Californium

Californium is a synthetic, highly radioactive element that is artificially produced and virtually absent in natural astronomical contexts. As a product of human-made nuclear reactions, californium is extremely rare beyond Earth and lacks astronomical significance. Its isotopes possess very short half-lives, typically ranging from days to centuries, further contributing to its scarcity and nonexistence in celestial bodies or cosmic environments. Californium's synthetic nature and the challenges associated with its production limit its presence to laboratory settings, such as in nuclear reactors or as a byproduct of nuclear processes.