This Earth has captured a second moon that is similar in size and mass to its original and its orbit is twice as close. This has tremendous effects on Earth and the people that will live there. The tides here are around six times greater, making coastal living much more difficult. The pull from a second moon that is so close creates a day that is four times as long as our own. More information can be found in in Neil Comin's book, What if Earth Had Two Moons (And Nine Other Thought-Provoking Speculations). Two moons effect requires the appropriate WHIMC texture pack.