Where do we come from?
How did the universe begin?
Why... is the universe the way it is?
Morning welcome to Gonville and Caius
More commonly known as Caius College
Caius College was founded in 1348... by Edmund Gonville
Where are we going?
Here we come to the portrait of probably our most famous Caian
Professor Stephen Hawking, the world famous cosmologist
And Iike his predecessor Sir lsaac Newton before him
He is Iucasian professor of mathematics for the university
And his particular sphere is research of the black hole
and the history of the universe culminating in his book
The Brief History of Time which worldwide has sold over eight million copies
All of my life I have been fascinated...
By the big questions that face us,
and have tried to find scientific answers to them
Perhaps that's why I have sold...
more books on physics than Madonna has on sex
This is Professor Hawking's...
study, which he will use when he's in residence in college
Who he'd use for his tutorials or meetings or any...
private work he needs to do
It's very much personal room with his books...
and his portraits and pictures. So it's really home from home...
when their in college
He's got in herited disease motor neurone disease
He can project his voice with a synthesiser
Which is attached to his wheel chair
I hope you enjoyed your visit. Bye, bye
If like me you have looked at the stars and tried to make sense of what you see,
you too have started to wonder what makes the universe exist
The questions are clear and deceptively simple
But the answers have always seemed wel I beyond our reach, until now
For thousands of years our view of the universe changed very little
But the discoveries of scientists from Gallilleo to Einstein
over the past four hundred years have advanced our understanding
at an ever increasing rate- and revolution ised the way we think
Further breakthroughs over the last few decades
have brought us closer than ever to secrets of the cosmos
These dramatic scientific discoveries reveal a universe full of
strange sounding ideas and remarkable images;
the Big Bang-black holes-invisible or dark matter-and a possible big crunch
The story of how we arrived at th is picture is the story of
Iearning to understand what we see
Eighty years ago at the Mount Wi lson Observatory i n Cal iforn ia,
a you ng astronomer looked th roug h the h u nd red i nch telescope deep i nto space
What Edwi n H u bble saw revol ution ised ou r view of ou r place i n the u n iverse
Er, we know than ks to H u bble, that...
that altogether with i n the I i m its of the observable u n iverse
there's someth i ng I i ke one h u nd red bi I l ion tri I l ion stars, it's a lot of stars
And we now know than ks to recent d iscoveries,
very recent d iscoveries also er what we had bel ieved
but had no proof of is that many of those stars have planets
So there are cou ntless tri I l ions of planets i n the observable u n iverse
T oday we see deeper i nto the u n iverse than ever before,
than ks to the space telescope named after Edwi n H u bble
The more we see, the less special ou r place i n the u n iverse seems
Two th i rds of the stars and planets and I ife,
if it's there, i n the u n iverse are bi I l ions of years older than we are
And if you ask what a bi I l ion years means er i n the h istory of I ife,
I must tell you that a billion years ago
the highest form of life on the earth was a worm,
three billion yeas ago the highest form of life on the earth were bacteria
So we m ust ask ou rselves we who are so proud of ou r accom pl ish ments er
what is ou r place i n the cosm ic perspective of I ife
if most of those bei ngs out there, if they are there,
are stand i n relationsh i p to us as we do to the worms on th is planet
and that is not meant to be a den ig rati ng remark
but on ly to suggest that h u man ki nd's g reatest experiences sti I l I ie ahead of us
T oday's scientific approach to u nderstand i ng
the u n iverse real ly began about 3,000 years ago
Before than people based thei r ideas on myths and legends
They cou ld see the stars and wonder about the sky and the heavens, but er...
they had very I ittle i nformation i ndeed, j ust what thei r eyes cou ld pick u p
They thought that everything they knew came out of...
the water. Obviously water was very i m portant...
su bstance, so that they gave water a sort of cosm ic sig n ificance
They thoug ht the heavens are made of many holes
and these holes represent the stars and just behind they had this divine fire
But then Greek philosophers like...
