I was surprised at the scarcity of geometry explanations in the movie- and this was clearly intentional. Some people believed it was all "fuzzy" or "not thought through"- while in fact the picture is entirely coherent, and the authors leave enough clues to put it together- but they simply choose not to explicitly elaborate in the movie. Paradoxically, this basically pulls the movie away from a harder-core SF content, into the soft of the interpersonal relationships- this was probably their intent.
This is a typical "hollow earth setup"- of course, this was never Earth, but a space habitat/colony, entirely artificial (don't let the grass fool you, the skeleton is made of metal) - as suggested by the nearby planet with a debris ring orbiting it (possibly a consequence of the same gravitational catastrophe). Agee's world lives on the inner side of this shell, while at the very end the characters punch through the metal shell and reach the true outside surface of this habitat- where the collapsed building are scattered.The "inner sky is in fact a device/factory located at the nucleus of this spherical shell- that serves as a "luminary" for the inner crust world- a central sun. At some point, the two characters flee that surface which was getting warmer and warmer - the sun was switching on in the morning.
So the story could be like this: people were inhabiting this colony, on the usual outer side, with normal gravity. At some point, they decided they have to move to the inside of the shell, and use a central "sun" (which clearly had to be built beforehand with this purpose in mind) - but for this you either need rotation ( a la G. O'Neil space settlements) or some reverse gravity. When this happened, the buildings and the people on the outer surface were repelled into the sky- probably for a short while, until the experiment was terminated and the buildings collapsed back onto the ground. The only people that survived were those inside the crust of the colony, in the tunnels. Also, a group of people were permanently inverted - had a"mutation" that would pull them towards the outside of the planet, rather than to the inside. These were Agee's people. This is reminiscent of Christopher Priest's novel "Inverted world" - with the hyperboloidal gravity.
So the irony is: the actual "inverted" people are the "puritans" in Agee's city - that is why they fall into the real sky once exposed to the true, outer surface- while the tunnel people are the survivors of the "normal" humans, the ones that could live on the outer surface. Other inversions: Agee's surface is not the real surface ( "the real world" as the picture says), the sky is not real, the sun they see during the day is actually a machine, the stars are the safety lights of this at nighttime, the clouds are the smoke output of the nucleus factory, the people that reverse fall into the sky are actually Agee's people, not the others (which simply fall down)- so all the original expectations are actually inverted at the end: the "normal-looking" folks are actually the mutants, and the underdogs in the tunnels are the "original" = "normal inhabitants". Interesting that the movie did not want to emphasize all these nuances, leaving the conclusions for the spectators -as a SF fan, I am particularly puzzled.
This is a typical "hollow earth setup"- of course, this was never Earth, but a space habitat/colony, entirely artificial (don't let the grass fool you, the skeleton is made of metal) - as suggested by the nearby planet with a debris ring orbiting it (possibly a consequence of the same gravitational catastrophe). Agee's world lives on the inner side of this shell, while at the very end the characters punch through the metal shell and reach the true outside surface of this habitat- where the collapsed building are scattered.The "inner sky is in fact a device/factory located at the nucleus of this spherical shell- that serves as a "luminary" for the inner crust world- a central sun. At some point, the two characters flee that surface which was getting warmer and warmer - the sun was switching on in the morning.
So the story could be like this: people were inhabiting this colony, on the usual outer side, with normal gravity. At some point, they decided they have to move to the inside of the shell, and use a central "sun" (which clearly had to be built beforehand with this purpose in mind) - but for this you either need rotation ( a la G. O'Neil space settlements) or some reverse gravity. When this happened, the buildings and the people on the outer surface were repelled into the sky- probably for a short while, until the experiment was terminated and the buildings collapsed back onto the ground. The only people that survived were those inside the crust of the colony, in the tunnels. Also, a group of people were permanently inverted - had a"mutation" that would pull them towards the outside of the planet, rather than to the inside. These were Agee's people. This is reminiscent of Christopher Priest's novel "Inverted world" - with the hyperboloidal gravity.
So the irony is: the actual "inverted" people are the "puritans" in Agee's city - that is why they fall into the real sky once exposed to the true, outer surface- while the tunnel people are the survivors of the "normal" humans, the ones that could live on the outer surface. Other inversions: Agee's surface is not the real surface ( "the real world" as the picture says), the sky is not real, the sun they see during the day is actually a machine, the stars are the safety lights of this at nighttime, the clouds are the smoke output of the nucleus factory, the people that reverse fall into the sky are actually Agee's people, not the others (which simply fall down)- so all the original expectations are actually inverted at the end: the "normal-looking" folks are actually the mutants, and the underdogs in the tunnels are the "original" = "normal inhabitants". Interesting that the movie did not want to emphasize all these nuances, leaving the conclusions for the spectators -as a SF fan, I am particularly puzzled.