The history of our world in 18 minutes David Christian
first a video yes it is a scrambled egg
but as you look at it I hope you’ll
begin to feel just slightly uneasy
because you may notice that what’s
actually happening is that the egg is on
scrambling itself and you will now see
the yolk and the white have separated
and now they’re going to be poured back
into the egg and we all know in our
heart of hearts that this is not the way
the universe works a scrambled egg is
mush tasty mush but it’s mush an egg is
a beautiful sophisticated thing that can
create even more sophisticated things
such as chickens and we know in our
heart of hearts that the universe does
not travel from mush to complexity in
fact this gut instinct is reflected in
one of the most fundamental laws of
physics the second law of thermodynamics
or the law of entropy what that says
basically is that the general tendency
of the universe is to move from order
and structure to lack of order lack of
structure in fact to mush and that’s why
that video feels a bit strange and yet
look around us what we see around us is
staggering complexity Eric pine hotter
estimates that in New York City alone
there are some 10 billion skews or
distinct commodities being traded that’s
hundreds of times as many species as
there are on earth and they’re being
traded by a species of almost 7 billion
individuals who are linked by trade
travel and the internet into a global
system of stupendous complexity so
here’s a great puzzle in a universe
ruled by the second law of
thermodynamics how is it possible to
generate the sort of complexity I’ve
described the sort of complexity
represented by you
and me and the convention center well
the answer seems to be the universe can
create complexity but with great
difficulty in pockets there appear what
my colleague Fred’s vehicle’s Goldilocks
conditions not too hot not too cold just
right for the creation of complexity and
slightly more complex things appear and
where you have slightly more complex
things you can get slightly more complex
things and in this way complexity builds
stage by stage each stage is magical
because it creates the impression of
something utterly new appearing almost
out of nowhere in the universe we refer
in big history to these moments as
threshold moments and at each threshold
the going gets tougher the complex
things get more fragile more vulnerable
the Goldilocks conditions get more
stringent and it’s more difficult to
create complexity now we as extremely
complex creatures desperately need to
know this story of how the universe
creates complexity despite the second
law and why complexity means
vulnerability and fragility and that’s
the story that we tell in big history
but to do it you have to do something
that may at first sight seemed
completely impossible
you have to survey the whole history of
the universe so let’s do it
let’s begin by winding the timeline back
13.7 billion years to the beginning of
time
around us there’s nothing there’s not
even time or space imagine the darkest
emptiest thing you can and cube it a
gazillion times and that’s where we are
and then suddenly BAM
a universe appears and the entire
universe and we’ve crossed our first
threshold the universe is tiny it’s
smaller than an atom it’s incredibly hot
it contains everything that’s in today’s
universe so we can imagine it’s busting
and it’s expanding at incredible speed
and at first it’s just a blur but very
quickly distinct things begin to appear
in that blur within the first second
energy itself shatters into distinct
forces including electromagnetism and
gravity and energy does something else
quite magical it congeals to form matter
quarks that will create protons and
leptons that include electrons and all
of that happens in the first second now
we move forward 380,000 years that’s
twice as long as humans have been on
this planet and now simple atoms appear
of hydrogen and helium now I want to
pause for a moment 380,000 years after
the origins of the universe because we
actually know quite a lot about the
universe at this stage we know above all
that it was extremely simple
it consisted of huge clouds of hydrogen
and helium atoms and they have no
structure they’re really a sort of
cosmic mush but that’s not completely
true recent studies by satellites such
as the W map satellite have shown that
in fact there are just tiny differences
in that background what you see here the
blue areas are about a thousandth of a
degree cooler than the red areas these
are tiny differences but it was enough
for the universe to move on to the next
stage of building complexity and this is
how it works
gravity is more powerful where there’s
more stuff so where you get slightly
denser areas gravity starts compacting
clouds of hydrogen and helium atoms so
we can imagine the early universe
breaking up into a billion
and each cloud is compacted gravity gets
more powerful as density increases the
temperature begins to rise at the center
of each cloud and then at the center of
each cloud the temperature crosses the
threshold temperature of 10 million
degrees protons start to fuse there’s a
huge release of energy and bam we have
our first stars from about 200 million
years after the Big Bang stars begin to
appear all through the universe billions
of them and the universe is now
significantly more interesting and more
complex stars will create the Goldilocks
conditions for crossing to new
thresholds when very large stars die
they create temperatures so high that
protons begin to fuse in all sorts of
exotic combinations to form all the
elements of the periodic table if like
me you’re wearing a gold ring it was
forged in a supernova explosion so now
the universe is chemically more complex
and in the chemically more complex
universe it’s possible to make more
things and that starts happening is that
around young sons young stars all these
elements combine they swirl around the
energy of the star stirs them around
they form the particles they form
snowflakes they form little dust motes
they form rocks they form asteroids and
eventually they form planets and moons
and that is how our solar system was
formed four and a half billion years ago
rocky planets like our earth are
significantly more complex than stars
because they contain a much greater
diversity of materials so we’ve crossed
a fourth threshold of complexity now the
going gets tougher the next stage
introduces entities that are
significantly more fragile significantly
more vulnerable but they’re also much
more creative and much more capable of
generating further complexity I’m
talking of course about living organisms
living organisms are created by
chemistry we are huge
Edge’s of chemicals so chemistry is
dominated by the electromagnetic force
that operates over smaller scales and
gravity which explains why you and I are
smaller than stars or planets now what
are the ideal conditions for chemistry
what are the Goldilocks conditions well
