Earth-Moon System Flashcards
A rapidly rotating plastic body will __________.
Distort from a spherical shape.
Pg. 83
The Earth is closer to an ______ than an actual sphere.
Oblate spheroid.
Pg. 83
The pull of the Sun and Moon on the Earth’s equatorial bulge works to __________.
Align the equatorial and ecliptic planes.
Pg. 83
Because of the net torque on the equatorial regions of earth, the result is a ____________.
Clockwise precession about the rotational axis.
Pg. 84
What is the Earth’s net axis procession period due to the torque provided by the Sun and the Moon?
25,800 years.
Pg. 84
The distortion of equipotential gravitational surfaces on a plastic body is commonly referred to as ______.
Tides.
Pg. 84
What is the Earth’s mean radius?
R = 6370 km
Pg. 85
The ratio of the differential forces due to the Sun and moon on the Earth is approximately ______.
dFmoon / dFsun = 0.44
Pg. 86
Moon-related tides have roughly ____ the amplitude of sun-related tides.
Twice
Pg. 87
What are spring tides?
When the moon and sun are at 180 degrees to each other and build tides on Earth constructively.
Pg. 89
What are neap tides?
When the sun and moon are at 90-degree angles to each other, their tide contributions add destructively causing lower tide levels than spring tides.
Pg. 90
What is tidal breaking?
The gradual slowing of the Earth due to tidal friction.
Pg. 90
What is the equation for the Roche limit?
r_roche = R2.44(rho_M/rho_m)^(1/3)
Pg. 94
What is the equation for the hill limit?
r_hill = R(M_m/2M_M)^(1/3)
Pg. 96
