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It is a good rule of
thumb that, in science,
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the simplest questions are
often the hardest to answer.
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Questions like, how did the universe begin?
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In fact, until relatively recently,
science simply didn't have the tools
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to begin to answer questions about
the origins of the universe.
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But in the last 100 years, a
series of breakthroughs have been
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made by men and women who, through
observation, determination
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and even sheer good luck, were able
to solve this epic cosmic mystery.
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This was real astronomical gold.
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I am going to recreate their
most famous discoveries
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and perform their greatest experiments...
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30,000 km/s.
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..that take us from the very
biggest objects in the universe
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to the infinitesimally small,
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until I reach the limits of
our knowledge by travelling
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back in time to recreate the
beginning of the universe.
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The moment one millionth of
a second after the universe
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sprang into existence.
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This is a time before matter
itself has formed in any way
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that we would recognise it.
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It is as close as we can
hope to get to creation,
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to the beginning of time,
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the beginning of the universe itself.
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It is a remarkable fact that science
took hundreds of years to come up
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with a theory to explain the
origins of the universe.
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All the more surprising,
given what a simple
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and fundamental question it is.
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There is something quintessentially
human about asking the question,
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where does all of this come from?
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Perhaps because it is a deeper,
more fundamental version of
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where I come from?
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Yet, for most of human history,
the answers to such an apparently
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simple question could only
be attempted by religion.
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It wasn't until the middle of
the 20th century that science
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built a coherent and persuasive
creation story of its own.
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It was a story based on theory,
predictions and observation,
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a story that could finally explain
what had happened at the very
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beginning of time, the beginning
of the universe itself.
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A little over 100 years ago, if
scientists considered the life of
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the universe at all, they considered
it eternal, infinite and stable.
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No beginning and no end.
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So even framing the question about
the origins of the universe
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was impossible.
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But at the beginning of the 20th
century, that began to change.
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New discoveries shook the old certainties
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and paved the way for questions
about where the universe came from.
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One observation transformed our idea about
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the true scale of the universe.
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It began with a mystery in the sky.
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By the early part of the 20th
century, it was well known
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that our solar system way
within a galaxy, the Milky Way.
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Every single star we can see
in the sky with the naked eye
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is within our own galaxy and,
until the 1920s, all these stars,
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this single galaxy, was the full
extent of the entire universe.
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Beyond it was just an empty void.
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But there were some enigmatic
objects up there as well,
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just discernible to the naked
eye that looked different.
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And one of the most notable is Andromeda.
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You can find Andromeda if
you know where to look.
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So, if you start from
Cassiopeia, those five stars
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shaped like a sideways letter M,
if you move across from the point,
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from the points of the M, slightly
up is where you should find it.
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Now, I'm going to use my binoculars
to help me in the first instance.
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And if I zoom across...
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Yeah, there it is.
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You can tell it's not a star.
I mean, it's basically
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a very faint smudge stuck
between those two stars.
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That is it straight up there -
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that is M31, the great Andromeda nebula.
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Now, they were called nebulae,
because they had this smudgy,
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sort of wispy, cloudy nature.
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In fact, the word nebula derives
from the Latin for cloud.
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These indistinct objects were found
scattered throughout the night sky.
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Telescopes revealed many of these
nebulae were far more complex
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than simple clouds of interstellar gas.
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They appeared to be vast
collections of stars
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and that raised two
intriguing possibilities.
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Were these stellar nurseries
places where stars were born,
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and therefore residing
within our own galaxy, or,
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much more profoundly, were these
beautiful, enigmatic objects
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galaxies in their own right sitting
way outside the Milky Way?
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The implications of that second
possibility were enormous.
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If true, it would instantly
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and utterly transform our idea
about the size of the universe.
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Here was an opportunity for an
ambitious astronomer to make
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a real name for themselves.
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Perhaps someone with a
really big telescope.
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Step forward this man - Edwin
Hubble, a man from Missouri,
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although if you had ever met
him, you'd never have guessed,
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because he developed this weird
persona, a pipe smoking tea drinker
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with a very affected
aristocratic English accent.
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Hubble is probably the most
famous astronomer ever,
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not least because of his consummate
skill at self-promotion,
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but also because of the incredible
measurements he would make.
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In Hubble's day, when
it came to observations
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and new discoveries, size mattered.
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Today, this is the most powerful
optical telescope in the world,
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the GTC, with a primary mirror
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over 10 metres, or 400 inches, in diameter.
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Far bigger than anything Hubble had.
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In September 1923,
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Hubble was working at what was
then the biggest telescope
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in the world, the 100-inch Hooker telescope
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at the Mount Wilson Observatory,
perched on top of the
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High Sierra mountains overlooking
Los Angeles in California.
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He was using the telescope to
study one of the most prominent
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nebulae in the sky, the Andromeda nebula.
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The same nebula I looked at earlier,
and it was while observing it
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that one very special star
caught Hubble's attention,
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one that could reveal the
true nature of Andromeda.
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And I am going to use this
telescope to look for it now.
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This is the control room of the
GTC and, tonight, they've pointed
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the telescope at Andromeda and they
are going to take a picture of it.
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It takes about a minute for the exposure
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- to give you a clear enough image?
- That's right.
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Now, the picture is finished,
so we're going to open it.
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OK, so, this is Andromeda here.
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That's Andromeda, that's right.
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And now, this is Hubble's original plate.
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Right, now, Hubble's star is
down here in this corner.
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Can you find it in your image?
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Yeah, if you take the
image and you compare it,
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you will see that we don't see that one.
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What we see is the edge of the galaxy,
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so we have to go a little
bit further west...
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- Oh, I see, so all this is just the edge.
- That's the edge.
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I was assuming it was
the centre of the galaxy.
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No, no, no.
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It just goes to show how much more
resolution your telescope can get.
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- That's right.
- OK, so, can we see that particular star?
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Yes, in order to find that particular star,
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because it is so faint,
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we have to look for references
which are brighter.
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And, in this case, you will
see four stars in here,
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which are these four stars.
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And the star Hubble found
will be this one here.
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That's it...
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That tiny star is the
one that Hubble found.
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That's amazing.
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And are you able to get a
magnitude for that star?
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Yeah, we have to do a little bit
of processing on the image,
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but we are able to get it.
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OK. Hubble had found his star.
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He knew it was special,
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because he compared his plate with
others taken over previous nights
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and he noticed that his star
changed in brightness -
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some nights it was brighter,
some nights it was dimmer.
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He realised this is a variable star,
and he saw the significance of it.
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He could see that this was
real astronomical gold.
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His star was a Cepheid variable.
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In the stellar bestiary,
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Cepheid variable stars
hold very special place...
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..because, by studying the way
their brightness changes,
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astronomers can calculate
how far away they are.
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Hubble's Cepheid was the first
to be discovered in a nebula,
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so he knew that, if he
could measure its period,
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he would be able to work
out its distance from us.
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So, Hubble set about meticulously measuring
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how his star's luminosity varied.
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It's not hard to imagine how exciting
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this must have been for Hubble.
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At his fingertips was the
opportunity to resolve
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a fundamental yet simple question -
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was this nebula within the
Milky Way or beyond it?
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The answer would reshape our
knowledge of the universe.
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Hubble measured the
luminosity, or brightness,
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of his star over many nights
and plotted this curve here.
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Now, when we measured tonight,
we found it had a value of 18.6
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and I know because they measured it
last night to be slightly dimmer
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that it falls on this side of the curve.
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But more important is the period,
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the time in days, from peak
brightness to peak brightness.
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Hubble measured this to be 31.415 days.
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This is the critical measurement.
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Armed with this and its
apparent brightness,
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Hubble calculated the distance
to the Andromeda nebula.
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It was immediately apparent that
this star is very far away.
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But when Hubble did his calculation,
he worked out that it was
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900,000 light years away,
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making this star the most
remote object ever recorded.
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It could mean only one thing -
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not only is Andromeda a
galaxy in its own right...
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..but it lies well beyond
our own Milky Way...
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..and the myriad of other elliptical
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and spiral nebulae were also
individual distant galaxies.
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It was a moment in human
consciousness when the universe
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had suddenly and dramatically
got considerably bigger.
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With this observation, Hubble had
redrawn the observable universe.
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It might not have directly challenged
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the idea of a stable universe,
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but it shattered long-held
assumptions and opened
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the possibility of other bigger secrets,
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like an origin to the universe.
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Into this profoundly-expanded
cosmos strode someone who would,
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without realising it, provide the
tools to unlock that secret.
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This guy.
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A story as great as one that explains
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the origins of the universe would
somehow feel wrong without involving
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a scientist as great as Albert Einstein.
