Line Milankovitch proposed in the early twentieth
century that the ice ages were caused by variations
in the Earth’s orbit around the Sun. For some time
this theory was considered untestable, largely
(5)because there was no sufficiently precise
chronology of the ice ages with which the orbital
variations could be matched.
To establish such a chronology it is necessary to
determine the relative amounts of land ice that
(10)existed at various times in the Earth’s
...
century that the ice ages were caused by variations
in the Earth’s orbit around the Sun. For some time
this theory was considered untestable, largely
(5)because there was no sufficiently precise
chronology of the ice ages with which the orbital
variations could be matched.
To establish such a chronology it is necessary to
determine the relative amounts of land ice that
(10)existed at various times in the Earth’s
...
