May I have your attention please you can now book your train tickets on Uber and get

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Trains, now on Uber. T's and C's apply. Check the Uber app.

This is scientific American's 60 second science.

I'm Christopher Intagata.

In 1947, the Norwegian Explorer Tour Heardal set sail from Peru on a balsa wood raft called

Kontiki.

As he explained a few years later in the documentary of the same name, Heardal was convinced that indigenous people from South America had used

a similar craft to settle Polynesia.

The only way to test my theory was to build one of these rafts, launch it in the sea off the coast of Peru, and find out if

wind and current would in fact waft us ashore on some Pacific island.

101 days and 4,

and 4,300 nautical miles later, his raft reached French Polynesia.

The expedition didn't really prove anything other than that the feat was possible,

and most scholars agreed then and now that the Pacific islands

were gradually settled from the other direction by people traveling from East Asia.

But a new study suggests that almost 900 years ago, Polynesians and Native South Americans did make contact,

and traces of that encounter live on in the genes of Polynesians today.

Whether the people were physically standing on an island in Polynesia when they began mingling,

or whether they were on the coast of South America, we can't say.

Alex Enidus, a computational scientist and geneticist at Stanford University.

His team compared the DNA of 800 individuals from 17 Pacific Islands and 15 Pacific

...