Abundance of the chemical elements in the Sun and outer planets is similar to that in the universe. Due to solar heating, the elements of Earth and the inner rocky planets of the Solar System have undergone an additional depletion of volatile hydrogen, helium, neon, nitrogen, and carbon (which volatilizes as methane). The crust, mantle, and core of the Earth show evidence of chemical segregation plus some sequestration by density. Lighter silicates of aluminum are found in the crust, with more magnesium silicate in the mantle, while metallic iron and nickel compose the core. The abundance of elements in specialized environments, such as atmospheres, or
Earth-Two comments by "52" co-writer Grant Morrison, this alternate universe is not the pre-"Crisis" Earth-Two. This separation between the pre-"Crisis" Earth-Two and post-"Crisis" Earth-2 is formally established in "Justice Society of America Annual" #1 (2008), with a story titled "Earth 2 Chapter One: Golden Age", in which the New Earth Power Girl arrives on post-"Crisis" Earth-2. Thinking that she has returned home to her long destroyed pre-"Crisis" Earth-Two. Power Girl crash lands and unconscious, on the closest parallel of the 52 Multiverse, the post-"Crisis" Earth-2, which appears similar to the pre-"Crisis" Earth-Two. She is found by the post-"Crisis" Earth-2 Huntress, who