>> Thank you Curtin
University for organising this
and giving me an opportunity
to tell you about something,
which I think, is quite exciting
and also happened in my career.
So I'm going to talk about
Quasars, their discovery,
and the key date here when
key paper was published
in "Nature" was on the
16th of March, 1963,
so that was 50 years
ago last Saturday.
And this is perhaps one
of the biggest events,
which has happened in astronomy.
There are a few other big events
but this one has had a huge
impact on the way we think
about the universe and on
astronomers and so I'm going
to tell you some of that story,
quite a bit about how it
happened and about some
of the machines that led to it.
As you see, this issue of
"Time Magazine", Martin Schmidt
who was one of the key
astronomers using the fabulous
200-inch optical telescope.
Biggest optical telescope in
the world for many, many decades
and discovered the Quasar.
And that's the 50th
anniversary, was on March 16th.
One of the huge paradigm
shifts which was triggered
by the discovery of
Quasars and that's part
of the story I'll tell
you was the realisation
that black holes weren't just
a figment of the imagination
of theorists but
are real objects
which play an important
role in the universe
so we'll get to that later.
So why am I telling
you this story?
It's really pretty special to
me because it was on March 1963,
the month when those
papers came out in "Nature"
that I started my
PhD in astronomy
at the Australia
National University
and I used the facilities at
the Parkes Radio Telescope
and worked -- my
supervisor was John Bolton
who features throughout
this story,
so it has been my
career this 50 years
of Quasars, in fact, exactly.
Here when I was a little bit
younger in a jumper knitted
by my wife -- well wife to be --
I hadn't actually gotten married
quite then and I'm at the focus
of a small telescope, a 60-foot
telescope that's near Parkes
and was the interferometer
I used in my thesis.
That doesn't feature anymore;
however, all of a sudden,
radio astronomy caught
the imagination
of pretty much everyone and
the BBC, for example filmed
"The Violent Universe".
This was part of the realisation
that our universe is formed
in my very violent
activities, Quasars are one.
The big bang of course itself,
stars exploding making
the elements
from which you have all evolved.
So this whole idea was really
come to life and especially
with these radio
observations I'll talk about.
So very brief summary here and
in going through these things,
I've tried to cater for both
from time to time the scientists
of you in the audience.
I'm trying to use when I can
simple language and please
at least at the end ask me
questions about anything
but we also I'm delighted to
see we have some young people
in the audience and so
I hope you bear with me
because I'm also
trying a little bit
to make sure they
can get some feel
of what we're talking
about as well.
So the discovery of
Quasars is a bizarre story.
It's nothing like the way you're
taught that science progresses.
It was full of wrong
directions, mistakes,
people not understanding what
they were seeing and to me
that is a really important
part of science and a reason
for looking at the history
of science is it's
no different today.
We might think we understand
all this but we have things
like dark matter, dark energy
and as you hear this story,
those of you either
thinking or wanting
to stretch your imaginations,
think about the way
that our predecessors
here went wrong
and the way they
made their mistakes
because we are surely
making similar mistakes now
and the real directions
are going to be different
from what people think they are.
The Quasars brought the black
holes into mainstream science
and astronomy and I'll talk
a bit about that and then
at the end I'll give you
only a glimpse because --
take me quite a bit of time
to cover all the history --
a glimpse of what we
might do in the future.
Now this talk is going to
have a fairly strong focus
on the astronomy we do
using radio wavelengths.
You're more used to
thinking about what you see
with your eyes, what you can
photograph with a camera,
that's the astronomy you
do using visual light;
but as this diagram
on the left shows,
there are many different
electromagnetic waves which come
to us from space and as
astronomers we usually can't go
out and do experiments.
We can only interpret the
information that comes to us
so we want to use all
the possible wavelengths
and you can see it goes
radio waves, inferred.
There's the tiny little
visible spectrum where all
of our past knowledge came
from and then the ultraviolet
and the X-ray and I'll
show you a few images
at these wavelengths.
But the radio is going
to play an important role
and so why is radio
being so important
for discovering Quasars?
Well the real reason are
the two points here written
on the screen.
