  The unknown constituents of the interior of our home planet have provoked the
human imagination and driven scientific exploration. We herein demonstrate that
large neutrino detectors could be used in the near future to significantly
improve our understanding of the Earth's inner chemical composition. Neutrinos,
which are naturally produced in the atmosphere, traverse the Earth and undergo
oscillations that depend on the Earth's electron density. The Earth's chemical
composition can be determined by combining observations from large neutrino
detectors with seismic measurements of the Earth's matter density. We present a
method that will allow us to perform a measurement that can distinguish between
composition models of the outer core. We show that the next-generation
large-volume neutrino detectors can provide sufficient sensitivity to reject
outer core models with large hydrogen content and thereby demonstrate the
potential of this novel method. In the future, dedicated instruments could be
capable of distinguishing between specific Earth composition models and thereby
reshape our understanding of the inner Earth in previously unimagined ways.
