Astronomy 2021A/B Study Guide - Midterm Guide: Cosmic Microwave Background, Milky Way, Oort Cloud
Document Summary
Extraterrestrial life: any sign of life, whether it be complex, simple or intelligent. Geocentric view: earth is the center of the universe (discarded this view) Solar system: possibilities: 8 planets + dwarf, mars (ice, past water, present water?, jupiter moons: europa best candidate for life (subsurface ocean), ganymede, planets + moons + asteroids. Calisto: saturn moon: titan (atmosphere, no liquid water, more subsurface liquids: (saturn"s moon) enceladus & triton (neptune"s moon) Nearest star is 4 light years away (100,000 years) Search for extraterrestrial life seti: search for signal from alien civilizations. Atomic structure: (made of protons, neutrons and electrons: nucleus (protons and neutrons found here) Electrical charge measures how strongly it will interact with other particles. Ions = when atoms lose or gain electrons: positive ion is one that has lost one or more electron, negative ion is one that has gained one or more electrons. Phases of matter: solid, liquid, gas and plasma.