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And so, of course, it does,
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because it was Einstein who provided
the theoretical foundations
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needed to study the universe
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and effectively invent the
science of cosmology.
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100 years ago, he proposed his
general theory of relativity.
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It turned physics on its head and gave us
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a completely new
understanding of the world.
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He proposed that gravity
was caused by the warping
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or bending of space-time by massive
objects like planets and stars.
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His theories were revolutionary.
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Einstein was a maverick who
ignored the conventional
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to follow his own remarkable instincts.
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One of his lecturers once told him,
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"You are a smart boy,
Einstein, a very smart boy.
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"But you have one great fault -
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"you do not allow yourself
to be told anything."
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Of course, it was this very
quality that would allow him
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to change the world of physics
and, of course, to mark him out
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as one of the greatest
thinkers of the 20th century.
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And in 1917, he took his
general theory of relativity
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and applied it to the entire universe.
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By following the logic of his theory,
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he arrived at something rather unsettling -
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the combined attraction of gravity from all
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the matter in the universe would pull every
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object in the cosmos
together, beginning slowly
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but gradually accelerating until...
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Gravity would ultimately
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and inevitably lead to the
collapse of the universe itself.
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But Einstein believed, like
virtually everyone else,
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that the universe was eternal
and static and certainly wasn't
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unstable or ever likely
to collapse in on itself.
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But his equations appeared
to show the opposite.
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In order to prevent the
demise of the universe
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and keep everything in balance,
he adds this in his equation -
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Lambda, or the Cosmological Constant.
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It is a sort of made-up
force of anti-gravity
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that acts against normal gravity itself.
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Now, he had no evidence for
this, but it helped ensure
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that his equations described
a stable universe.
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Within his grasp was the secret
to the origins of the universe.
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Yet Einstein simply couldn't,
or wouldn't, bring himself
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to accept the implications
of his own equations.
243
00:17:01,040 --> 00:17:04,880
With hindsight, it seems
remarkable that Einstein did this.
244
00:17:04,880 --> 00:17:08,320
I mean, here was a man who
had revolutionised science
245
00:17:08,320 --> 00:17:10,920
by rejecting conventional wisdom
246
00:17:10,920 --> 00:17:14,840
and yet, he couldn't bring
himself to trust his own theory.
247
00:17:14,840 --> 00:17:18,000
He felt compelled to massage his equation
248
00:17:18,000 --> 00:17:20,240
to fit the established view.
249
00:17:20,240 --> 00:17:22,880
He even admitted that the
Cosmological Constant
250
00:17:22,880 --> 00:17:27,360
was necessary only for the
purposes of making a quasi-static
251
00:17:27,360 --> 00:17:32,240
distribution of matter, basically
to keep things the way they were.
252
00:17:32,240 --> 00:17:35,880
Whatever his reasons, this
little character, Lambda,
253
00:17:35,880 --> 00:17:37,440
would return to haunt him.
254
00:17:41,240 --> 00:17:44,560
Because, while it prevented
Einstein from understanding
255
00:17:44,560 --> 00:17:45,800
the implications...
256
00:17:48,360 --> 00:17:51,880
..his ideas opened the way
for someone else to propose
257
00:17:51,880 --> 00:17:54,520
a theory for the origin of the universe.
258
00:17:59,720 --> 00:18:04,520
He was a young part-time university
lecturer of theoretical physics.
259
00:18:06,560 --> 00:18:09,920
His idea was so radical, it
shocked the world of physics
260
00:18:09,920 --> 00:18:12,280
and split the scientific community.
261
00:18:12,280 --> 00:18:16,560
He started an argument that wouldn't
be resolved for half a century.
262
00:18:16,560 --> 00:18:18,600
His name was Georges Lemaitre.
263
00:18:21,240 --> 00:18:24,280
Now, the eagle-eyed might
spot the dog collar.
264
00:18:24,280 --> 00:18:28,200
In fact, he was both a physicist
and an ordained priest.
265
00:18:28,200 --> 00:18:30,720
Of this apparently curious dual role,
266
00:18:30,720 --> 00:18:34,200
Lemaitre said, "There were two
ways of pursuing the truth.
267
00:18:34,200 --> 00:18:36,440
"I decided to follow both."
268
00:18:36,440 --> 00:18:39,080
And, using Einstein's theory of relativity,
269
00:18:39,080 --> 00:18:41,880
he developed his own cosmological models.
270
00:18:43,320 --> 00:18:46,360
Lemaitre's model described a universe that,
271
00:18:46,360 --> 00:18:49,760
far from being static,
was actually expanding,
272
00:18:49,760 --> 00:18:52,520
with galaxies hurtling
away from one another.
273
00:18:56,840 --> 00:19:00,040
Furthermore, Lemaitre saw
the implications of this.
274
00:19:00,040 --> 00:19:03,600
Winding back time, he deduced
that there had to be a moment
275
00:19:03,600 --> 00:19:08,000
when the entire universe was
squeezed into a tiny volume,
276
00:19:08,000 --> 00:19:10,720
something he dubbed the primeval atom.
277
00:19:13,600 --> 00:19:17,520
This was essentially the first
description of what became known
278
00:19:17,520 --> 00:19:21,880
as the big bang theory, the moment
of creation of the universe.
279
00:19:27,680 --> 00:19:31,360
These were revolutionary ideas
and so he published them
280
00:19:31,360 --> 00:19:35,840
in the Annales de la Societe
Scientifique de Bruxelles,
281
00:19:35,840 --> 00:19:39,600
where they were promptly ignored
by the scientific community.
282
00:19:41,760 --> 00:19:45,960
So, he travelled to Brussels to
try to gain support for his idea.
283
00:19:49,400 --> 00:19:54,280
The 1927 Solvay Conference, held
here in Brussels, was probably
284
00:19:54,280 --> 00:19:58,240
the most famous and greatest
meeting of minds ever assembled.
285
00:20:01,400 --> 00:20:02,640
But for our story,
286
00:20:02,640 --> 00:20:05,560
the most significant meeting
didn't happen here.
287
00:20:05,560 --> 00:20:08,840
It wasn't planned and happened
away from the conference.
288
00:20:10,800 --> 00:20:12,040
It happened here.
289
00:20:14,440 --> 00:20:18,520
In this park, the unknown Lemaitre
approached the most famous,
290
00:20:18,520 --> 00:20:21,120
the most feted scientist in the world -
291
00:20:21,120 --> 00:20:22,520
Albert Einstein.
292
00:20:25,000 --> 00:20:29,520
Here, finally, was his chance to
explain his idea about an expanding
293
00:20:29,520 --> 00:20:34,920
universe to the very person whose
theory he had used to derive it.
294
00:20:34,920 --> 00:20:38,800
You can only imagine Lemaitre's
trepidation as he approached.
295
00:20:38,800 --> 00:20:41,880
If Einstein endorsed his radical idea,
296
00:20:41,880 --> 00:20:43,720
then surely it would be accepted.
297
00:20:43,720 --> 00:20:47,520
Surely this brilliant mind,
this titan of physics,
298
00:20:47,520 --> 00:20:51,280
this deeply original thinker, would
see the merits of his theory.
299
00:20:52,760 --> 00:20:55,080
But after a brief discussion,
300
00:20:55,080 --> 00:20:58,240
Einstein rejected his idea out of hand.
301
00:20:58,240 --> 00:20:59,880
According to Lemaitre, he said,
302
00:20:59,880 --> 00:21:02,160
"Vos calculs sont corrects,
303
00:21:02,160 --> 00:21:05,200
"mais votre physique est abominable."
304
00:21:05,200 --> 00:21:06,840
As far as Einstein was concerned,
305
00:21:06,840 --> 00:21:09,880
his maths might have been
correct, but his understanding
306
00:21:09,880 --> 00:21:13,560
of how the real world worked
was, well, abominable.
307
00:21:16,040 --> 00:21:20,680
Once again, Einstein dismissed
the idea of a dynamic universe.
308
00:21:25,280 --> 00:21:28,400
Lemaitre's paper should
have ignited science,
309
00:21:28,400 --> 00:21:31,720
but without the backing of such a
huge and influential figure as
310
00:21:31,720 --> 00:21:37,960
Einstein, his ground-breaking idea
was doomed to be quietly forgotten,
311
00:21:37,960 --> 00:21:42,800
unless some observation or
evidence showed up to support
312
00:21:42,800 --> 00:21:44,960
the idea of an expanding universe.
313
00:21:52,160 --> 00:21:55,760
Edwin Hubble, here, was riding
high after his discovery that
314
00:21:55,760 --> 00:21:58,400
proved there were galaxies
outside of our own.
