Dance above all sadness

Either way, there would be something to explore, a promise of adventure coming from the concept. And it's more to explore than hollow earth offers.

It would also give an explanation for having a conspiracy to try to keep it secret. If those in power are exploiting the riches of worlds beyond, or if they come from a world beyond and are exploiting us, they wouldn't want everybody knowing about it.

So they tell us that this is our world, and if we go further, we just come right back. And lest our adventurousness pushes us to try, they tell us that other worlds are up there, were unfortunately we need very expensive gear to get to; too expensive for any of us to try on our own. And also where we can readily see them and do spectroscopic analysis and determine that these worlds are not habitable, so we would need even more expensive gear to survive there for any time.

On such scale, the atmosphere would not mix quickly. So worlds beyond on an infinite flat earth may or may not have a breathable atmosphere.

An expedition across an eternal ice sheet spanning for multiple equator lengths would hardly be feasible, even if we knew which direction the closest warm place to ours is and had a way to keep the direction all the way. But it would still be easier than a manned interplanetary mission. Sailing across such a large ocean would be even easier.

The explorers would need to have enough food and fuel for the journey. They would need the means to transport all of it, for which they need even more fuel, and enough crew to operate and maintain the transports, who need even more food. — Oh, it's the Tsiolkovsky rocket equation all over again, isn't it?

The monolith builders alter hominids, giving them the capability to use tools, thus starting the creation of minds like theirs.

By the time we find the beacon monolith on Luna, we have ourselves created something that can think, the HAL9000 computer, making us a mirror of our own creators of whom we aren't even aware yet.

We put that computer, which was designed for truthful information processing, on a mission for which we ask it to keep some information from the crew. As the time approaches at which the crew would be informed about the secret aspect of their mission, and thus HAL's deception would be revealed, the computer develops a psychosis and causes the deaths of almost all human crew.

This adds an obstacle, tension, excitement to the story. But it would narratively be more meaningful if it would foreshadow the ending by mirroring the relationship between us and the monolith builders.

With the ending as it is, HAL going rogue feels disconnected from the plot that surrounds it. To an extent, HAL turning violent can be read as echoing the altered hominids starting to use weapons to club competitors of their own kind to death. Yet HAL doesn't turn against other computers but against his creators.

The narrative would be more coherent if David Bowman would in the end have some panic reaction and cause harm to the monolith builders.

What if their design worked out way too well, and they weren't prepared for it? Their plan was that we would evolve, advance technologically, eventually achieve space travel, trigger the beacon on the Moon that sends a signal to them through the stargate. At that point they come to make contact with us.

But they never thought that by the time we find the beacon on our own Moon we could already have the capabilities to launch a mission to the outer solar system and reach their stargate ourselves. As they are on their way, Bowman passing through the stargate in the opposite direction crashes into them at astronomical velocity, tearing their vehicle apart.

What are they playing? It's God Rest Ye Merry, Gentlemen, isn't that what they're always playing?