What are those pale spots that seem to sparkle in the binoculars?
What are those dark areas? Why do they seem smoother than the lighter areas?
What are those pale lines radiating far from centerpoints?
Was there volcanic activity on the moon?
How much is the moon changing over the centuries?
Which features came first, and which are newest?
We'll add some geological terms:
Catastrophism - Features are explained by sudden powerful events like
meteor collisions
volcanic eruptions
moonquakes.
Gradualism - Features are explained by longer processes such as
dust accumulation
rise/fall of low/high elevations
hot/cold effects of solar heating/shade (temperature change)
shrinkage/cracking of rock as it cools from a molten state
erosion (sandblasting) from dust landing at high speeds
darkening of the surface due to sunlight, a'la desert varnish.
We might anticipate that the moonscape gets its sharpest and most distinct features from catastrophes,
and that those features would be softened by gradual processes.
Let's walk through a month of moonshots, and see what we can figure out:
A few observations:
Since the advent of telescopes and photography, the moonscape has not changed in any observable
way. We see no new craters or mares forming, no flashes as large objects collide with the
moon, no volcanic activity. All catastrophes seem to be in the distant past, and the moon is in a
static state.
We infer that gradual processes (breakdown through expansion/contraction, falling dust and small
meteorites) are underway, effectively softening the lunar features. A famous example is dust
thick enough for footprints when astronauts first walked on the moon in 1969.
The shadows confirm that the highlands are of higher altitude than the mares.
The darkest spots may not be much deeper than the mares surrounding them. The shadows
do not show them to be deep like craters.
Chronology:
The highlands (very rough appearance, large craters, pale color) may be the oldest
of the lunar landscape. The entire surface might have once looked like the highlands.
The mares (smoother and darker areas) might have come next. The mares seem
seem to be very large craters (round shapes, ringed by mountains) that were then filled
with molten rock.
Smaller craters were then formed on both the highlands and the mares.
Last, the crater Tycho and other very pale spots (the 'sparkle') were formed by a
meteor shower. The rays are evident on all types of lunar surface. The pale color
("unknown white mineral") might be from:
meteors consisting of pale material (not likely! The debris from crater-formation
are more from the ground than the projectile.)
the rock below the surface being much paler than the surface itself. By this
hypothesis, the dust is darker than the surface below AND/OR the 'pre-dust' rock
surface is darkened over time. It follows that the rays and pale spots will
eventurally disappear as they darken and/or are covered by falling dust.
The features are remarkably sharp, whether looking with the naked eye, with binoculars or with
telescopes. We can infer that gradual (softening) processes are either happening extremely slowly,
or that the visible features have been in place a small number of centuries. We cannot
verify that gradual processes work at a uniform rate of speed.
