ASTR 100 Study Guide - Final Guide: Electron Degeneracy Pressure, Degenerate Matter, Thermostat
Document Summary
Age of the solar system: radiometric dating of isotopes in old rocks and meteorites isotopes have extra neutrons and decay at certain rate: half life of uranium is 4500 myr. Determined by: gravity: massive worlds can better hold onto gas molecules, distance from the sun: fast/hotter gas is harder to hold onto, presence of a magnetic field: prevents solar wind from eroding atmosphere. Rover found evidence of dry river beds and a polar cap composed of co2 on mars: residual cap that didn"t melt was dominated by h2o, evidence that atmosphere was thicker in the past. As mars cooled, its magnetic field weakened: solar wind eroded atmosphere and created major climate change. Hotter objects emit more light at all frequencies per unit area. Hotter objects emit photons of higher average energy. Absorption line spectrum: cool gas cloud between us and light/heat source can absorb light of specific wavelength, leaving absorption lines that are unique to each gas.
