I think you're missing the point of the song it's not actually about Earth bur that of the musings of an Alien traveler into why this Planet is abandoned, loosely based on Keats "On First Looking into Chapman's Homer". After observing conditions on the Planet, the Alien imparts a bit of age old wisdom to the vanished inhabitants sayingFrom life alone to life as one Think not now your journey's done For though your ship be sturdy No mercy has the sea Will you survive on the ocean of being?

The Image isn't supposed to be taken literal it's more of a Philosophical thought listen to the song.

Remember...No matter where you go there you are