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 "", depicts a possible future in which refugees from a destroyed Earth 2 come to Earth 0 and prompt society to fracture. Over the course of the series, several new characters are introduced, such as Yolanda Montez, an Avatar of the Red who is a counterpart of Alan Scott; a second Red Arrow, an Earth 2 equivalent of Oliver Queen; and Dick Grayson, a journalist who goes on a mission to find his son after his wife Barbara Gordon is killed during the invasion. Others change alignment; Wonder Woman and Steppenwolf's daughter Fury sides with Mister Miracle and the other