Chapter 15

Rocky Moves In

Dodecahedrons, astrophage cooling, and 689 years of life

Rocky moves to the Hail Mary in a xenonite dodecahedral ball with life support. Grace discovers Eridians live an average of 689 years, that Rocky has been at Tau Ceti for 46 years, and that together they can compensate for each other's weaknesses.

Rocky's geodesic ball: survival engineering

In the book

Rocky builds a transparent xenonite dodecahedron with an inner life support suit using astrophages as coolant. He navigates with powerful magnets on iron guides.

The science behind it

A dodecahedron is a Platonic solid with 12 pentagonal faces. Rocky has pentagonal symmetry, so pentagonal faces make sense for his anatomy. Geometrically, it's nearly spherical (good for pressure containment) but buildable with flat panels.

Astrophages at 96.415°C absorb any heat above that temperature, acting as perfect coolant. For Rocky (who lives at 210°C), the astrophage absorbs excess ambient heat. The ball stays at ~96°C: cold for Rocky, but bearable inside insulating xenonite.

Without gravity or wheels, Rocky moves with powerful magnets adhering to iron guides in the tunnel. Magnets allow directional control from inside the ball without external contact.

Key terms

Dodecahedron
Solid with 12 pentagonal faces. One of 5 Platonic solids. Nearly spherical but made of flat panels.
Platonic solids
The 5 regular polyhedra: tetrahedron, cube, octahedron, dodecahedron, icosahedron. The only shapes where all faces are identical regular polygons.

Eridian longevity: 689-year average

In the book

Rocky is 291 years old (born when George Washington was young). Eridians live an average of 689 years.

The science behind it

Kleiber's rule suggests larger organisms tend to live longer. Eridians weigh 168 kg and have partially inorganic metabolism (metal bones, mercury blood), which could reduce biological wear.

A civilization where individuals live 700 years accumulates knowledge extraordinarily. An Eridian scientist can spend a century mastering their field before contributing. This might explain advances like xenonite.

Rocky has been at Tau Ceti for 46 years alone. For a being with 689-year life expectancy, 46 years is like 5-6 years for a human: a long time, but not a lifetime.

Key terms

Kleiber's rule
Empirical law: basal metabolism scales with body mass to the 3/4 power. Larger organisms have relatively slower metabolism.
Knowledge accumulation
Longevity allows individuals to develop deep expertise. Eridian civilization has an advantage in technical specialization.

Grace + Rocky: synergy of two civilizations

In the book

Rocky is an engineer without scientific training. His scientists died. Grace has scientific knowledge but lacks Rocky's fabrication tools.

The science behind it

Grace brings: broad scientific knowledge (molecular biology, physics, chemistry), computers with analysis software, human lab instruments, the external collection unit Rocky needed.

Rocky brings: xenonite (strongest known material), extraordinary fabrication capability (can build anything with five prehensile hands), intimate knowledge of the Blip-A and Eridian biology.

Rocky tried for 46 years to solve the Tau Ceti problem without the right instrument. A single external sampling instrument marks the difference between success and failure. The right tools are as important as knowledge.

Key terms

Synergy
When combining two elements produces a result greater than the sum of both separately. Grace + Rocky > Grace alone + Rocky alone.