Did our planet once have two moons

This from Nature magazine. The blurb states the hypothesis simply and is quoted here in its entirety.
...
The Moon is a satellite of two distinct halves. The nearside that
faces us all the time is low in altitude, flat and dark coloured
whereas the farside is mountainous and deeply cratered. A new
hypothesis suggests that Earth once had two moons, and that this lunar
dichotomy was the result of a collision between them.