315
00:21:58,400 --> 00:22:01,000
He was feted by Hollywood glitterati,
316
00:22:01,000 --> 00:22:03,000
a guest of honour at the Oscars,
317
00:22:03,000 --> 00:22:05,840
and, with access to the world's
most powerful telescope,
318
00:22:05,840 --> 00:22:07,920
he was ready for his next challenge.
319
00:22:13,240 --> 00:22:17,520
He had heard of some unusual
observations that many galaxies
320
00:22:17,520 --> 00:22:19,880
appeared to be moving away from us.
321
00:22:21,800 --> 00:22:24,360
No-one could understand why this might be.
322
00:22:27,080 --> 00:22:30,720
So, in 1928, the world's
most famous astronomer
323
00:22:30,720 --> 00:22:35,400
turned his attention to this new
cosmic mystery and began to measure
324
00:22:35,400 --> 00:22:39,160
the speed that these galaxies
were moving relative to Earth.
325
00:22:44,200 --> 00:22:47,640
To measure the velocity that a
galaxy was receding from us,
326
00:22:47,640 --> 00:22:50,320
Hubble use something called redshift.
327
00:22:50,320 --> 00:22:54,160
Now, it's not a perfect analogy,
but the effect is similar to one
328
00:22:54,160 --> 00:22:56,720
most of us are familiar with in sound -
329
00:22:56,720 --> 00:23:00,160
the pitch of a car engine as
it approaches us is higher,
330
00:23:00,160 --> 00:23:02,800
because the sound waves are compressed,
331
00:23:02,800 --> 00:23:06,040
but the pitch drops lower
as the car recedes,
332
00:23:06,040 --> 00:23:08,400
because the sound waves are stretched.
333
00:23:11,480 --> 00:23:13,720
The effect is similar with light waves.
334
00:23:13,720 --> 00:23:17,560
As the source of light moves towards
us, the observed wavelength
335
00:23:17,560 --> 00:23:21,040
is squashed towards the violet
or blue end of the spectrum.
336
00:23:21,040 --> 00:23:23,640
But if the source is moving away from us,
337
00:23:23,640 --> 00:23:27,280
the wavelength is stretched towards
the red end of the spectrum,
338
00:23:27,280 --> 00:23:30,480
or redshifted, in the
parlance of astronomers.
339
00:23:30,480 --> 00:23:33,680
And the greater the velocity
the object is receding,
340
00:23:33,680 --> 00:23:35,200
the greater the redshift.
341
00:23:39,440 --> 00:23:43,720
With his assistant, Milton Humason,
Hubble spent the next year
342
00:23:43,720 --> 00:23:46,720
carefully measuring the
redshift of galaxies.
343
00:23:47,920 --> 00:23:50,840
And I have got the chance to
do the same thing right now
344
00:23:50,840 --> 00:23:52,400
using this telescope.
345
00:23:55,560 --> 00:23:59,160
OK, Massimo, have you
found a galaxy for me?
346
00:23:59,160 --> 00:24:01,880
Yes, I found this galaxy.
347
00:24:01,880 --> 00:24:03,920
So, how far away is this?
348
00:24:03,920 --> 00:24:08,400
It is approximately 430 megaparsec far.
349
00:24:08,400 --> 00:24:12,440
So, if you convert that to light years...
430 x 3.26...
350
00:24:12,440 --> 00:24:17,280
So it's about 1.5 billion light years away.
351
00:24:17,280 --> 00:24:19,080
- Yeah, yeah.
- OK.
352
00:24:21,160 --> 00:24:25,800
Hubble needed to measure the average
light coming from the galaxy
353
00:24:25,800 --> 00:24:29,440
in order to get a spectrum, so that
he could calculate the redshift.
354
00:24:29,440 --> 00:24:33,560
Now, Humason did this by
exposing a photographic plate
355
00:24:33,560 --> 00:24:36,920
and it took him a whole week
to collect enough light
356
00:24:36,920 --> 00:24:38,320
to get the spectrum.
357
00:24:38,320 --> 00:24:42,040
But here at the TNG, the Galileo
Telescope, they use instead
358
00:24:42,040 --> 00:24:45,960
a very sensitive chip that can
do this much more quickly.
359
00:24:45,960 --> 00:24:49,040
How long does it take for
you to get a spectrum?
360
00:24:49,040 --> 00:24:52,520
Approximately 10, 15 minutes.
361
00:24:52,520 --> 00:24:55,680
So, 10 or 15 minutes'
exposure compared with a week
362
00:24:55,680 --> 00:24:57,280
back in Hubble's time -
363
00:24:57,280 --> 00:25:00,160
far more powerful than
anything they had back then.
364
00:25:02,120 --> 00:25:05,360
- It's done.
- The spectrum is quite good.
365
00:25:05,360 --> 00:25:07,040
Ah.
366
00:25:07,040 --> 00:25:10,480
OK, so this is the raw
spectrum that has been taken.
367
00:25:10,480 --> 00:25:13,840
Is there a particular emission
line here that you will
368
00:25:13,840 --> 00:25:16,026
use as your reference
to measure the redshift?
369
00:25:16,031 --> 00:25:16,760
Yeah.
370
00:25:16,760 --> 00:25:20,880
Here, for example, you
have an emission line,
371
00:25:20,880 --> 00:25:24,880
but to obtain real spectra,
372
00:25:24,880 --> 00:25:29,240
you have to clean it to
obtain the final one.
373
00:25:29,240 --> 00:25:32,619
Ah, this is the
cleaned-up version of that.
374
00:25:32,624 --> 00:25:33,800
Yes, of that.
375
00:25:33,800 --> 00:25:37,096
So this is the actual emission
lines from the galaxy...
376
00:25:37,101 --> 00:25:38,200
Yes.
377
00:25:38,200 --> 00:25:41,440
And this one below, I
guess, is the reference?
378
00:25:41,440 --> 00:25:43,480
The reference, correct,
379
00:25:43,480 --> 00:25:46,320
of a galaxy with redshift zero.
380
00:25:46,320 --> 00:25:49,076
OK, so one that isn't
moving away relative to us.
381
00:25:49,081 --> 00:25:50,000
Yes.
382
00:25:50,000 --> 00:25:54,280
And so it is very clear here, if you
compare the top one with this one,
383
00:25:54,280 --> 00:25:57,200
every emission peak is shifted.
384
00:25:57,200 --> 00:25:59,440
It's shifted in the red.
385
00:25:59,440 --> 00:26:03,000
The reference line for
the sample is H-Alpha,
386
00:26:03,000 --> 00:26:07,240
and, from these, you can compute
the redshift of this galaxy.
387
00:26:07,240 --> 00:26:10,440
And can you work out from that how fast
388
00:26:10,440 --> 00:26:12,760
the galaxy is moving away from us?
389
00:26:12,760 --> 00:26:14,800
In principle, you can obtain this.
390
00:26:14,800 --> 00:26:16,800
OK, so what is the formula?
391
00:26:16,800 --> 00:26:20,720
The formula is the difference
between the reference wavelength
392
00:26:20,720 --> 00:26:22,880
and the observed wavelength,
393
00:26:22,880 --> 00:26:27,000
divided by the reference
wavelength and multiplied by C.
394
00:26:27,000 --> 00:26:28,560
This is the Doppler effect.
395
00:26:28,560 --> 00:26:30,840
- Let's see if we can do that roughly.
- Yes.
396
00:26:30,840 --> 00:26:32,240
OK, so this is about...
397
00:26:32,240 --> 00:26:37,440
7,200, approximate.
398
00:26:37,440 --> 00:26:38,960
OK.
399
00:26:38,960 --> 00:26:42,440
Minus 6,563.
400
00:26:42,440 --> 00:26:44,640
- ..63. - OK. - Over...
401
00:26:44,640 --> 00:26:46,640
6,563.
402
00:26:46,640 --> 00:26:48,736
And that is the fraction
of the speed of light?
403
00:26:48,741 --> 00:26:49,440
Yes.
404
00:26:49,440 --> 00:26:51,760
OK, so, I might as well do this.
405
00:26:51,760 --> 00:26:54,400
I should do it with my calculator, but...
406
00:26:54,400 --> 00:26:56,240
So...
407
00:27:02,680 --> 00:27:06,240
OK. So then that we divide by 6,563.
408
00:27:06,240 --> 00:27:09,320
OK, so it is roughly 0.1
the speed of light.
409
00:27:11,360 --> 00:27:16,200
So it is about 30,000 km/s, yes?
410
00:27:16,200 --> 00:27:17,760
- Correct.
