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Boosted by jsonstein@masto.deoan.org ("Jeff Sonstein"):
grobi@defcon.social wrote:

Tidal locking

results in the Moon rotating about its axis in about the same time it takes to orbit the Earth. Except for libration effects, this results in it keeping the same face turned towards the Earth, as seen in the figure on the upper left. (The Moon is shown in polar view, and is not drawn to scale.)

+ Upper left:
> If the Moon didn't spin at all, then it would alternately show its near and far sides to the Earth while moving around our planet in orbit.

+ Upper right:
> If rotational frequency is larger than orbital frequency, a small torque counteracting the rotation arises, eventually locking the frequencies (situation depicted in green)

+ Down left:
> A simulation shows the variability in the portion of the Moon visible from Earth due to libration over the course of an orbit. Lighting phases from the Sun are not included.

+ Down right:
> Animation of the Moon as it cycles through its phases. The apparent wobbling of the Moon is known as libration

From Wikipedia, the free encyclopedia

CREDITS
Contributors to Wikimedia projects
* Stigmatella aurantiaca
* Jim McKeeth
* Tom Ruen
* Poopooman-ger

#space #moon #astrophotography #photography #science #astronomy #nature #NASA #ESA #education

Attachments:

• gifv: At left, the Moon rotates at the same rate it orbits the Earth, keeping the same face toward the planet. At right, if the Moon did not rotate then the face would change over the course of an orbit. Viewed from above; not to scale. CREDIT Stigmatella aurantiaca
• gifv: This simulation shows the variability in the portion of the Moon visible from Earth due to libration over the course of an orbit. Lighting phases from the Sun are not included. One anomalistic lunar cycle (Apogee to Apogee) for April 2007. No phase shown. CREDIT Tom Ruen - Own work, created with "Full Sky Observatory" Source bitmap for projection from Nasa's Clementine Spacecraft: USGS: Global simple cylindrical projection at 10 km/pixel. Software: "Full Sky Observatory", by Tom Ruen, described at File:FullSkyAstronomySoftwareLogo.png Source book: "Astronomical Formulae for Calculators, 4th edition", Jean Meeus, 1988, published by "Willmann-Bell, Inc" Chapter 30 "Position of the Moon"
• gifv: Animation of the Moon as it cycles through its phases. The apparent wobbling of the Moon is known as libration. CREDIT Poopooman-ger