Surfing one of the longest waves in the world — on the Amazon river | The Nature of Things

Once the volcanic activity of the inner earth has built the land
other forces take over shaping and remodelling
the surface of the earth. And there’s one force that’s
tearing across the planet powerful enough to change
the length of a day. (Surfer shouts) It’s happening under your feet,
right now, as you watch this and you
won’t have even noticed, but clues are there
if you know where to look. All the noise and then half
an hour later it is roaring just down here at the point. When the cattle hear the roar
of the Pororocoa they all leave. If you live here
it pays to fear this force, but Marcelo Alves is leading
an expedition to face it, head on. (Speaking Portuguese) The Pororoca scares me, but I’m also drawn to the fear. I don’t know
what I’m going to find. To understand
the power of what’s coming you need to go back in time. The Babylonians kept
astronomical records that allow us to compare the
length of our day with theirs. And when you do you find
something strange – every century days are getting
1.8 milliseconds longer. Go back 350 million years, and the day
was just 23 hours long. Or put another way – the earth used to spin faster. (Chanting, shakers rattle) Back in the Amazon,
Marcelo has made camp. And they begin a traditional
ritual to prepare themselves
for the ancient force that has the power
to slow down the earth. The first time I saw it,
it was a fantastic thing, there was trees
being torn down. it is the roar of the forest. it is what rips the trees out, with a power you can’t stop. This is a huge force, it’ll change everything
in an hour. This force they call
“Pororocca” is in fact a tidal bore. A huge bulge of water that rushes into this river
on extreme tides. All caused by the gravitational
pull of the moon. The moon orbits around
the earth, this creates a gravitational
force, which pulls the earth’s water, and that creates a bulge here, and one on the other side. These are the tides. (Tribal call) Marcelo and his
expedition, are here to surf the Pororocca. The best thing about
surfing the Pororocoa is when you finally find
that dream wave. Every time we come here
we are on a hunt. Today this river
will change shape in front of their eyes. Thanks to the gravitational
pull of the moon. But that’s not all. The force of the moon will also
slow down the earth’s spin by making our planet
a bit less round a bit more like a rugby ball. This is the moon
and this is the earth. And it’s shaped like that because the oceans are pulled
towards the moon, and so as earth is spinning this bulge is a little bit
ahead of the moon. So the moon pulls
on the bulge, and slows down the rotation
of the earth a little bit. Making the day a little
bit longer. And so the pull
of the moon, the same force that gives us
the tides, slows down the earth. And today will change the shape
of this river. (Water rushes) Woo-hoo! Now this is it, We are surfing the Pororoca
that we were looking for. Woooo! (Water rushes) In six hours… what can I do? Have a nice dive
and then come back. For six hours the gravitational pull
of the moon has been slowing
the earth’s spin with a force equivalent
to 6,000 jets. (Jet engines roar) Making every day just
that little bit longer. (Jet engines roar)

6 thoughts on “Surfing one of the longest waves in the world — on the Amazon river | The Nature of Things”

  1. Be nice to watch. But I have more morals than Suzuki, and will not watch anything with him.
    But that is CBC.

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