51–60 of 380 posts
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Either we live in an unusually under dense region of the universe or our models are wrong ("new physics").
Or it's a simulation and someone keeps pushing changes to production.
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> Of course, all the results have error bars. Not to mention the underlying philosophical assumptions, such that the "rate of time" has been constant across all of... time. Aka: How do we know a "year" 13 Billion "years" ago bears any resemblance to one now? What would it mean for it not to?
I’d assume that we have some notion of how the laws of physics have changed, if at all, since the Big Bang. We measure time in vibrations of a cesium isotope IIRC
A little background based on a few articles about this plus my recollection of PBS Space Time videos on this: There are at least two ways to try to figure out the rate of expansion of the universe (which is called the Hubble Constant). • From variations in the cosmic microwave background (CMB) which are the result of certain conditions in the early universe it is possible to figure out what the expansion rate should…
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Almost all claims any serious scientist makes concern the observable universe. Also, these are very smart people. You'd be surprised what we can work out with a few very reasonable assumptions and the observations we made. The dismissiveness really isn't warranted.
IE. I'm criticizing pop-science, not science.
Earlier quoted context omitted.
> Of course, all the results have error bars. Not to mention the underlying philosophical assumptions, such that the "rate of time" has been constant across all of... time. Aka: How do we know a "year" 13 Billion "years" ago bears any resemblance to one now? What would it mean for it not to?
I’d assume that we have some notion of how the laws of physics have changed, if at all, since the Big Bang. We measure time in vibrations of a cesium isotope IIRC
https://en.wikipedia.org/wiki/Natural_nuclear_fission_reacto...
Hubble's law: https://en.wikipedia.org/wiki/Hubble%27s_law Expansion of the universe: https://en.wikipedia.org/wiki/Expansion_of_the_universe : > While objects cannot move faster than light, this limitation only applies with respect to local reference frames and does not limit the recession rates of cosmologically distant objects Given that v is velocity in the opposite direction, and c is the constant reference fram…
As far as I know this is not necessary because the speed of light is constant regardless of the velocity of both the source and the observer (this is Einstein's special relativity: https://en.m.wikipedia.org/wiki/Special_relativity)
A little background based on a few articles about this plus my recollection of PBS Space Time videos on this: There are at least two ways to try to figure out the rate of expansion of the universe (which is called the Hubble Constant). • From variations in the cosmic microwave background (CMB) which are the result of certain conditions in the early universe it is possible to figure out what the expansion rate should…
This, together with the endless philosophising around dark energy, dark matter and whatnot paints a pretty strong arrow towards our models having some flaws when it comes to their large-scale application. I hope to live long enough to see where we made our mistake and get a better model.