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TED2011

David Christian: The history of our world in 18 minutes

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Backed by stunning illustrations, David Christian narrates a complete history of the universe, from the Big Bang to the Internet, in a riveting 18 minutes. This is "Big History": an enlightening, wide-angle look at complexity, life and humanity, set against our slim share of the cosmic timeline.

- Historian
David Christian teaches an ambitious world history course that tells the tale of the entire universe -- from the Big Bang 13 billion years ago to present day. Full bio

First, a video.
00:15
(Video) Yes, it is a scrambled egg.
00:24
But as you look at it,
00:28
I hope you'll begin to feel
00:30
just slightly uneasy.
00:32
Because you may notice that what's actually happening
00:36
is that the egg is unscrambling itself.
00:39
And you'll now see the yolk and the white have separated.
00:42
And now they're going to be poured back into the egg.
00:44
And we all know in our heart of hearts
00:47
that this is not the way the universe works.
00:50
A scrambled egg is mush -- tasty mush -- but it's mush.
00:54
An egg is a beautiful, sophisticated thing
00:57
that can create even more sophisticated things,
01:00
such as chickens.
01:02
And we know in our heart of hearts
01:04
that the universe does not travel
01:06
from mush to complexity.
01:08
In fact, this gut instinct
01:10
is reflected in one of the most fundamental laws of physics,
01:12
the second law of thermodynamics, or the law of entropy.
01:15
What that says basically
01:18
is that the general tendency of the universe
01:20
is to move from order
01:23
and structure
01:25
to lack of order, lack of structure --
01:27
in fact, to mush.
01:29
And that's why that video
01:31
feels a bit strange.
01:33
And yet,
01:35
look around us.
01:37
What we see around us
01:39
is staggering complexity.
01:41
Eric Beinhocker estimates that in New York City alone,
01:43
there are some 10 billion SKUs, or distinct commodities, being traded.
01:46
That's hundreds of times as many species
01:50
as there are on Earth.
01:53
And they're being traded by a species
01:55
of almost seven billion individuals,
01:57
who are linked by trade, travel, and the Internet
01:59
into a global system
02:02
of stupendous complexity.
02:04
So here's a great puzzle:
02:07
in a universe
02:09
ruled by the second law of thermodynamics,
02:11
how is it possible
02:14
to generate the sort of complexity I've described,
02:16
the sort of complexity represented by you and me
02:19
and the convention center?
02:22
Well, the answer seems to be,
02:25
the universe can create complexity,
02:28
but with great difficulty.
02:31
In pockets,
02:33
there appear what my colleague, Fred Spier,
02:35
calls "Goldilocks conditions" --
02:37
not too hot, not too cold,
02:39
just right for the creation of complexity.
02:41
And slightly more complex things appear.
02:44
And where you have slightly more complex things,
02:46
you can get slightly more complex things.
02:48
And in this way, complexity builds
02:50
stage by stage.
02:53
Each stage is magical
02:55
because it creates the impression of something utterly new
02:58
appearing almost out of nowhere in the universe.
03:01
We refer in big history to these moments
03:04
as threshold moments.
03:06
And at each threshold,
03:08
the going gets tougher.
03:10
The complex things get more fragile,
03:12
more vulnerable;
03:15
the Goldilocks conditions get more stringent,
03:17
and it's more difficult
03:20
to create complexity.
03:22
Now, we, as extremely complex creatures,
03:24
desperately need to know this story
03:27
of how the universe creates complexity
03:30
despite the second law,
03:32
and why complexity
03:34
means vulnerability
03:36
and fragility.
03:38
And that's the story that we tell in big history.
03:40
But to do it, you have do something
03:43
that may, at first sight, seem completely impossible.
03:45
You have to survey the whole history of the universe.
03:47
So let's do it.
03:52
(Laughter)
03:54
Let's begin by winding the timeline back
03:56
13.7 billion years,
03:59
to the beginning of time.
04:02
Around us, there's nothing.
04:12
There's not even time or space.
04:14
Imagine the darkest, emptiest thing you can
04:18
and cube it a gazillion times
04:21
and that's where we are.
04:23
And then suddenly,
04:25
bang! A universe appears, an entire universe.
04:28
And we've crossed our first threshold.
04:31
The universe is tiny; it's smaller than an atom.
04:33
It's incredibly hot.
04:35
It contains everything that's in today's universe,