The brightest Quasar in the sky
and the one we're going to talk
about a lot, 3C273, is the 6th
strongest, brightest source
in the sky at radio wavelengths.
So if you're going
through radio objects
to find something interesting
you've only got to count
down to number 6 and
you find a Quasar
and as I will show
you numbers 2,
3 and 4 are incredibly
interesting as well.
However, if you were going to
look at the stars that you see
when you go out in the
dark sky you've got to get
to 3 million before you
find a Quasar so you've got
to do an awful lot of searching
and that's really the reason
why it was the radio wavelength
that highlighted this
very unusual phenomena.
So here is a picture taken
through a reasonably
good telescope of a piece
of the Milky Way, like you would
see with your eyes at night
and the dark band across
the centre of the Milky Way
and all the little dots
sprinkled all over it.
These are stars.
These are stars like our
sun further away, billions
and billions of them as
Carl Sagan would say.
The radio sky if you had radio
eyes looks totally different
and here is a -- is a Recent
picture of the radio sky.
The band you see across
the middle is our galaxy
and that's very bright
in the radio.
That's where in light you have
the dark rift caused by all
of the dust then outside
of that, you see the haze,
which is radio emission
coming from our entire galaxy.
That was what was first detected
when the universe was first seen
in radio waves and as
you will find out as I go
through this talk, all
the little spots sprinkled
around the screen,
they're not stars.
The radio astronomers thought
they were going to be stars
and that's going to
be part of this story.
They are almost all
galaxies at huge distances
and so it's very different.
So both universes are real.
The universe you see with your
eyes and this universe you see
with the radio waves and
it's perhaps also interesting
to think of the two
wavelengths that we can observe
through the atmosphere, it's
the radio and the visible,
why we've evolved to
use eyes and light
but there's no biological entity
which actually using radio waves
to sense or communicate
and two reasons for this,
one is radio wavelengths
are rather long
from centimetres to meters.
They're very -- sort of a human
size but it's kind of difficult
to build an optics system
like your eye which can work
with radio waves;
however, a piece of wire --
I meant to bring a
piece, I forgot --
just a piece of wire
will pick up radio waves
so that's not very complicated.
But the other problem is, no
biological system has been able
to separate metallic
conductors out because
of the electric potentials
involved.
So even dinosaurs
which were big enough still
didn't use radio waves.
Okay. Let's go on.
Now we're going to go through
the entire universe in looking
at this story of the Quasars and
as I said, my apologies for some
of you who know all this but
I think it's always useful
to think about these
scales again.
Astronomers get quite used to
talking about huge distances,
small distances and
we do it often enough
that it means something to
us, but unless you are used
to doing that, the distances we
talk about won't mean very much
but we are pretty good at
thinking about how far back
in time things happened.
We can think about how
long ago, you know, when --
when various things
happened, you know,
when your grandfather was born.
Those are kind of time scales
we can understand and because
of the study of the earth
and the rocks and the things
on the earth people have a
pretty good feel for time.
So the way we talk about
the scale of the universe
and make it fairly easy
to understand is to talk
about things in terms
of how long it took
the light to get here.
The light travels pretty fast.
186,000-kilometers per --
miles per second, sorry.
So for example, it can
go all the way around --
around the earth in
a 7th of a second.
So we would call that a
7th of a light second.
That's the distance
around the earth.
It takes light about
8 minutes to get
to the earth from the sun.
So that's 8 light minutes away.
It takes about 40 minutes
for the light to get
from the planet Jupiter
to the earth
so that's 40 light minutes away.
And then within -- within an
hour you've got a good part
of the solar system.
Then big jump.
Nearest star, 4 light years.
So we've got this little
village of objects just here
in the solar system and then
we have a big gap until we get
to other stars, which very
probably have solar systems too.
So I'm just trying to get you
that feel of how empty space is
and how far away things are.
Now as I go through
my talk, every now
and then I will tell you how
far away things are using light
years and giving some analogy to
something that you can refer to.
Okay. Now the other thing I have
to do is go back a
little bit further
in time to set the scene.
This is a normal human time.
So during the war, there was a
lot of developments of the kind
of instruments you need
to pick up radio waves
and Stanley Hey was one of
the key people doing this
in the United Kingdom using
the strange little thing
to the right there which
is the telescope he used.
