ASTRO 106 Lecture Notes - Lecture 2: Blueshift, Cyanobacteria, Micropaleontology
Document Summary
Some hallmarks: order, metabolism, growth, reproduction, respond to stimuli, ability to evolve. And then getting smaller nitrogen, calcium, etc living mass dominated (96%) by the most abundant non-inert elements : o,c,h,&n. Earth made mostly of silicates (in crust, rock) Can bond with itself and other elements (o,n, and h) in a networked lattice. Has a strong double bond when binding with another c-atom. Rarely found in earth life (exo skeletons) Maybe not but almost surely a liquid of some kind is needed to facilitate chemical reactions. Water is a great liquid: stays liquid at higher temperatures (good for fast chemistry, polar molecule endows it with useful chemical properties, water ice floats in liquid water. Yess: there are plenty of these elements all around us now but Just after the big bang (13. 7 billion years ago: protons and neutrons, when cooled enough, some protons and neutrons combine to form helium, result: 76% h, .
