I have found myself wondering about the background history and lore of the show, like how did earth suddenly gain enough water for there to be zero land?  How did the Hideauze

  • SPOILERS*

come to be on earth

  • END SPOILERS*? 

How long ago did earth freeze over?  Did earth actually freeze over due to climate change caused by the sun? (Ledo lives in a military state historical records are quite possibly changed in order to make the government look better, like say hypothetically humanity caused nuclear winter on itself, the government would probably want to cover that up)