5 ms·

I'd like to see more work done with investigating field self-interaction. This 2020 paper by Alexandre Deur is very interesting. "[W]e find that relativistic

I'd like to see more work done with investigating field self-interaction. This 2020 paper by Alexandre Deur is very interesting. "[W]e find that relativistic corrections to the rotation curves of disk galaxies are significant at large galactic radii." "Relativistic corrections to the rotation curves of disk galaxies" - https://arxiv.org/pdf/2004.05905.pdf https://arxiv.org/pdf/2004.05905.pdf And a blog covering the paper: https://astrobites.org/2020/08/17/the-alternative-to-dark-matter-may-be-general-relativity-itself/ https://astrobites.org/2020/08/17/the-alternative-to-dark-ma...

nimish 3y ago
Yep, there's a lot of stuff that properly using general relativity would address in a much cleaner way than dark matter. Ignoring the relativistic nature and nonlinearity of GR is a very large problem with FLRW and other toy models, but they have become embedded in cosmology to the point where it's heresy to question them.
AnotherGoodName 3y ago
The fun part about this is that gravity has to either be self interacting or capable of propagating faster than light. If gravity wasn't self interacting it wouldn't follow the shortest path that gravity itself creates. Light does follow this path. Gravity would move in different directions and at different velocities to light across the universe which is full of gravitational field if it wasn't self interacting. We have seen zero evidence that gravity does propagate differently to light. In fact ligo and other gravity experiments have only confirmed it's the same. So gravity is almost certainly self interacting. What does this mean? Well it wouldn't change much at small scales. There's not enough effect at say planetary scales to really notice. But what happens when you have a field self interacting across vast distances and involving vast galaxy sized masses? Well your link looks at this and yes it matches some of the anomaly's we are at large scale. It's a good theory and I suspect despite being hard to argue against it will face opposition since it means a lot of scientists were chasing a dead end.
- deleted 3y ago
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- Zamicol 3y ago
  In my mind, gravity must self interact due to moving at exactly the same speed as light (and light is affected by gravity). To put this in quantitative terms, the paper "Gravitational Waves and Gamma-rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A" (https://arxiv.org/abs/1710.05834 https://arxiv.org/abs/1710.05834) constrains the "difference between the speed of gravity and the speed of light to be between −3×10^−15 and +7×10^−16 times the speed of light."
  - AnotherGoodName 3y ago
    Yep I feel like ligo and Virgo are the Michelson Morley experiment of this century. They have shown something that is not well accounted for in current theories. Just as MM showed light is always observed travelling at the same velocity Ligo has shown gravity is self interacting. Now we need to change our models and build mathematical frameworks to account for this. It is not acceptable to have a theory that doesn't account for this post Ligo.
    - HardlyCurious 3y ago
      I'm not convinced of that interpretation of MM. MM found a signal below the margin of error. I think if they spun the table faster the signal would grow in strength. But subsequent experiments stopped rotating the assembly at all and just relied on the rotation of earth, and thus had even slower rotation and even smaller signals. But at this point nobody is going to revisit MM, attempting to do so would immediately ruin your scientific reputation.
      - oneshtein 3y ago
        Some of us have no scientific reputation at all, so we are free from the reputation trap.

nimish 3y ago

Yep, there's a lot of stuff that properly using general relativity would address in a much cleaner way than dark matter. Ignoring the relativistic nature and nonlinearity of GR is a very large problem with FLRW and other toy models, but they have become embedded in cosmology to the point where it's heresy to question them.

AnotherGoodName 3y ago

The fun part about this is that gravity has to either be self interacting or capable of propagating faster than light. If gravity wasn't self interacting it wouldn't follow the shortest path that gravity itself creates. Light does follow this path. Gravity would move in different directions and at different velocities to light across the universe which is full of gravitational field if it wasn't self interacting. We have seen zero evidence that gravity does propagate differently to light. In fact ligo and other gravity experiments have only confirmed it's the same. So gravity is almost certainly self interacting. What does this mean? Well it wouldn't change much at small scales. There's not enough effect at say planetary scales to really notice. But what happens when you have a field self interacting across vast distances and involving vast galaxy sized masses? Well your link looks at this and yes it matches some of the anomaly's we are at large scale. It's a good theory and I suspect despite being hard to argue against it will face opposition since it means a lot of scientists were chasing a dead end.

deleted 3y ago
[deleted]
Zamicol 3y ago
In my mind, gravity must self interact due to moving at exactly the same speed as light (and light is affected by gravity). To put this in quantitative terms, the paper "Gravitational Waves and Gamma-rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A" (https://arxiv.org/abs/1710.05834 https://arxiv.org/abs/1710.05834) constrains the "difference between the speed of gravity and the speed of light to be between −3×10^−15 and +7×10^−16 times the speed of light."
- AnotherGoodName 3y ago
  Yep I feel like ligo and Virgo are the Michelson Morley experiment of this century. They have shown something that is not well accounted for in current theories. Just as MM showed light is always observed travelling at the same velocity Ligo has shown gravity is self interacting. Now we need to change our models and build mathematical frameworks to account for this. It is not acceptable to have a theory that doesn't account for this post Ligo.
  - HardlyCurious 3y ago
    I'm not convinced of that interpretation of MM. MM found a signal below the margin of error. I think if they spun the table faster the signal would grow in strength. But subsequent experiments stopped rotating the assembly at all and just relied on the rotation of earth, and thus had even slower rotation and even smaller signals. But at this point nobody is going to revisit MM, attempting to do so would immediately ruin your scientific reputation.
    - oneshtein 3y ago
      Some of us have no scientific reputation at all, so we are free from the reputation trap.