WEBVTT

00:00:00.361 --> 00:00:02.076
Are you alone in the universe?

00:00:02.452 --> 00:00:04.478
Or are you connected to anything?

00:00:05.048 --> 00:00:08.678
First of all, you’re part of a group of
mammals that’s still very young,

00:00:08.678 --> 00:00:10.787
but we can make YouTube
videos already,

00:00:10.787 --> 00:00:12.747
and build Large Hadron Colliders!

00:00:13.017 --> 00:00:15.888
We’ve also split the atom and
invented Pokémon.

00:00:16.228 --> 00:00:17.983
We stem from an ancient lifeform

00:00:17.983 --> 00:00:20.887
that began living about
three and a half billion years ago.

00:00:21.357 --> 00:00:24.475
We feel like we’re in control of this
planet, but we aren’t really.

00:00:25.115 --> 00:00:28.720
One little asteroid or one creative virus
is really all it would take

00:00:28.720 --> 00:00:30.034
to kill us off for good!

00:00:30.454 --> 00:00:33.936
Humanity credits itself with being
able to destroy the planet,

00:00:33.936 --> 00:00:36.127
but even with all our nuclear toys,

00:00:36.127 --> 00:00:39.530
we would probably just cause a
huge mass extinction, at best.

00:00:40.250 --> 00:00:43.457
Maybe we could kill 90% of
everything living on this planet.

00:00:43.817 --> 00:00:44.771
Big deal!

00:00:45.261 --> 00:00:48.641
A few million years later, life
would be back everywhere.

00:00:49.221 --> 00:00:52.034
Most microscopic life and
life below the surface

00:00:52.034 --> 00:00:54.357
wouldn’t even be disturbed
that much, probably.

00:00:55.017 --> 00:00:57.970
On a geological timescale,
our impact on Earth

00:00:57.970 --> 00:00:59.404
is kind of laughable.

00:00:59.924 --> 00:01:01.965
We’re actually not that powerful.

00:01:02.605 --> 00:01:05.403
We live on this tiny wet rock
that speeds through space

00:01:05.403 --> 00:01:07.496
following a massive ball of
burning plasma.

00:01:07.896 --> 00:01:10.511
One day, this ball of plasma
will stop burning

00:01:10.511 --> 00:01:13.124
and most likely kill us in the process.

00:01:13.634 --> 00:01:17.176
If we survive the death of the Sun
and colonize the galaxy,

00:01:17.176 --> 00:01:19.315
theoretically, we could survive until

00:01:19.315 --> 00:01:21.340
the last star in the universe goes out.

00:01:21.430 --> 00:01:24.090
After that, life becomes
pretty impossible.

00:01:24.530 --> 00:01:26.651
Okay, so everything has an end.

00:01:27.061 --> 00:01:29.820
Where does this leave you
as an individual?

00:01:37.097 --> 00:01:39.605
At one point in your life,
for about half an hour,

00:01:39.605 --> 00:01:42.886
you were only one single cell
inside your mother’s womb.

00:01:43.136 --> 00:01:45.866
A creature just 0.1 mm in diameter.

00:01:46.666 --> 00:01:49.952
Today, you consist of about
50 trillion cells.

00:01:50.482 --> 00:01:53.897
50 trillion incredibly complex
little biological machines

00:01:53.897 --> 00:01:57.536
that are much bigger and more complex
than the average bacteria!

00:01:58.136 --> 00:02:00.381
They operate by the laws of
physics and chemistry

00:02:00.381 --> 00:02:04.362
and use micromachines to build proteins,
make energy usable, devour food,

00:02:04.362 --> 00:02:07.652
transport resources, transmit information,
or reproduce.

00:02:08.172 --> 00:02:12.968
They communicate, duplicate, commit
suicide, fight off intruders, and fulfil

00:02:12.968 --> 00:02:16.281
super-specialized duties for the
greater good of keeping you alive

00:02:16.281 --> 00:02:18.221
so you can have babies.

00:02:18.681 --> 00:02:22.861
But where is the “you” part in this, if
you’re made of trillions of little things?

00:02:23.481 --> 00:02:26.635
The basic information for “you”
is stored in the DNA,

00:02:26.635 --> 00:02:29.262
a molecule that encodes
the genetic instructions

00:02:29.262 --> 00:02:32.482
used in the development and functioning
of all known living things.

00:02:32.892 --> 00:02:35.883
If you were to unravel it,
it would be two meters long!

00:02:36.653 --> 00:02:39.827
If you combined all the little
DNA strings in all your cells,

00:02:39.827 --> 00:02:43.949
you’d get a string so long that it would
stretch to Pluto and back to Earth.

00:02:44.299 --> 00:02:45.721
That’s pretty long!

00:02:46.451 --> 00:02:51.522
And your DNA is a direct connection
to your very first ancestor.

00:02:52.262 --> 00:02:53.755
Take a second to think about this:

00:02:54.405 --> 00:02:57.035
in every cell of your body,
there’s a little string of stuff

00:02:57.035 --> 00:03:01.082
that’s been there in various forms
for 3.4 billion years.

00:03:01.732 --> 00:03:05.946
It evolved, it mutated, it
duplicated trillions of times,

00:03:05.946 --> 00:03:10.056
but it directly connects you to the
first living being on this planet.

