The Expanding Universe: Redshift and the Big Bang Theory

Video Description

This video is part of a comprehensive series initially developed for William Paterson University and CUNY Hunter, aimed at supporting online classes and course materials for introductory astronomy. By engaging with all the videos within this series, you will effectively complete a full undergraduate course in astronomy, equipping yourself with the knowledge and skills necessary to navigate the night sky with confidence, learning all the basics and many advanced topics! Redshift, a key concept of the Big Bang, is explored. Edwin Hubble’s groundbreaking discoveries are extended to the cosmological redshift-distance relationship. Starting with Hubble’s initial exploration of nearby galaxies, his discovery of the expanding universe is expanded upon. The cosmological principle, stating the universe’s homogeneity and isotropy, is explained. Redshift, the change in light’s wavelength due to object motion, supports the theory of the universe’s expansion. Historical data and modern techniques are used to measure galaxy distances and velocities, revealing the universe’s expansion. Vesto Slipher’s work measuring the redshift of spiral nebulae led to the discovery that most galaxies are moving away from us. Hubble demonstrated a linear relationship between distance and recession velocity, now known as Hubble’s Law, using standard candles, Cepheid variables, and measuring distances to these galaxies using large telescopes and painstakingly collecting spectra over many nights. Challenges faced by early 20th-century astronomers, their contributions, and technological hurdles are also covered. Hubble’s measurement of a 500 km/s/Mpc expansion rate, refined to the modern value of 72 km/s/Mpc, underscores the ongoing scientific endeavor to understand the universe’s expansion rate. Contemporary research, including recent measurements, highlights the tension between direct and indirect measurements of the Hubble constant. Light’s journey across spacetime demonstrates the expanding universe, with fascinating implications such as the simultaneous occurrence of the Big Bang in all parts of the universe, supported by robust observational evidence. #BigBang #Redshift #ExpandingUniverse #EdwinHubble #Cosmology #science #universeexploration #GalaxyDistances #CepheidVariables #CosmicHistory