the first you need energy but not too
much in the center of the star there’s
so much energy that any atoms that
combine will just get busted apart again
but not too little in intergalactic
space there’s so little energy that
atoms can’t combine what you want is
just the right amount and planets it
turns out are just right because they’re
close to stars but not too close you
also need a great diversity of chemical
elements and you need liquids such as
water why well in gases atoms move past
each other so fast that they can’t hitch
up in solids atoms stuck together they
can’t move in liquids they can cruise
and cuddle and link up to form molecules
now where do you find such Goldilocks
conditions
well planets are great and our early
Earth was almost perfect it was just the
right distance from its star to contain
huge oceans of liquid water and deep
beneath those oceans that cracks in the
earth crust you got heat seeping up from
inside the earth and you’ve got a great
diversity of elements so at those deep
oceanic vents fantastic chemistry began
to happen and atoms combined in all
sorts of exotic combinations but of
course life is more than just exotic
chemistry how do you stabilize those
huge molecules that seem to be viable
well it’s here that life introduces an
entirely new trick you don’t stabilize
the individual you stabilize the
template the thing that carries
information and you allow the template
to copy itself and DNA of course is the
beautiful molecule that contains that
information you’ll be familiar with the
double helix of DNA each rung contains
information
so DNA contains information about how to
make living organisms and DNA also
copies itself so it copies itself and
scatters the templates through the ocean
so the information spreads notice that
information has become part of our story
the real beauty of DNA though is in its
imperfections as it copies itself once
in every billion runs there tends to be
an error and what that means is that DNA
is in effect learning it’s accumulating
new ways of making living organisms
because some of those errors work so DNA
is learning and it’s building greater
diversity and greater complexity and we
can see this happening over the last
four billion years for most of that time
of life on earth living organisms have
been relatively simple single cells but
they had great diversity and inside
great complexity then from about 600 to
800 million years ago multi-celled
organisms appear you get fungi you get
fish you get plants you get and figure
you get reptiles and then of course you
get the dinosaurs and occasionally there
are disasters 65 million years ago an
asteroid landed on earth near the
Yucatan Peninsula creating conditions
equivalent to those of a nuclear war and
the dinosaurs were wiped out terrible
news for the dinosaurs but great news
for our mammalian ancestors who
flourished in lanisha’s left empty by
the dinosaurs and we human beings are
part of that creative evolutionary pulse
that began 65 million years ago with the
landing of an asteroid humans appeared
about 200,000 years ago and I believe we
count as a threshold in this great story
let me explain why we’ve seen that DNA
learns in a sense it accumulates
information but it is so slow
DNA accumulates information through
random errors that just some of which
just happened to work but DNA had
actually generated a faster way of
learning it had produced organisms with
brains
and those organisms can learn in real
time they accumulate information they
learn the sad thing is when they die the
information dies with them now what
makes humans different is human language
we are blessed with a language a system
of communication so powerful and so
precise that we can share what we’ve
learned with such precision that it can
accumulate in the collective memory and
that means it can outlast the
individuals who learnt that information
and it can accumulate from generation to
generation and that’s why as a species
we are so creative and so powerful and
that’s why we have a history we seem to
be the only species in four billion
years to have this gift I call this
ability collective learning it’s what
makes us different we can see that work
in the earliest stages of human history
we evolved as a species in the savanna
lands of Africa but then you see humans
migrating into new environments into
desert lands into jungles into the Ice
Age tundra of Siberia tough tough
environment into the Americas into
Australasia each migration involved
learning learning new ways of exploiting
the environment new ways of dealing with
their surroundings then 10,000 years ago
exploiting a sudden change in global
climates with the end of the last ice
age humans learnt to farm
farming was an energy bonanza and
exploiting that energy human populations
multiplied human societies got larger
denser more interconnected and then from
about 500 years ago humans began to link
up globally through shipping through
trains through Telegraph through the
Internet until now we seem to form a
single global brain of almost 7 billion
individuals and that brain is learning
at warp speed and then the last 200
years something else has happened we’ve
stumbled on another energy bonanza in
fossil fuels so fossil fuels and
collective learning together explain the
staggering complexity we see around us
so here we are back at the convention
center we’ve been on a journey a return
journey 13.7 billion years I hope you
agree this is a powerful story and it’s
a story in which humans play an
astonishing and creative role but it
also contains warnings collective
learning is a very very powerful force
and it’s not clear that we humans are in
charge of it I remember very vividly as
a child growing up in England living
through the Cuban Missile Crisis for a
few days the entire biosphere seemed to
be on the verge of destruction and the
same weapons are still here and they’re
still armed if we avoid that trap others
are waiting for us we’re burning fossil
fuels at such a rate that we seemed to
be undermining the Goldilocks conditions
that made it possible for human
civilizations to flourish over the last
10,000 years
so what big history can do is show us
the nature of our complexity and
fragility and the dangers that face us
but it can also show us our power with
collective learning and now finally this
is what I want I want my grandson Daniel
and his friends and his generation
throughout the world to know the story
of big history and to know it so well
that they understand both the challenges
that face us and the opportunities that
face us and that’s why a group of us are
building a free online syllabus in big
history for high school students
throughout the world we believe that big
history will be a vital intellectual
tool for them as Daniel and his
generation face the huge challenges and
also the huge opportunities ahead of
them at this threshold moment in the
history of our beautiful planet
I thank you for your attention