Pythagoras on the island of Samos, saw the universe in a totally new way
They thought they er had er...
to find a more accurate way of expressi ng thei r views about the u n iverse,
and er that way d ramatical ly tu rned out to be mathematics
Usi ng mathematics the Greeks began to question ancient beliefs
T o prove that the earth was not flat a g reek ph i losopher cal led Eratosthenes
devised an experi ment. The scientific method was born
He real ised that identical objects on a flat earth
shou ld always cast identical shadows. So,...
at the same ti me of day, i n two places, many m i les apart,
he put th is to the test
It was a beautifu I way er that he d iscovered where he used two sticks
He noticed that the rays com i ng from the su n...
prod uced d ifferent amou nts of shade...
i n each of the two sticks
Si nce the two sticks cast shadows of d ifferent lengths...
the earth's su rface had to be cu rved
And from the ang le of the shadows, Eratosthenes...
esti mated the earth's ci rcu mference. At twenty five thousand m i les
he was less than a h u nd red m i les out
Mathematics had beg u n to reveal the u n iverse as we see it today
The earth was not flat, it was rou nd
T oday's scientists also rely on mathematics
Ei nstei n's eq uations for g ravity pred ict what are cal led black holes
A black hole is a gaping void in space that sucks in and devours
anything that gets too near
It becomes com pact, massive and therefore able,
if it encounters someth i ng else, able to eat some more matter
It becomes the eater of al I th i ngs
But mathematical ly beautifu I theories are not always supported by observation
I n the earl iest days of astronomy,
the ancient G reeks fou nd the heavens less perfect than they had fi rst i mag i ned
Looki ng at the skies more closely,
they began to see stars move in a way which defied their logic
If every n ig ht you go out and you have a carefu I look er seei ng towards south,
after two or th ree days if you watch agai n you' I l see five stars
They look as movi ng from west towards the east someti mes
they look stayi ng sti I l
then they beg i n to move more er from the east towards the west...
and th is is someth i ng u n usual i n respect to the other stars of the sky
wh ich don't change any position
They gave these wanderi ng stars a name: planetos
They were seei ng the five nearest planets
The G reeks were convi nced the planets
had to be perfect spheres orbiti ng i n perfect ci rcu lar motion
But that did not fit with their observations
The astronomer Ptolemy finally found a way to explain what they saw
he added tiny circular adjustments to circular planetary orbits
and put everyth i ng i nside a...
sphere of fixed stars, with the earth at the centre
Ptolemy I ived over a centu ry after the death of Ch rist
The newly formed Christian church taught that
we on earth were the centre of God's creation
The cosmology of er the ch u rch is the cosmology of the Genesis
and er if someth i ng er has the same ideas as they are descri bed i n Genesis it's okay
For those who cou ld u nderstand the mathematics of Ptolemy's model,
wel I it's a model wh ich can foretel I the position of the planets
with any accuracy which is satisfying
And er on the other hand
there is nothing which can contradict the idea of the Genesis
Th ree, two, one, zero...
Lift off
T oday the clai ms of the scri ptu res are bei ng put to test by experi ments...
Iau nched i nto the heavens. The COBE satel I ite was able...
probe deep i nto space,
and back i n ti me,
to detect what ou r u n iverse was I i ke d u ri ng its earl iest moments
If you' re rel ig ious it's I i ke you know
you' re you' re seei ng the handwriti ng of God
when he wrote out how he was goi ng to make the u n iverse
Here's how the u n iverse is put together rig ht,
j ust you know read between the I i nes
and you' I l and you' I l know the rest of you for maki ng the u n iverse
Steady i m provements i n tech nology over the...
years have enabled us to test ou r theories about the u n iverse
But before such detai led observational evidence was avai lable...
bel ief i n any theory was as m uch a matter of faith and conviction as the...
