Wednesday, April 18, 2018

Cosmic waterfall

I'm going to briefly revisit an issue I often discuss. Did ancient people believe the world was flat? Did appearances indicate that the world was flat? Was prescientific observation inadequate to detect the falsity of a flat earth?

Consider a beach. The ocean extends from the shoreline to the horizon. Is the horizon the end of the world? If the world is flat, then the horizon is a waterfall, at the outer limits of the world. 

But if the horizon is a waterfall, wouldn't the ocean rapidly empty? It's not like a river with a continuous flow of water upstream. From an observer's standpoint, the ocean extends from the shoreline to the horizon. If the horizon is a waterfall, there's no source of water to resupply the ocean. 

An ocean isn't like a channel of water, narrow and long. where downstream water pouring over the waterfall is constantly replenished by more water upstream. Rather, there's a vastly wide expanse of water with nothing behind it except dry land. Yes, there may be the mouth of a river somewhere along the beach. But if the horizon is a waterfall, the pipeline is hardly equal to the waterfall. A river, however, wide and deep, is slender and shallow compared to the sea. If there's a waterfall from one end of the horizon to the other, a river won't maintain the water level. The flow rate is hopelessly inadequate to keep it from draining away. The seabed would be dry in a matter of hours, or less. 

I'm not saying every ancient observer thought this through. But it stands to reason that the ancient world had some very smart, attentive observers who noticed every detail of their natural surroundings and drew inferences from what they saw. 

4 comments:

  1. I can think of a response of someone like Walton to you. Since ancient people did not know that most of the water that becomes rain is evaporation, they probably thought the water in the oceans is replenished by the water that falls from the windows of heaven, and since they didn’t know exactly how large the oceans were they never questioned the cosmic waterfall. Also if the water under the earth is a quasi magical source, then your water supply problem is solved. Magical thinking has Infinite resources.

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  2. Just playing devils advocate.

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    Replies
    1. Does that make you Kevin Lomax to John Milton?

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    2. "Since ancient people did not know that most of the water that becomes rain is evaporation, they probably thought the water in the oceans is replenished by the water that falls from the windows of heaven…"

      Occasional rainy days in-between weeks of dry weather. Why would they think rainwater sufficient of offset the runoff?

      "…and since they didn’t know exactly how large the oceans were they never questioned the cosmic waterfall."

      Insofar as they thought the oceans were smaller and shallower than we do, they'd empty that much faster if the entire horizon is a waterfall.

      "Also if the water under the earth is a quasi magical source, then your water supply problem is solved."

      To my knowledge, in mythology and practice alike they associated groundwater with sweet/freshwater rather than sea/saltwater. So groundwater couldn't be the source of oceans.

      "Magical thinking has Infinite resources."

      But as a matter of experience, they lived in a world that was for the most part very disenchanted.

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