Meldasin

Meldasin is a fictional substance featured in the science fiction novel "Project Hail Mary" by Andy Weir. In the narrative, meldasin is a component of the astrophage, the alien microorganism that is consuming Earth's sun and threatening all life on the planet. Meldasin is described as a unique energy-storing compound that allows the astrophage to convert solar energy with extraordinary efficiency. This high efficiency is key to the astrophage's ability to reproduce and spread so rapidly, posing a significant existential threat.

The protagonist, Ryland Grace, discovers the properties of meldasin during his mission to find a solution to the astrophage problem. His research into meldasin reveals its potential for both destruction and salvation. While it fuels the astrophage's destructive capabilities, its unique energy-storing properties also offer a theoretical pathway for harnessing clean and abundant energy. The scientific understanding of meldasin becomes central to the plot, driving the protagonist's efforts to neutralize the threat and potentially benefit humanity. The compound's existence and characteristics are entirely within the realm of speculative science fiction, serving as a crucial plot device in the novel.