- Thank you.
411
00:27:19,080 --> 00:27:20,280
OK.
412
00:27:20,280 --> 00:27:22,480
I'm actually quite pleased
at my maths here,
413
00:27:22,480 --> 00:27:24,640
because I was under pressure.
414
00:27:24,640 --> 00:27:30,160
So, this galaxy is 1.5 billion light
years away from the Milky Way
415
00:27:30,160 --> 00:27:32,120
and, from the redshift,
416
00:27:32,120 --> 00:27:35,200
we have worked out it
is moving away from us
417
00:27:35,200 --> 00:27:37,160
at 1/10 the speed of light.
418
00:27:37,160 --> 00:27:40,880
That means it is moving
away from us at three...
419
00:27:40,880 --> 00:27:44,080
At, sorry, 30,000 km/s.
420
00:27:45,960 --> 00:27:47,640
Boom.
421
00:27:47,640 --> 00:27:48,920
Science.
422
00:27:53,400 --> 00:27:56,080
Once he had calculated
the speed of the galaxy,
423
00:27:56,080 --> 00:27:58,800
Hubble then measured how far away it was.
424
00:28:04,680 --> 00:28:07,280
Once Hubble had both his measurements,
425
00:28:07,280 --> 00:28:12,080
he could start putting them on a
graph of velocity against distance.
426
00:28:12,080 --> 00:28:14,680
Now, he made 46 different measurements
427
00:28:14,680 --> 00:28:18,000
and, when he put them on the graph,
he noticed a pattern emerging.
428
00:28:18,000 --> 00:28:21,080
He could draw a line
through all these points -
429
00:28:21,080 --> 00:28:23,600
each one of them is an individual galaxy.
430
00:28:23,600 --> 00:28:26,720
He noticed a connection
between the velocity
431
00:28:26,720 --> 00:28:28,440
and the distance of a galaxy.
432
00:28:28,440 --> 00:28:31,080
In fact, the further away it was,
433
00:28:31,080 --> 00:28:33,520
the faster it was moving away from us.
434
00:28:36,160 --> 00:28:40,600
In a stable universe, the speeds
of galaxies should appear random.
435
00:28:42,120 --> 00:28:44,600
You wouldn't expect a clear relationship
436
00:28:44,600 --> 00:28:47,680
between the distance of a
galaxy and its velocity.
437
00:28:49,520 --> 00:28:53,640
Hubble's graph showed that
the universe was expanding,
438
00:28:53,640 --> 00:28:56,720
which has profound
implications for the idea
439
00:28:56,720 --> 00:28:58,640
of a beginning to the universe.
440
00:29:01,160 --> 00:29:04,200
What this means is that it is
not just that the galaxies
441
00:29:04,200 --> 00:29:07,120
are all speeding away from
us and from each other
442
00:29:07,120 --> 00:29:09,680
but that, if you could wind the clock back,
443
00:29:09,680 --> 00:29:12,960
there would have been a time when
they were all squeezed together
444
00:29:12,960 --> 00:29:14,280
in the same place.
445
00:29:23,360 --> 00:29:25,960
Here, finally, was the first observation,
446
00:29:25,960 --> 00:29:29,880
the first piece of evidence that
Lemaitre's idea of a moment
447
00:29:29,880 --> 00:29:33,680
of creation, of a universe
evolving from a Big Bang,
448
00:29:33,680 --> 00:29:35,080
might be correct.
449
00:29:51,120 --> 00:29:54,440
Thanks to Hubble's work, Georges Lemaitre,
450
00:29:54,440 --> 00:29:56,640
the unknown Belgian cleric,
451
00:29:56,640 --> 00:30:00,480
the theoretician without proper
international credentials,
452
00:30:00,480 --> 00:30:03,640
the man whose physics
Einstein called abominable,
453
00:30:03,640 --> 00:30:07,640
was belatedly rightly
recognised for his bold theory.
454
00:30:10,600 --> 00:30:12,280
Most significantly,
455
00:30:12,280 --> 00:30:16,560
the biggest name in physics came
around to this revolutionary idea.
456
00:30:19,640 --> 00:30:22,920
In 1931, on a visit to
Hubble's observatory,
457
00:30:22,920 --> 00:30:28,160
Einstein publicly endorsed the Big
Bang expanding universe model.
458
00:30:28,160 --> 00:30:30,360
"The redshifts of distant nebulae
459
00:30:30,360 --> 00:30:34,520
"has smashed my old construction
like a hammer blow," he said.
460
00:30:34,520 --> 00:30:39,760
Einstein dropped the cosmological constant.
He even wrote to Lemaitre,
461
00:30:39,760 --> 00:30:43,880
"Ever since I introduced the term,
I have had a bad conscience.
462
00:30:43,880 --> 00:30:46,640
"I am unable to believe
that such an ugly thing
463
00:30:46,640 --> 00:30:49,440
"should be realised in nature."
464
00:30:49,440 --> 00:30:52,200
It must have been quite an
absolution for Lemaitre.
465
00:30:52,200 --> 00:30:56,040
Having been practically cast out
into the scientific wilderness,
466
00:30:56,040 --> 00:31:00,120
he was now firmly at the centre
of a cosmological revolution.
467
00:31:08,360 --> 00:31:12,240
The idea of the Big Bang was
finally gaining traction.
468
00:31:14,640 --> 00:31:17,360
But, despite Einstein's seal of approval,
469
00:31:17,360 --> 00:31:20,040
and the observations of Hubble,
470
00:31:20,040 --> 00:31:22,080
the argument was far from over.
471
00:31:31,200 --> 00:31:33,480
There were still significant objections
472
00:31:33,480 --> 00:31:36,920
if the idea of a Big Bang
was to be widely accepted.
473
00:31:36,920 --> 00:31:40,640
A scientific theory of creation
isn't just about explaining
474
00:31:40,640 --> 00:31:42,680
the expansion of the universe -
475
00:31:42,680 --> 00:31:45,960
there were more profound issues to resolve.
476
00:31:47,720 --> 00:31:53,120
The problem was, the Big Bang raised
as many questions as it answered.
477
00:31:53,120 --> 00:31:56,920
Like, if the universe had
erupted from a single point,
478
00:31:56,920 --> 00:31:59,480
where did all the matter come from?
479
00:32:04,160 --> 00:32:07,400
To go further, the Big Bang
theory needed to explain
480
00:32:07,400 --> 00:32:10,240
how matter itself had been formed.
481
00:32:13,560 --> 00:32:16,240
Well, before that could be
answered, we need to know
482
00:32:16,240 --> 00:32:19,920
what the universe is actually made
of - the elemental building blocks.
483
00:32:19,920 --> 00:32:23,080
And working that out took an
incredible bit of insight
484
00:32:23,080 --> 00:32:26,880
by a remarkable woman - Cecilia Payne.
485
00:32:26,880 --> 00:32:30,400
She studied at Cambridge University,
but wasn't awarded a degree,
486
00:32:30,400 --> 00:32:32,680
because, well, she was a woman.
487
00:32:32,680 --> 00:32:34,360
So, to continue to her studies,
488
00:32:34,360 --> 00:32:36,680
she needed to go somewhere
more enlightened.
489
00:32:36,680 --> 00:32:38,720
She left England for America
490
00:32:38,720 --> 00:32:43,080
and it was there that she revealed
the composition of the universe.
491
00:32:55,360 --> 00:32:58,680
If you were to ask someone what
the most common elements were,
492
00:32:58,680 --> 00:33:01,520
an atmospheric scientist
might say nitrogen.
493
00:33:01,520 --> 00:33:04,880
After all, it makes up more than
three quarters of the atmosphere.
494
00:33:04,880 --> 00:33:10,640
A geologist might say silicon
or iron or oxygen...
495
00:33:10,640 --> 00:33:13,960
which all seems very
quaint and Earth-centric
496
00:33:13,960 --> 00:33:16,000
and really rather parochial.
497
00:33:27,920 --> 00:33:31,480
So, astronomers thought it
better to look at the sun.
498
00:33:35,280 --> 00:33:38,600
Which makes sense, given
that most of what we see
499
00:33:38,600 --> 00:33:41,200
when we look out into the cosmos is stars.
500
00:33:46,000 --> 00:33:48,960
The first attempts to analyse
the composition of the sun
501
00:33:48,960 --> 00:33:51,400
were done with a set-up rather like this.
502
00:33:51,400 --> 00:33:53,000
Well, not exactly like this -
503
00:33:53,000 --> 00:33:56,240
this is a cutting-edge
21st-century solar telescope.
504
00:33:56,240 --> 00:33:59,240
But the basic idea was exactly the same.
