NATS 1740 Study Guide - Thermostat, Solar Cycle, Nuclear Fusion

• School: York University
• Department: Natural Science
• Course: NATS 1740
• Professor: Randy Hoffman

Document Summary

19th century suggested sun generates energy by slowly contracting in size (gravitational contraction) or (kelvin-hemholtz contraction) Flaw because this determined sun shines for 25 million years but fossils on earth older than that. We learned that sun converts mass into energy via nuclear fusion. Gravitational contraction released the energy that made the suns core hot enough for fusion. Sun shines today because it has achieved 2 kinds of balances that keeps its size and energy output stable. Gravitational equilibrium (hydrostatic): is between the outward push or internal gas pressure and the inward pull of gravity. Everywhere inside the sun, the outward push of pressure balances the inward pull of gravity. Energy balance: between rate at which fusion releases energy in t he suns core and rate at which the suns surface radiates this energy into space. Does not rotate at the same rate as a spinning ball. Power: rate at which energy is used or released.