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00:00we live on one level of existence but there are others these hidden dimensions of reality are
00:08everywhere far away across the light years beneath our feet and even inside you and me
00:17we are made of atoms there are more atoms in your eye than there are stars in all the
00:25galaxies of the known universe the same is true of any solid object larger than tip of your little
00:36finger I'm a collection of three billion billion billion intricately arranged atoms called Neil
00:43deGrasse Tyson you're a similar collection with a different name we don't usually think of ourselves
00:49this way because that level of reality lies beyond the realm of our senses but we're not
00:55gonna let that stop us we can go deeper into the wonder
01:25so
01:29so
01:33so
01:37so
01:41so
01:45so
01:48so
01:52so
01:56so
02:00so
02:04so
02:08so
02:10so
02:14so
02:16so
02:22atoms let matter do funny things
02:47to understand
02:48to understand water you need to know what its atoms are doing
02:51every molecule of water is composed of two tiny hydrogen atoms attached to a larger oxygen atom
02:57that's why we call it h2o if it's not too hot or too cold the molecules can slide and tumble past
03:04each other there's still some stickiness between the molecules but not enough to lock them into a rigid solid
03:10so
03:10that's what makes something liquid
03:12the sun warms the water and with more energy the molecules move faster
03:17that's all the temperature is those molecules are moving fast enough to break the weak bonds that hold them to their neighbors
03:25that's evaporation the air we breathe is made of nitrogen and oxygen molecules with a scattering of water vapor and carbon dioxide
03:34in coming
03:36that's condensation
03:38a dewdrop is the momentary triumph of condensation over evaporation and while it lasts
03:45it's a little cosmos with its own worlds
03:49creatures
03:50drama
03:51to explore the far-flung realms of this dewdrop we're gonna need a ship
03:57one with twin engines
04:00science
04:01and imagination
04:02that's a single-celled paramecia
04:10one of a multitude of skilled hunter warriors that roam the dewdrop
04:15but they too are hunted
04:17the dileptis
04:22the paramecium's mortal enemy
04:24the paramecium might get lucky and score a direct hit
04:27even if it doesn't
04:28the recoil from the barrage
04:30will put some distance between the paramecium and its attacker
04:33what can i say
04:38that's life in the dewdrop
04:39that little guy is a tardigrade
04:41an animal smaller than the head of a pen
04:47don't underestimate them
04:49tardigrades have been living on this planet a lot longer than we have
05:05about 500 million years
05:11for every one of us
05:13there's at least a billion of them
05:15they can make a living anywhere on earth
05:22the frigid peaks of the tallest mountains
05:25cauldrons of erupting volcanoes
05:27into the deep ocean vents in the bottom of the sea
05:30tardigrades are so tough
05:31they can survive naked in the vacuum of space
05:34they've survived all five of the most recent mass extinctions on this planet
05:39a visitor from another world could be forgiven for thinking of earth as the planet of the tardigrades
05:49we're ever going to get to the bottom of this dewdrop better get a move on
05:57every leaf and tiny clump of moss has hundreds of thousands of microscopic mouths called stomata
06:04plants breathe through them taking in carbon dioxide exhaling the oxygen that we need to live
06:10the plants can survive without us
06:13but we and all the other animals would be toast without them
06:16the plants make food out of sunlight
06:20we animals can't do that
06:22to see how they do it
06:24we have to go deeper
06:26make ourselves about a thousand times smaller
06:29to get into their treasure house
06:31the place where they keep the good stuff
06:33the chlorophyll
06:35that's the molecule that converts sunlight into energy
06:42every one of those rectangles is a plant cell
06:44and those tiny green vehicles are its energy factories
06:49if we could steal their trade secrets
06:51it would trigger a new industrial revolution
06:54but to spy on them
06:55we're going to need to go deeper still
07:03what alien world has the ship of the imagination carried us to this time it's the cosmos contained within a dewdrop
07:17we're on an industrial espionage mission
07:19if we can penetrate the trade secrets of the manufacturing process in that chloroplast
07:24let's just say our whole future hangs in the balance
07:31this chloroplast is using sunlight to break water molecules into atoms of hydrogen and oxygen
07:36and oxygen
07:38it combines the hydrogen with carbon dioxide to make sugar
07:42and releases the oxygen as a waste product
07:44to see how it happens we have to go even deeper
07:47get even smaller
07:49we're talking atomic scale bingo this assembly line is the heart of the
07:56molecular-industrial complex at the molecular level things happen too fast
