Thank you for your response and for sharing your perspective on the interpretation of Type Ia supernovae data and the recent findings from the James Webb Space Telescope (JWST) and the Dark Energy Spectroscopic Instrument (DESI). Your argument challenges the premise of cosmic acceleration by suggesting that observational discrepancies in supernova brightness could be attributed to light scattering rather than an expanding universe driven by dark energy.
However, the assertion that "there may be no additional accelerated expansion of the universe" contradicts multiple independent lines of observational evidence that have consistently supported cosmic acceleration. While it is valuable to reassess Type Ia supernovae as standard candles and consider alternative explanations for their apparent dimming, the broader confirmation of accelerated expansion does not rely solely on supernovae data.
Multiple Lines of Evidence Supporting Cosmic Acceleration
Baryon Acoustic Oscillations (BAO):
Large-scale surveys such as the Sloan Digital Sky Survey (SDSS) and DESI have mapped BAO features in the distribution of galaxies, providing independent confirmation of an accelerating universe. BAO measurements are not susceptible to the same potential systematic uncertainties as supernovae brightness and offer a robust, geometrical probe of cosmic expansion.
Cosmic Microwave Background (CMB) Observations:
The Planck satellite and WMAP have measured the CMB power spectrum, which reveals indirect but strong constraints on the presence of dark energy through the integrated Sachs-Wolfe effect. These measurements align with a ΛCDM cosmology where a cosmological constant (or an equivalent dark energy component) drives late-time acceleration.
Galaxy Cluster Dynamics and Mass Distribution:
Observational studies, such as those by Chernin et al. (2013), have directly analysed the dynamics of galaxy clusters like the Coma Cluster. These studies indicate an outward acceleration that cannot be explained purely by gravitational interactions among visible and dark matter components. This provides a direct, large-scale confirmation of cosmic acceleration independent of supernovae data.
Weak Lensing and Large-Scale Structure Growth:
The large-scale distribution of galaxies and the weak lensing of background light due to mass distribution in the universe further support an accelerating expansion. These gravitational lensing measurements align with models requiring a dark energy component.
Re-evaluating the Role of Type Ia Supernovae
Your reference to JWST’s higher-redshift supernovae images suggesting greater-than-expected light scattering is an intriguing possibility that warrants further examination. However, even if alternative mechanisms contribute to Type Ia supernovae dimming, they do not negate the entirety of the independent observational framework supporting cosmic acceleration.
Therefore, the claim that "there may be no additional accelerated expansion of the universe" does not hold when considering the full spectrum of astrophysical data. The conclusions drawn from a single observational effect—light scattering in supernovae—must be weighed against a comprehensive suite of cosmological measurements that have independently verified cosmic acceleration.
Below, I include further supporting discussion on dark energy’s role in galaxy clusters and the broader cosmic expansion.
Dark Energy’s Influence on Galaxy Clusters and the Accelerated Recession of Galaxies:
The Extended Classical Mechanics (ECM) expands upon traditional classical mechanics by incorporating additional complexities to analyse intricate systems while remaining grounded in Newtonian principles. Unlike the standard framework, ECM considers factors such as the internal structure of objects (beyond point masses) and aspects of continuum mechanics to study deformable bodies.
This approach aligns with the findings of the intercontinental observational study titled "Dark Energy and the Structure of the Coma Cluster of Galaxies" (2013), conducted by A. D. Chernin, G. S. Bisnovatyi-Kogan, P. Teerikorpi, M. J. Valtonen, G. G. Byrd, and M. Merafina. The research was carried out across multiple institutions, including Tuorla Observatory (University of Turku, Finland), Sternberg Astronomical Institute (Moscow University, Russia), Space Research Institute (Russian Academy of Sciences, Russia), University of Alabama (USA), and the Department of Physics (University of Rome "La Sapienza", Italy). Their study confirmed the universally accelerated recession of galaxies within the Coma Cluster (Abell 1656), a massive galaxy cluster in the constellation Coma Berenices.
Key Finding: The Role of Dark Energy in Galactic Recession
The presence of dark energy significantly influences the structure and dynamics of galaxy clusters, as evidenced by the Coma Cluster. Modelled as a uniform vacuum-like fluid with a negative effective gravitating density, dark energy induces a repulsive force that counteracts gravitational attraction. The key determinant of this effect is the zero-gravity radius (Rᴢɢ), beyond which dark energy’s repulsion dominates over the cluster’s gravitational pull. Observations and theoretical models indicate that at distances beyond Rᴢɢ ≈ 20 Mpc, the mass contribution of dark energy surpasses that of the cluster’s gravitating mass, leading to effective outward acceleration. This localized manifestation of cosmic antigravity aligns with the broader accelerated expansion of the universe, demonstrating how dark energy drives the recession of galaxies by overcoming gravitational binding at large scales.
Best regards,
Soumendra Nath Thakur