resu It of any scientific scruti ny
Ptolemy's model of the u n iverse,
went vi rtual ly u nchal lenged for one thousand five h u nd red years, su pported...
al I the ti me by the Ch u rch,
wh ich was at that ti me the repository of learn i ng
Lord receive ou r g ifts
Let our offerings make us holy and bri ng us salvation
But by the sixteenth centu ry cathol ic scholars were faced
with i ncreasi ng ly accu rate observations of the heavens
It was on ly a matter of ti me
before the ch u rch's teach i ngs were u ndone by its own scholar priests
vice president teach i ng h istory of science, col lege d u rham
man not j ust i n the sense he was a cathol ic,
but he actual ly held a ch u rch office, as a canon of a cathed ral...
He had a g reat ad m i ration for Ptolymaic astronomy
Copern icus wanted to retu rn to a si m ple idea of planets
movi ng i n perfect ci rcles without the need for Ptolemy's adj ustments
He found their orbits would almost meet this ideal
if he took the earth from the centre of the u n iverse
and replaced it with the sun
It was a revol utionary moment for cosmology. Copern icus had rad ical ly re-...
organ ised the model of the u n iverse, wh ich had lasted for centu ries
He began began an i rreversi ble process...
that has downg raded us from the centre of the u n iverse,...
to the outer su bu rbs of one among m i I l ions of galaxies
We now have evidence...
that we are not i m portant...
i n yet another way
It seems that the ki nd of matter that we are made...
constitutes on ly a smal I fraction of the u n iverse.
Over n i nety percent is someth i ng we can not even see
Dark matter
It sort of puts one as a h u man bei ng i n some perspective,
that you know we we, the earth is not the centre of the solar system etc and...
we' re not even made of particu larly com mon matter that's arou nd,
because most of it's dark matter
I n the sixteenth centu ry the Ch u rch was su re
that God had put man and earth at the h u b of the u n iverse
And Copern icus's idea that planets shou ld orbit
the su n i n perfect ci rcles d id not q u ite match observations
So Ptolemy's earth centered u n iverse
seemed preferable
Copern icus d ied i n 1 543.
Some sixty years later, Johan nes Kepler,
a German astronomer provided strong su pport for the su n centered theory
after he d iscovered a new way to explai n the motion of planets
He broke with two with two thousand years of...
ph i losoph ical and astronom ical trad ition
What Kepler finished up with was non-ci rcu lar motion
He real ised that the planets are actually travelling in elliptical orbits
The great thing about Kepler's system is he can do everything
Copernicus did simply with one clear curve of the eclipse,
a colossal achievement
At fi rst the ch u rch fai led to see what was com i ng. But when the...
Ital ian scientist Gal I i leo Gal I i lei pu bl ished Copern icus's idea for...
everyone to read,
the Vatican fi nal ly took d rastic action to cu rb h is popu I ist i nsti ncts
We are now at the top floor of the villa ll Juliello
and the place where Gal I i leo...
spend h is last years of I ife as a prisoner
I n isolation, al I Gal I i leo cou ld do was fi n ish h is work on the
Iaws of motion which he had begun long before his house arrest
One problem he solved was why the earth seems to be sti I l
As it moves we move with it. We si m ply ride on its su rface
But he cou ld n't explai n why we d id n't fal I off
It was while working on the laws of motion that Gal I i leo...
stu m bled on someth i ng wh ich was desti ned to make nonsense of
the Ch u rch's view of the U n iverse
At the end of 1 609 he heard that there were i n i nto the market some
fu n ny objects wh ich were a tu be with some g lasses,
who were g ivi ng some fu n ny performance.
