3. Origin of the solar system

11. Solar Systems Form by Accretion
Let us study the sequence in slightly more detail:
The processes by which dust particles began to adhere to one another and form hierarchy of planetesimals of varying sizes are poorly understood, but it is clear that for accretion to commence, the relative velocities of dust grains had to be minimized so that they approached each other very slowly, thereby allowing surface chemical forces to cause them to adhere during gentle impacts. Dust grains began to adhere, building up a first generation of a small aggregations or planetisimals, perhaps with dimensions up to a few cm.
Thus a thin, relatively dense disk of dust and small planetisimals collected quickly in the equatorial plane.

18. Planetary migration
Giant planets have migrated over time, Uranus and Neptune were closer in but migrated out after Saturn and Jupiter went into 2:1 resonance
Jupiter also migrated slightly inward – interactions with left over material led to late heavy bombardment

20. Exosolar systems
3557 known systems, 601 known to have multiple planets (two have 7 planets)
Some problems for standard theory: orbits not often circular and not coplanar and not all orbit in same direction!
Maybe planetary interactions are generally more important than in our solar system

21. Formation of the moon

25. e=(ra-rp)/(ra+rp), a=(rp+ra)/2

28. Main problem is simulations show that moon is dominantly composed of impactor mantle but oxygen isotopes of moon and Earth are identical
Can fix by having higher velocity impactor or make impactor more similar to proto-Earth

29. Meteorites and the composition of the Earth

38. Timing of core/moon formation

40. Conventional radiogenic isotope systematics used in geology:
Principles of Isotope Geology:
Conventional radiogenic isotope systematics used in geology:
147Sm - 143Nd t 1/2 = 10.6 x 1010 yrs
87Rb - 87Sr t 1/2 = 48.8 x 109 yrs
238U - 206Pb t 1/2 = 4.47 x 109 yrs
235U - 207Pb t 1/2 = x 109 yrs
232Th- 208Pb t 1/2 = x 109 yrs
187Re - 187Os t 1/2 = 42.3 x 109 yrs
176Lu - 176Hf t 1/2 = 35.7 x 109 yrs

41. The Law of Radioactive Decay
The basic equation: 1 - dN dt
N or = N l
# parent atoms
D* = Nelt - N = N(elt -1)
 age of a sample (t) if we know:
D* the amount of the daughter nuclide produced
N the amount of the original parent nuclide remaining
l the decay constant for the system in question
(= ln 2/ t ½)
More conventionally, D(present) = Do + D*
time 
Note half-life is a constant (as is decay constant)

42. These systematics are being used as chronometers
model age
isochron age
and as petrogenetic tracers….

46. Hf is enriched in the silicate mantle after core formation

48. Major structural divisions of the Earth