Of course they did. It was the Celestials. They needed to open up the earth in order to put their celestial egg inside. The extra matter formed the Moon, where the Watcher would live and watch until the egg hatches. 

Galactud eats the eggs. It’s a form of population control. That’s why he’s constantly bothering the earth. But he’s not cool with killing off all the earthlings. That’s why he sends his herald ahead of him - to warn the inhabitants in case they can get offworld. 

Everyone knows this. Right?