Th is i nstru ment was com i ng from Hol land and was sold as a toy
When Gal I i leo took it he began to be transformed from a toy...
to an i nstru ment
He started to use the mag n ification powers of
the telescope to look at the skies
Th is is a major step i n h is career and also i n the h istory of modern cosmology
The telescope transformed what cou ld be seen
Gal I i leo became fasci nated by distant planets like Jupiter
According to the Church his telescope should have revealed
a Universe where everything orbits the Earth. A system of perfect spheres
But it wasn't I i ke that
The moon was not so pol ished and so rou nd as people bel ieved,
but they were presented with val leys and mou ntai ns exactly as the earth
And he moved afterwards to other bod ies, he started to observe Mercu ry, Mars
But he was captu red by J u piter
He started to observe seriously J u piter i n Jan uary 1 61 0
and diary notes is very touching, says I have d iscovered a fu n ny body,
something like that which is ci rcu lati ng arou nd J u piter,
7 Jan uary if I remem ber correctly
And the day after he was immediately at the su nset at the telescope
Hardly believing his eyes he sketched what he saw
In a few days he became aware that these moons...
as he cal led them, were fou r,
and they were satel I ites because they were doi ng...
rhyth m ic and cycl ic performances arou nd the body of J u piter
Anyth i ng orbiti ng J u piter could not be orbiting the Earth
The church's model of the universe no longer made sense
Th is was the decisive step why Gal I i leo became convinced...
so he started to publish and started to produce...
work sayi ng be carefu I we can not stay...
anymore with Ptolemy. What the bi ble was sayi ng i n many ti mes...
about the position of the su n and the motion of the...
su n arou nd the earth was not tenable anymore
Gal I i leo entered a fig ht with the authorities...
the book of Copern icus was suspended and sent to correction
Gal I i leo was cal led to Rome at the T ri bu nal of I nq u isition
Fi nal ly he was condem ned
Gallileo retracted his claims, rather than face the full wrath of the Church,
perhaps even death at the stake
He was sentenced to spend the rest of h is I ife u nder house arrest
It's the beg i n n i ng of confl ict between science and rel ig ion, science and...
and theology and it's attention wh ich is goi ng to be...
many other episodes d u ri ng the modern age
Anyone who looks th roug h a telescope today
wi I l feel the same sense of wonder that Gal I i leo d id...
We can now see stars and galaxies so far away that the I ig ht from them
travel I i ng across space takes bi I l ions of years to reach us
We are looki ng back i n ti me, seei ng how they were
I ig ht years ago
Observi ng is er al most mystical
It's the act that really puts me i n contact with the rest of the u n iverse
I often th i n k if someone's looki ng back at me I wonder
if their telescope is bigger than mine
T oday's telescopes depend on refi nements i ntrod uced by lsaac Newton,
who was born i n 1 642, the year Gal I i leo d ied
I feel I have I i n ks
to both Newton and Gallileo
I now hold the same professorship at... Cam bridge that Newton once held,
and I was born...th ree h u nd red years to the day after Gal I i leo d ied
I n 1 660, with no formal ed ucation Newton
Ieft this house in Woolsthorpe to go to university
At Cam bridge more or less by chance...
he picked u p about fou r or five books on mathematics and he set to work to read...
them. Six months later he was maki ng...
i m portant contri butions to mathematics,
eig hteen months later he was the g reatest mathematician al ive
J ust staggeri ng, he taug ht h i mself,
j ust from fou r or five books and it al I came out of that
Newton's refi nements to the desig n of
Gal I i leo's telescope proved that he was more than j ust a theoretician
By i ncorporati ng an i nternal m i rror
he dou bled the telescope's power
The news of th is telescope was d istri buted arou nd Eu rope...
and that's actual ly what made h is name
And later on that desig n of telescope tu rned out to be the best one of
al I for studyi ng the heavens, so er i n that way he g reatly advanced astronomy
Newton had been at Cam bridge for several years
when the plag ue forced h i m to come back home here to Woolsthorpe
and at the time he left Cambridge he was beginning to think about
the laws of motion, how things are moving and he had the idea that
basically things would essentially move in a straight line
if they were left on their own
He was beginning to think of the forces...