08:02for us to see so we'll have to slow them down about a billion times
08:09those larger molecules are carbon dioxide each one of them is made of one
08:14carbon and two oxygen atoms when sunlight strikes a green molecule
08:18chlorophyll it sets in motion a series of chemical reactions breaking apart water
08:23molecules and freeing energetic electrons
08:28and that's just the day shift when sunlight supplies the incoming stream of
08:32energy there's a second shift that works day and night using the solar energy kept
08:38in reserve the energy of the free electrons is put to work combining
08:43carbon dioxide with hydrogen from the water the end product is sugar which
08:49stores the solar energy the chloroplast is a three billion year old solar energy
08:56collector this sub microscopic solar battery is what drives all the forests and
09:02the fields and the plankton of the seas and the animals including us the solar powered biosphere
09:11collects and processes six times more power than our entire civilization we understand on a chemical
09:18level how photosynthesis works we can recreate the process in the laboratory but we're not as good at it
09:24as plants are and it's not surprising considering nature has been at this for billions of years and we've
09:31only just started but if we could figure out the trade secrets of photosynthesis every other source of energy we depend on today
09:39coal oil natural gas would become obsolete photosynthesis is the ultimate green power it doesn't pollute the air and is in fact carbon neutral
09:51artificial photosynthesis on a big enough scale could reduce the greenhouse effect that's driving climate change in a dangerous direction
09:58uh-oh places evaporating time to get out of here
10:04how fleeting is the life of a dew drop it condenses from thin air and the cool of the night only to vanish with the heat of the day
10:10and what if its inhabitants the tardigrades they'll be fine they can go without water for years
10:22it's hard to imagine but plants covered the surface of the earth for hundreds of millions of years before they put forth their first flower
10:29that was about a hundred million years ago shortly before the dinosaurs were wiped out
10:36our world must have been a relatively drab looking place back then dominated by shades of green and brown
10:44yeah there were giant trees and ferns and other plant life but not the purple of an iris or the crimson of a red red rose
10:54orchids were among the first flowering species to appear on earth and they're the most diverse
11:11darwin was particularly fascinated by the comet orchid of madagascar a flower whose pollen is hidden at the bottom of a very long thin spur
11:21there can be no stronger test of an idea than its predictive power
11:26on the basis of his theory of evolution through natural selection
11:30darwin speculated that somewhere on the island of madagascar
11:34there must live flying insects with extraordinarily lengthy tongues
11:39ones long enough to reach the pollen
11:42no one had ever seen such a beast there
11:45but darwin insisted that an animal fitting this description must exist
11:50few people at the time believed him
11:53it wasn't until more than 50 years later
11:56that darwin was proven right
11:59in 1903 a huge hawk moth called the morgan sphinx was discovered in madagascar
12:06attracted by the comet orchid's scent
12:09the moth slurps its pollen with its foot long tongue
12:13exactly as darwin expected it would
12:20it's even more amazing that the morgan sphinx was discovered
12:24when you consider that more than 90 percent of madagascar's rainforests have been destroyed
12:29in the years since darwin's famous prediction this moth species could have easily become extinct with all the others
12:38every one of them a unique phrase of life's poetry written in the atoms by eons of evolution
12:46ah fragrance of lilacs
12:53it's one of those scents that triggers a whole constellation of associations
12:58all those dunes of long ago
13:01but how does that happen
13:03how does a smell prompt a movie to start running in your head
13:07it's not something we can see
13:09could it be a wave of energy like light
13:12or is it some kind of microscopic particle
13:15it's actually a molecule
13:17every odor we can sense
13:19whether it comes from burnt toast
13:21gasoline or a field of lilacs
13:24it's a cloud of molecules
13:26these molecules have particular shapes
13:30when i inhale them
13:32they stimulate a particular set of receptor cells in my nose
13:36an electrical signal then travels to my brain
13:40which identifies this scent as lilac
13:46other scents are carried by different molecules with different shapes
13:50but when i smell a flower
13:52or the smoke from a campfire
13:54with the grease of a motor gear
13:56i'm often flooded with memories
14:00why is it that a simple thing such as the scent of a flower
14:04can trigger powerful memories?
