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
The Restaurant at the End of the Universe randomly, hoping Deep Thought's computational matrix in Earth would have rubbed off on his subconscious. The letters spell "What do you get when you multiply six by nine" before running out, although the Neanderthals manage to spell "forty-two" with the tiles, implying that it is they, rather than the Golgafrinchans, who were intended to be part of Earth's computer matrix. After some brief contemplation, Ford and Arthur realise that this is, in fact, a detrimental "cock-up", and that the Earth will never produce the proper Question, thus destroying all hope of ever finding out what it is. As Ford convinces