that might be at work and one of the most obvious
is the pull of gravity which is pulling an object towards the earth
There's a popular myth that Newton discovered gravity
after watching an apple fall from a tree
I think it's probably true that he did start thinking about
these things from seeing apples fall,
but l' m absolutely certain that
he didn't have the complete theory of universal gravitation back here
in the plague year that the fu I l worki ng out came m uch later
His idea of gravity and he called it universal gravity,
because that is a very i m portant th i ng,
is that every single piece of matter i n the u n iverse pu I ls
every other piece of matter i n the u n iverse towards it and vice-versa
The earth is bi I l ions of ti mes more massive than
the apple so so basical ly the earth is moving ever so slightly towards
the apple but you just can't see that
The apple the motion of the apple is much more pronounced than that of the earth
The importance of the apple is that it symbolises the idea that
the laws of nature that are working on the earth
are also working throughout the whole u n iverse
Newton tu ned h is theory of g ravity to the heavens to see if Kepler's ideas...
wou ld match u p with h is own. He com bi ned Gal I i leo's...
Iaws of motion with h is own eq uations for g ravity
And he saw that together they explai ned precisely the path...
of the moon rou nd the earth
And that was enoug h to g ive Newton the h i nts to then
apply those same tech n iq ues of Gal I i leo
but now to the planets and that essential ly...
the whole of the u n iverse
Even the Ch u rch was fi nal ly convi nced
Newton swept away the last vestiges of the old Ptolemaic system
He believed that gravity would control the whole universe
It was gravity which kept us on a moving Earth
And gravity would keep all the stars i n the u n iverse movi ng
Newton's u n iverse wou ld stretch out forever
He was the fi rst person who had a mathematical descri ption of
the u n iverse wh ich man ifestly...
worked. And the title of h is g reat book,
the Pri nci pia that real ly makes the poi nt,
he descri bed it as the mathematical pri nci pals of...
natu ral ph i losophy
Accord i ng to Newtons theory...
the u n iverse ran I i ke clockwork...forever...
I th i n k people were comforted
by the thoug ht that even thoug h they g rew old
and d ied the u n iverse was eternal and unchanging
Inspired by Newton's ideas
an age of gentlemen astronomers began
I am Wi I l iam Brandon the 7th Earl of Rosse, great g reat g randson of the...
3rd Earl, who is also another Wi I l iam
H is g reat ach ievement was the bu i ld i ng of...
the g reat six foot telescope or the Leviation of the Parsons T own,
as it was cal led
That was the biggest and the most powerfu I telescope
i n the world u p to the present centu ry
The 3rd Earl...
bu i It h is telescope i n 1 850, i n the marshy lrish countryside outside Dublin
He made everything he needed himself here
He made it in a foundry that he set up in the bottom of the moat,
that was fuelled by the turf from the local bogs by making the most of
all the resources he had
My name is Francisco Diego,
I am involved with optical design at University College London
and we are planning to build a new mirror for this telescope
The Leviathan...
of Parsonstown worked in the same way as Newton's telescope:
i mages from space were concentrated on a concave m i rror
I n Newton's telescope th is m i rror was five i nches wide
Two h u nd red years later the th i rd Earl had bu i It h i mself a...
m i rror with a massive six foot d iameter
With er telescopes I i ke Gal I i leos's or Newton's you cou ld on ly er...
see the solar system
I mean the moon, the su n, the planets and er al most noth i ng else
And you see here a plate...
of the six foot telescope with an
observer... here i n position
Remem beri ng of cou rse that th is is a reflecti ng telescope
so the observers had to get i nto position at the at the top to look rig ht...
down the length of the tube to see the i mage reflected
i n the g iant six foot m i rror at the bottom
I was browsi ng i n you r library and found this book
This is a transactions of the Royal Society...
