The Edges of Our Universe
2021/04/02 by Toby Ord, Ord, Toby · 5 voices · 2 citations
Physics and Astronomy · Earth and Planetary Sciences · #Space Science and Extraterrestrial Life #Cosmology and Gravitation Theories #Earth Systems and Cosmic Evolution
paper · pdf · doi:10.48550/arxiv.2104.01191
Abstract
This paper explores the fundamental causal limits on how much of the universe we can observe or affect. It distinguishes four principal regions: the affectable universe, the observable universe, the eventually observable universe, and the ultimately observable universe. It then shows how these (and other) causal limits set physical bounds on what spacefaring civilisations could achieve over the longterm future.
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Discussions
- The Edges of Our Universe [hn, 107 points, 49 comments]
- The universe is mostly made up of dark matter and energy, but even if you just look at normal matter stars are a surprisingly small portion. Most baryonic matter is incredibly hot and diffuse plasma. [bsky, 27 points, 4 comments]
- You can find out much more about the affectable universe and the ultimate limits of causality in our universe in a paper I wrote called 'The Edges of Our Universe': 17/17 arxiv.org/pdf/2104.01191 [bsky, 3 points, 1 comments]
- The Edges of Our Universe and Implications for Spacefaring Civilizations [pdf] [hn, 2 points, 0 comments]
- The Edges of Our Universe [hn, 2 points, 0 comments]
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