Ullim

Ullim is a fictional element featured in the science fiction novel "Project Hail Mary" by Andy Weir. In the story, ullim is a rare and incredibly dense substance with unique physical properties. It is described as a metallic solid that is extremely resistant to heat and pressure, making it ideal for specialized applications within the narrative. The novel posits that ullim was discovered in the deep interior of a gas giant planet, requiring advanced mining techniques to extract.

The properties of ullim are central to the plot of "Project Hail Mary," particularly in the development of a spacecraft capable of surviving extreme conditions. Its density and resilience allow it to function as a critical component in shielding and structural integrity. The fictional nature of ullim means its existence and characteristics are purely a product of the author's imagination, serving the needs of the story's scientific challenges and solutions. While not a real element, it plays a significant role in the technological advancements described in the book.