CAS AS 102 Chapter Notes - Chapter 14: Potential Energy, Solar Core, Gravitational Potential
Document Summary
Photometry: accurate measurement of light intensity from an object at a particular time. Before 20th century, no one could explain the source of. Changed id-19th century when sun"s size and distance were measured. Ruled out coal, wood, or any chemical burning. Due to large mass, sun would have to contract very slightly each year to maintain its temperature. Gravitational potential energy/luminosity approx 25 million years. Studies of rocks and fossils suggested that earth was much older than 25 million years. It can be powered by nuclear energt (e=mc^2) Nuclear potential energy (core)/luminosity = 10 billion years. Sun is in an equilibrium that keeps its size and energy output stable. Between outward push and internal gas pressure and inward pull of gravity. Weight of upper layers compresses lower layers. Between the rate at which fusion releases energy in sun"s core and the rate at which sun"s surface radiates this energy into space.