14:09it has to do with the way our brains have evolved
14:13our sense of smell kicks in
14:15when the olfactory nerve in our brain is stimulated
14:20that nerve is located very close to the amygdala
14:23a structure that is integral to our experience of emotion
14:29it's also very close to the hippocampus
14:31which helps us form memories
14:37the network of neurons that carry the scent signal
14:39from my nose to my brain
14:41has been fine-tuned over hundreds of millions of years of evolution
14:45it's a survival mechanism that can alert us to danger or guide us to safety
14:51if you can detect the predator before he's near enough to strike
14:57or the fire before it traps you in the forest
14:59you have a much better chance to survive and pass on your genes to the next generation
15:05that lovely scent from this field of flowers sets off a unique combination of nerve signals
15:19only that exact combination
15:21can crack the safe where the memory of lilacs is stored inside my brain
15:29wonder who they're for
15:31maybe we'll find out later
15:33maybe we'll find out later
15:35but first
15:37there's another hidden cosmos
15:39the plants are softly breathing
15:49inhaling molecules of carbon dioxide
15:53and exhaling molecules of oxygen
15:55and i'm doing the opposite
16:09unlike snowflakes and fingerprints
16:11atoms or molecules of the same kind
16:13are utterly identical to one another
16:15with every breath we take
16:17we inhale as many molecules
16:19as there are stars and all the galaxies
16:21in the visible universe
16:23and every breath we exhale
16:25and every breath we exhale
16:27is circulated through the air
16:29and mixed gradually across the continents
16:31becomes available for others to breathe
16:33breathe with me
16:35breathe with me
16:47we all just inhaled about a hundred million molecules
16:49that once passed through the lungs
16:51of everyone who ever lived before us
16:55think of it
16:57this kind of atomic reincarnation
16:59is another link to our distant ancestors
17:01including those who first launched us
17:03on our explorations of the unseen universes
17:05these universes
17:07these universes are as real as you
17:09or me
17:11and they surround us
17:13there was a moment
17:17when we awakened
17:19to a new way of thinking and seeing
17:21it happened about
17:232,500 years ago
17:25on the greek islands that lie between
17:27the empires of the east
17:29and the west
17:31there merchants, tourists, and sailors
17:33freely mingled
17:35exchanging tales of great kings and gods
17:37in Ionian cities
17:39and towns like Miletus
17:41in what is now Turkey
17:43the most fundamental elements
17:45of the way we live now
17:47first appeared
17:49here
17:51for the first time
17:53reenactments of aspects of life
17:55created and executed by professionals
17:57with the expectation
17:59of touching something deep within the hearts
18:01of the audience
18:03or just making them laugh
18:05the first plays
18:07dramas and comedies were performed
18:09here also was born
18:11a radical new idea
18:13government by the people
18:15the first inklings
18:16imperfect then as now
18:17of a democracy
18:19and the notion that the ordinary citizen
18:21might possess certain rights
18:23come to us from this time
18:25and place
18:27but in my view
18:29the most revolutionary innovation of all
18:31to come to us from this ancient world
18:33was the idea
18:35that natural events
18:37were neither punishment nor reward
18:39from the capricious gods
18:41the workings of nature
18:43could be explained
18:45without invoking the supernatural
18:47the first person to express this thought
18:49was a man named Thales
18:51when the thunder clapped
18:53or the earth quaked
18:54it was not because
18:55something you did
18:56had somehow displeased
18:57the very demanding gods
18:59no
19:00it was the result
19:01of natural processes
19:02that we were capable
19:03of understanding
19:05though none of the books
19:06he is said to have written
19:07survive
19:08Thales kindled a flame
19:10that still burns
19:11to this day
19:12the very idea
19:13of cosmos
19:14out of chaos
19:15a universe
19:16governed by the order
19:17of natural laws
19:18that we could actually figure out
19:20this is the epic adventure
19:23that began in the mind
19:25of Thales
19:26only a century
19:28following Thales death
19:29another genius came along
19:31and he more than any other
19:33and he more than any other
19:34was the first to discover
19:35the existence
19:36of the hidden universes
19:37that surround us
19:38Democritus of Abdurba
19:41was a true scientist
19:43a man with a passionate desire
19:45to know the cosmos
19:46and to have fun
19:48this is the man who once said
19:50a life without parties
19:51would be like an endless road
19:53without an inn
19:54you mean that's it?
