Starship Asterisk*

neufer wrote: ↑Sun Mar 18, 2018 4:53 pm

The libration of the Moon over a single lunar month. Also visible is the slight variation in the Moon's visual size from Earth.

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gorade wrote: ↑Sun Mar 18, 2018 4:30 pm
The Moon seems totally locked to the Earth by gravitational forces.
Does that mean, that this locking happened before it became totally solid? If it were solid and rigid and its gravitational center just were located nearer to Earth, it ought to end up rocking back and forth. Isn't that what Mercury does?
To stop rocking something has to consume the kinetic energy of a pendulum.
Thus there has been, or is still a liquid or at least movable part inside the Moon, that generated heat.
Do I think incorrectly in some way here?

The Moon rotates with a fixed period of 27.321661 days
with LITTLE OR NO ROCKING!.

The Moon appears to rock back and forth with
respect to the Earth (i.e., libration) because:

• 1) It is in an elliptical orbit of eccentricity = 0.0549, and

• 2) it has an axial tilt to that orbital plane of 6.687°.

gorade wrote: ↑Sun Mar 18, 2018 4:30 pm
The Moon seems totally locked to the Earth by gravitational forces.
Does that mean, that this locking happened before it became totally solid? If it were solid and rigid and its gravitational center just were located nearer to Earth, it ought to end up rocking back and forth. Isn't that what Mercury does?
To stop rocking something has to consume the kinetic energy of a pendulum.
Thus there has been, or is still a liquid or at least movable part inside the Moon, that generated heat.
Do I think incorrectly in some way here?

• 1) It is in an elliptical orbit of eccentricity = 0.0549, and

• 2) it has an axial tilt to that orbital plane of 6.687°.

Guest wrote: ↑Sun Mar 18, 2018 9:46 am
why are there virtually no maria on the dark side?

• 1) The Moon "having been amalgamated from two different bodies" or

• 2) The tidally locked Moon having a quasi-molten near side during the Late Heavy Bombardment
  due to the proximity of a very hot & thermally radiant Earth.

https://en.wikipedia.org/wiki/Late_Heavy_Bombardment wrote:
<<The Late Heavy Bombardment (abbreviated LHB and also known as the lunar cataclysm) is an event thought to have occurred approximately 4.1 to 3.8 billion years (Ga) ago, at a time corresponding to the Neohadean and Eoarchean eras on Earth. During this interval, a disproportionately large number of asteroids are theorized to have collided with the early terrestrial planets in the inner Solar System, including Mercury, Venus, Earth, and Mars.>>

https://en.wikipedia.org/wiki/Theia_(planet) wrote:

Animation of collision event between Earth and Theia.

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<<Theia is a hypothesized ancient planetary-mass object in the early Solar System that, according to the giant impact hypothesis, collided with another planetary-mass object, Gaia (the early Earth) around 4.5 billion years ago.According to the hypothesis, Theia was an Earth trojan about the size of Mars, with diameter of about 6,102 km. Geologist Edward Young of the University of California, Los Angeles, drawing on an analysis of rocks collected by Apollo missions 12, 15, and 17, proposes that Theia collided head-on with Earth, in contrast to the previous theory that suggested a glancing impact. Models of the impact indicate that Theia's debris gathered around Earth to form the early Moon.

According to the giant-impact hypothesis, Theia orbited the Sun, nearly along the orbit of the proto-Earth, by staying close to one or the other of the Sun–Earth system's two more stable Lagrangian points (i.e. either L4 or L5). Theia was eventually perturbed away from that relationship by the gravitational influence of Jupiter and/or Venus, resulting in a collision between Theia and Earth. The far side of the Moon has a crust that is 48 km thicker than the near side of the Moon. This is thought to be due to the Moon having been amalgamated from two different bodies.>>

Chris Peterson wrote: ↑Sun Mar 18, 2018 2:18 pm

orin stepanek wrote: ↑Sun Mar 18, 2018 11:45 am
Actually Luna does rotate; once every lunar cycle as revolves around the Earth!

As would be quite apparent given a Focault pendulum or modern accelerometer set up on the Moon.

orin stepanek wrote: ↑Sun Mar 18, 2018 11:45 am Actually Luna does rotate; once every lunar cycle as revolves around the Earth!

ta152h0 wrote: ↑Sun Mar 18, 2018 10:24 am Anything in existence that would show the locations of all objects on that surface ? Ranger, Surveyor, Apollo, etc

Guest wrote: ↑Sun Mar 18, 2018 9:46 am why are there virtually no maria on the dark side?

Guest wrote: ↑Sun Mar 18, 2018 9:46 am why are there virtually no maria on the dark side?