Radtas

Radtas are a fictional species featured in the science fiction novel "Project Hail Mary" by Andy Weir. They are an extraterrestrial, silicon-based life form native to the planet Erid. Radtas are characterized by their quadrupedal locomotion, their rocky, crystalline exoskeletons, and their ability to survive in environments with extreme temperatures and pressures. Their physiology is significantly different from carbon-based life, relying on silicon compounds for their biological processes and breathing an atmosphere rich in sulfur.

Communication among Radtas is achieved through a combination of vibrations and bio-luminescent displays emitted from specialized organs. They possess a collective consciousness, meaning individuals are interconnected and share thoughts and experiences, though they also exhibit individual personalities and roles within their society. Their civilization is ancient and technologically advanced, having developed sophisticated methods for space travel and energy manipulation. The Radtas' primary motivation in "Project Hail Mary" stems from a desperate need to find a solution to an existential threat facing their home system, leading them to send an emissary to Earth.