ERS120H5 Lecture Notes - Lecture 1: Big Bang, Outer Core, Seismic Tomography
Document Summary
13. 7 billion years ago the big bang. The meteorites formed around the same time as earth and then fell back down to the surface thus giving a more accurate time frame in regards to when earth formed. The big bang theory: explosion from a small point, irregular distribution of hydrogen, helium and other lighter elements. A nebula forms from hydrogen, helium and heavier elements. It starts to spin and flatten into a disk: the disks eventually turn into rings (of a solar system) This is what pluto was demoted to: they grow from meteors and get hotter and hotter. The hotter a planet or planetestimal gets, the more spherical it becomes. This happens over a long period of time. A planet the size of mars hit earth: after the collision, dust and larger particles formed a nebula, became a disk and eventually formed the moon. The moon is basically a floating mantle.