19:56that's all there is
19:58just a bunch of atoms
19:59in a void?
20:00yep
20:01well think about it
20:04the world has to be made
20:06of countless indivisible particles
20:08in the void
20:09otherwise nothing could move
20:11or grow
20:12be divided
20:13or change
20:14without atoms
20:15and empty space
20:18for them to move in
20:19the world would be solid
20:21static
20:22and dead
20:23so don't be sad
20:24my friend
20:25just think of the infinite possibilities
20:27that arise
20:28from different arrangements
20:30of those atoms
20:36here's to the atoms
20:38in this cup
20:39and in this wine
20:41and to the laughter
20:43they make possible
20:44dispersed through the clay of the cup
20:49are microscopic mineral grains
20:51different kinds of crystals
20:53each with its own distinctive
20:55atomic architecture
20:56mineral structures are exquisite
21:00but they have a limited repertoire
21:02a grain of quartz
21:04is a lattice of the same three atoms
21:06repeated without variation
21:08over and over again
21:10even a relatively complex mineral lattice
21:15like topaz
21:16composed of ten or so atoms
21:18can only repeat the identical atomic structure
21:21again and again
21:27to lift matter to another dimension
21:29to free it from the lattice prison
21:31of endless repetition
21:32you need an atom
21:33that can bond
21:34in all directions
21:35with other atoms
21:36like itself
21:37as well as with atoms
21:38of different kinds
21:39behold
21:48the carbon atom
21:49the essential element
21:51for life on earth
21:52why?
21:53carbon is special
21:54because it can bond
21:55with up to four other atoms
21:58at a time
21:59it can connect
22:00with many different kinds of atoms
22:02as well as other carbon atoms
22:04it can curl into rings
22:05and string together into chains
22:06building molecules
22:07it can curl into rings
22:08and string together into chains
22:10building molecules
22:11far more complex
22:12than any crystal
22:17no other atom has the same flexibility
22:20even atoms that have similar chemical properties
22:23like silicon
22:24can't form the amazing variety of molecules
22:27built on carbon
22:28the carbon-based molecules
22:30we call proteins
22:31the molecules of life
22:33contain literally hundreds of thousands of atoms
22:37carbon atoms are the backbone of the molecules
22:40that make every living thing on earth
22:43including us
22:44that's the difference between rocks and living things
22:48life can make enormous molecules of stunning size and complexity
22:54freeing matter to improvise
22:57evolve
22:59and even love
23:27take it easy dad
23:34he never actually touched her
23:37in everyday life on our world
23:39on the scale of atoms
23:41material objects never really touch
23:44each atom has a tiny nucleus at its center
23:48surrounded by an electron cloud of lines of force
23:51as the atoms approach each other
23:54the boys electron clouds
23:56push away the girls
23:58more than 99.9% of the matter of any atom
24:01is concentrated in its nucleus
24:03the nucleus is surrounded by an electron cloud
24:07which produces an invisible field of force
24:10and acts like a shock absorber
24:12the configuration of the electron cloud
24:15determines the nature of an element
24:17in the ordinary course of things here on earth
24:19the nuclei never touch
24:21we have a sensation of touching
24:23we have a sensation of touching
24:24but that's really just our invisible force field
24:26overlapping and repelling each other
24:28the nucleus is very small compared to the rest of the atom
24:46if an atom were the size of this cathedral
24:53its nucleus would be the size of that mote of dust
25:01an atom is mostly empty space
25:05to understand the nature of matter
25:07we have to go deeper still
25:09to a place a hundred thousand times smaller than the atom
25:13its nucleus
25:14the simplest and most plentiful atom in the cosmos
25:20is hydrogen
25:21its nucleus is a single proton
25:24which makes hydrogen element number one
25:27the clouds that surround it
25:29are the realms where this atom's lone electron is permitted to roam
25:33what happens when you have a nucleus of two protons
25:37protons repel each other
25:39in order to hold them together in a nucleus
25:41you need other particles called neutrons
25:44their job is to keep the protons from getting out of line
25:48they overwhelm the protons with their strong attractive nuclear force
25:53a nucleus with two protons is element number two
25:57otherwise known as helium
25:59a nucleus with six protons is element number six
26:03which is carbon
26:04the fundamental building block of life
26:07the nucleus of a gold atom has 79 protons
26:10they attract 79 electrons and clouds around it
26:14the way light interacts with those electrons
26:17is what makes gold glitter
26:19every additional proton in the nucleus
26:22requires enough neutrons to bind them together
26:25up to a point
26:27there's an upper limit to the number of neutrons
26:29you can stuff into a nucleus
26:31before it becomes unstable
26:33I know a place
26:35where the nuclei of different atoms
26:37actually do touch each other
26:39the sun looks like a solid object
26:49but it's not
26:51it's so hot that all its atoms are always in their gaseous state
26:57the bonds that join atoms to make solids and liquids on earth are not strong enough to withstand the heat of the broiling sun
27:15those arcing streams of incandescent gas that dwarf the earth are guided by magnetic lines of force that emanate from below the surface of the sun
27:27why is the sun so hot?
