Discussion Overview
The discussion centers on the calculation of observable mass in the universe based on critical density, specifically addressing which volume to use: the 13.7 billion light year radius or the 45 billion light year radius of the expanded universe. The conversation explores implications of these choices on the estimated mass of observable matter.
Discussion Character
- Debate/contested
- Mathematical reasoning
Main Points Raised
- One participant calculates the critical density to be about E-29 gm/cm3 and notes that using different volumes leads to significantly different mass estimates (4.6 x E54 gm vs. 1.8 x E56 gm).
- Another participant suggests that the volume based on the 13.7 billion year radius should be used, arguing that matter density dilutes with expansion, making this choice more logical.
- A third participant echoes the previous suggestion about using the 13.7 billion year radius and introduces a thought about Hubble's constant and its relation to the volume of the universe, while acknowledging potential flaws in their reasoning.
- One participant presents conflicting sources regarding which volume to use, citing a Wikipedia article that supports the larger volume and a NASA source advocating for the smaller volume, seeking further input.
Areas of Agreement / Disagreement
Participants express differing views on which volume to use for calculating observable mass, with no consensus reached on the correct approach. Multiple competing perspectives remain in the discussion.
Contextual Notes
Participants reference different sources and interpretations regarding the volumes, indicating a lack of resolution on the definitions and implications of the volumes in question.