Exploring The Moon Flashcards
(9 cards)
How do the Moon’s internal, divisions compare with Earth’s
Same 4
Crust is roughly 3 times thicker than Earth
Moon’ core is 25% of radius compared to Earth’s 50%
How are the moons near and far sides different
Near side has many Maria, is less cratered as it is younger. Thinner crust
Far side is mostly terrae, more cratered as it is older Thicker Crust and not visible.
Maria are darker than terra
How has information been gathered about he far side of the moon
Russian spacecraft Luna 3 was the first to photograph it in 1959
Escape velocity
The velocity a spacecraft must reach in order to escape Earth’s gravity, the energy requirements of which can only be met with a rocket
Understand and prove the Giant Impact Hypothesis
A planet sized body collided with the early Earth. The ejected material was put into orbit and eventually formed the moon
Evidence for - similar oxygen isotope ratios, Moon’s low iron composition suggests it was formed from Earth’s mantle, Angular momentum of the Earth-Moon system suggests a massive impact
Understand and prove capture theory
The moon formed elsewhere in the solar system and was gravitationally captured by Earth.
Evidence for - other Planets like Mars have captured moons, could explain differences in composition
Against - Highly unlikely as Earth does not have much gravity, doesn’t explain similar isotopes, the Moon’s stable, near-circular orbit is hard to explain from capture
Understand and prove Co-accretion Theory
The Earth and Moon, formed together at the same time from the same region of the solar nebula
Evidence for - Explains similar compositions, Easy to imagine to bodies forming side by side
Against - Can’t explain why the moon has so little Iron compared to Earth, Doesn’t explain the high angular momentum of the Earth - Moon system
Define angular momentum (of a system)
The momentum of the spins and orbits of the bodies in a system
