<p><a href="https://en.wikipedia.org/wiki/Passenger_pigeon" rel="nofollow noreferrer">Passenger Pigeons</a>. Passenger Pigeons were known to fly almost directly west from European coasts out into the apparently endless Atlantic, and not return until later in the year, when they always came back. No-one seemed to notice that they weren't in fact flying to Asia and therefore had to be landing <em>somewhere else</em>.</p>
<p>Given that the classical Greeks had a rather accurate estimate of the world's total diameter, knowledge of Passenger Pigeons, contact with both Asia and Ireland, and that no-one (until quite modern times) <em>actually</em> believed the world to be flat; anyone from that point on could have observed that a landmass of some reasonable size must exist somewhere west of Europe. Someone sufficiently curious could have tested the flight endurance of such birds and estimated the distance to the nearest shore of that land.</p>
<p>This also works for a sufficiently scientifically minded observer of Passenger Pigeons on the east coast of the Americas watching them fly away and come back every year.</p>

CC BY-SA 4.0
2024-08-05T13:06:13.490Z
There's no way to prove the passenger pigeons didn't come from Japan. Remember the way Columbus underestimated the size of the Earth.
Spencer
CC BY-SA 4.0
2024-08-06T10:38:05.630Z
@Spencer True so we need either a mainland Asian culture with close enough ties with Japan to trade books on birdlife or someone to conquer the islands wholesale, that second one never happened but the relationship between Japan and China were pretty cordial from the end of the Jōmon period on until the end of the first millennium AD.
Ash
CC BY-SA 4.0
2024-08-06T20:28:31.873Z
Passenger pigeons in this situation only prove there was land to the west of Europe. It doesn't prove there was a continent or two. Without better knowledge one could also assume the pigeons went to a large island or a number of islands.
Fred
CC BY-SA 4.0
2024-08-07T04:54:10.567Z
@Fred It would have to be a large landmass given the number and size of the birds involved, that's all the OP asked for, proof of a large landmass. There are other birds that migrate which prove there is *something* there but there were millions of tonnes of Passenger Pigeons making the annual trip.
Ash
CC BY-SA 4.0
2024-08-04T09:36:18.610Z
2024-08-04T09:36:18.610Z
Ash
<p>Did you hear about the damage due to the <a href="https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami" rel="nofollow noreferrer">2011 Tōhoku tsunami</a> in Ireland, like the tsunami caused by the <a href="https://en.wikipedia.org/wiki/1755_Lisbon_earthquake" rel="nofollow noreferrer">1755 Lisbon earthquake</a> did?  No?  Me neither.</p>
<p>The Pacific <a href="https://en.wikipedia.org/wiki/Ring_of_Fire" rel="nofollow noreferrer">Ring of Fire</a> is a tectonic belt of volcanoes and earthquakes that trigger tsunamis on a somewhat regular basis.  For example, the <a href="https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami" rel="nofollow noreferrer">2011 Tōhoku earthquake</a> triggered a tsunami.  No tsunami was observed on the West Coast of Europe or Africa.  Therefore, there must be a landmass somewhere between Japan and Europe/Africa, large enough to stop the tsunami from travelling from Japan to Europe.</p>
<p>Had no such landmass existed, we would have seen tsunamis hitting the European and African West Coast occasionally, including in the historical record.  The ancient Greeks had experience with volcanic eruptions, landslides, and tsunamis, so as soon as we had enough communication to hear about major geophysical events in Japan, we could have linked such tsunamis to events in Japan and conclude there's (almost) only water in-between.</p>
<p>We cannot infer the size of the landmass from this observation, except that it must be large enough to block a large wave.</p>
<p>Residents of the West Coast of the Americas could detect a volcanic eruption due to aerosols emitted, and link this to tsunamis observed.  They could thus infer the presence of land between the Atlantic and Pacific oceans, but it would not give much information about the size.</p>

