Chemistry Review: Universe to Habitable Planets

Notes

MODULE 1-4 SPCE 70 REVIEW DISCUSSION SPCE 70 Review Discussion Page 1 of 45 MODULE 1 ORIGIN, EVOLUTION, AND COMPOSITION OF THE UNIVERSE SPCE 70 Review Discussion Page 2 of 45 ORIGIN AND DEVELOPMENT OF THE UNIVERSE 1.1. Observational and Experimental Evidences A cosmological model must be consistent with available evidence, including: The expansion of the universe (Hubble’s Law) Cosmic microwave background (CMB) radiation The abundance of hydrogen and helium The ages of the oldest stars The distribution and motion of galaxies SPCE 70 Review Discussion A scientific model is an explanation or representation used to describe how something works. In cosmology, scientists develop models to explain the origin, structure, age, composition, and development of the universe. Suppose Model A estimates that the universe is 13.8 billion years old, while Model B estimates that it is only five billion years old. If scientists discover stars older than ten billion years, Model B becomes scientifically unreasonable. A star cannot normally be older than the universe in which it formed. This demonstrates an important feature of science: models are evaluated and revised using evidence. A model is not a...