We’re not sure how Ryder crater, perched on the rim of a larger, older crater, was formed. By an asteroid that split? By one that grazed the surface? Or is this odd shape the result of the crater's location on a steep slope?

Moon Phase and Libration, 2021

Animation showing the geocentric phase, libration, position angle of the axis, and apparent diameter of the Moon throughout the year 2021, at hourly intervals.

What the Moon will look like from Earth, every hour of every day of 2021.