Astronomical observations reveal a major deficiency in our understanding of physics—the
detectable mass is insufficient to explain the observed motions in a huge variety of systems …

Horizon-scale images of black holes (BHs) and their shadows have opened an
unprecedented window onto tests of gravity and fundamental physics in the strong-field …

We test Milgromian dynamics (MOND) using wide binary stars (WBs) with separations of 2–
30 kAU. Locally, the WB orbital velocity in MOND should exceed the Newtonian prediction …

Due to their low surface brightness, dwarf galaxies are particularly susceptible to tidal forces.
The expected degree of disturbance depends on the assumed gravity law and whether they …

The KBC void is a local underdensity with the observed relative density contrast δ≡ 1−
ρ/ρ0= 0.46±0.06 between 40 and 300 Mpc around the Local Group. If mass is conserved in …

ABSTRACT El Gordo (ACT-CL J0102-4915) is an extremely massive galaxy cluster (M
200≈ 3× 1015 M⊙) at redshift z= 0.87 composed of two subclusters with a mass ratio of 3.6 …

The existence of mutually correlated thin and rotating planes of satellite galaxies around
both the Milky Way (MW) and Andromeda (M31) calls for an explanation. Previous work in …

The dynamical stability of disk galaxies is sensitive to whether their anomalous rotation
curves are caused by dark matter halos or Milgromian dynamics (MOND). We investigate …

Axions, and axionlike particles, have come back into fashion in the last decades as a
possible solution to the galactic-scale crisis suffered by the cold dark matter model. In the …

When bars form within galaxy formation simulations in the standard cosmological context,
dynamical friction with dark matter (DM) causes them to rotate rather slowly. However …