Constraining Cosmological Parameters With Type Ia Supernovae, The Cosmic Microwave Background, And Baryon Acoustic Oscillations: A Multi-Probe Analytical Review

This conference paper examines how three major observational probes, Type Ia supernovae, the cosmic microwave background, and baryon acoustic oscillations, jointly constrain the central parameters of modern cosmology. The research problem addressed here is straightforward but fundamental: no single probe can independently determine the Hubble constant, matter density, spatial geometry, and dark-energy behavior without some level of degeneracy or model dependence. The paper therefore adopts a comparative analytical framework that evaluates the physical basis, redshift sensitivity, and systematic limitations of each probe before assessing their combined explanatory power. The review shows that Type Ia supernovae remain the most direct tracer of late-time acceleration, the cosmic microwave background provides the tightest early-universe anchor, and baryon acoustic oscillations supply an essential geometric bridge between them. Recent joint analyses continue to support a spatially flat cosmological model close to LambdaCDM, with dark energy still broadly consistent with a cosmological constant. At the same time, residual tensions, especially around H0 and the possible evolution of dark energy, indicate that precision has outpaced complete physical consensus. The paper argues that the strongest current insight is not the dominance of one probe, but the methodological necessity of combining all three.