Board Thread:Naruto Discussions/@comment-434627-20160606143610/@comment-734582-20160606153246

There are two possible interpretations.

One: IT casts no shadows. This is shown by the light even being indoors. The IT cut through the planet and put everyone under genjutsu.

However, The Last shows a second possibility. You see, it's most definitely a round planet, but the Ninja world only is a single continent. The moon can in fact reflect the light back and bask half the planet in the light of IT: the inhabited side. The other half never gets put under Infinite Tsukuyomi...but nobody lives there.