00:03:10.716 --> 00:03:14.429
We could say you “touched” every living
being that came before you

00:03:14.429 --> 00:03:15.838
with your DNA.

00:03:16.988 --> 00:03:19.119
But you are more than your DNA.

00:03:19.639 --> 00:03:22.746
Your body is made of
seven octillion atoms.

00:03:23.196 --> 00:03:26.707
That’s seven billion billion billions.

00:03:27.547 --> 00:03:32.143
Roughly 93% of the mass the human body
is made up of just three elements:

00:03:32.143 --> 00:03:34.885
oxygen, carbon, and hydrogen.

00:03:35.445 --> 00:03:38.801
Oxygen and hydrogen are predominantly
found in water,

00:03:38.801 --> 00:03:41.897
which makes up about 60%
of the body by weight.

00:03:42.447 --> 00:03:44.977
Carbon is, maybe, the most
important element for life.

00:03:45.477 --> 00:03:48.987
It can easily bond with other atoms,
which allows for the building of long

00:03:48.987 --> 00:03:52.762
complex chains of molecules,
which make up the solid part of you.

00:03:53.182 --> 00:03:56.942
The remaining 7% is a tour of
the periodic table of elements:

00:03:56.942 --> 00:04:01.266
nitrogen, calcium, phosphorus, potassium,
sulfur, sodium, chlorine, magnesium,

00:04:01.266 --> 00:04:04.935
iron, fluorine, zinc, copper, iodine,
selenium, chromium, manganese,

00:04:04.935 --> 00:04:08.400
molybdenum, cobalt, lithium, strontium,
aluminum, silicon, lead, vanadium,

00:04:08.400 --> 00:04:10.997
arsenic, and bromine… phew!

00:04:11.497 --> 00:04:15.127
By the way, this also means
you’re about 0.5% metal,

00:04:15.127 --> 00:04:17.436
no matter what your favorite music is.

00:04:18.006 --> 00:04:20.639
Anyway, these elements perform
various functions like

00:04:20.639 --> 00:04:23.992
enabling oxygen transport,
building of bones and cell structures,

00:04:23.992 --> 00:04:27.250
carrying signals, driving chemical
reactions, and a lot more.

00:04:27.650 --> 00:04:30.816
Your body is in a constant
state of transition.

00:04:31.626 --> 00:04:35.838
Every 16 days, 75% of “you”
has been replaced,

00:04:35.838 --> 00:04:40.941
because a healthy human exchanges about
100% of their water in that time period.

00:04:41.531 --> 00:04:45.917
Each year, about 98% of your atoms are
replaced by new ones,

00:04:45.917 --> 00:04:50.277
and every 5 years, close to all of the
atoms that make up your body

00:04:50.277 --> 00:04:52.347
weren’t there five years ago.

00:04:52.657 --> 00:04:56.180
So, you could call yourself
a temporary collection of atoms.

00:04:56.650 --> 00:04:58.907
But where did these atoms come from?

00:04:59.967 --> 00:05:03.731
In the beginning of the universe, there
were mostly hydrogen and helium atoms.

00:05:04.301 --> 00:05:08.833
Enormous gas clouds formed over millenia
and grew denser and denser,

00:05:08.833 --> 00:05:12.881
until they collapsed under their own
gravity, giving birth to the first stars.

00:05:13.301 --> 00:05:14.753
In the cores of these stars,

00:05:14.753 --> 00:05:18.643
hydrogen was converted into helium
under extreme conditions.

00:05:19.133 --> 00:05:22.247
After millions of years, the
hydrogen became exhausted,

00:05:22.247 --> 00:05:24.174
and the stars began dying.

00:05:24.844 --> 00:05:27.980
Under super-extreme conditions,
all elements we know today

00:05:27.980 --> 00:05:33.525
were created a fraction of a second before
they died and exploded in supernovas.

00:05:33.815 --> 00:05:35.973
They shot most of their
contents into space,

00:05:35.973 --> 00:05:38.681
while the cores collapsed and
became black holes.

00:05:39.271 --> 00:05:42.146
All these elements traveled through space
for who knows how long.

00:05:42.146 --> 00:05:45.851
Until they arrived at a different cloud
that was slowly forming a new star—

00:05:45.851 --> 00:05:46.880
our Sun.

00:05:47.180 --> 00:05:49.783
These elements, that once
were the insides of a star,

00:05:49.783 --> 00:05:52.458
formed planets and found
their way onto Earth,

00:05:52.458 --> 00:05:54.869
where they enabled life to begin.

00:05:55.389 --> 00:05:59.619
So we are directly connected to
the first stars ever born in the universe.

00:05:59.619 --> 00:06:01.311
We are part of the universe.

00:06:01.541 --> 00:06:05.879
The idea of being a deeply connected
minuscule part of an enormous structure

00:06:05.879 --> 00:06:07.681
is really mindblowing.

00:06:08.601 --> 00:06:12.732
We don’t know what all this means,
or if it means anything at all.

00:06:13.162 --> 00:06:15.788
We know that we are made of little
parts that connect us

00:06:15.788 --> 00:06:19.136
to everything in the universe, to
the beginning of everything.

00:06:19.136 --> 00:06:21.216
Then this is kind of a nice thought:

00:06:21.216 --> 00:06:25.969
you are not alone; you never
were; you never will be.