Determine the nature of dark matter

Determine the fundamental nature of dark matter, specifying its composition and interactions and whether it consists of macroscopic composites (such as primordial black holes, solitons, or strangelets) or new weakly interacting particles, in order to resolve its identity within modern physics.

Background

The paper explores the possibility that dark matter is composed of macroscopic, high-mass objects with very low number density, a paradigm distinct from weakly interacting particle dark matter. It proposes using Ganymede as a natural detector for macroscopic dark matter impacts, arguing that the moon's differentiated structure and long surface age could record distinctive signatures.

This framing situates their study within the broader context that, despite extensive searches and constraints across multiple mass ranges and interaction types, the fundamental identity of dark matter remains unresolved.

References

The nature of dark matter (DM) constitutes one of the largest open problems in physics.

— Dark wounds on icy moons: Ganymede's subsurface ocean as a dark matter detector  (2508.00054 - DeRocco, 31 Jul 2025) in Section 1 (Introduction)

One of the great mysteries of contemporary science is dark matter, an exotic substance of unknown nature that, in theory, makes up about 27% of the total mass-energy density of the universe, and which does not appear to emit, absorb, or reflect any kind of light, meaning that it is invisible and can only be detected through its gravitational effects on objects around it.

— Illuminating dark matter I: A guide for physics teachers  (2406.15356 - Pinochet, 2024) in Abstract

The nature of the dark matter however remains unclear.

— Constraining the dark matter origin of the halo-like 20 GeV $γ$-ray excess with the AMS-02 antiproton data  (2512.12176 - Wang et al., 13 Dec 2025) in Section 1, Introduction

However, CDM has never been observed directly and the true nature of it still is unknown.

— Cosmology without the cosmological principle: A study of the large-scale structure effects in the background universe  (2608.15983 - Pastén, 17 Aug 2026) in Chapter 1, Section 1.1, subsection “Theoretical challenges for standard cosmology,” item 3, “The Cold Dark Matter”