The fact that the "gods" of our ancestors left the Earth and went to the planet behind the Sun was well known to the ancients. That is why on Earth still many monuments remain, telling of the "gods", the contacts with them and about where they went... Surviving written records tell of a very sudden and quick departure of the "gods".
Their hasty takeoff was due to serious circumstances, so serious that the "gods" literally had to leave the planet on the spot with whatever technical means available to them.