04:37
so you can imagine, it's busting.
04:39
And it's expanding at incredible speed.
04:41
And at first, it's just a blur,
04:44
but very quickly distinct things begin to appear in that blur.
04:46
Within the first second,
04:49
energy itself shatters into distinct forces
04:51
including electromagnetism and gravity.
04:54
And energy does something else quite magical:
04:56
it congeals to form matter --
04:59
quarks that will create protons
05:02
and leptons that include electrons.
05:04
And all of that happens in the first second.
05:07
Now we move forward 380,000 years.
05:09
That's twice as long as humans have been on this planet.
05:14
And now simple atoms appear
05:17
of hydrogen and helium.
05:20
Now I want to pause for a moment,
05:23
380,000 years after the origins of the universe,
05:25
because we actually know quite a lot
05:28
about the universe at this stage.
05:30
We know above all that it was extremely simple.
05:32
It consisted of huge clouds
05:35
of hydrogen and helium atoms,
05:37
and they have no structure.
05:39
They're really a sort of cosmic mush.
05:41
But that's not completely true.
05:44
Recent studies
05:46
by satellites such as the WMAP satellite
05:48
have shown that, in fact, there are just tiny differences in that background.
05:51
What you see here,
05:55
the blue areas are about a thousandth of a degree cooler
05:57
than the red areas.
06:00
These are tiny differences,
06:02
but it was enough for the universe to move on
06:04
to the next stage of building complexity.
06:06
And this is how it works.
06:08
Gravity is more powerful
06:10
where there's more stuff.
06:13
So where you get slightly denser areas,
06:15
gravity starts compacting clouds
06:17
of hydrogen and helium atoms.
06:19
So we can imagine the early universe breaking up
06:21
into a billion clouds.
06:23
And each cloud is compacted,
06:25
gravity gets more powerful as density increases,
06:27
the temperature begins to rise at the center of each cloud,
06:30
and then, at the center of each cloud,
06:32
the temperature crosses the threshold temperature
06:34
of 10 million degrees,
06:37
protons start to fuse,
06:39
there's a huge release of energy,
06:41
and, bam!
06:44
We have our first stars.
06:46
From about 200 million years after the Big Bang,
06:48
stars begin to appear all through the universe,
06:52
billions of them.
06:55
And the universe is now significantly more interesting
06:57
and more complex.
07:00
Stars will create the Goldilocks conditions
07:03
for crossing two new thresholds.
07:05
When very large stars die,
07:08
they create temperatures so high
07:10
that protons begin to fuse in all sorts of exotic combinations,
07:13
to form all the elements of the periodic table.
07:16
If, like me, you're wearing a gold ring,
07:19
it was forged in a supernova explosion.
07:22
So now the universe is chemically more complex.
07:25
And in a chemically more complex universe,
07:28
it's possible to make more things.
07:31
And what starts happening
07:33
is that, around young suns,
07:35
young stars,
07:37
all these elements combine, they swirl around,
07:39
the energy of the star stirs them around,
07:41
they form particles, they form snowflakes,
07:43
they form little dust motes,
07:46
they form rocks, they form asteroids,
07:48
and eventually, they form planets and moons.
07:50
And that is how our solar system was formed,
07:53
four and a half billion years ago.
07:56
Rocky planets like our Earth
07:59
are significantly more complex than stars
08:02
because they contain a much greater diversity of materials.
08:05
So we've crossed a fourth threshold of complexity.
08:08
Now, the going gets tougher.
08:12
The next stage introduces entities
08:16
that are significantly more fragile,
08:18
significantly more vulnerable,
08:20
but they're also much more creative
08:22
and much more capable of generating further complexity.
08:25
I'm talking, of course,
08:28
about living organisms.
08:30
Living organisms are created by chemistry.
08:32
We are huge packages of chemicals.
08:34
So, chemistry is dominated by the electromagnetic force.
08:38
That operates over smaller scales than gravity,
08:41
which explains why you and I
08:43
are smaller than stars or planets.
08:45
Now, what are the ideal conditions for chemistry?
08:47
What are the Goldilocks conditions?
08:50
Well, first, you need energy,
08:52
but not too much.
08:54
In the center of a star, there's so much energy
08:56
that any atoms that combine will just get busted apart again.
08:58
But not too little.
09:01
In intergalactic space, there's so little energy
09:03
that atoms can't combine.
