ASTRON 1F03 Lecture Notes - Lecture 9: Protoplanetary Disk, Martian Meteorite, Viking Program
Document Summary
If sheltered from direct sunlight, water ice can persist. Plenty of ice in high latitude (near poles). Viking probes tested the biological responses (inconclusive: perchlorate). Suv sized full wet chemistry lab on board. Atmospheres of the inner planets: mercury, venus, earth, mars, young planets, forming primary atmospheres, captured gases in a protoplanetary, sunlight heated the atmospheres. Rapid thermal motion of light atoms and: volcanoes released gases and comets and asteroids contributed water and other disk, mostly hydrogen and helium. molecules caused the primary atmospheres to escape. molecules to form secondary atmospheres. Mars 5. 0 km/s: atmosphere gas particle speed. Hydrogen (weight 2): average speed 2. 7 km/s at 27 c. Enough particles at higher than average speeds (say 5 6x average) to lose a lot over 4 billion years if that speed is greater than escape velocity. New planets from primary atmospheres by sweeping up gas in the accretion disk. All terrestrial bodies lost their primary atmospheres.