CC BY-SA 4.0
2024-08-06T10:23:25.533Z
I'd argue that we didn't really appreciate the distances that those surge waves covered until relatively recently.
Ash
CC BY-SA 4.0
2024-08-06T12:53:30.987Z
@Ash Maybe we didn't, but observing a link between volcanic eruptions and tsunamis half a planet away is possible without modern technology.
gerrit
CC BY-SA 4.0
2024-08-06T13:06:46.237Z
I'll give you that observing the events is possible half a world away I'm not sure that observing a link between the 10m wave on the Japanese coast that ran inland as far as topography allowed on March 11, 2011 and it's 3m or less counterpart in the Americas that was often lost in the normal background chop is though. Even in NZ we couldn't pick out the Tohoku Tsunami wave when it arrived, it was only the way it ran up the beach that gave it away, it crested at the same height as the swell that day, at least down at Himatangi.
Ash
CC BY-SA 4.0
2024-08-06T14:29:55.700Z
@Ash Hm?  Reportedly, [it did 10 million USD in damage in California and 7 million USD in Oregon](https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami#Elsewhere_across_the_Pacific).  Peanuts compared to bad weather, but measurable.
gerrit
CC BY-SA 4.0
2024-08-07T05:12:32.403Z
Yes in some places it wrecked coastlines all around the pacific and in other places it was a ripple, or less, which is what I mean about it being hard to make a link between the total devastation of Japan and the results, or lack of, many other places.
Ash
CC BY-SA 4.0
2024-08-07T06:19:26.173Z
@Ash Hard, maybe, but science has achieved harder things :)
gerrit
CC BY-SA 4.0
2024-08-06T08:04:13.613Z
2024-08-06T08:16:35.530Z
2024-08-06T08:16:35.530Z
gerrit
<p>The existence of the Americas to the peoples of the old world is, nowadays, indisputable. However, this was not the case 600 years ago (<a href="https://en.wikipedia.org/wiki/Vinland" rel="nofollow noreferrer">for most of Europe</a>).</p>
<p>Columbus landed in the Bahamas, leading to widespread knowledge of the Americas in Europe, quite by accident, expecting to find the East Indies. As a result, the existence of the Americas has never been scientifically tested.</p>
<p>This is a stunning lapse of the scientific method. A lapse that must be rectified as a matter of urgency.<sup>[citation needed]</sup></p>
<p>The question is this: <strong>how could someone infer the existence of a large landmass between the east coast of Asia and the west coast of Europe, <em>without direct observation</em>?</strong>*</p>
<p>Extra brownie points for:</p>
<ul>
<li>Simplicity: how soon after (or – even – how long before) the late 15<sup>th</sup> century could the prediction be made?</li>
<li>Reversibility: could the method be used by an observer in the new world to infer the existence of the old world?</li>
</ul>
<p><sub>*&quot;Going over there and looking&quot;, broadly construed.</sub></p>

CC BY-SA 4.0
2024-08-03T22:59:16.880Z
I feel like this is really a question for the [History of Science and Mathematics](https://hsm.stackexchange.com) stack.
Spencer
CC BY-SA 4.0
2024-08-05T01:12:38.627Z
@Spencer: I was thinking something more along the lines of [Puzzling Stack Exchange](https://puzzling.stackexchange.com).
Lee Mosher
CC BY-SA 4.0
2024-08-06T07:54:36.547Z
Do you mean using contemporary methods, or also using modern methods?  I like the question as a hypothetical, actually.  What indirect evidence do Europeans have to prove America [actually exists](https://en.wikipedia.org/wiki/Bielefeld_conspiracy)?  It might be hard to answer without specifying what other knowledge we are "allowed" to use.
gerrit
CC BY-SA 4.0
2024-08-06T13:58:32.907Z
I'm just throwing a guess, but maybe tides measurements would be able to highlight the lack of a landmass across the Atlantic Ocean? Tides vary across oceanic basins due to the Coriolis effect (see amphidromic points: https://en.wikipedia.org/wiki/Amphidromic_point), so if the basin was largely opened to the West it would change the tides patterns along the coasts of Europe and Africa. Though I'm not sure if this alone would be enough to demonstrate the absence of a landmass...
Jean-Marie Prival
CC BY-SA 4.0
2024-08-06T14:34:39.440Z
[Friendly floatees](https://en.wikipedia.org/wiki/Friendly_Floatees_spill) (or just bottle messages) might also work, sort of, except that they can and do go around a landmass.
gerrit
CC BY-SA 4.0
2024-08-06T20:39:55.090Z
This question is somewhat nonsensical given that direct observation is a perfectly valid means of obtaining data/information in science. The fact that observation of the Americas prove they exist no further proof is required. Changing your question slightly, disallowing direct observation, how would you use the scientific method to prove that you exist?
Fred
CC BY-SA 4.0
2024-08-07T01:02:31.247Z
This question could be greatly improved by deleting the last sentence of the second paragraph (regarding scientific testing), and the entire 3rd paragraph.  It could be summarized "as a matter of curiosity, would there be a way to detect a large land mass other than direct observation?"
Mark
<geography><remote-sensing><hypothetical><continent>
Indirect evidence for the Americas
EnronEvolved
# Indirect evidence for the Americas