27:29because its own stupendous gravity is squeezing its atoms together
27:34the energy of gravity is being transformed into the energy of moving atoms
27:41that's what heat is
27:43the deeper we go into the sun the greater the squeezing and the higher the temperature
27:49in the heart of the sun the atoms are moving so fast that when they collide they fuse
27:56their nuclei touch
27:58the sun is a nuclear fusion reactor held together by its own gravity
28:05it's balanced between the inward pull of gravity and the outward push of its hot gases
28:11that balance has lasted billions of years
28:18providing stability that made possible the evolution of life on earth
28:22the sun's core
28:24the fusion of hydrogen into helium releases nuclear energy in the form of photons
28:29these particles of light
28:31slowly work their way to the surface where they're seen as sunlight
28:35helium is the ash of the sun's nuclear furnace
28:39the sun is a medium-sized star
28:42its core is only a lukewarm 10 million degrees
28:46hot enough to fuse hydrogen but too cold to fuse helium
28:50there are many stars in the galaxy that get much hotter because they're more massive and have more gravity
28:56such stars fuse helium into heavier elements like carbon and oxygen
29:01in their old age they gently diffuse these elements into space
29:08other stars more massive yet live fast and die young in cataclysmic supernova explosions
29:16in our galaxy such stars go supernova about once a century
29:21those explosions are far hotter than the core of the sun
29:26hot enough to transform elements like iron into all the heavier ones and spew them into space
29:33the large magellanic cloud is a neighboring galaxy of our milky way
29:38it's visible in the skies of the southern hemisphere
29:40when a supernova explodes its brightness rivals that of its entire galaxy
29:46but all that light is only about one percent of the energy liberated in the explosion
30:03the rest of the energy is carried off by the most common and the most mysterious particles in the cosmos
30:09there are trillions of them passing through you right now
30:12and yet tracking down even one of them will take us to one of the strangest places on earth
30:18stalking the wild neutrino was the rarest of sport
30:30the lengths one must go to track them down is nothing short of astonishing
30:36welcome to super kamioka
30:39subterranean japanese neutrino detection chamber
30:42we're more than a half mile beneath our surface
30:45you might ask well who in their right mind would bury an astronomical observatory so far underground
30:51those who hunt the most elusive prey in the cosmos
30:55the neutrino
30:56this enormous array of light detectors surrounding 50,000 tons of distilled water
31:01is a trap designed to catch neutrinos only
31:05other particles such as cosmic rays
31:07mostly protons and electrons that rain down from space
31:10cannot get through all that rock above us
31:13but matter poses no obstacle to neutrino
31:16a neutrino could pass through a hundred light years of steel
31:20without even slowing down
31:22neutrinos hardly interact with matter at all
31:25that's why you need so much of it to catch even one of them
31:29on those rare occasions when a neutrino actually does collide with a particle of ordinary matter
31:34it produces a ghostly ring-shaped flash of light
31:37you're lying in wait
31:40for a particle that weighs next to nothing
31:43even the minuscule electron has more than a million times its mass
31:48there
31:51when the supernova in the large magellanic cloud blew its top in 1987
31:55this is what it would have looked like in here
31:57now remember the large magellanic cloud is in our southern hemisphere
32:01so the neutrinos didn't come through that half mile of rock above us
32:05we had to pass through the thousands of miles of rock and iron below us to reach this detector
32:11but the coolest thing was that those neutrinos hit Earth
32:14three hours before the light from the supernova did
32:17if nothing can travel faster than light
32:20how could that possibly be
32:29this is a dead star walking
32:32it may look normal but deep within it something cataclysmic is happening
32:36this blue supergiant star has already begun to explode inside
32:48like rats deserting the sinking ship
32:51the neutrinos produced in the heart of the exploding star
32:54race outward at near the speed of light
32:57through the overlying mass in only a few seconds
33:00but the shockwave of the exploding gas
33:03plods along from the center of the star