09:05
What you want is just the right amount,
09:08
and planets, it turns out, are just right,
09:10
because they're close to stars, but not too close.
09:12
You also need a great diversity of chemical elements,
09:15
and you need liquid such as water.
09:18
Why?
09:21
Well, in gasses, atoms move past each other so fast
09:23
that they can't hitch up.
09:26
In solids,
09:28
atoms are stuck together, they can't move.
09:30
In liquids,
09:33
they can cruise and cuddle
09:35
and link up to form molecules.
09:37
Now, where do you find such Goldilocks conditions?
09:40
Well, planets are great,
09:43
and our early Earth
09:45
was almost perfect.
09:47
It was just the right distance from its star
09:49
to contain huge oceans of open water.
09:51
And deep beneath those oceans,
09:54
at cracks in the Earth's crust,
09:56
you've got heat seeping up from inside the Earth,
09:58
and you've got a great diversity of elements.
10:01
So at those deep oceanic vents,
10:03
fantastic chemistry began to happen,
10:05
and atoms combined in all sorts of exotic combinations.
10:08
But of course, life is more
10:12
than just exotic chemistry.
10:14
How do you stabilize
10:16
those huge molecules
10:18
that seem to be viable?
10:20
Well, it's here that life introduces
10:23
an entirely new trick.
10:25
You don't stabilize the individual;
10:28
you stabilize the template,
10:30
the thing that carries information,
10:32
and you allow the template to copy itself.
10:34
And DNA, of course,
10:36
is the beautiful molecule
10:38
that contains that information.
10:40
You'll be familiar with the double helix of DNA.
10:42
Each rung contains information.
10:45
So, DNA contains information
10:47
about how to make living organisms.
10:49
And DNA also copies itself.
10:52
So, it copies itself
10:54
and scatters the templates through the ocean.
10:56
So the information spreads.
10:58
Notice that information has become part of our story.
11:00
The real beauty of DNA though
11:03
is in its imperfections.
11:05
As it copies itself,
11:07
once in every billion rungs,
11:09
there tends to be an error.
11:11
And what that means
11:13
is that DNA is, in effect, learning.
11:15
It's accumulating new ways of making living organisms
11:18
because some of those errors work.
11:20
So DNA's learning
11:22
and it's building greater diversity and greater complexity.
11:24
And we can see this happening over the last four billion years.
11:27
For most of that time of life on Earth,
11:30
living organisms have been relatively simple --
11:32
single cells.
11:34
But they had great diversity,
11:36
and, inside, great complexity.
11:38
Then from about 600 to 800 million years ago,
11:40
multi-celled organisms appear.
11:43
You get fungi, you get fish,
11:45
you get plants,
11:47
you get amphibia, you get reptiles,
11:49
and then, of course, you get the dinosaurs.
11:52
And occasionally, there are disasters.
11:55
Sixty-five million years ago,
11:59
an asteroid landed on Earth
12:01
near the Yucatan Peninsula,
12:03
creating conditions equivalent to those of a nuclear war,
12:05
and the dinosaurs were wiped out.
12:08
Terrible news for the dinosaurs,
12:10
but great news for our mammalian ancestors,
12:14
who flourished
12:17
in the niches left empty by the dinosaurs.
12:19
And we human beings
12:22
are part of that creative evolutionary pulse
12:24
that began 65 million years ago
12:27
with the landing of an asteroid.
12:30
Humans appeared about 200,000 years ago.
12:33
And I believe we count
12:36
as a threshold in this great story.
12:38
Let me explain why.
12:40
We've seen that DNA learns in a sense,
12:42
it accumulates information.
12:45
But it is so slow.
12:47
DNA accumulates information
12:49
through random errors,
12:51
some of which just happen to work.
12:53
But DNA had actually generated a faster way of learning:
12:56
it had produced organisms with brains,
12:58
and those organisms can learn in real time.
13:01
They accumulate information, they learn.
13:04
The sad thing is,
13:07
when they die, the information dies with them.
13:09
Now what makes humans different
13:12
is human language.
13:14
We are blessed with a language, a system of communication,
13:16
so powerful and so precise
13:18
that we can share what we've learned with such precision
13:21
that it can accumulate in the collective memory.
13:24
And that means
13:27
it can outlast the individuals who learned that information,
13:29
and it can accumulate from generation to generation.
13:32
And that's why, as a species, we're so creative
13:36
and so powerful,
13:38
and that's why we have a history.
13:40
