Varying Expansion Rates for Solar System

In summary: Sean M Carroll have both found solutions to Einstein's equation that include a Lorentz-violating, fixed-norm vector field theory. This theory results in a rescaling of Newton's constant, which can be compared in both the Newtonian regime and cosmological observations. This comparison can lead to observable deviations from ordinary general relativity, with potential constraints from Big Bang nucleosynthesis. Further constraints can also be derived from considering perturbations of this theory, particularly during inflation. This research is the subject of a companion publication. In summary, Carroll and Lim's work explores a potential window for observational constraints on the parameters of a vector field theory by comparing rescalings of Newton's constant in different observational regimes.
  • #1
Wave's_Hand_Particle
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Compared to the rest of the Universe:Sean M Carroll and Eugene A Lim.

Quote:The different rescalings of Newton’s constant in the Solar System versus the universe as a whole offer a potential window for observational constraints on the parameters of our vector field. Newton’s constant enters cosmological observations in different ways, including measurements of the expansion rate in the present universe, the formation of late time large-scale structure (e.g [38]) and the properties of perturbations in the Cosmic Microwave Background. However, the most straightforward test comes from the predictions of primordial abundances from Big Bang nucleosynthesis (BBN). Changes to the effective value of Newton’s constant are equivalent to the presence of additional (or lack of some) radiation components, leading to a change in the rate of expansion.

Also their conclusions state:We have found solutions to Einstein’s equation in the presence of other matter fields for a class of Lorentz-violating, fixed-norm vector field theories, and find that they act to rescale the value of Newton’s constant. By comparing these rescalings in the Newtonian regime
to those in cosmology, we find an observable deviation from ordinary general relativity.
Following this, we use the predictions of BBN to place constraints on the value of the norm of this vector field.
Further constraints on this theory, in addition to those already cited in this paper on the βi’s, can be derived when we consider its perturbations. In particular, the presence of this vector field during inflation will modify the primordial spectrum of perturbations leading to observable features on both the temperature and polarization anisotropy spectra of the Cosmic Microwave Background. This investigation is the subject of a companion publication.

Surely I have I read this wrong?..any deviation of Gravitational effects would be comparable to the Galaxy and Universe, NOT as to the Solar System and Universe?

An expansion rate due to the the density of matter for our Solar System, must be coupled/offset, to the local expansion rate due to the 'local' Pressure purely from our Sun?
 
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  • #2
It would appear from your extract that they are comparing solar system observations, i.e. the standard GR and Newtonian tests, with cosmological deductions from BB nucleosynthesis etc.

Garth
 

1. What is "Varying Expansion Rates for Solar System"?

"Varying Expansion Rates for Solar System" refers to the phenomenon where different objects within our solar system, such as planets and moons, expand and contract at different rates due to various factors such as their composition and distance from the sun.

2. What causes the varying expansion rates within the solar system?

The varying expansion rates within the solar system are primarily caused by differences in the objects' composition and distance from the sun. For example, rocky planets like Earth expand and contract due to changes in temperature, while gas giants like Jupiter expand and contract due to their gaseous atmospheres.

3. How is the varying expansion rates for the solar system measured?

The varying expansion rates for the solar system can be measured through various methods such as using telescopes to observe changes in the sizes of planets and moons, analyzing data from spacecrafts that have visited these objects, and studying their gravitational interactions with other objects.

4. What impact do varying expansion rates have on the solar system?

Varying expansion rates can have significant impacts on the solar system. For example, they can affect the orbits and rotations of planets and moons, influence the formation and evolution of these objects, and even contribute to the creation of geological features such as tectonic plates and volcanic activity.

5. Can varying expansion rates for the solar system change over time?

Yes, varying expansion rates for the solar system can change over time. This can be due to a variety of factors such as changes in the objects' composition, external forces acting on them, and even the influence of other celestial bodies. Scientists continue to study and monitor these changes to gain a better understanding of our solar system.

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