33:06at one ten thousandth the speed of light
33:09until it finally reaches the star's surface
33:12turning it into supernova 1987A
33:22it took hours for the explosion to reach the surface of the star
33:25and blow it wide open exposing the super hot core
33:28the neutrinos had an insurmountable head star
33:31that's why the flash of light arrived on Earth
33:34so much later than the shower of neutrinos
33:37before anyone had ever snared the wild neutrino
33:41it existed in the mind a theoretical physicist
33:45just as Charles Darwin knew
33:47there must be an extremely long-nosed creature
33:50flying around somewhere in Madagascar
33:52a 20th century physicist named Wolfgang Paul
33:55was desperately seeking a particle
34:00to rescue one of the pillars of modern physics
34:03the law of the conservation of energy
34:15so why didn't I flinch?
34:17because the laws of science differ fundamentally
34:19from those of other human endeavors
34:22in order for an idea to become a scientific law
34:25it has to be unbreakable
34:27that's why I was willing to bet this face
34:29on the laws of conservation of energy
34:32now if you try this at home
34:35take care not to give the cannonball a push
34:38that's adding energy
34:39and the ball will surely come back and do some damage
34:42you just have to let it go
34:44like this
34:46by lifting the ball
34:47you give it gravitational energy
34:49which is the potential to fall and accelerate
34:52the cannonball is going fastest
34:54when it's at the bottom of its arc
34:55at that moment
34:57it's converted all of its gravitational energy
34:59to the energy of motion
35:01as it swings
35:02the cannonball is constantly exchanging
35:04one of these two kinds of energy for the other
35:06but the total amount of energy remains constant
35:09that's an example of the law of conservation of energy
35:13once the cannonball is released
35:16it can never gain more energy than it had to begin with
35:19it has no way to fly up and break my nose
35:22the energy accounting books are always strictly balanced
35:26there's no such thing as cheating
35:28so in the 20th century
35:30when physicists first calculated the energy of atoms precisely
35:33they were startled to discover an apparent violation of this law
35:38they found that in some radioactive atoms
35:42the nucleus can spontaneously eject an electron
35:45this transforms the atom into a different element
35:49the physicists were mystified
35:51the energy of the escaped electron
35:53plus that of the new atom
35:55adds up to less than the energy in the original nucleus
35:59but the law says
36:01thou shalt not destroy or create energy
36:04so where did the missing energy go?
36:07in 1930
36:09Wolfgang Pauli
36:11predicted there must be an undiscovered particle
36:14one that makes off with the missing energy
36:16at the time
36:18Pauli lamented that such a phantom particle
36:21might be so minute, swift and evasive
36:24as to forever defy detection
36:27but that was a rare failure of his imagination
36:31because science is always searching for a way to go deeper still
36:35a generation later
36:36Pauli's neutrinos were actually detected for the first time
36:39in radiation from a nuclear reactor
36:42and we've been finding them with difficulty ever since
36:46there are scientists today
36:48who are trying to find a way to ride those neutrinos
36:52all the way back to the beginning of time
36:57we'll go as far as they have gone
36:59to come up against the wall of forever
37:10the wall of forever is nothing new
37:12our ancestors came up against it
37:14almost as soon as they first started imagining it
37:17a million dawns ago
37:20in the 13th century BC
37:22the Egyptians built this temple at Abu Simbel
37:25to honor the pharaoh Ramses II
37:28depicted here in four colossal statues
37:31reigning even above this mighty king
37:34is the falcon headed Ra Haraki
37:37god of the sun
37:38the temple was designed
37:45so that the light from the rising sun
37:47could only enter the sanctuary
37:49on two days every year
37:51as the rays enter the temple
37:54they burnish the statues of the gods
37:56with their golden light
37:57before penetrating the sanctuary
38:00even then
38:03one god remains in shadow
38:05ta
38:07lord of creation
38:09as if the origin of the universe
38:11must forever be concealed
38:18feel the sun on your face
38:21the energy that warms you
38:23began its journey some 10 million years ago
38:26the heart of the sun
38:31unlike neutrinos
38:32the photons needed that long
38:34to work the way out
38:35from the core to the surface
38:37why?
