Copernicium
![Nicolaus Copernicus, who postulated the heliocentric theory that the Earth orbits around the Sun, contradicting prior belief.](/Images/godic/202502/19/Nikolaus_Kopernikus5852.jpg")
Copernicium is a chemical element with symbol Cn and atomic number 112. It is an extremely radioactive synthetic element that can only be created in a laboratory. The most stable known isotope, copernicium-285, has a half-life of approximately 29 seconds, but it is possible that this copernicium isotope may have a nuclear isomer with a longer half-life, 8.9 min. Copernicium was first created in 1996 by the GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany. It is named after the astronomer Nicolaus Copernicus.