AS101 Lecture 8: Lesson 8
Document Summary
Universe only contained hydrogen, helium, and lithium originally. Heavier elements produced when stars die where they spew out their mass into the universe and the next generation of stars contain some of those heavier elements making some new ones. This is called galactic process and how the universe gets these atoms. 2% of hydrogen and helium in the galaxy transformed into heavier elements forming terrestrial planets. Nebula cloud of dust and gas formed was a few light years in diameter. Trigger was a shock wave from a nearby nova or supernova. Temperature slowly decreased with distance from the centre of the protosun. Certain materials could condense at certain distances from the sun. The temperature drops to the freezing point for water as we move away from the sun signifying a special point known as the ice line or the frost line.
