Astrobiology - 18:28 Waterasamolecule...

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The Origin of water and the oceans 18:28 Water as a molecule Deuterium 2H=HDO (I proton 1 neutron) Protium 1H=H20 Water in interstellar clouds o H2+cosmic rays (h2+)+(e-) …. water Earth is a dry planetary body o There is water but most of it is magnetic metals (core) o Water in all the oceans: 1.4 x 10^24 g o Why so dry? When the earth was young there was no water Other planetary bodies contained water (up to 20%) Primitive meteorites (carbonaceous chondrites) Water is not liquid it is attached to minerals) Antarctic micromedeorites Commets contain up to 50% water The Late Vaneer hypothesis When the planets formed at the end a few extraterrestrial bodies  brought old carbon and water to the earth Water from comets cannot have been the main contributor to the  earth’s water because it has too much deuterium whereas the  meteorites have almost matching deuterium levels to that of the earth 1% mass of the earth made of these meteorites will produce the  same amount of water found on the earth
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How did oceans form Stage 1 o Water addition Impact with planetoid Evaporated all liquids in external atmosphere Formed the moon Atmosphere formation (310-480 bars {today our atmosphere is 1 bar}) Water and CO2 Stage 2 o Greenhouse effect Earth too hot for liquid water to form Thin crust on surface of earth begins to form Stage 3 o Condensation Earth begins to cool and water separates from gaseous solution Stage 4 o Co2 recycling CO2 begins to attach to crust to form landscapes   Hadean-Archean Transition Oceans where 50 decrees C High salinity Na-Ca-Cl Dominant Hydrothermal-controlled salinity Acidic and anoic
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Formation of planets 18:28 Planets first start as planetesmals
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Formation of planets 18:28 Ultimately only the largest planetesmals survive Collision of particles in space after formation of the sun Planets beyond the frost line are the gas giants Formed more quickly Heavy things went to the core and the core gravatized other particles (bottom  up) Usefull because they absorb solar debris that would otherwise hit earth Inner solar system formes rocky planets frin rock and metal These elements made up only 0.6% of the nebula so the planets coulent grow  that big They are also too close to the sun to let gas attach The earth was bombarded by bodies resembling present day meteores  o Bombardment heated the earth Aided gravitational compactment Bodes law Found ratio between sun and other planets The moon Largest satalite in solar system (ratio between planet size to moon size)
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