Introduction The standard ΛCDM (Lambda Cold Dark Matter) model attributes the accelerated expansion of the universe to an unknown form of dark energy. However, persistent discrepancies—such as the Hubble tension and inconsistencies in Baryon Acoustic Oscillations (BAO)—suggest the need for an alternative framework. The Self-Regulating Gravity-Energy-Mass (SR-GEM) model emerges as a fundamental shift in our understanding of cosmic expansion. By introducing a dynamically evolving gravitational constant GeffG_{\text{eff}}Geff, SR-GEM explains the universe’s accelerating expansion without requiring dark energy. This work derives the modified Friedmann equations under SR-GEM, applies them to observational data, and demonstrates consistency with expansion rate measurements and BAO observations. Key Contributions ✅ No Dark Energy Required: SR-GEM reproduces observed expansion dynamics without introducing an unknown energy component.✅ Mathematical Walkthrough of Expansion Model: Full derivation of the SR-GEM-modified Friedmann equations.✅ Resolution of the Hubble Tension: SR-GEM predicts a higher Hubble constant that aligns with local measurements.✅ Consistent BAO Predictions: The model accurately scales BAO features without requiring additional parameters. Conclusion This study demonstrates that cosmic acceleration is a natural consequence of self-regulating gravity, eliminating the need for dark energy. The results suggest that SR-GEM can serve as a powerful alternative to ΛCDM, of

The accelerating expansion of the universe is one of the most profound discoveries in modern cosmology, pointing to a universe in which 70% of the mass-energy density has an unknown form spread uniformly across the universe. This result has been well established using a combination of cosmological probes (e.g., Planck Collaboration et al. 2016), resulting in a "standard model" of modern cosmology that is a combination of a cosmological constant with cold dark matter and baryons. The first compelling evidence for the acceleration came in the late 1990's, when two independent teams studying type Ia supernovae discovered that distant SNe Ia were dimmer than expected. The combined analysis of modern cosmology experiments, including SNe Ia, the Hubble constant, baryon acoustic oscillations, and the cosmic microwave background has now measured the contributions of matter and the cosmological constant to the energy density of the universe to better than 0.01, providing a secure measurement of acceleration. A recent study (Tr{\o}st Nielsen et al. 2015) has claimed that the evidence for acceleration from SNe Ia is "marginal." Here we demonstrate errors in that analysis which reduce the acceleration significance from SNe Ia, and further demonstrate that conservative constraints on the curvature or matter density of the universe increase the significance even more. Analyzing the Joint Light-curve Analysis supernova sample, we find 4.2{\sigma} evidence for acceleration with SNe Ia alone,

The accelerating expansion of the universe is one of the most profound discoveries in modern cosmology, pointing to a universe in which 70% of the mass-energy density has an unknown form spread uniformly across the universe. This result has been well established using a combination of cosmological probes (e.g., Planck Collaboration et al. 2016), resulting in a "standard model" of modern cosmology that is a combination of a cosmological constant with cold dark matter and baryons. The first compelling evidence for the acceleration came in the late 1990's, when two independent teams studying type Ia supernovae discovered that distant SNe Ia were dimmer than expected. The combined analysis of modern cosmology experiments, including SNe Ia, the Hubble constant, baryon acoustic oscillations, and the cosmic microwave background has now measured the contributions of matter and the cosmological constant to the energy density of the universe to better than 0.01, providing a secure measurement of acceleration. A recent study (Tr{\o}st Nielsen et al. 2015) has claimed that the evidence for acceleration from SNe Ia is "marginal." Here we demonstrate errors in that analysis which reduce the acceleration significance from SNe Ia, and further demonstrate that conservative constraints on the curvature or matter density of the universe increase the significance even more. Analyzing the Joint Light-curve Analysis supernova sample, we find 4.2{\sigma} evidence for acceleration with SNe Ia alone,

Dark Energy versus Modified Gravity There is now strong observational evidence that the expansion of the universe is accelerating. The standard explanation invokes an unknown "dark energy" component. But such scenarios are faced with serious theoretical problems, which has led to increased interest in models where instead General Relativity is modified in a way that leads to the observed accelerated expansion. The question then arises whether the two scenarios can be distinguished. Here we show that this may not be so easy, demonstrating explicitely that a generalised dark energy model can match the growth rate of the DGP model and reproduce the 3+1 dimensional metric perturbations. Cosmological observations are then unable to distinguish the two cases. Published as: Phys.Rev.Lett.98:121301,2007 DOI: 10.1103/PhysRevLett.98.121301 arXiv categories: astro-ph gr-qc hep-ph

Recent supernovae of type Ia measurements and other astronomical observations suggest that our universe is in accelerating phase of evolution at the present epoch. While a dark energy of unknown form is usually proposed as the most feasible mechanism for the acceleration, there are appears some alternative conception that some effects arising from generalization of Einstein equation can mimic dark energy through a modified Friedmann equation. In this work we investigate some observational constraints on modified Friedmann equation obtained from generalized Lagrangian ${\cal L} \propto R^n$ in minimal coupling with matter in Palatini formalism. We mainly concentrate on the constraints of model parameters from distant supernovae but other constraint from baryon oscillation prior is also considered. We obtain the confidence levels on two additional model parameter ($n$,$\Omega_{m,0}$). We conclude that the FRW model of First-Order Non-linear gravity survives several observational test like SNIa observation and baryon oscillation peaks. We find preferred value of $\Omega_{m,0} \simeq 0.3$ from combined analysis of supernovae data and baryon oscillation peak. For deeper statistical analysis we apply Akaike and Bayesian information criteria of model selection for comparison prediction of the model with prediction of concordance $\Lambda$CDM model.

the rate of expansion. With dark energy, the expansion not only continues but accelerates. The ultimate fate of an open universe with dark energy is either The ultimate fate of the universe is a topic in physical cosmology, whose theoretical restrictions allow possible scenarios for the evolution of the universe and the ultimate fate of the universe to be described and evaluated. Based on available observational evidence, deciding the fate and evolution of the universe has become a valid cosmological question, being beyond the mostly untestable const In his 1979 paper "Time Without End: Physics and Biology in an Open Universe," physicist Freeman Dyson proposed a scenario for the far future in which intelligent life could achieve a form of immortality by processing an infinite number of thoughts. This concept, known as "Dyson's eternal intelligence," was originally predicated on an open universe, a cosmological model that expands forever. In the context of a zero cosmological constant (a flat or open universe without dark energy), the universe would continue to cool as it expands, but at a decelerating rate. Dyson's idea was that intelligent beings could store a finite amount of energy and expend it in increasingly smaller fractions. After each expenditure of energy for thought processes, these beings would enter a state of hibernation for immense periods, allowing the universe to cool further. As the ambient temperature of the universe drops, the minimum energy required for a computation (a thought) also decreases, theoretically allowing for an infinite number of thoughts to be processed over an infinite subjective time, even with a finite energy reserve. However, this scenario faces challenges, as the…

expansion of the universe is accelerating, an observation attributed to a concept called dark energy. The concept of an expanding universe was introduced The Big Bang is a physical theory that describes how the universe expanded from an early state of high density and temperature. Various cosmological models based on the Big Bang concept explain a broad range of phenomena, including the abundance of light elements, the cosmic microwave background (CMB) radiation, the redshift of galaxies and the large-scale structure of the universe. The observed u Indepen…