15.First Billion Years

Question 1

How do we do absolute Dati g with isotopes

Answer 1

Use decay curves, can ,easier N now and and D now and Ideally N0=Nnow +Dnow but not always a good assumption bc coul have been some daughter in the beginning
We can use slope=e^lambdatime -1

Question 2

What is the origin of the moon and why is it interesting?

Answer 2

Earth and moon are made of largely the same stuff so not just a captured asteroid
Hupothisis that earth collided w planet sized body which produce earth moon system
Moon is receding from Earth and was initially very close

Question 3

Structure of earth

Answer 3

Solid Crust on top
Solid upper mantle , mainly periodite
Solid lower mantle
Liquid outer core
Solid inner core

Question 4

What are plate tectonics

Answer 4

The lithosphere (crust and uppermost mantl)is divided not tectonic plates that move over the asthenosphere

Question 5

What is the origin of earths magnetic field and why is it relevant to astrobiology.

Answer 5

Heat and Coriolis effective créâtes connective coils and an electric current then magnetic field
Magnetic field deflects solar wind from earth so they don’t destroy atmosphere so useful for habitability

Question 6

What is the origin of earths water

Answer 6

Outgassing from the mantle eg from minerals coming out the magma ocean
“Late veneer” of material outer disk to inner so earth impacted but things that have water in eg commets (small contribution)

Question 7

Origin of the atmosphere

Answer 7

Initial atmosphere was envelope of h2 and he when it formed
Now atmosphere from Outgassing from magma ocean and volcanoes ones once crust was formed

Question 8

What is late heavy bombardment

Answer 8

Pulse of impacts from lunar highlands cluster that would wipe out écosystems
Wouldn’t have completely sterilised earth

Question 9

Describe differentiation

Answer 9

Start with ball of material heaviest materials sink to form cores lowe density for magma and crusts