(Asked by: username_0 on 2024-08-03)

The existence of the Americas to the peoples of the old world is, nowadays, indisputable. However, this was not the case 600 years ago ([for most of Europe](https://en.wikipedia.org/wiki/Vinland)).

Columbus landed in the Bahamas, leading to widespread knowledge of the Americas in Europe, quite by accident, expecting to find the East Indies. As a result, the existence of the Americas has never been scientifically tested.

This is a stunning lapse of the scientific method. A lapse that must be rectified as a matter of urgency.[citation needed]

The question is this: **how could someone infer the existence of a large landmass between the east coast of Asia and the west coast of Europe, *without direct observation*?**\*

Extra brownie points for:

* Simplicity: how soon after (or – even – how long before) the late 15th century could the prediction be made?
* Reversibility: could the method be used by an observer in the new world to infer the existence of the old world?

\*"Going over there and looking", broadly construed.

**Tags:** geography, remote-sensing, hypothetical, continent

> **Comments:**
> **username_1**: I feel like this is really a question for the [History of Science and Mathematics](https://hsm.stackexchange.com) stack.  
> **username_2**: @username_1: I was thinking something more along the lines of [Puzzling Stack Exchange](https://puzzling.stackexchange.com).  
> **username_3**: Do you mean using contemporary methods, or also using modern methods?  I like the question as a hypothetical, actually.  What indirect evidence do Europeans have to prove America [actually exists](https://en.wikipedia.org/wiki/Bielefeld_conspiracy)?  It might be hard to answer without specifying what other knowledge we are "allowed" to use.  
> **username_4**: I'm just throwing a guess, but maybe tides measurements would be able to highlight the lack of a landmass across the Atlantic Ocean? Tides vary across oceanic basins due to the Coriolis effect (see amphidromic points: https://en.wikipedia.org/wiki/Amphidromic_point), so if the basin was largely opened to the West it would change the tides patterns along the coasts of Europe and Africa. Though I'm not sure if this alone would be enough to demonstrate the absence of a landmass...  
> **username_3**: [Friendly floatees](https://en.wikipedia.org/wiki/Friendly_Floatees_spill) (or just bottle messages) might also work, sort of, except that they can and do go around a landmass.  
> **username_5**: This question is somewhat nonsensical given that direct observation is a perfectly valid means of obtaining data/information in science. The fact that observation of the Americas prove they exist no further proof is required. Changing your question slightly, disallowing direct observation, how would you use the scientific method to prove that you exist?  
> **username_6**: This question could be greatly improved by deleting the last sentence of the second paragraph (regarding scientific testing), and the entire 3rd paragraph.  It could be summarized "as a matter of curiosity, would there be a way to detect a large land mass other than direct observation?"  

---

## 2 answers

### Answer by username_7 on 2024-08-04. Score: 2

[Passenger Pigeons](https://en.wikipedia.org/wiki/Passenger_pigeon). Passenger Pigeons were known to fly almost directly west from European coasts out into the apparently endless Atlantic, and not return until later in the year, when they always came back. No-one seemed to notice that they weren't in fact flying to Asia and therefore had to be landing *somewhere else*.

