overly long thread about threads :-), you should only get pulled apart if the deceleration parameter q of the universe is less than zero, i.e. if the universal expansion is acclerating. (This happens only when there is a cosmological constant). Otherwise you will only experience compressive forces.

There isn't any good way of illustrating this without some nasty tensor algebra, though. If anyone wants to see the nasty tensor algebra, I can provde links where this has been previously discussed, and the numbers for our current universe (which does have a cosmological constant) have been calculated.