The Origin of the Solar System - Peel My Class Sites：太阳系的起源-剥我的班级网站.pptVIP

SNC1D0 The Origin of the Solar System: Solar Nebular Theory Origin of Our Solar System Nebular Theory – our Solar System formed from a giant, swirling cloud of gas dust. Solar nebula – name given to the cloud of gas from which our own Solar System formed The nebular theory holds that our Solar System formed out of a nebula that collapsed under its own gravity. View of the Orion Nebula Gravitational Collapse The solar nebular was initially somewhat spherical and a few light years in diameter. very cold rotating slightly It was given a “push” by some event. perhaps the shock wave from a nearby supernova As the nebula shrank, gravity increased, causing collapse. As the nebula “falls” inward, energy from the collapse is converted to heat. Conservation of Energy As the nebula’s radius decreases, it rotates faster Conservation of Angular Momentum Flattening of the Solar Nebula As the nebula collapses, the wind created causes clumps of gas collide merge. Swirling winds cause the nebula to assume the shape of a disk. As the nebula collapses, the centre heats up.The stellar winds cause the gases spins faster, and flatten out. Orderly Motions in the Solar System The Sun formed in the very center of the nebula. temperature density were high enough for nuclear fusion reactions to begin (uses hydrogen for fuel) The planets formed in the rest of the disk. This would explain the following: all planets lie along one plane (in the disk) all planets orbit in one direction (the spin direction of the disk) most planetary orbits are near circular (avoids collisions in the disk) Formation of the Inner Planets Heavy particles don’t travel for on stellar winds Stick to one another because of electromagnetic force created by spinning winds When large enough, create own gravity and create more material Form inner rocky planets. Formation of Outer Planets SUMMARY SLIDE * *