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How do we know that gravity is constant in proportion to mass and not a function of time? General relativity tells us mass slows down time, but we assume slowi

How do we know that gravity is constant in proportion to mass and not a function of time? General relativity tells us mass slows down time, but we assume slowing down action doesn't affect gravity. If gravitons, or other quanta of gravity, exists wouldn't general relativity infer that massive objects have less gravity in proportion to mass than less massive objects? We know from general relativity that massive galactic cores have less time in proportion to their mass compared with galactic arms, which have more time (action) relative to their mass. Why wouldn't general relativity's slow down in time also mean less gravity in proportion to mass?

semi-extrinsic 9y ago
Well, if the strength of gravity was linear in redshift, astronomers would have detected it decades ago.
- jboy55 9y ago
  Apologies if this is naive, I was looking for a free book for a flight a week ago and I downloaded 'The Einstein theory of relativity; a concise statement' by H A Lorentz, 1920, available here https://archive.org/details/einsteintheoryr00einsgoog https://archive.org/details/einsteintheoryr00einsgoog as well. On page 22, Lorentz states a 3rd experimental test for the theory, "If his (Einstein) theory is correct as it stands, there ought, in a gravitational field, to be a displacement of the lines of the spectrum towards the red." He adds, "No such effect has been discovered. ... there is no way of accounting for this failure if Einstein's theory in its present form is assumed." He goes on to say that some modification would be necessary. What eventually happened to this 3rd test?
  - whatshisface 9y ago
    Here's the wikipedia page for the test you're talking about: https://en.wikipedia.org/wiki/Gravitational_redshift https://en.wikipedia.org/wiki/Gravitational_redshift >The first accurate measurement of the gravitational redshift of a white dwarf was done by Popper in 1954, measuring a 21 km/sec gravitational redshift of 40 Eridani B. The effect has been seen in experiments. (See the section on experimental verification.)
  - deleted 9y ago
    [deleted]
- Zamicol 9y ago
  I wouldn't expect gravity to be linear, but exponential just like time in general relativity.

semi-extrinsic 9y ago

Well, if the strength of gravity was linear in redshift, astronomers would have detected it decades ago.

jboy55 9y ago
Apologies if this is naive, I was looking for a free book for a flight a week ago and I downloaded 'The Einstein theory of relativity; a concise statement' by H A Lorentz, 1920, available here https://archive.org/details/einsteintheoryr00einsgoog https://archive.org/details/einsteintheoryr00einsgoog as well. On page 22, Lorentz states a 3rd experimental test for the theory, "If his (Einstein) theory is correct as it stands, there ought, in a gravitational field, to be a displacement of the lines of the spectrum towards the red." He adds, "No such effect has been discovered. ... there is no way of accounting for this failure if Einstein's theory in its present form is assumed." He goes on to say that some modification would be necessary. What eventually happened to this 3rd test?
- whatshisface 9y ago
  Here's the wikipedia page for the test you're talking about: https://en.wikipedia.org/wiki/Gravitational_redshift https://en.wikipedia.org/wiki/Gravitational_redshift >The first accurate measurement of the gravitational redshift of a white dwarf was done by Popper in 1954, measuring a 21 km/sec gravitational redshift of 40 Eridani B. The effect has been seen in experiments. (See the section on experimental verification.)
- deleted 9y ago
  [deleted]
Zamicol 9y ago
I wouldn't expect gravity to be linear, but exponential just like time in general relativity.