1 850 or something like that
And there is the 3rd Earl's lovely drawing of the Whirlpool
The whirlpool galaxy
The first time the whirlpool galaxy was ever seen
The telescope gave new detail
to what had been assumed to be clouds of gas
However at the ti me observers d id n't real ise that
they were actual ly seei ng th roug h the m i I l ions of stars
in our own Milky Way Galaxy to other equally vast galaxies of stars
Meanwhile scientists were beginning to realise that
some of the secrets of the u n iverse lay h idden i n I ig ht...
itself. A tech n iq ue was soon to be fou nd to u n lock them
It was cal led spectroscopy
Spectroscopy is the u m analysis...
of I ig ht
The er i nformation that we get from starl ig ht
or from su n I ig ht or from I ig ht i n general is is tremendous, is enormous
Spectroscopy was d iscovered...
i n about 1 81 4, by a German optical physicist...
Joseph Von Frauen hofer
He was an optical man ufactu rer. He was worki ng i n a com pany wh ich was bu i ld i ng...
Ienses for astronomers
He was very method ical, he used...
to write everyth i ng he he d id...
and fortu nately we have these texts of h is own very words of the...
fantastic d iscovery
I n a sh uttered room I al lowed su n I ig ht to pass th roug h
a narrow open i ng i n the sh utters...
onto a prism
I fou nd with the telescope al most cou ntless...
strong and weak vertical I i nes crossi ng the spectru m
wh ich however are darker than the remai n i ng part of the spectru m
of the colou r i mage. Some seem to be nearly com pletely black
He cou ld n't explai n the orig i n of these I i nes,
he j ust saw that part of the spectru m was m issi ng
Hidden in these black lines was extraord i nary new i nformation
about the chem ical structu re of the U n iverse
Lig ht is orig i nated i n atoms
Light is originated every time
that um electrons in these atoms are jumping up and down
It's a em ittti ng or absorbi ng I ig ht at a particu lar freq uency
So each chem ical element has a particu lar way of behaviou r,
the the electrons are j u m pi ng i n particu lar places
So depend i ng on these places is the position of the line in the spectrum
So if the line appears here you may say ah this is hydrogen,
but if the line appears here no this is not hydrogen this is sodium etc.
So in the solar spectrum we have the finger prints of
a lot of chemical elements that we can identify i n ou r labs,
because with the same eq u i pment we take a spectru m of a, of a lam p,
say for exam ple an arc of i ron and we can prod uce the same I i nes i n ou r labs
and we match the I i nes from the su n with the I i nes from the,
from the er er er lam p i n ou r, i n ou r laboratory and the match is perfect
Usi ng spectroscopy it was fou nd that
the chem ical content of ou r su n was identical to that
of any star i n the U n iverse
Ou r su n and ou r solar system itself, was j ust one of an i nfi n ite n u m ber of others
Perhaps we ou rselves have no special place i n the u n iverse
The chem istry of stars is more or less the same as the chem istry of the su n,
so the su n becomes a star or stars become su ns.
Th is is a a... big revol ution. Th is is I i ke Copern ican revol ution
when when you abandon the idea that the earth is the centre of the u n iverse
and you say wel I er it's no longer the centre of the u n iverse,
now the su n may be the centre at least of the solar system
and that that was a major revol ution i n i n science
Now we have another revol ution i n wh ich we say wel l
we are not u h so special about it because u h ou r own bod ies,
ou r own chem istry, ou r blood, ou r bones, ou r ski ns,
they are made of u h hyd rogen, n itrogen,
oxygen u h etc sod i u m etc and we fi nd hyd rogen and oxygen etc
i n i n er i n nebu lae, i n stars, i n i n the u n iverse
So it is the same chem istry, so there's noth i ng special about it
If people and planets share the same chem istry,
perhaps everyth i ng i n the Universe has the same beginning
The cl ue to ou r com mon origins came from another discovery about light...
by the Austrian scientist, Christian Dopler
The Dopler shift has been...