505
00:34:08,800 --> 00:34:10,680
The basic idea's very simple.
506
00:34:10,680 --> 00:34:13,960
The sun's light is reflected
off this mirror here,
507
00:34:13,960 --> 00:34:17,080
up into a second mirror...
508
00:34:17,080 --> 00:34:20,400
where it bounces off, down
through the top of the tower,
509
00:34:20,400 --> 00:34:23,080
all the way to the bottom,
ten storeys down,
510
00:34:23,080 --> 00:34:27,880
where it's focused and split
into a spectrum and analysed.
511
00:34:45,960 --> 00:34:48,440
This is the control room
of the solar telescope.
512
00:34:48,440 --> 00:34:51,120
The base of the telescope is over there.
513
00:34:51,120 --> 00:34:54,960
And here, I've got a live
feed image of the sun.
514
00:34:54,960 --> 00:34:58,320
And what I've got up here
is a zoomed-in section
515
00:34:58,320 --> 00:35:00,760
of the spectrum of the
light coming from the sun.
516
00:35:00,760 --> 00:35:02,640
Now, it's in black and white,
517
00:35:02,640 --> 00:35:06,080
but it actually corresponds to
the green part of the spectrum.
518
00:35:06,080 --> 00:35:10,320
These two thick dark lines
correspond to the element iron.
519
00:35:10,320 --> 00:35:13,240
They tell us there's iron in the sun.
520
00:35:13,240 --> 00:35:16,680
Now, here I have the spectrum
in much more detail,
521
00:35:16,680 --> 00:35:19,680
and these two lines
correspond to these two dips
522
00:35:19,680 --> 00:35:21,600
in the absorption spectrum
523
00:35:21,600 --> 00:35:25,200
at very specific wavelengths. This is iron.
524
00:35:25,200 --> 00:35:29,040
If I look at different parts of the
spectrum, I can see other elements.
525
00:35:29,040 --> 00:35:34,600
This big dip here is hydrogen.
These two dips represent oxygen.
526
00:35:34,600 --> 00:35:38,120
And this dip corresponds
to the element magnesium.
527
00:35:39,880 --> 00:35:42,720
All these dips and lines in the spectrum
528
00:35:42,720 --> 00:35:47,240
indicate the presence of these
elements in the sun's atmosphere.
529
00:35:47,240 --> 00:35:51,080
Effectively, a fingerprint
of the sun's composition.
530
00:35:53,800 --> 00:35:57,040
To a geologist, these elements
are all very familiar.
531
00:35:57,040 --> 00:36:00,440
It appears, at first glance, that
the sun is made of the same stuff
532
00:36:00,440 --> 00:36:05,280
as the Earth, that the sun
is simply a very hot rock.
533
00:36:14,800 --> 00:36:16,960
And that would have been that
534
00:36:16,960 --> 00:36:20,240
were it not for the
insight of Cecilia Payne.
535
00:36:23,040 --> 00:36:27,080
She realised that the spectrographs
were being affected by processes
536
00:36:27,080 --> 00:36:28,960
in the sun's atmosphere.
537
00:36:32,560 --> 00:36:36,400
These would distort the apparent
abundance of the elements
538
00:36:36,400 --> 00:36:37,880
that make up the sun.
539
00:36:40,120 --> 00:36:43,880
So, she recalculated the relative
abundances of the elements
540
00:36:43,880 --> 00:36:47,480
and discovered that the sun
was composed almost entirely
541
00:36:47,480 --> 00:36:49,960
of just two elements -
542
00:36:49,960 --> 00:36:52,200
hydrogen and helium.
543
00:36:52,200 --> 00:36:55,960
All the other elements -
carbon, oxygen, sodium, iron -
544
00:36:55,960 --> 00:36:58,520
that made the sun seem so Earth-like
545
00:36:58,520 --> 00:37:02,280
amounted to just a tiny
fraction of its composition.
546
00:37:02,280 --> 00:37:04,520
When she first presented this result,
547
00:37:04,520 --> 00:37:06,360
it was considered impossible.
548
00:37:06,360 --> 00:37:08,800
In fact, when she wrote up her work,
549
00:37:08,800 --> 00:37:12,760
she was persuaded to add the comment
that these calculated abundances
550
00:37:12,760 --> 00:37:17,080
of hydrogen and helium were
almost certainly not true.
551
00:37:18,920 --> 00:37:22,520
The idea was only accepted
some four years later,
552
00:37:22,520 --> 00:37:25,640
when the director of a
prestigious observatory
553
00:37:25,640 --> 00:37:31,080
arrived at exactly the same
conclusion by different means.
554
00:37:31,080 --> 00:37:33,960
Ironically, this director
was the very same man
555
00:37:33,960 --> 00:37:38,040
who'd initially dismissed Payne's
work as clearly impossible.
556
00:37:41,120 --> 00:37:46,360
Payne's revelation about the ratio
of hydrogen and helium was found
557
00:37:46,360 --> 00:37:51,400
to be remarkably consistent for
almost every star in the galaxy.
558
00:37:51,400 --> 00:37:54,040
That led to a big conclusion.
559
00:37:54,040 --> 00:37:57,840
The universe is dominated by
just two elements, the simplest
560
00:37:57,840 --> 00:38:01,560
and lightest elements -
hydrogen and helium.
561
00:38:01,560 --> 00:38:06,120
Together, they make up more than 98%
of all the matter in the universe.
562
00:38:06,120 --> 00:38:08,400
All the other elements that
are so important to us -
563
00:38:08,400 --> 00:38:13,120
like carbon, oxygen, iron
- amount to less than 2%.
564
00:38:16,520 --> 00:38:20,240
So now the challenge for
supporters of the Big Bang theory
565
00:38:20,240 --> 00:38:22,360
was very clear and simple -
566
00:38:22,360 --> 00:38:26,040
could the Big Bang theory
explain the creation
567
00:38:26,040 --> 00:38:31,840
AND the observed ratios of hydrogen
and helium found in the stars?
568
00:38:40,560 --> 00:38:45,480
But to answer that would require
a fundamental shift of emphasis.
569
00:38:48,920 --> 00:38:53,160
Rather than consider the almost
infinite vastness of the universe,
570
00:38:53,160 --> 00:38:55,480
it was necessary to consider
571
00:38:55,480 --> 00:38:58,880
the infinitesimally small
world of the atom.
572
00:38:58,880 --> 00:39:01,480
And that required, not an astronomer,
573
00:39:01,480 --> 00:39:04,920
but an entirely different
kind of physicist.
574
00:39:04,920 --> 00:39:07,720
George Gamow was a Russian
nuclear physicist
575
00:39:07,720 --> 00:39:12,080
and an enthusiastic advocate
of the Big Bang idea.
576
00:39:12,080 --> 00:39:16,360
He turned his attention to the
earliest moments of the universe.
577
00:39:22,840 --> 00:39:24,400
Here, he felt,
578
00:39:24,400 --> 00:39:27,960
was where the answer to the
composition of the universe lay.
579
00:39:27,960 --> 00:39:32,640
This was when he believed hydrogen
and helium were first forged,
580
00:39:32,640 --> 00:39:35,680
and he proposed it would
have happened very soon
581
00:39:35,680 --> 00:39:38,640
after the birth of the universe.
582
00:39:38,640 --> 00:39:41,720
He set about building a mathematical model
583
00:39:41,720 --> 00:39:45,640
of the earliest stages of the universe.
584
00:39:45,640 --> 00:39:48,880
He was thinking about the universe
in terms of seconds and minutes,
585
00:39:48,880 --> 00:39:51,200
rather than billions of years.
586
00:39:51,200 --> 00:39:54,000
And he recruited a young protege,
587
00:39:54,000 --> 00:39:57,680
this chap, Ralph Alpher, to help him.
588
00:39:57,680 --> 00:40:00,560
After years of hard work, some
of which, according to Alpher,
589
00:40:00,560 --> 00:40:03,360
were aided by hard drinking in a bar,
590
00:40:03,360 --> 00:40:05,360
they presented their idea.
591
00:40:06,640 --> 00:40:09,880
By rewinding the universe, it
was clear to them that there
592
00:40:09,880 --> 00:40:13,800
would have been a time when the
early universe was incredibly dense
593
00:40:13,800 --> 00:40:16,160
and phenomenally hot.
594
00:40:16,160 --> 00:40:19,000
At this stage, which they
calculated to be just three minutes
595
00:40:19,000 --> 00:40:22,160
after the Big Bang, the
universe would have been so hot
596
00:40:22,160 --> 00:40:24,560
that atoms themselves couldn't exist,
597
00:40:24,560 --> 00:40:26,960
only their constituent parts,
598
00:40:26,960 --> 00:40:30,240
a kind of superheated primordial soup
599
00:40:30,240 --> 00:40:33,040
of protons, neutrons and electrons.
