Sunlight turns them to stone. They cannot come up.
Short-wave ultraviolet mineralises skin and covering within minutes. Their materials were specified for a world without sky.
UV phototoxicity and petrification
Vulnerability · Dermis and integumentPlate · AETERNA · UV phototoxicity and petrification · theoretical reconstruction
Ultraviolet on that integument. Phototoxicity severe enough that surface daylight is a phase change, not an inconvenience. Sunlight turns them to stone is the folklore. The drawing is a dermis that cannot come up.
UVA (315–400 nm): no measurable effect at sixty minutes. UVB (280–315 nm): integument discolours at four minutes, rigidifies at twelve — the same calcification seen in isolated . Skin without integument does not respond to UVB in the test window. UVC (200–280 nm), which does not reach a living surface under an ozone column, hits everything: integument calcifies in forty seconds; unprotected dermis begins collagen-equivalent cross-linking at ninety seconds and proceeds toward a mineralised, brittle mass.
The petrification myth is a photochemical mineralisation of a UV-intolerant organism and its grown covering. They do not avoid the sun because they are modest. They avoid it because their materials science was specified for a world without a sky.
Ch. 6
Dwarfs in Theory