The Pacific Ocean is big. Like, really, really big

Because of the way that flat maps are drawn with the Atlantic Ocean in the middle and the Pacific Ocean split and placed at the left and right extremes, it is easy to not realize how big the latter ocean is. Google maps now shows maps on a spherical basis and if you zoom out, you get a view of how the ocean covers pretty much half the globe. You see the Americas on the right edge, Asia on the left edge, and only Australia, New Zealand, and Papua New Guinea form the major land masses.

But it is not all water. The ocean is pockmarked with a large number of tiny islands that are too small to show up on the map at this scale. The red flag shows Tahiti. But these islands were populated by the Polynesians a long time ago. Where these people came from and how they navigated this 10 million square miles of ocean to find and populate every single one of these islands makes for a fascinating story.

In the May 2019 issue of Harper’s Magazine, Damien Searles reviews the book Sea People: The Puzzle of Polynesia by Christine Thompson who discusses the challenges faced by these pioneering peoples. He quotes a passage from the book:

All the islands inside this triangle were originally settled by a clearly identifiable group of voyagers: a people with a single language and set of customs, a particular body of myths, a distinctive arsenal of tools and skills, and a “portmanteau biota” of plants and animals that they carried with them wherever they went. They had no knowledge of writing or metal tools- no maps or compasses – and yet they succeeded in colonizing the largest ocean on the planet, occupying every habitable rock between New Guinea and the Galapagos, and establishing what was, until the modern era, the largest single culture area in the world.

Who were these people and where did they come from? There have been many wild speculations but the best current scholarship suggests that they came from the East despite the fact that the ocean currents generally flowed in the other direction. Thompson’s book focuses on how scientists figured out the history of the Polynesians.

The key questions, of course, are how, and from where. Pacific winds at the relevant latitudes blow west, which would suggest a point of origin in the Americas, but the languages of the South American coasts have nothing to do with Polynesian languages; the locals there were not seafarers; and the pigs, dogs, and chickens found throughout Polynesia were unknown in South America.

When, in the late twentieth century, the mystery of how ancient proto- Polynesians could sail east, against the prevailing trade winds blowing west, was finally solved, the answer “turned out [to be] just as Tupaia had described it to Cook”: wait for the wind to blow east after all, which did happen occasionally.

Modern scientific tools such as DNA testing has solvd many of the puzzles. This map traces the pattern of migration over a period of 2,000 years.

There are still unsolved questions, such the kinds of navigation tools that the Polynesians used to find these tiny islands in a vast ocean and how they obtained sweet potatoes which come from North America.


  1. says

    “You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist, but that’s just peanuts to space the Pacific Ocean.”

  2. Rob Grigjanis says

    I’d never noticed before that the time between the settlement of Samoa and the settlement of the (relatively nearby) Cook Islands was so long: 1500 years.

  3. Andrew Dalke says

    A lot of what we know about traditional Polynesian navigation ( ) comes from Mau Piailug ( ) who was one of the last of the traditional navigators. He decided that, rather than keeping the knowledge secret, as was the guild practice, he would share his knowledge with the Polynesian Voyaging Society. See also

    The non-instrument sailing is done by a synthesis of a large number of factors -- wave height, starts, winds, clouds, the movement of birds, and so on. You asked about how they found small islands. covers that topic. For example, “The diurnal flights of such birds are the most useful signs for expanding landfall, since their flights to and from an island gives a fairly specific direction to the wayfinder. As the birds leave an island in the morning, the wayfinder can sail in the direction the birds are coming from to find land; as the birds return to an island in the late afternoon, the wayfinder can follow the birds to land.”

    As the Wikipedia page about Mau Piailug points out “this constant synthesis makes it easy to spot the navigator by being the one with red eyes from sleep deprivation”.

  4. Runout Groover says

    I recently learned that the word used for sweet potatoes by NZ Māori, kumara, is also what the Incas called it. Seems pretty certain that Polynesian sailors traded with S Americans.

  5. fentex says

    Rob Grigjanis @ #3;

    I’d never noticed before that the time between the settlement of Samoa and the settlement of the (relatively nearby) Cook Islands was so long: 1500 years.