600
00:40:33,040 --> 00:40:35,960
They even gave this soup a name - ylem,
601
00:40:35,960 --> 00:40:38,360
from an old English word for matter.
602
00:40:40,880 --> 00:40:45,120
Then came the crucial moment...
603
00:40:45,120 --> 00:40:48,160
a time when conditions
were right for the nuclei
604
00:40:48,160 --> 00:40:50,480
of the first elements to be forged.
605
00:40:50,480 --> 00:40:52,560
In a short period of time,
606
00:40:52,560 --> 00:40:55,240
which they estimated to
be less than 15 minutes,
607
00:40:55,240 --> 00:41:00,000
hydrogen nuclei proton were
coming together to form helium,
608
00:41:00,000 --> 00:41:02,440
in the process of nuclear fusion.
609
00:41:05,160 --> 00:41:09,720
Moreover, the ratios of hydrogen and
helium predicted by their model
610
00:41:09,720 --> 00:41:13,040
matched that measured in the stars.
611
00:41:16,520 --> 00:41:20,240
They announced their results
in a paper published in 1948.
612
00:41:22,000 --> 00:41:24,560
However, Gamow added another
author to the paper -
613
00:41:24,560 --> 00:41:26,880
the famous nuclear physicist, Hans Bethe,
614
00:41:26,880 --> 00:41:28,720
who had nothing to do with the work.
615
00:41:28,720 --> 00:41:30,600
Gamow added his name for a laugh.
616
00:41:30,600 --> 00:41:32,880
He thought it made a good science pun,
617
00:41:32,880 --> 00:41:38,080
because the authors of the paper now
read, "Alpher, Bethe and Gamow."
618
00:41:38,080 --> 00:41:41,440
The young Alpher, however, was less
amused to be sharing the credit
619
00:41:41,440 --> 00:41:44,720
with someone who'd done no work.
620
00:41:44,720 --> 00:41:47,280
By way of reconciliation, the story goes,
621
00:41:47,280 --> 00:41:50,040
Gamow produced a bottle
of Cointreau for Alpher
622
00:41:50,040 --> 00:41:53,880
but with the label changed to read, "Ylem."
623
00:41:56,880 --> 00:42:01,080
The ability to make calculations
that explained the origins of matter
624
00:42:01,080 --> 00:42:06,720
in the first few minutes after a
Big Bang was remarkable in itself.
625
00:42:06,720 --> 00:42:09,400
But there was a very significant prediction
626
00:42:09,400 --> 00:42:11,880
that emerged from their work.
627
00:42:11,880 --> 00:42:15,920
A prediction that had the
potential to deliver the proof
628
00:42:15,920 --> 00:42:19,720
that the universe had
begun with a Big Bang.
629
00:42:19,720 --> 00:42:22,880
Alpher continued to study the
early evolving universe,
630
00:42:22,880 --> 00:42:25,160
focusing on what happened next.
631
00:42:25,160 --> 00:42:28,720
He pictured the universe at
this stage as a seething fog
632
00:42:28,720 --> 00:42:31,280
of free electrons and atomic nuclei.
633
00:42:31,280 --> 00:42:34,400
Then it dropped to a critical temperature,
634
00:42:34,400 --> 00:42:37,720
a temperature cool enough
for electrons to latch on
635
00:42:37,720 --> 00:42:41,000
to the nuclei of hydrogen and helium.
636
00:42:41,000 --> 00:42:43,000
At this precise point,
637
00:42:43,000 --> 00:42:47,120
light was released to travel
freely throughout the universe.
638
00:42:47,120 --> 00:42:49,680
The first light of creation.
639
00:42:57,200 --> 00:43:00,360
This might have remained nothing
more than an academic curiosity
640
00:43:00,360 --> 00:43:02,800
had it not been for Alpher's insight.
641
00:43:02,800 --> 00:43:05,320
You see, he realised that
this light from the beginning
642
00:43:05,320 --> 00:43:08,040
of the universe should
still be reaching us now,
643
00:43:08,040 --> 00:43:09,800
after billions of years.
644
00:43:09,800 --> 00:43:13,720
Very weak, very faint, but
observable in all directions.
645
00:43:13,720 --> 00:43:17,560
He calculated that the expansion of
the universe should be stretching
646
00:43:17,560 --> 00:43:21,640
the wavelength of this light beyond
the range of the visible spectrum
647
00:43:21,640 --> 00:43:25,080
and should now be arriving
as microwave radiation.
648
00:43:28,280 --> 00:43:32,160
So, find this predicted
ancient microwave signature
649
00:43:32,160 --> 00:43:35,240
and it will prove, not just the
theory of the early evolution
650
00:43:35,240 --> 00:43:40,080
of the universe, but the entire
Big Bang theory itself. Simple.
651
00:43:41,680 --> 00:43:44,320
The problem was, this was the late 1940s
652
00:43:44,320 --> 00:43:48,520
and no-one had any way of
detecting such a weak signal.
653
00:43:48,520 --> 00:43:51,120
The acid test was quietly forgotten.
654
00:43:56,320 --> 00:43:59,600
Supporters of the Big Bang
now had the prediction
655
00:43:59,600 --> 00:44:03,040
and observation of an expanding universe.
656
00:44:04,920 --> 00:44:07,560
And a theory for how elements were forged
657
00:44:07,560 --> 00:44:10,360
in the first few minutes
after the Big Bang.
658
00:44:13,080 --> 00:44:17,000
But without the clinching evidence
for this, the argument over
659
00:44:17,000 --> 00:44:20,200
whether the Big Bang theory
was correct rumbled on.
660
00:44:24,400 --> 00:44:27,880
The opponents of the Big Bang
continually tweaked and adjusted
661
00:44:27,880 --> 00:44:32,640
their theories to make their idea
of an eternal and infinite universe
662
00:44:32,640 --> 00:44:34,480
fit the new observations.
663
00:44:34,480 --> 00:44:39,160
The scientific community was
still pretty evenly split.
664
00:44:40,280 --> 00:44:44,160
Conclusive proof of the Big Bang
theory would eventually emerge
665
00:44:44,160 --> 00:44:46,040
some 15 years later.
666
00:44:46,040 --> 00:44:48,800
It would be revealed quite unexpectedly
667
00:44:48,800 --> 00:44:52,120
by two young radio engineers.
668
00:44:54,400 --> 00:44:58,280
In 1964, Arno Penzias and Robert Wilson -
669
00:44:58,280 --> 00:45:00,520
that's Penzias on the right there -
670
00:45:00,520 --> 00:45:04,680
discovered something so momentous,
it won them the Nobel Prize.
671
00:45:09,000 --> 00:45:14,040
This telescope is dedicated to
study their accidental discovery.
672
00:45:15,920 --> 00:45:20,040
In 1964, Penzias and Wilson were
working at the Bell Laboratories
673
00:45:20,040 --> 00:45:23,160
in the US where they were
given this, a bizarre
674
00:45:23,160 --> 00:45:26,640
and obsolete piece of kit to play with.
675
00:45:26,640 --> 00:45:29,920
It looks, for all the world,
like an enormous ear trumpet.
676
00:45:29,920 --> 00:45:33,120
But when they turned their telescope on,
677
00:45:33,120 --> 00:45:38,000
they found that the sky was
saturated with microwave radiation.
678
00:45:40,320 --> 00:45:43,520
All warm bodies emit microwave radiation,
679
00:45:43,520 --> 00:45:47,560
whether it's from the atmosphere
or from the instrument itself.
680
00:45:47,560 --> 00:45:52,000
And today's mobile communications
flood the sky with it.
681
00:45:52,000 --> 00:45:57,360
FAINT STATIC
682
00:45:57,360 --> 00:46:00,520
So, before they could do
any useful measurements,
683
00:46:00,520 --> 00:46:03,760
they had to calibrate
their Horn Antenna to see
684
00:46:03,760 --> 00:46:06,320
if they could reduce this "noise."
685
00:46:06,320 --> 00:46:09,120
FAINT STATIC
686
00:46:09,120 --> 00:46:11,760
Even after accounting for the atmosphere
687
00:46:11,760 --> 00:46:13,320
and their instrumentation -
688
00:46:13,320 --> 00:46:16,080
of course, there were no mobile
phones to worry about back then -
689
00:46:16,080 --> 00:46:18,320
they were still left with this persistent
690
00:46:18,320 --> 00:46:20,920
and deeply irritating background noise.
