GEOG 272 Lecture Notes - Lecture 1: Outgassing, Photodissociation, Cing
1 Nov 2017
School
Department
Course
Professor
Document Summary
I-evolution of atmosphere ~powerpoint slides 2-5: atmosphere = dynamic & delicate, thin blanket held to the surface by gravity. Early atmosphere composition: lot of uncertainty some of the ideas: 4. 6 billions years ago : formation of earth. Started off as cloud of gas & dust which gradually compacted under the influence of gravity: primordial atmosphere = very light gases : hydrogen, helium, ammonia, methane very brief (0. 1 billion years) Moon was created 4. 5 billion years ago and the atmosphere was lost. Gravity not strong enough to hold onto the atmosphere. Dislodged by a collision (single collision w/ a large object or multiple collisions w/ smaller ob- jects) > loss of the primordial atmosphere: existing atmosphere gradually developed: The earliest stage of this atmosphere started off with outgassing : the release of gas out of. Earth"s surface (mostly co2, sulphuric gases hydrogen sulfide nitrogen (n2), water vapour.
