Scyphi told the sun to do it.

"I'll return for youuuuuuuu!" Luna cried as she shot toward the moon. "One day, sister!"

Celestia waved a tearful goodbye. Luna at least could finally go home, while she herself would stay behind on this dreadful dirtball of a planet.

A loud thump caught her attention.

"Nope. Still banished from the moon. By the moon."