Given that the classical Greeks had a rather accurate estimate of the world's total diameter, knowledge of Passenger Pigeons, contact with both Asia and Ireland, and that no-one (until quite modern times) *actually* believed the world to be flat; anyone from that point on could have observed that a landmass of some reasonable size must exist somewhere west of Europe. Someone sufficiently curious could have tested the flight endurance of such birds and estimated the distance to the nearest shore of that land.

This also works for a sufficiently scientifically minded observer of Passenger Pigeons on the east coast of the Americas watching them fly away and come back every year.

> **Comments:**
> **username_1**: There's no way to prove the passenger pigeons didn't come from Japan. Remember the way Columbus underestimated the size of the Earth.  
> **username_7**: @username_1 True so we need either a mainland Asian culture with close enough ties with Japan to trade books on birdlife or someone to conquer the islands wholesale, that second one never happened but the relationship between Japan and China were pretty cordial from the end of the Jōmon period on until the end of the first millennium AD.  
> **username_5**: Passenger pigeons in this situation only prove there was land to the west of Europe. It doesn't prove there was a continent or two. Without better knowledge one could also assume the pigeons went to a large island or a number of islands.  
> **username_7**: @username_5 It would have to be a large landmass given the number and size of the birds involved, that's all the OP asked for, proof of a large landmass. There are other birds that migrate which prove there is *something* there but there were millions of tonnes of Passenger Pigeons making the annual trip.  

---

### Answer by username_3 on 2024-08-06. Score: 1

Did you hear about the damage due to the [2011 Tōhoku tsunami](https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami) in Ireland, like the tsunami caused by the [1755 Lisbon earthquake](https://en.wikipedia.org/wiki/1755_Lisbon_earthquake) did? No? Me neither.

The Pacific [Ring of Fire](https://en.wikipedia.org/wiki/Ring_of_Fire) is a tectonic belt of volcanoes and earthquakes that trigger tsunamis on a somewhat regular basis. For example, the [2011 Tōhoku earthquake](https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami) triggered a tsunami. No tsunami was observed on the West Coast of Europe or Africa. Therefore, there must be a landmass somewhere between Japan and Europe/Africa, large enough to stop the tsunami from travelling from Japan to Europe.

Had no such landmass existed, we would have seen tsunamis hitting the European and African West Coast occasionally, including in the historical record. The ancient Greeks had experience with volcanic eruptions, landslides, and tsunamis, so as soon as we had enough communication to hear about major geophysical events in Japan, we could have linked such tsunamis to events in Japan and conclude there's (almost) only water in-between.

We cannot infer the size of the landmass from this observation, except that it must be large enough to block a large wave.

Residents of the West Coast of the Americas could detect a volcanic eruption due to aerosols emitted, and link this to tsunamis observed. They could thus infer the presence of land between the Atlantic and Pacific oceans, but it would not give much information about the size.

> **Comments:**
> **username_7**: I'd argue that we didn't really appreciate the distances that those surge waves covered until relatively recently.  
> **username_3**: @username_7 Maybe we didn't, but observing a link between volcanic eruptions and tsunamis half a planet away is possible without modern technology.  
> **username_7**: I'll give you that observing the events is possible half a world away I'm not sure that observing a link between the 10m wave on the Japanese coast that ran inland as far as topography allowed on March 11, 2011 and it's 3m or less counterpart in the Americas that was often lost in the normal background chop is though. Even in NZ we couldn't pick out the Tohoku Tsunami wave when it arrived, it was only the way it ran up the beach that gave it away, it crested at the same height as the swell that day, at least down at Himatangi.  
> **username_3**: @username_7 Hm?  Reportedly, [it did 10 million USD in damage in California and 7 million USD in Oregon](https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami#Elsewhere_across_the_Pacific).  Peanuts compared to bad weather, but measurable.  
> **username_7**: Yes in some places it wrecked coastlines all around the pacific and in other places it was a ripple, or less, which is what I mean about it being hard to make a link between the total devastation of Japan and the results, or lack of, many other places.  
> **username_3**: @username_7 Hard, maybe, but science has achieved harder things :)  

---