691
00:46:20,920 --> 00:46:23,640
It was registered on their
instruments as a radiation
692
00:46:23,640 --> 00:46:27,840
with a constant temperature of
three degrees above absolute zero,
693
00:46:27,840 --> 00:46:30,920
a microwave hiss that
they couldn't get rid of
694
00:46:30,920 --> 00:46:32,920
no matter what they tried.
695
00:46:34,320 --> 00:46:39,360
FAINT STATIC
696
00:46:39,360 --> 00:46:42,840
Even more annoying for them was
the fact that it seemed to be
697
00:46:42,840 --> 00:46:46,040
everywhere they pointed their
celestial ear trumpet.
698
00:46:48,760 --> 00:46:52,480
They were about to give up when
Penzias attended a meeting
699
00:46:52,480 --> 00:46:56,120
where he casually mentioned
this irritant to a colleague.
700
00:46:56,120 --> 00:46:58,880
A few weeks later, the same
colleague phoned him up and said
701
00:46:58,880 --> 00:47:01,240
he knew of some researchers in Princeton
702
00:47:01,240 --> 00:47:04,360
who are looking for just such a signal.
703
00:47:06,600 --> 00:47:10,200
Unwittingly, Penzias and
Wilson had stumbled upon
704
00:47:10,200 --> 00:47:13,360
that predicted radiation
- Alpher's burst of light
705
00:47:13,360 --> 00:47:15,920
from the early evolution of the universe.
706
00:47:15,920 --> 00:47:20,080
Here, at last, was proof
of the Big Bang theory.
707
00:47:31,600 --> 00:47:35,000
It's quite remarkable to think
that this microwave radiation
708
00:47:35,000 --> 00:47:37,800
has travelled across the
furthest reaches of space,
709
00:47:37,800 --> 00:47:40,480
from 13.8 billion years ago
710
00:47:40,480 --> 00:47:44,000
when that first light from
the Big Bang was released.
711
00:47:44,000 --> 00:47:46,920
As Penzias himself said,
when you go outside,
712
00:47:46,920 --> 00:47:51,200
you're getting a tiny bit of warmth
from the Big Bang on your scalp.
713
00:47:51,200 --> 00:47:54,200
And, yes, I probably feel
it a bit more than most.
714
00:47:58,200 --> 00:48:02,360
Almost 40 years after
Lemaitre first postulated it,
715
00:48:02,360 --> 00:48:07,560
the idea of the Big Bang had finally
entered the scientific mainstream.
716
00:48:10,960 --> 00:48:14,920
But the discovery of this cosmic
microwave background radiation,
717
00:48:14,920 --> 00:48:19,240
the CMB, and the proof of
the Big Bang theory itself,
718
00:48:19,240 --> 00:48:21,600
isn't the end of our story.
719
00:48:28,600 --> 00:48:32,920
We've probed back to the first
few minutes after the Big Bang.
720
00:48:37,200 --> 00:48:40,680
And beyond this lies a new
frontier of knowledge.
721
00:49:01,640 --> 00:49:04,720
There are still very big questions
to resolve about the beginning
722
00:49:04,720 --> 00:49:06,520
of the universe, questions like,
723
00:49:06,520 --> 00:49:09,000
"Where did all the matter
itself come from?"
724
00:49:09,000 --> 00:49:12,360
And "How do you get
something from nothing?"
725
00:49:12,360 --> 00:49:15,560
The answers to these
questions lie further back,
726
00:49:15,560 --> 00:49:18,120
hidden behind the curtain of the CMB.
727
00:49:18,120 --> 00:49:21,680
Their secrets lie in the
primordial universe,
728
00:49:21,680 --> 00:49:25,200
within the very first
second of its existence.
729
00:49:31,360 --> 00:49:35,400
This is where the edge of
our understanding now lies,
730
00:49:35,400 --> 00:49:39,880
and this is where scientists
are focusing their efforts...
731
00:49:39,880 --> 00:49:42,040
not by looking into the skies,
732
00:49:42,040 --> 00:49:45,520
but here on the border of
Switzerland and France.
733
00:49:48,280 --> 00:49:50,480
More specifically, at CERN,
734
00:49:50,480 --> 00:49:53,640
with the largest particle
accelerator in the world,
735
00:49:53,640 --> 00:49:57,320
the Large Hadron Collider, or LHC.
736
00:50:00,080 --> 00:50:03,760
Now, you might be wondering what a
particle accelerator has to do with
737
00:50:03,760 --> 00:50:06,720
the early universe, because the
connection between the two
738
00:50:06,720 --> 00:50:08,240
is far from obvious.
739
00:50:08,240 --> 00:50:11,240
The thing to remember is that,
when the universe was very young,
740
00:50:11,240 --> 00:50:13,840
it was much smaller and so all the matter -
741
00:50:13,840 --> 00:50:16,800
everything that makes up the
stars, the galaxies, black holes -
742
00:50:16,800 --> 00:50:21,040
all had to be confined
into a much smaller space.
743
00:50:21,040 --> 00:50:24,440
At that stage, the universe
was phenomenally hot and,
744
00:50:24,440 --> 00:50:28,080
more significantly, its
energy density was very high.
745
00:50:31,800 --> 00:50:36,240
It was then that the first
matter sprang into existence.
746
00:50:36,240 --> 00:50:40,160
The LHC can't yet replicate that process...
747
00:50:42,920 --> 00:50:45,920
..but it can allow us
to study the properties
748
00:50:45,920 --> 00:50:48,360
of these fundamental particles.
749
00:50:48,360 --> 00:50:52,960
Once a year, the LHC stops its
normal business of colliding
750
00:50:52,960 --> 00:50:56,680
beams of protons, and instead
uses much more massive particles
751
00:50:56,680 --> 00:51:00,600
to create collisions with energies
more than 80 times greater
752
00:51:00,600 --> 00:51:03,640
than that produced from two protons.
753
00:51:03,640 --> 00:51:07,160
They do this by accelerating atoms of lead,
754
00:51:07,160 --> 00:51:09,160
stripped of all their electrons,
755
00:51:09,160 --> 00:51:11,720
up to speeds close to that of light,
756
00:51:11,720 --> 00:51:14,040
and smashing them together.
757
00:51:14,040 --> 00:51:17,280
And that lets us see
something pretty special.
758
00:51:22,520 --> 00:51:26,000
The collisions are so
intense that, for a moment,
759
00:51:26,000 --> 00:51:29,400
we create something unique -
760
00:51:29,400 --> 00:51:34,080
a world not of atoms or
even neutrons and protons -
761
00:51:34,080 --> 00:51:39,240
but of quarks and gluons and leptons
- exotically named particles
762
00:51:39,240 --> 00:51:43,880
that came together to form atoms
in the first millionth of a second
763
00:51:43,880 --> 00:51:49,000
after the Big Bang, and have
been locked away ever since.
764
00:51:49,000 --> 00:51:54,000
Down there, underneath that lead
shielding, we're recreating a stage
765
00:51:54,000 --> 00:51:58,280
in the universe's evolution
called the quark-gluon plasma.
766
00:51:58,280 --> 00:52:02,520
Now, this is the moment immediately
before the quarks become trapped
767
00:52:02,520 --> 00:52:06,160
by the gluons to create
protons and neutrons,
768
00:52:06,160 --> 00:52:09,600
which themselves go on to
form the nuclei of atoms.
769
00:52:09,600 --> 00:52:12,240
The phrase we use - grandly -
770
00:52:12,240 --> 00:52:15,240
is the confinement of the quarks.
771
00:52:23,280 --> 00:52:25,560
To develop the necessary energy,
772
00:52:25,560 --> 00:52:30,680
the lead nuclei are passed through
a chain of smaller accelerators,
773
00:52:30,680 --> 00:52:33,800
gradually ramping up the
energy until they're finally
774
00:52:33,800 --> 00:52:38,480
fed into the largest
accelerator on Earth, the LHC.
775
00:52:38,480 --> 00:52:42,640
Now, the maximum energy a beam
can achieve is directly related
776
00:52:42,640 --> 00:52:44,720
to the size of the accelerator,
777
00:52:44,720 --> 00:52:48,640
and the LHC has a circumference of 27km.
778
00:52:48,640 --> 00:52:51,640
That means the beams here
can achieve an energy
779
00:52:51,640 --> 00:52:55,440
of 1,000 tera-electronvolts.
780
00:52:55,440 --> 00:52:58,800
Now, actually, that's less than
you might imagine, because
781
00:52:58,800 --> 00:53:03,000
it's equivalent to the energy that
a housefly hits a window pane.
