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Wouldn't the gravitational pull increase? For example you would see less gravitational lensing in older galaxy clusters.

by Geee 8y ago

madaxe_again 8y ago
Yes, but it wouldn’t be locally measurable, as as the article notes mass is dimensional, meaning from your reference frame you’d notice no change. As to looking at older galaxies - maybe - but if the relativistic mass of photons is also changing due to the same phenomenon, there would be no difference in observations.
pdonis 8y ago
I think it's worse than that: it looks to me like this model will either not predict what it's claimed to predict, or will violate local stress-energy conservation. Basically, if stress-energy is locally conserved, particle masses can't just increase out of nowhere: the energy that goes into the increasing masses has to come from somewhere, and so the overall energy, which is what drives the dynamics of the universe, doesn't change, so the model can't predict anything different from standard cosmology. OTOH, if stress-energy is not locally conserved, then we should be able to observe such violations of conservation. But no such observation has ever been made: we have extremely strong evidence of local stress-energy conservation.
- nabla9 8y ago
  >we have extremely strong evidence of local stress-energy conservation. Can you observe tiny scale invariant change in just few hundred years? > model can't predict anything different from standard cosmology. I think that's the goal of emergent scale symmetry at this point. Alternative to standard cosmology that explains the same things. To differentiate between the two you need to figure out what is different.
- GlobalFrog 8y ago
  I can see your point, but is the introduction of dark energy in the current favored model better? Instead of having an energy coming from nowhere that increases particle mass, we have something coming from nowhere that expands space.
  - pdonis 8y ago
    > Instead of having an energy coming from nowhere that increases particle mass, we have something coming from nowhere that expands space. Dark energy does not "come from nowhere". It's locally conserved everywhere. It has to be: the covariant derivative of the metric is identically zero, and the "stress-energy tensor" of dark energy is just a constant times the metric.

Wouldn't the gravitational pull increase? For example you would see less gravitational lensing in older galaxy clusters.

by Geee 8y ago

Wouldn't the gravitational pull increase? For example you would see less gravitational lensing in older galaxy clusters.

madaxe_again 8y ago

Yes, but it wouldn’t be locally measurable, as as the article notes mass is dimensional, meaning from your reference frame you’d notice no change. As to looking at older galaxies - maybe - but if the relativistic mass of photons is also changing due to the same phenomenon, there would be no difference in observations.

pdonis 8y ago

I think it's worse than that: it looks to me like this model will either not predict what it's claimed to predict, or will violate local stress-energy conservation. Basically, if stress-energy is locally conserved, particle masses can't just increase out of nowhere: the energy that goes into the increasing masses has to come from somewhere, and so the overall energy, which is what drives the dynamics of the universe, doesn't change, so the model can't predict anything different from standard cosmology. OTOH, if stress-energy is not locally conserved, then we should be able to observe such violations of conservation. But no such observation has ever been made: we have extremely strong evidence of local stress-energy conservation.

nabla9 8y ago
>we have extremely strong evidence of local stress-energy conservation. Can you observe tiny scale invariant change in just few hundred years? > model can't predict anything different from standard cosmology. I think that's the goal of emergent scale symmetry at this point. Alternative to standard cosmology that explains the same things. To differentiate between the two you need to figure out what is different.
GlobalFrog 8y ago
I can see your point, but is the introduction of dark energy in the current favored model better? Instead of having an energy coming from nowhere that increases particle mass, we have something coming from nowhere that expands space.
- pdonis 8y ago
  > Instead of having an energy coming from nowhere that increases particle mass, we have something coming from nowhere that expands space. Dark energy does not "come from nowhere". It's locally conserved everywhere. It has to be: the covariant derivative of the metric is identically zero, and the "stress-energy tensor" of dark energy is just a constant times the metric.