    Have you seen the Pixar movie Moana? The story revolves around a fear stopping Polynesians from continuing their explorations -- that is a plot point drawn from history. For some unknown reason their was a long break in Polynesian exploration, and no one knows why.

  6. Rob Grigjanis says

    fentex @7: My first thought was that they probably stopped because they didn’t need new territory yet. I’ve never really bought the “intrepid explorer” stuff. People generally move when they have to; insufficient resources, conflicts, etc. Maybe there was simply a long period in which a sort of population stability was reached, which ended somewhere around 500-700 CE, for any of several reasons (climate, cultural shifts, etc). Just guessin’…

  7. Steve Cameron says

    Shortly after the Second World War, adventurer Thor Heyerdahl attempted to prove his theory that Polynesia was settled by South Americans on balsa wood rafts using the prevailing westerly ocean currents. He made a hell of a good documentary out of his several weeks long ocean voyage, called Kon-Tiki, and if you haven’t seen it, I highly recommend it (though I don’t have any idea where you might find it… I borrowed the VHS from my library 20 or so years ago). If I remember right, it won the Oscar for best documentary in 1948. Because of that doc I always assumed (or hoped, more accurately) he was right — despite the consensus among anthropologists that it was highly unlikely. It’s kind of sad for me now to read that the DNA evidence pretty much rules out Heyerdahl’s theory. Still a great movie though.

  8. brucegee1962 says

    I recently read Aurora by Kim Stanley Robinson, which is about a multi-generation ship’s journey to a different solar system. It’s thought-provoking and worth reading, so I should spoiler alert my comments.

    I had a few problems with some of the premises — that a future society would have near-godlike science in one area (the ability to break down anything into its constituent elements and recreate it into something else) but not in a related area (the ability to come up with a cure for an alien disease).

    There were two main conclusions I got from the book. One was that no other planet will ever be as hospitable to our species as the one we spent millions of years adapting to, so we shouldn’t see spaceflight as a solution that gets us out of the responsibility for not ruining the planet we’ve got. I agree with that one. But the other conclusion seemed to be that going out into space could never be worth it — that it was too dangerous, that the descendants of the original colonists who decided to go onto the colony ships would resent their ancestors for putting them into such a dangerous situation. Someone makes a statement about earth being a cradle, and mankind can’t stay in its cradle forever, and it’s worth any number of deaths to jump to the next world — and the protagonist who was almost one of those deaths walks over and punches him in the nose.

    I thought about those Polynesians when I read that. They must have brought their kids with them when they went sailing to other islands. And some of those boats must have gone down. Maybe lots of them. I thought that, if Kim Stanley Robinson was right and we shouldn’t go on to other planets, then we’d lost something important that the Polynesians must have had.

  9. Andrew Dalke says

    Steve Cameron @#9: You should be aware of some of the response to Heyerdahl’s expedition. I’ll quote from the link I gave earlier:

    “Three individuals back in the mid-1960s got together as they were very disturbed by the fact that individuals like Thor Heyerdahl suggested that the Polynesians could not sail upwind, into the weather. They could not come from Asia — from west to east --against the prevailing tradewinds. Their canoes were not very seaworthy. There were those like Andrew Sharp in New Zealand who said, that from an anthropological point of view, Polynesians came from an Asian origin, but they were not smart enough to navigate more than. one hundred miles in the open ocean. These three people – Ben Finney, Herb Kawainui Kane, and Tommy Holmes – got together and said, well, we want to debate that. And the only way we can debate it is to build a canoe and sail to Tahiti.”

    “Thor Hyerdahl had said that it was impossible to get from western Polynesia to eastern Polynesia -- to Tahiti -- because of the easterly trade winds. He thought that vessels could not tack against it. We trained for two years and we waited for the most optimal weather patterns. We cut down our crew. We cut down our water. We made the canoe light so that it would perform better. We hoped to make the voyage in 35 days. The key was the preparation. We went to Samoa and waited for the weather. We had planned for a 35 day voyage, the longest ever, and we did it in seven days.”

  10. fentex says

    Aurora by Kim Stanley Robinson

    A very depressing book.

    At the time it was published there were quite a few such takes on traditional SF concepts -- cynical rather than inspirational. It was a bad time if you wanted to read SF for any sense of wonder.

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