Transcript Ch 15 – The Formation of the Solar System

Ch 15 – The Formation of the Solar System
Modeling the origin of the solar system
Model Requirements
•Each Planet is relatively isolated in space
•The orbits of the planets are nearly circular
•The orbits of the planets all lie in nearly the same plane.
•The direction in which the planets orbit the sun is the
same as the direction in which the sun rotates about its
axis.
•The direction in which most of the planets rotate is
roughly the same as the direction in which the sun rotates.
•Our planetary system is highly differentiated. (the inner
terrestrial planets are much different than the outer
Jovian planets)
•The asteroids are very old and exhibit a range of
properties not characteristic of either the inner or
outer planets(except Pluto) or their moons
•The comets are primitive, icy fragments that do not orbit
in the ecliptic plane and reside primarily at large distances
from the sun.
Condensation
Theory
Large, rotating dust cloud gravitationally collapses
The Solar nebula flattens into a spinning disk
Angular momentum is conserved
Nebular gas is expelled by the strong solar
wind (T-Tauri phase)
Finally, after approximately 100 million years,
the protoplanets have formed. A billion years
more were required for the solar wind to
“sweep” out much of the left over solar debris.
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