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The Dark Universe: A Mirror of the Limits of Human Understanding

  • Date: 2025
  • Proposal to: John Templeton Foundation
  • Manager: Giovanni Montani
  • Team: an experienced Postdoctoral Fellow, having a solid background in General Relativity, Cosmology and Quantum Physics and a PhD Student, who has expertise in Theoretical Cosmology

The Dark Universe: A Mirror of the Limits of Human Understanding

Modern cosmology faces persistent conceptual paradoxes that challenge the coherence of its theoretical framework. Since the 19th century, problems like the "night sky paradox" have revealed limits in our understanding of the Universe. The advent of General Relativity and the Big Bang model resolved some early issues, but new tensions soon emerged. By the late 20th century, the Standard Model of cosmology was seen to require extreme fine-tuning-giving rise to the "horizon," "flatness," and "entropy" paradoxes. Inflation theory aimed to solve these by erasing initial conditions and creating new ones compatible with observed structures.

The discovery of the accelerating Universe through Type Ia supernovae (SNIa) observations added further complexity. It required introducing dark energy-a component with negative pressure-alongside dark matter. In the current Λ Cold Dark Matter (ΛCDM) model, dark energy accounts for ~70% of the total energy density, yet only ~5% of the Universe consists of directly observable matter. This deep disconnect between model and observation is a source of serious epistemic concern.

More recently, "cosmological tensions" have emerged, most notably the Hubble tension: a significant discrepancy (~4σ) between early- and late-Universe measurements of the Hubble constant. The DESI Collaboration has added evidence suggesting that dark energy may be evolving over time, favoring dynamical models such as the Chevallier–Polarski–Linder parametrization over ΛCDM. These findings signal the need for a fundamental revision of the pillars of cosmology.

This 33-month project, budgeted at $610,000, supports young researchers tackling these conceptual challenges. Under the coordination of PI Prof. Giovanni Montani, it comprises two interconnected tasks:

  • 1. Cosmological Studies (≈ 2/3 of the project)
    An experienced postdoctoral researcher and one Ph.D. students will develop an extended cosmological framework, generalizing ΛCDM by incorporating interacting dark matter and dark energy within a modified gravity context. The dark sector will be modeled using axion physics coupled with a scalar quintessence field. This interaction will be treated using tools from quantum field theory and statistical mechanics. The gravitational framework will rely on a scalar-tensor theory extending the Einstein–Hilbert action, such as the Horndeski class.

    The other Ph.D. student and the PI will also reassess standard candle calibration procedures, especially regarding the acoustic horizon at recombination. Using this revised approach, SNIa data will be re-evaluated to test its implications for the Hubble tension. A central question is whether the new framework predicts a significantly different Hubble constant, offering a natural resolution to the observed discrepancy.

  • 2. Philosophical Issues (≈ 1/3 of the project)
    This task, led by a postdoctoral researcher in philosophy of science, explores whether the recurring paradoxes in cosmology reflect cognitive biases inherent to the human mind’s conceptualization of the cosmos. It will examine cosmological ideas from ancient cultures to modern theories to identify enduring patterns in human thought about the Universe.

    • Some remarks

    A key focus will be the notion of reference frames in cosmology. Could our assumptions about reference frames distort how we interpret astronomical data? Might revising these assumptions help resolve current observational anomalies? This inquiry integrates closely with Task 1, highlighting how observational and conceptual tools are deeply interdependent.

    In sum, this project addresses the epistemological and theoretical limits of modern cosmology by combining advanced physical modeling with a critical philosophical analysis. It aims not only to refine our scientific picture of the Universe but also to question how our cognitive frameworks shape that picture.