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comment by mk
mk  ·  505 days ago  ·  link  ·    ·  parent  ·  post: Cosmology Has Some Big Problems

Do you remember what some of those difficult to reconcile observations were?

Devac  ·  505 days ago  ·  link  ·  

Oof, I'd have to find those notebooks to be certain, but, logically, initial inflation would have to be a lot slower and happen later in the universe's evolution to accommodate this model. Presumably, the observable universe would be smaller than what we can observe, but that doesn't need to be the case, just something that I find likely to be one.

What I do remember is that we did a cluster dynamics simulation[1] starting with standard initial conditions (matter starts randomly positioned on a sphere, mass distribution of 'chunks' is logarithmic and something about the distribution of initial velocities that I can't recall but will probably add in an edit) and the end result lacked those bubbles surrounded by supercluster filaments you get with dark matter (which, in fact, do exist).

That said, I'll try to find those notes, if only because I don't like to second-guess my memory.

[1] - Reasonably smaller scale than the ones you can do on a proper supercomputer. IIRC, we were constrained to 128 GB memory and only got allocated 50 hours on uni grid.

kleinbl00  ·  505 days ago  ·  link  ·  

Max Tegmark's Our Mathematical Universe delves into measurements of the age of the universe in a highly readable way. The problem isn't so much that the observations are "difficult to reconcile" it's that independent observational methods have gained agreement to about three orders of magnitude since 2012.