We seem to be the only species in four billion years
13:42
to have this gift.
13:45
I call this ability
13:47
collective learning.
13:49
It's what makes us different.
13:51
We can see it at work
13:53
in the earliest stages of human history.
13:55
We evolved as a species
13:57
in the savanna lands of Africa,
13:59
but then you see humans migrating into new environments,
14:01
into desert lands, into jungles,
14:04
into the ice age tundra of Siberia --
14:06
tough, tough environment --
14:08
into the Americas, into Australasia.
14:10
Each migration involved learning --
14:12
learning new ways of exploiting the environment,
14:14
new ways of dealing with their surroundings.
14:17
Then 10,000 years ago,
14:19
exploiting a sudden change in global climate
14:21
with the end of the last ice age,
14:23
humans learned to farm.
14:25
Farming was an energy bonanza.
14:28
And exploiting that energy,
14:30
human populations multiplied.
14:32
Human societies got larger, denser,
14:34
more interconnected.
14:36
And then from about 500 years ago,
14:38
humans began to link up globally
14:42
through shipping, through trains,
14:44
through telegraph, through the Internet,
14:46
until now we seem to form
14:49
a single global brain
14:51
of almost seven billion individuals.
14:53
And that brain is learning at warp speed.
14:55
And in the last 200 years, something else has happened.
15:00
We've stumbled on another energy bonanza
15:02
in fossil fuels.
15:04
So fossil fuels and collective learning together
15:06
explain the staggering complexity
15:09
we see around us.
15:11
So, here we are,
15:16
back at the convention center.
15:19
We've been on a journey, a return journey,
15:21
of 13.7 billion years.
15:23
I hope you agree that this is a powerful story.
15:26
And it's a story in which humans
15:29
play an astonishing and creative role.
15:31
But it also contains warnings.
15:34
Collective learning is a very, very powerful force,
15:37
and it's not clear
15:41
that we humans are in charge of it.
15:43
I remember very vividly as a child growing up in England,
15:46
living through the Cuban Missile Crisis.
15:49
For a few days,
15:52
the entire biosphere
15:54
seemed to be on the verge of destruction.
15:56
And the same weapons are still here,
15:59
and they are still armed.
16:02
If we avoid that trap,
16:04
others are waiting for us.
16:06
We're burning fossil fuels at such a rate
16:08
that we seem to be undermining the Goldilocks conditions
16:11
that made it possible for human civilizations
16:14
to flourish over the last 10,000 years.
16:16
So what big history can do
16:20
is show us the nature of our complexity and fragility
16:22
and the dangers that face us,
16:25
but it can also show us
16:27
our power with collective learning.
16:30
And now, finally,
16:32
this is what I want.
16:35
I want my grandson, Daniel,
16:39
and his friends and his generation,
16:42
throughout the world,
16:44
to know the story of big history,
16:46
and to know it so well
16:49
that they understand
16:51
both the challenges that face us
16:53
and the opportunities that face us.
16:55
And that's why a group of us
16:58
are building a free, online syllabus
17:00
in big history
17:02
for high school students throughout the world.
17:04
We believe that big history
17:06
will be a vital intellectual tool for them,
17:09
as Daniel and his generation
17:12
face the huge challenges
17:15
and also the huge opportunities
17:17
ahead of them at this threshold moment
17:19
in the history of our beautiful planet.
17:22
I thank you for your attention.
17:26
(Applause)
17:28

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About the speaker:

David Christian - Historian
David Christian teaches an ambitious world history course that tells the tale of the entire universe -- from the Big Bang 13 billion years ago to present day.

Why you should listen

David Christian is by training a historian of Russia and the Soviet Union, but since the 1980s he has become interested in world history on very large scales. He has written on the social and material history of the 19th-century Russian peasantry, in particular on aspects of diet and the role of alcohol. In 1989, he began teaching courses on "Big History," surveying the past on the largest possible scales, including those of biology and astronomy.

Christian is a member of the Australian Academy of the Humanities. Over the next few years he will also be working with the support of Bill Gates to create an online course in "Big History" for high school students.

Watch the Big History series on H2 >>  

More profile about the speaker
David Christian | Speaker | TED.com