APOD: Rotating Moon from LRO (2018 Mar 18)

[APOD Robot]

Rotating Moon from LRO

Explanation: No one, presently, sees the Moon rotate like this. That's because the Earth's moon is tidally locked to the Earth, showing us only one side. Given modern digital technology, however, combined with many detailed images returned by the Lunar Reconnaissance Orbiter (LRO), a high resolution virtual Moon rotation movie has been composed. The above time-lapse video starts with the standard Earth view of the Moon. Quickly, though, Mare Orientale, a large crater with a dark center that is difficult to see from the Earth, rotates into view just below the equator. From an entire lunar month condensed into 24 seconds, the video clearly shows that the Earth side of the Moon contains an abundance of dark lunar maria, while the lunar far side is dominated by bright lunar highlands. Currently, over 20 new missions to the Moon are under active development from four different countries, most of which have expected launch dates either this year or next.

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[heehaw]

I am so often struck by how poor the quality of my brain is, that e.g. I never thought of the (in retrospect obvious) possibility of making a movie like this one. It is great! Wonderful!

[heehaw]

I might add that today's Earth Science Picture of the Day looks fake - because of the extraordinary absence of clouds: http://epod.usra.edu/blog/

[Guest]

why are there virtually no maria on the dark side?

[BDanielMayfield]

why are there virtually no maria on the dark side?

The "dark side" you ask? Which side is that, as the near side is much darker than the far.

[starsurfer]

why are there virtually no maria on the dark side?

I usually find that people called Maria are too nice to join the dark side.

[starsurfer]

If you look really closely, you can see secret NASA bases and glass pyramids.

[ta152h0]

Anything in existence that would show the locations of all objects on that surface ? Ranger, Surveyor, Apollo, etc

[eaglekepr]

Anything in existence that would show the locations of all objects on that surface ? Ranger, Surveyor, Apollo, etc

I like to use the Lunar Quick Map http://target.lroc.asu.edu/q3/. It's VERY thorough, but you can select your overlay layers... "Anthropogenic Features" will show landers.

[orin stepanek]

Actually Luna does rotate; once every lunar cycle as revolves around the Earth!

[LWB]

They should make vertical rotation to show the poles as well.

[Chris Peterson]

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.

[neufer]

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.

An Earth based Focault pendulum is only needed to prove that the star field, itself, doesn't rotate.

When we observe the Moon moving through that fixed star field while still facing us we know the Moon is rotating.

The Moon returns to the same star field about once every 27.3 days (its sidereal period).

But it takes about 29.5 days (its synodic period) for the Moon to show the same phase to the Earth (a lunar cycle).

[gorade]

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?

[neufer]

why are there virtually no maria on the dark side?

The far side of the Moon has a crust that is 48 km thicker than the near side of the Moon. This may be due to:

• 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.

<<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.>>

Animation of collision event between Earth and Theia.

---

<<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.>>

[neufer]

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

---

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°.

[Boomer12k]

Awesome!!!

:---[===] *

[Boomer12k]

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

---

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°.

Reminds me of being on a ride at the fair....
:---[===] *