Can the flyby anomaly be attributed to earth-bound dark matter?

TL;DR

This paper explores whether earth-bound dark matter could explain the flyby anomaly by analyzing scattering interactions and density requirements, considering various constraints and the possibility of high local dark matter concentrations.

Contribution

It provides a preliminary assessment of dark matter interactions as a potential cause for the flyby anomaly, including density estimates and scattering process implications.

Findings

Dark matter interactions could account for both positive and negative flyby velocity anomalies.

The required dark matter density near Earth would be much higher than the galactic halo density.

Constraints suggest dark matter must be non-self-annihilating, with large scattering cross sections and light masses.

Abstract

We make preliminary estimates to assess whether the recently reported flyby anomaly can be attributed to dark matter interactions. We consider both elastic and exothermic inelastic scattering from dark matter constituents; for isotropic dark matter velocity distributions, the former decrease, while the latter increase, the final flyby velocity. The fact that the observed flyby velocity anomaly shows examples with both positive and negative signs, requires the dominance of different dark matter scattering processes along different flyby trajectories. The magnitude of the observed anomalies requires dark matter densities many orders of magnitude greater than the galactic halo density. Such a large density could result from an accumulation cascade, in which the solar system-bound dark matter density is much higher than the galactic halo density, and the earth-bound density is much higher than the solar system-bound density. We discuss a number of strong constraints on the hypothesis of a dark matter explanation for the flyby anomaly. These require dark matter to be non-self-annihilating, with the dark matter scattering cross section on nucleons much larger, and the dark matter mass much lighter, than usually assumed.