PCS 182 Lecture Notes - Lecture 8: Milky Way, Reproducibility, Plate Tectonics
27 Jul 2017
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Pcs182 life in the milky way galaxy week 1 + week 2. Experiment ( watch overnight for irish fairies) Reproducibility (friend makes same experiment, similar conclusion) Respirate: o2 in oxidation = o2 combines with organic molecules and releases chemical energy . Move: a change in location or position. Secrete: to generate saliva, mucus, milk, hormones, digestive juices. Life is made out of star materials (nitrogen, carbon, hydrogen, oxygen) Only ~8% of starts are > ~4 mo (the sun) Stars 8 mo live only a few million years (not very long) Ejected elements merge with intergalactic clouds of ~75% h, ~24% helium and ~1% other. New star systems condense inside these clouds. Appropriate (cid:373)aterials produ(cid:272)e ro(cid:272)ky/(cid:449)atery pla(cid:374)ets a(cid:374)d possi(cid:271)ly life for(cid:373)s: mass of star. Age of our sun/earth system is 4. 54 billion years. Earth life arose when system was ~1 billion years old (~3. 7 billion years ago) Star must live long enough for biology to develop on one of its planets.