perhaps one of the most important tools i n astrophysics,
I wou ld say i n cosmology now, because it is ou r speedometer if you I i ke,
it is the, the the meter that we use to measu re the speed of
al most everyth i ng i n the u n iverse
Dopler suggested that
if an object emitting light is moving towards or away from us,
then the light it gives off will appear to be altered
We can't observe th is is i n everyday life, because light moves too fast
But we experience the same effect with sou nd
As the sou rce of the sou nd moves the sou nd waves
change thei r shape They are sq uashed together as the sou nd approaches
and stretched as the sou nd... moves away. The change i n pitch is aud i ble and...
th is is the Dopler sh ift
By analysi ng star I ig ht...
scientists fou nd the Dopler sh ift at work i n the spectru m
If the I ig ht sou rce was approach i ng,
the Frauenhofer lines are shifted towards the bl ue end of the spectru m
It's a bl ue sh ift
If the light source is receeding,
these I i nes move towards the red end of the spectru m. A red sh ift
These extraord i nary patterns i n starl ig ht
broug ht the dawn of a new age for cosmology
It became possi ble to tel I not on ly
what the u n iverse was made of but also how it was movi ng
The breakth roug h came...
by analysi ng I ig ht from deep i n the u n iverse
Lig ht seen th roug h powerfu l new telescopes i n America
They cou ld reveal detai ls... of the u n iverse never seen before
Everybody knew what the M i I ky Way galaxy was,
the col lection of bi I l ions of stars to which the sun belonged,
but nobody knew what these little patches...of nebu las material,
that looked I i ke spi rals and er pancakes and so on were
and some people thoug ht that the M i I ky way galaxy was the whole u n iverse
and these I ittle spi rals were wisps of gas er in that universe
The most famous person that worked at Mou nt Wi lson was Edwi n H u bble...
who came here when he was q u ite you ng actual ly,
rig ht after h is service i n World War 1, and H u bble had the golden touch
He had a knack of picking the important problems
Using the new hundred inch telescope,
Hubble looked deep into space at the nebulous objects first identified
in lreland by William Parsons, the 3rd Earl of Rosse
Making use of...
Observatory roof open i ng the extraord i nary clarity of
the atmosphere over Mou nt Wi lson, wh ich is the best on the conti nent
He was able to distinguish individual stars i n these I ittle clouds...of gas,
these so cal led nebulae and that told him in itself that
they were not er wisps of gas in our galaxy,
but galaxies in their own right, each one containing billions...
of stars and that the universe,
the true universe was populated with countless numbers of island universes,
each one like our Milky Way galaxy
The distances that he measured were absolutely stu pefyi ng
to the astronomers at that time
He fou nd that the and rom ida nebu lar wh ich is the closest galaxy to us I i ke ou r own,
was at least one m i I l ion I ig ht years away and a I ig ht year is six tri I l ion m i les,
a very very g reat d istance, far outside the edge of ou r M i I ky Way...galaxy
For the fi rst ti me we knew how big the u n iverse was with that d iscovery
A col leag ue of H u bble's, Vesto Sl i pher,
began to use Doppler's theory to analyse I ig ht
All of the galaxies that he could see arou nd h i m had... red sh ifts,
er they were sh ifted towards longer wavelengths and that
wou ld mean of cou rse that relative to us they were movi ng away
Er when Sl i pher gave th is report everybody stood u p and cheered
They d id n't know what it meant,
but they had a gut feeling that is was something cosmic in significance
Unknown to Slipher,
an obscu re German physicist was working on a theoretical explanation
It was an extraord i nary u ndertaki ng for a patent clerk,
who had shown I ittle academ ic prom ise,
but he was about to devise a revol utionary view of the u n iverse,
i n wh ich he pictu red space and ti me as the same th i ng.
