A full moon rises over the Juscelino Kubitschek Memorial in Brasilia. (Ueslei Marcelino/Reuters)

Well, a new study published in Nature magazine says our moon might not have always been so solitary a lunar soul.

This diagram provided by Martin Jutzi and Erik Asphaug of the University of California at Santa Cruz via Nature shows a simulation of four stages of a collision between the moon and a companion moon, 4 percent of the lunar mass, about 4 billion years ago. (AP)

This is not the first time science has tried to explain the moon’s different sides. Others have posited tidal forces or the way the moon’s crust cooled when it first formed.

“The fact that the nearside of the moon looks so different to the farside has been a puzzle since the dawn of the space age,” Francis Nimmo, one of the authors of a 2010 paper in Science proposing tidal forces as the cause, told Nature magazine.

(Personally, I like the latest theory best: a space showdown with our moon earning its unique spot in the sky.)