Placing direct limits on the mass of earth-bound dark matter

TL;DR

This paper uses precise measurements of the earth-moon system to place stringent upper limits on the amount of dark matter bound to Earth, finding it to be less than four parts in a billion of Earth's mass.

Contribution

It introduces a novel method to directly constrain earth-bound dark matter using existing lunar laser ranging and satellite data.

Findings

Earth-bound dark matter is less than 4 x 10^-9 of Earth's mass.

The method provides a new way to limit local dark matter concentrations.

Current measurements tightly constrain dark matter near Earth.

Abstract

We point out that by comparing the total mass (in gravitational units) of the earth-moon system, as determined by lunar laser ranging, with the sum of the lunar mass as independently determined by its gravitational action on satellites or asteroids, and the earth mass, as determined by the LAGEOS geodetic survey satellite, one can get a direct measure of the mass of earth-bound dark matter lying between the radius of the moon's orbit and the geodetic satellite orbit. Current data show that the mass of such earth-bound dark matter must be less than $4 \times 10^{-9}$ of the earth's mass.