Can a dark inferno melt the Earth’s core?

The search for dark matter is one of the crucial open problems in both particle physics and cosmology. If dark matter scatters with Standard Model particles, it could accumulate inside the Earth and begin to annihilate, producing heat within the Earth’s core. While past work has been done on the effect that this heat would have once it reached the surface, we model the flow of heat through the Earth’s core by numerically solving the heat equation to model dark matter’s effect on the interior of the planet. We compute how long it takes for the core to come into thermal equilibrium and show that for a wide range of dark matter parameters, a substantial fraction of the inner core would be melted by dark matter annihilation. Our analysis produces new limits on dark matter annihilating in the Earth, points out important new effects that must be considered when studying planetary heating by dark matter, and suggests new dark matter observables that could be searched for in exoplanet populations.