High Redshift Galaxy Formation: A Pressure Driven Gravity Approach

This thesis proposes an alternative explanation for the observed abundance of massive galaxies at high redshifts (z>10), which present a major challenge to the ΛCDM model. Using the Pressure Driven Gravity (PDG) framework, gravity is modelled not as a manifestation of spacetime curvature, but as a hydrodynamic effect arising from pressure gradients in a compressible, superfluid-like vacuum medium. This allows for significantly faster structure formation in the early universe, bypassing the collapse delays imposed by general relativity.The thesis derives modified Jeans instability conditions, simulates early galaxy formation using smoothed particle hydrodynamics (SPH), and compares the model’s predictions with recent JWST and ALMA data. Key observational features—such as the steep UV luminosity function slope, compact galaxy sizes and early dust enrichment—are shown to emerge naturally within the PDG framework without requiring tuned star formation efficiencies or exotic particle physics.Bayesian model comparisons demonstrate that PDG outperforms ΛCDM, MOND, WDM and early dark energy models in fitting JWST observations. The model remains consistent with CMB, BAO and Standard Model constraints, offering a compelling and testable fluid-dynamic alternative to standard cosmology.