782
00:53:03,000 --> 00:53:05,160
But the critical difference here
783
00:53:05,160 --> 00:53:07,760
is that the energy is concentrated,
784
00:53:07,760 --> 00:53:10,240
it's the energy density that's important.
785
00:53:10,240 --> 00:53:14,720
The LHC can squeeze all that energy
down to a space that's less than
786
00:53:14,720 --> 00:53:18,200
a trillionth of the size of a single atom.
787
00:53:19,880 --> 00:53:24,560
This is something that can happen
nowhere else in the known universe.
788
00:53:33,480 --> 00:53:37,120
The two beams of lead nuclei
are travelling around the ring
789
00:53:37,120 --> 00:53:38,920
in opposite directions.
790
00:53:38,920 --> 00:53:42,720
They're meeting deep underneath
this control room at the detector.
791
00:53:42,720 --> 00:53:46,640
We can see live feed pictures of
the detector up on that screen.
792
00:53:46,640 --> 00:53:47,880
Now, underneath us,
793
00:53:47,880 --> 00:53:53,680
they're travelling at a speed
of 99.9998% the speed of light.
794
00:53:53,680 --> 00:53:57,840
That means they're covering the
full 27km circumference of the ring
795
00:53:57,840 --> 00:54:01,360
more than 11,000 times per second.
796
00:54:01,360 --> 00:54:03,960
When the beams reach maximum energy -
797
00:54:03,960 --> 00:54:06,680
and we can see up there, it says
"iron physics stable beams" -
798
00:54:06,680 --> 00:54:08,880
that means they can be crossed.
799
00:54:08,880 --> 00:54:10,560
Just like in Ghostbusters.
800
00:54:10,560 --> 00:54:14,640
At that point, a tiny fraction
of the lead nuclei will collide
801
00:54:14,640 --> 00:54:18,480
and create a super-hot,
super-dense fireball
802
00:54:18,480 --> 00:54:23,480
with a temperature 400,000 times
hotter than the centre of the sun,
803
00:54:23,480 --> 00:54:26,440
and a density that would
be equivalent to squeezing
804
00:54:26,440 --> 00:54:30,120
the whole of Mont Blanc down
to the size of a grape.
805
00:54:42,840 --> 00:54:46,480
That looks like a fantastic image there.
806
00:54:46,480 --> 00:54:49,880
- Can you tell me what we're seeing?
- It's amazing, actually, isn't it?
807
00:54:49,880 --> 00:54:54,120
It's literally tens of thousands of
particles and antimatter particles
808
00:54:54,120 --> 00:54:56,696
flying out - this kind of
aftermath of this explosion.
809
00:54:56,701 --> 00:54:57,560
Right.
810
00:54:57,560 --> 00:55:00,600
So the coloured particle trails here
811
00:55:00,600 --> 00:55:03,600
AREN'T the quarks and gluons themselves,
812
00:55:03,600 --> 00:55:08,520
but evidence of the quark-gluon
plasma created by the collision.
813
00:55:08,520 --> 00:55:11,600
We have to infer its properties
from looking at the debris
814
00:55:11,600 --> 00:55:15,720
that flies out. It's a bit like
working out how an aircraft works
815
00:55:15,720 --> 00:55:19,080
by looking at the debris of a plane crash.
That's what we see.
816
00:55:19,080 --> 00:55:22,960
What I find amazing is, what we're
doing here is trying to recreate
817
00:55:22,960 --> 00:55:27,960
that moment in the early universe
where the quarks and gluons
818
00:55:27,960 --> 00:55:30,480
were all free to float around,
cos the energy was so high,
819
00:55:30,480 --> 00:55:33,720
and then it cooled and they stacked
together. You're doing the opposite.
820
00:55:33,720 --> 00:55:36,640
We're starting with normal
matter, smashing it together,
821
00:55:36,640 --> 00:55:41,160
and going back to that
unconfined state, that plasma.
822
00:55:41,160 --> 00:55:43,560
Yeah. I like to think about
it as a time machine.
823
00:55:43,560 --> 00:55:45,640
We're actually winding back the clock.
824
00:55:45,640 --> 00:55:49,520
And this is the only way that we can
study the properties of free quarks,
825
00:55:49,520 --> 00:55:53,080
because these quarks have been
imprisoned inside particles
826
00:55:53,080 --> 00:55:56,520
like protons and neutrons
for 13.8 billion years.
827
00:55:56,520 --> 00:56:00,120
That's pretty incredible, isn't it?
Finally, after 13.8 billion years,
828
00:56:00,120 --> 00:56:01,720
you can set these quarks free -
829
00:56:01,720 --> 00:56:04,480
- even if it's for a fraction of a second.
- Yes.
830
00:56:06,920 --> 00:56:11,240
While we don't yet know how
matter sprang into existence,
831
00:56:11,240 --> 00:56:13,680
studying these collisions allows us
832
00:56:13,680 --> 00:56:17,720
to make the first tentative
steps towards that discovery.
833
00:56:19,280 --> 00:56:22,840
What we've just witnessed is the
earliest stages of the universe
834
00:56:22,840 --> 00:56:26,400
that anyone - anywhere -
has been able to observe.
835
00:56:26,400 --> 00:56:30,400
It's the closet we've got to
the moment of the Big Bang.
836
00:56:30,400 --> 00:56:33,000
And, let's face it, it's not bad.
837
00:56:33,000 --> 00:56:36,560
One millionth of a second
after the Big Bang itself.
838
00:56:40,040 --> 00:56:42,280
Even going this far back in time
839
00:56:42,280 --> 00:56:45,880
still leaves physics with
unanswered questions.
840
00:56:50,560 --> 00:56:54,240
Beyond this is where some of the
deeper mysteries of the universe
841
00:56:54,240 --> 00:56:59,520
are hiding. How the fundamental
forces that bind matter together -
842
00:56:59,520 --> 00:57:02,400
gravity, electromagnetism
and the nuclear forces -
843
00:57:02,400 --> 00:57:04,800
are connected to each other.
844
00:57:04,800 --> 00:57:07,600
How the particles that
make up matter itself
845
00:57:07,600 --> 00:57:10,600
condensed out of a fog of energy.
846
00:57:10,600 --> 00:57:13,760
How mass is generated from
the force that binds protons
847
00:57:13,760 --> 00:57:15,920
and neutrons together.
848
00:57:15,920 --> 00:57:20,920
And how the universe itself
underwent a super-fast expansion
849
00:57:20,920 --> 00:57:26,240
in one billion-billion-
billion-billionth of a second
850
00:57:26,240 --> 00:57:28,640
to create the structure of the cosmos.
851
00:57:30,480 --> 00:57:34,640
At the moment, we have no way of
observing any of these phenomena.
852
00:57:36,280 --> 00:57:40,480
This is the realm of abstract
theory and speculation.
853
00:57:44,960 --> 00:57:48,080
If we're ever going to replicate
this early stage of the universe's
854
00:57:48,080 --> 00:57:52,960
evolution, we're going to need to
create considerably higher energies.
855
00:57:52,960 --> 00:57:56,200
Frankly, we're going to need
to build a bigger collider.
856
00:57:56,200 --> 00:57:59,640
And that's a problem. And
it's not just one of expense,
857
00:57:59,640 --> 00:58:03,400
although it would be
phenomenally expensive.
858
00:58:03,400 --> 00:58:07,560
No, it's more one of finding
the room to build it.
859
00:58:09,440 --> 00:58:12,880
Remember when I said the energy's
related to the circumference
860
00:58:12,880 --> 00:58:16,680
of the accelerator? Well,
the LHC, down below me,
861
00:58:16,680 --> 00:58:19,800
has a circumference of 27km.
862
00:58:19,800 --> 00:58:22,840
It runs beneath the Jura Mountains
863
00:58:22,840 --> 00:58:26,520
and straddles both France and Switzerland.
864
00:58:26,520 --> 00:58:31,760
In order to look back and observe the
universe at this earliest stage,
865
00:58:31,760 --> 00:58:34,120
well, we'd need to build an accelerator
866
00:58:34,120 --> 00:58:38,080
with a circumference larger
than the orbit of Pluto.
867
00:58:42,600 --> 00:58:45,560
Revealing the origin of the
universe begs another,
868
00:58:45,560 --> 00:58:48,200
even more profound question -
869
00:58:48,200 --> 00:58:50,480
how will it end?
870
00:58:50,480 --> 00:58:54,240
Next time, I discover whether the
universe will end with a bang
871
00:58:54,240 --> 00:58:56,560
or a whimper.
872
00:58:56,560 --> 00:59:00,400
Want to discover more about the
beginnings of the universe?
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