Does Local Gravity Override Dark Matter in Galactic Rotation?

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Discussion Overview

The discussion explores the influence of local gravitational effects on the rotation of stars at the edges of galaxies, questioning whether these effects could account for observed rotation curves without invoking dark matter. Participants consider various scenarios and analogies, including the Earth-Moon system and three-body problems, to illustrate their points.

Discussion Character

  • Debate/contested
  • Exploratory
  • Technical explanation

Main Points Raised

  • Some participants propose that local gravitational interactions among stars could lead to faster rotation rates than predicted by models based solely on individual star masses.
  • Others argue that the gravitational influence of nearby stars does not alter the orbital velocity of stars around the galaxy's center, suggesting that the calculations leading to the dark matter hypothesis remain valid.
  • A participant questions whether the calculations regarding dark matter could be incorrect due to the complexity of local gravitational effects.
  • There is a discussion about the implications of mass distribution in a galaxy versus the solar system, with one participant suggesting that different mass distributions could affect rotation curves.
  • Some participants explore hypothetical scenarios involving binary systems and the effects of mass on orbital periods, raising questions about how these scenarios relate to the observed dynamics of galaxies.
  • A later reply discusses the gravitational effects of a three-body system, questioning if such a configuration could produce similar rotation curves as those observed in galaxies, potentially negating the need for dark matter.

Areas of Agreement / Disagreement

Participants do not reach consensus; multiple competing views remain regarding the role of local gravity in galactic rotation and the validity of dark matter as an explanation for observed phenomena.

Contextual Notes

Participants express uncertainty about the calculations involved in determining the effects of local gravity and the implications of mass distribution in different systems. Some assumptions about gravitational interactions and orbital mechanics are not fully resolved.

  • #31
weirdoguy said:
Is anyone saying that string theory is empirically verified? No. So what's your point? Besides, this thread is about plain old classical gravity. Physicists may be wrong when it comes to untested models like string "theories", but gravity - Newtionian and Einsteinian - has been tested and observationally verified on so many levels that putting it's validity in doubt is very unreasonable, to say the least.
OK. More to the point what empirical evidence is there for "dark matter"?
 
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  • #32
This has nothing to do with this thread, so start your own with this question. Or search for other threads about this issue, because it has been discussed here multiple times.
 
  • #33
weirdoguy said:
This has nothing to do with this thread, so start your own with this question. Or search for threads for other threads about this issue, because it has been discussed here multiple times.
 
  • #34
Ibix said:
...the general problem with advancing science isn't coming up with new ideas. It's coming up with new ideas that aren't obviously wrong to anyone who knows anything about the topic.
:oldbiggrin:
 
  • #35
Viopia said:
OK. More to the point what empirical evidence is there for "dark matter"?
It's a pity you're banned, and that this is off-topic. Else I would have you look up the Bullet Cluster.
 
  • #36
The thread topic has been sufficiently discussed. Thread closed.
 

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