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A_A@lemmy.world Joined: 2023-06-13

i have been studying cosmology from this source :

https://www.astro.ucla.edu/~wright/cosmo_02.htm
... and have a problem with this part :
(( dynamics ... ))

With a constant mass interior to D(t) producing the acceleration of the edge (...)

The problem i have is they describe the situation as symmetric from the center of a sphere and try to apply this symmetry to the edge of the sphere while, since galaxies are escaping at relativistic velocities, the situation at the edge cannot be described as symmetric in the way that would imply that :

The gravitational effect of the external matter vanishes (...)

Welcome to the nostalgia-filled piefed instance of yesteryear.

Open Registration with Application questionnaire.

If you have a question or comment you can post in !meta@retrofed.com or message @DosDude@retrofed.com or @Die4Ever@retrofed.com

In case of downtime and/or emergency, we will post updates on @DosDude@mastodon.social

Some rules we try to uphold:

Be civil. Bigotry is not welcome. This includes (but is not limited to): transphobia, queerphobia, racism, ageism and ableism. We do not promote hate.
Communities need to be Retro or Retro-adjacent.
Please don't upload pornographic content. (use an external image host for that)