An iron star is a hypothetical type of compact star that could occur in the universe in the extremely far future, after perhaps 10^1500 years. The premise behind the formation of iron stars states that cold fusion occurring via quantum tunnelling would cause the light nuclei in ordinary matter to fuse into iron-56 nuclei. Fission and alpha-particle emission would make heavy nuclei decay into iron, converting them to cold spheres of iron. This iron star has lived for 10^10^75 years & is depressed