He was Al bert Ei nstei n
He was forced to learn a lot of very com pl icated mathematics,
erm i n order to do so. But i n 1 91 5 fi nal ly the theory was born
Al bert Ei nstei n's general theory of relativity published
in 1 91 5 overturned Newton's theory of gravity
In Einstein's theory objects did not pull directly on one another
Instead they made dimples or warps in space and time
One object passi ng another wou ld have its path deflected by these warps
and therefore wou ld seem to be attracted towards it
And the equations had further implications
So one thing to understand about general relativity is that
you can't have a whole col lection of matter say of galaxies
or stars wh ich are sitti ng i n static config u ration
with respect to each other and expect them to stay there
They won't, they are goi ng to col lapse i n towards each other.
So th is means that...
U m you can't have a static model of the u n iverse i n general relativity
The model, the u n iverse either has to be expand i ng or it has to be contracti ng
It has to be dynam ical i n some way it can't possi bly be static
Even Einstein resisted the implications of his theory at first and
he adjusted the maths to avoid them
But he couldn't prevent other scientists from seeing the possibilities
The astronomers looked...
at Sl i pher's d iscovery of the motion of the galaxies and the pred iction that
the u n iverse expands and said ah ha these are two sides of one coi n,
they fit together
And Hubble again with that golden touch for working on the big problems
turned his attention to this question and he asked himself how can I investigate it
And the way he did so was to start to measu re the red sh ifts as they' re cal led,
the...velocities with wh ich these u h galaxies are movi ng away from us
H u bble began the process of systematically analysing light
from thousands of galaxies usi ng spectroscopy. The resu lts were staggeri ng
And he fou nd someth i ng known today as H u bble's Law,
q u ite extraord i nary that the red sh ift
or the velocity of recession from us is proportional to d istance
If a galaxy at this distance is movi ng away from you
at a certai n speed a galaxy twice as far away wi I l be g uaranteed
to be movi ng away from you at twice the speed
H u bble actual ly changed... the pictu re of the u n iverse,
because the Ptolemaic pictu re was static and
Newton's pictu re of the u n iverse was static
U h but H u bble showed that the u n iverse is dynam ic
Everyth i ng is movi ng away from everything else
G reek astronomers thoug ht most of them, not al I of them...
that the earth was the centre of the u n iverse
Copern icus showed that was not so and
thoug ht the su n was the centre of the u n iverse
Other later astronomers showed no the su n was not the centre of the u n iverse,
but many of them thoug ht that
the centre of ou r galaxy was the centre of the u n iverse
H u bble showed that there is no centre and that
was a tremendous scientific theolog ical and philosophical accomplishment
He showed that the universe is as far as the telescope can see is populated
with countless numbers of island universes and there is no difference whatsoever
There is no centre
The second er i m pl ication of h is fi nd i ng was u h wel I to explai n it,
imagine that the picture of the expanding galaxies,
moving away from us and one another is a movie stri p
Now ru n that i n reverse and
al I the galaxies going backward i n ti me come closer and
closer together and fi nal ly they all meet together at one point,
speaki ng loosely because there is no one poi nt,
there is no centre i n the u n iverse, they al I come together
at an i nfi n itely dense and yet i nfi n itely extended er moment and beyond
that of infinite density one cannot go
So that moment marks the beginning of the birth of the universe and
all of the things that we see arou nd us, every star, every planet,
every I ivi ng th i ng on the earth and
i n the cosmos owes it's genesis to that moment
You can cal I it the Big Bang,
but you can also cal I it with accu racy the moment of creation
T oday, the space telescope named after H u bble, sends us these actual photog raphs
from the fu rthest corners of ou r u n iverse. Confi rm i ng that seei ng tru ly is bel ievi ng
From sitting at the centre of the u n iverse...
we now fi nd ou rselves orbiti ng an average sized su n,
wh ich is j ust one of m i I l ions of stars i n ou r...own M i I ky Way galaxy
And ou r galaxy itself... is j ust one of bi I l ions of galaxies,
i n a U n iverse that is infinite and expanding
But th is is far from the end of a long history of enquiry
Huge questions remain to be answered,
before we can hope to have a com plete pictu re of the u n iverse we I ive i n