conclusions, that is precisely its utility. To cite just one example of the utility, the lunar origin of
tektites strongly supports the idea that the Moon was formed by fission of the Earth.
Fig.151“Tektites are indeed much more like terrestrial rocks than one would expect of a chance
assemblage. If tektites come from a lunar magma, then deep inside the Moon there must be
material that is very much like the mantle of the Earth--more like the mantle than it is like the
shallower parts of the Moon from which the lunar surface basalts have originated. If the Moon
was formed by fission of the Earth, the object that became the Moon would have been heated
intensely and from the outside, and would have lost most of its original mass and in particular the
more volatile elements. The lavas constituting most of the Moon's present surface were erupted
early in the Moon's history, when its heat was concentrated in the shallow depleted zone quite
near the surface. During the recent periods represented by tektite falls, the sources of lunar