[swatcoder]

> They still had no idea what the sun, moon, and planets were,

The composition of celestial bodies is useless trivia until you have some very modern material and energy sciences that might start turning to them for inspiration. There will almost certainly be a collapse of the modern world, and losing that information will be the very very least of our problems.

> nor even the layout of the solar system.

Depending on which civilizations you're talking about and how ancient you mean, the paths of visible roving bodies (planets) were actually pretty well known in many places for thousands of years. The models used to anticipate positions were often more convoluted than ours, but projected space and heliocentrism are ultimately just an optimization that wasn't obvious, necessary, or meaningful given what little practical use there was to the paths of those planets until very recently.

What those pop history shows mostly achieve is just reminding people that astronomical and scientific knowledge didn't start in the European Enlightenment, which is the takeaway that many people (in the US, especially) carry after high school. They're not really meant for someone like yourself. There's much more you might actually be impressed by in academic history/archaeology/anthropology and even in certain written pop history sources.

[antognini]

Also worth noting that pretty much every ancient civilization ended up figuring out the order of the planets, at least relative to earth. (It turns out not to be so difficult since this is directly related to their sidereal periods.)

[WalterBright]

If you stand at the center of a circle, and have a man walk a circle at radius r from you, and another man walk a circle at radius 2r, it will take the second man twice as long to complete the circle.

It's not a great leap to apply that to the planets.

But it's not proof that the planets were ordered that way.

Science happens when one invents an explanation for observed phenomena, and then the explanation (theory) makes a prediction, then an experiment is devised, and the theory is validated if the prediction matches the theory, or tossed aside if it doesn't. In other words, the scientific method. That appeared fairly recently, and the consequences were an explosion of knowledge.

[jrussino]

> There will almost certainly be a collapse of the modern world

I hope your certainty is misplaced; this is just about the most horrifying prediction I can imagine.

As far as I can tell, we're at a particularly precarious transition point with regard to how much energy we consume. If society "collapses" before hitting some technological checkpoint we don't get to try again - at least, not for a looong time - because we've nearly used up all of the low-hanging fruit in the planet's energy resources (fossil fuels).

[WalterBright]

Sure they watched the paths. That doesn't tell them what they were, how far away they were, helicentric vs geocentric, etc. Anybody can watch paths and notice they repeat.

> heliocentrism are ultimately just an optimization that wasn't obvious, necessary, or meaningful given what little practical use there was to the paths of those planets until very recently

True, but that wasn't my observation. My observation is it was not advanced, sophisticated, etc.

[felipeerias]

It was actually extremely complex and sophisticated. Getting accurate measurements was seriously tricky and making sense of them involved doing complex calculations (particularly spherical trigonometry) by hand. Some phenomena, like the precession of the equinoxes, required aggregating observations which had been taken over several centuries.

A good book to get a sense of this complexity is “The Light Ages” by Seb Falk.

[WalterBright]

Unfortunately, a calculation that matches a pattern does not confer any understanding of the nature of the solar system.