Folks at the NASA GSFC Scientific Visualization Studio created this amazing animation showing our view of the Moon over the entire year of 2012 with time resolution of *one hour*!
The tipping, tilting, and rocking are due to the Moon’s elliptical orbit coupled with its tilt. This is explained in the video captions– check it out! It’s called libration. The Moon’s orbit around the Earth is elliptical, so sometimes it moves faster in its orbit than other times. However, the Moon’s spin is constant. The geometry of these two things add together, allowing us to sometimes peek a little bit over the eastern and western horizons. Not only that, the Moon’s orbit is tilted a bit with respect to our Equator, so we sometimes get a little peak over the north and south poles too.
The images are based on observations by the Lunar Reconnaissance Orbiter, which has been taken super-high-res images and altimetry data since it went into orbit our satellite in June 2009. The images show far more than just the lunar phase. For one thing, using the LRO altimeter data, it can calculate the lengths, directions, and positions of all the shadows of mountains, crater rims, and so on, knowing the angle of the Sun over the horizon.
Posted by: Soderman/NLSI Staff