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
Return to the Centre of the Earth ... you recorded and wrote ["Journey"] with what you knew existed with instruments and recording techniques, so you pushed as far you could go. Now if you do it again, is different because you would not be pushing anything". Wakeman was advised to put the idea on hold and think about a new "epic" album with a new story and music, of which he'll "know when the right time is". After the meeting at Arista, Wakeman went on to pursue other projects and forgot about the idea until it was revisited in 1996, when he received telephone calls from four