38:38because they were colliding
38:40billions of times per second
38:41with the sun's atoms
38:43every collision sending them off
38:44in a random direction
38:46once they finally reached the surface
38:49they were free to dash non-stop
38:51at the speed of light
38:53in a mere 8 minutes and 20 seconds
38:55from the sun to you
38:5910 million year old light on your face
39:05what was happening
39:06when that light left the heart of the sun?
39:16the cosmic calendar compresses the entire 13.8 billion year history of the universe
39:21into a single year
39:23every month
39:24represents about a billion years
39:26every day
39:27about 40 million years
39:29the universe is so old
39:31that on the cosmic calendar
39:3210 million years ago
39:34only takes us back as far as
39:366 p.m.
39:38on the last evening
39:40of the last day
39:41of the year
39:42what about us?
39:44humans had yet to evolve
39:4610 million years ago
39:48our ancestors
39:49were anthropoid apes
39:50swinging through the trees
39:51of Africa
39:52to us
39:5310 million years
39:54seems like a long time
39:55but it's only the length
39:57of an afternoon
39:58on the time scale
39:59of the cosmos
40:04the sun began fusing hydrogen
40:064500 million years ago
40:08august 31st
40:10on the cosmic calendar
40:12our Milky Way galaxy
40:14is about 10,000 million years old
40:17the first galaxies
40:19formed a few billion years earlier
40:21and something keeps me from going any further back in time
40:26what is this?
40:28it's the nature of light and time
40:32because light travels at a finite speed
40:34to look across space
40:35is to look back in time
40:36because light travels at a finite speed
40:38to look across space
40:39is to look back in time
40:41so the farther we see
40:43the older the light
40:45this is as far back
40:47in the history of the cosmos
40:48as we can see
40:49with light
40:50it's a baby picture of the universe
40:51when it was only 380,000 years old
40:53that's 15 minutes
40:54into change
40:55the universe
40:56it's a baby picture of the universe
40:58when it was only 380,000 years old
40:59that's 15 minutes
41:00into change
41:01the universe
41:02that's 15 minutes
41:04into January 1st
41:05on the cosmic calendar
41:07if we look as far as we can see
41:09in any direction
41:10using microwave telescopes
41:12this is what we see
41:14the glow left over
41:15from the big bang
41:17imagine that all the matter
41:18and energy
41:19of the observable universe
41:21was concentrated
41:22into something
41:23no larger than this
41:27that's the size of the universe
41:29when it was a trillionth
41:30of a trillionth
41:31of a trillionth
41:32of a trillionth
41:33of a second old
41:34all the matter and energy
41:36of the hundred billion galaxies
41:38now splayed out
41:39across the billions
41:40of light years
41:41were once pent up
41:42in something the size
41:44of a marble
41:45you imagine how tightly packed
41:47that marble must have been
41:48far too dense
41:49for any kind of light
41:50to move through it
41:51but no obstacle
41:52for the likes of neutrinos
41:54the big bang must have produced
41:57stupendous numbers of neutrinos
41:59which flew unhindered
42:00through that inconceivable
42:01crush of matter
42:02the very thing that makes them
42:04almost impossible to detect
42:05is what allows neutrinos
42:07to sail through the curtain
42:09that conceals the beginning of time
42:11the beginning of time
42:13where are they now
42:14they're here
42:15they're there
42:16everywhere throughout the universe
42:18neutrinos from creation
42:20are within you
42:22from a marble
42:24to the cosmos
42:37this is the road
42:38that Thales and Democritus
42:39put us on
42:40some 2500 years ago
42:43a road of endless searching
42:45a relentless systematic hunt
42:47for new worlds
42:48and an ever deepening understanding
42:50of nature
42:53who among you
42:54will pick up that torch
42:55and take us down
42:57that next stretch of road