Earth the Biography: Oceans | National Geographic

three quarters of Earth is covered in
water
it’s why it’s called the blue planet but
imagine Earth without its oceans and
instead with all the water in the world
gather together in a bowl
there’s not that much really but this
water is what makes Earth different from
every other planet in the solar system
the oceans have been here for almost
four billion years carving the coastline
driving the climate and controlling the
destiny of life itself
but four and a half billion years ago
and our planet was born it was just a
molten infernal
there was no place for any liquid water
at all
yet the ingredients needed to create
water where they’re locked away deep
inside the earth on the planet form
as the Faust volcanoes erupted one of
the gases that bellowed Oh was still and
as a planet cooled it formed clothes
it rained for thousands of years
as the Faust rivers formed they began to
fill up the lower lying areas on our
young planet possibly creating the first
oceans but it’s reckoned even this
relentless downpour only delivered
around half the water that makes up her
oceans today the rest came from outer
space this is a comet filmed in 2005
it’s about four miles across and like
all comets it’s made of rock and water
in the form of ice to discover just how
much water comets contain scientists
deliberately crashed a space probe
straight into it
after it plowed into the surface more
than 250,000 tons of water austin to
space
in Earth’s formative years it was hit by
thousands of comets like this
by the time the bombardment finished its
thought they delivered up to half the
water in our oceans