Fermat's Library on X: "Deriving human size from fundamental constants
In this week's paper, William Press argues that intelligent life requires:<br>(i) complex chemistry<br>(ii) a substantial atmosphere<br>(iii) bodies strong enough to withstand gravity
From these premises, he derives the density of" / X<br>Post
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Fermat's Library on X: "Deriving human size from fundamental constants
In this week's paper, William Press argues that intelligent life requires:<br>(i) complex chemistry<br>(ii) a substantial atmosphere<br>(iii) bodies strong enough to withstand gravity
From these premises, he derives the density of"
Fermat's Library
@fermatslibrary
Deriving human size from fundamental constants
In this week's paper, William Press argues that intelligent life requires:<br>(i) complex chemistry<br>(ii) a substantial atmosphere<br>(iii) bodies strong enough to withstand gravity
From these premises, he derives the density of organisms, the environmental temperature, the mass and radius of their planets, and ultimately the characteristic size and lifespan of intelligent beings.
The only free parameter is the effective bond energy, ε ≈ 0.003 Ry (hydrogen bonds). Creature size depends only weakly on ε (∝ ε^1/4), but lifespan depends very strongly (∝ ε^–2.75).
His conclusion: intelligent beings should be roughly Earth-sized and inhabit Earth-like planets, yet their timescales for metabolism and lifespan could vary drastically with local chemistry and stellar conditions.
Read the annotated paper here: fermatslibrary.com/s/man-ssize-in…
span:not(:empty)~span:not(:empty)]:before:content-['·'] [&>span:not(:empty)~span:not(:empty)]:before:px-1 [&>span:not(:empty)~span:not(:empty)]:before:shrink-0">3:14 PM · Aug 14, 202698.9KViews
27<br>80<br>832<br>536
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@PhDPersuasion
Aug 14
I mean it's not like he knew the answer ahead of time
37<br>1.5K
span:not(:empty)~span:not(:empty)]:before:content-['·'] [&>span:not(:empty)~span:not(:empty)]:before:px-1 [&>span:not(:empty)~span:not(:empty)]:before:shrink-0 min-w-0 overflow-hidden">Life Thru Book
@LifeThruBook
Aug 14
This is the kind of physics I love: starting with something as complicated as intelligent life and asking how much of it can be explained by a few fundamental constants.
24<br>2.2K
span:not(:empty)~span:not(:empty)]:before:content-['·'] [&>span:not(:empty)~span:not(:empty)]:before:px-1 [&>span:not(:empty)~span:not(:empty)]:before:shrink-0 min-w-0 overflow-hidden">Christian Rishøj
@crishoj
Aug 14
Neat!<br>Grok made this interactive explainer:
The Right Size
From eagle-shadow-meadow-acre.grok.me
16<br>2.2K
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