No, that everything is moving on spheres is standard Ptolemaic cosmology. Everything in the heavens moves in perfect circles around the earth. And because the moon and planets do not actually move in perfect circles, Ptolemy introduces “epicycles” to bridge the gap between the observed motion of the moon and planets (which are of course actually moving in ellipses, and the planets are orbiting the sun rather than the earth), which posit that these bodies are on smaller spheres rotating around a point on the sphere that’s rotating around the earth. (Wikipedia on epicycles)
Note that this standard cosmology doesn’t really make sense if the earth is flat instead of spherical.
The Greeks wrote about their measurement of the size of the Earth - an interesting discovery even if it is widely known that the Earth is round. The fact that the Greeks thought that the size of the Earth was interesting enough to write about doesn’t say a thing about whether the roundness of the Earth was common knowledge or not.
As I understood it, the concept was each heavenly body was essentially embedded in a transparent sphere, each concentric around the earth. Whether by Shakespeare’s time, that was considered old-fashoined (versus loose bodies wandering the heavens) was what I was referring to. Which implies the earth as sphere - the central sphere - as a very early concept, the Greek knowledge was not lost in the “dark ages”.
I suppose the point is that the average uneducated peasant probably did not give it much thought, but probably also heard the phrase (and perhaps a minor understanding what it meant) from travelling monstrels and such, songs, church activities, and other interactions with people in the know. After all, how often does earth as a globe impact our daily lives and actvities unless we’re contemplating long distance travel?
Which suggests that the fact it was a sphere may have been known well before then by other cultures. The Babylonians, among others, did a lot of astronomical observations.
It’s been 100 posts, so I’m going to fight the hypothetical. The Pacific Ocean alone has some 30,000 islands, so while CC’s journey was probably doomed, perhaps Europe could have island hopped its way to the Far East. I’d be dubious, except the Polynesians did it with canoes.
What proportion of those 30,000 are within navigable distance of the westerly travelling conquistadors?
There is a near fatal gap from the America’s west coast.
They aren’t evenly distributed across the Pacific. For starters 17,000 are in Indonesia.
The Polynesians did it west to east, with the initial stages over thousands of years, allowing their Lapita ancestors the opportunity to develop the technology and deep knowledge required to find microscopic dots of land in vast expanses of ocean.
As @penultima_thule points out, the islands are not laid out nicely, chequer-board style, allowing you to hop from one to the other.
When Cook sailed in the Pacific he had the benefit of taking on Tupaia, who was a specialist navigator-priest, who had detailed sailing knowledge of huge areas of the Pacific including places he’d never visited, which he knew by memory. If Columbus had found a similar bloke he might have benefited from it, but from my limited reading about him he was not someone who took or understood advice or other peoples’ competencies when they were better than his own.
Well, he did take interpreters with him on his voyages - on the first voyage a converted Jew named Luis de Torres, who was fluent in Arabic, and on the subsequent voyage captured natives who had been brought to Spain to learn Spanish. So I don’t think he would have refused to make use of any expert advice available.
It appears Magellan subscribed to the “smaller earth” thory to some extent, he expected the voyage from Tierra del Fuego to the Indies to be a short one. Regardless, they sailed across the Pacific without seeing land until they reached Guam (barely) after more than 3 months. They apparently saied through the middle of the Polynesian islands without encountering any of them. Presumably without North America, lacking Polynesian navigation knowledge, other explorers would have fared no better.
Along the northern part of the Pacific, there’s Hawaii and Midway, and Johnson Atoll which appears to be a barely-there island with an air base purpose-built by dredging the surrounding seabed. You’d need to dip below the equator to find any islands for most of the voyage. Note Pitcairn was abandoned by the Polynesians as unliveable,
To be clear, I’m saying that plate tectonics still existed when super-continent Pangea was around. So there were hot spots beneath moving plates and resulting island chains. In terms of the OP, there would be scattered islands where North and South America are seated now.
Would Columbus have sailed without coming within sight of a single one of these hypothetical islands? I am not a navigator, but offhand I would say probably yes. I guess I could pivot to a technicality and note that the Caribbean plate differs from the North American plate, but both are in the Americas and we discussed meandering and continent-dependent ocean currents upthread. Besides, the Caribbean plate includes much of Mexico and Central America. But in this alternate history, I do hypothesize that European and Polynesian island hopping could have bridged Asia and Europe via the Atlantic, over longish time spans. Probably more Polynesian than European: they had an earlier start. I mean they made it to freaking Easter Island.
Ok, London to Tokyo by sea going around Africa is 11,400 miles. London to San Francisco by air added to San Francisco to Tokyo totals to 10,500 miles. The African route seems more straightforwards.
Positing an Australia located around say Cincinnati would be cheating. But if there were a number of islands the size of Cuba along the way, I can imagine a western trade route arising organically over time.
The tectonic plates move on the order of single digits in centimeters per year. 500 years ago places might have been 50 meters away from where they are not. Not much room to fit in mythical islands in Columbus’s time.
Well, maybe. Given the monstrous counter-factual that North and South America simply don’t exist, what else is different out there?
Assuming those continents simply go “poof” but nothing else changes is one scenario. Another scenario is the Americas don’t merge into a single large landmass.
Generally continents are inherently big blobs. Unlike asteroids, they do not coalesce from legions of tiny islands; instead they are born as large solid plates of above-sea-level crust. So a super-Indonesia of e.g. 100K islands in a cloud / archipelago where the Americas are now is stupidly unlikely.
I was imagining a Cuba sized glob near the Yellowstone supervolcano. I agree you can imagine the hypothetical any way you want. But if you keep plate tectonics and geology as we understand it, there will be magma plumes and possibly island chains, formed over millions of years. All major plates have continents or islands on them: it’s reasonable to assume the same was true when Pangaea was around.
But hey, you can also assume a landless void, like we did for the first 100 posts or so. No worries.
Another interesting factoid - a lot of early North American exploration was driven by the search for the passage through to China. There’s even a rapids in Montreal called Lachine because a local explorer in the early days was sure that just upriver somewhere was a route to China. Henry Hudson (Hudson River, Hudson Bay) was marooned in Hudson Bay by mutinous crew who wanted to turn back. Numerous explorers tried to find a way through the Arctic. (We’ve finally found one - it involves burning enough carbon to melt the ice) Even if there were a large ocean opening instead of Panama, or northern Canada, or Texas, found early on, the exploration of North America would have been very different and much less urgent.
If there was a narrow gap in Panama I imagine not much would change in terms of where people settled, but if Central America simply wasn’t there I imagine the south coast of North America and the north coast of South America would both be full of port towns.