And what he discovered amongst
all the radio emission coming
from space was in one part of
the sky in the constellation
of Cygnus there was a spot which
was fluctuating in intensity
and so that told him
straight away if it's going
to be changing intensity it
cannot be on a time scale
of minutes, in this case.
It cannot be more than
a few light minutes
across because otherwise
one side
of it wouldn't know what
the other side was doing
so he was able to
quite correctly say
that object has got
to be pretty small
and maybe it's even
something like --
like our sun but
much further away.
So that's when they started
talking about radio stars.
However, this brightest
radio object
in the sky there was no --
nothing obviously visible there.
There was nothing
that you could see.
So what was it?
It wasn't known and the
question was asked is all
of that emission
coming from the galaxy?
Is that because there
are lots of objects,
lots of stars like this?
And for the specialists
here just
in case you don't remember
there was no theory
for synchrotron emission,
no non-thermal radiation
theory at that time.
That didn't come for
another 10 plus years
after this before
there was any knowledge
of how these radio
waves were made.
So that was happening
in Cambridge.
At the end of the war
there were lots of people
who had been involved
in building radar
for the Second World War
including a group in Australia
and I picked one
lady Ruby Payne-Scott
who is kind of special.
You will find out there's quite
a few characters in this story
and they're interesting people
and I'll talk a little
bit about some of them.
So Ruby Payne-Scott had
been looking with CSIR
in the radar systems that were
developed in World War II.
And these funny antennas here,
one here, another one here
that you see on the cliffs,
this is Dover Heights
just near Sidney Harbour,
they were antennas
that had been used
for doing World War II radar.
But what they put together
was a very clever scheme.
Here's the antenna here,
that's this guy sitting on top
of the cliff and When you look
up at the sky you might see the
radio waves coming in down here
but there would be
a reflected one
which would come bounce off the
sea and you would also see that.
And these two radio waves would
interfere with each other.
This was a standard thing done
by the radar people off the
ships doing radar they would see
the direct reflection.
They would also get
one bounced off the sea
and that already worked out from
that interference pattern you
could calculate quite accurately
the angle.
Now radio waves are very
long so determining exactly
where they came from was quite
difficult and this was one
of the ways of doing it.
When the sun comes up,
it's daylight of course;
you can't see the stars at all.
Now radio wavelengths the
sun is reasonably bright
but it isn't the brightest
thing in the sky normally
and you wouldn't have
the day/night difference
at radio waves that
you have in light.
But every now and then, the
sun was making quite a lot
of radio waves and
this was known.
And so Ruby used this
system to try and work
out where those radio waves
were coming from on the sun.
Are they coming from the
whole disk of the sun?
The sun isn't actually hot
enough to make the radio waves
by processes that were known
and this is what they
found in the radio.
This is an image -- usually I'll
show you modern images rather
than ones from the time because
they're more interesting,
more exciting.
So this is an image of where
the radio emission comes from
and it turns out it was
coming from the sunspots
and it was Ruby Payne-Scott,
first woman radio astronomer,
who actually deduced that.
So the radio waves
were actually coming
from these little
tiny spots on the sun.
Now as we get better telescopes,
we look in the UV and we look
from satellites from
above the atmosphere,
what it was actually finding
were these incredible loops.
There are huge magnetic
explosions in the sun and as
that material explodes out
of the surface there's a lot
of particles, high-energy
electrons and they were the ones
that were making
the radio waves.
Now the step that's important
for my story here I'm not going
to say any more about the sun,
but this was the first time
people connected radio waves
with explosive events
happening out there in space.
It wasn't the actual heat of
the sun making the radio waves.
It does make some radio waves.
It was these explosions
and radio waves are very easily
excited by explosive activity.
So what were these
other radio sources?
Like the small one that
Hey had found and I'm going
through this story because it
mimics what's going to happen
in the Quasar story a bit later.
People were getting most of
the interpretation wrong.
They'd found one
small radio source.
That was correct and then they
jumped to the collusion that all
of the radio emission
would be made of those.
They had seen these sun
spots making radio flares
and so they thought, ah,
other stars are going
to have even bigger sunspots
and so these radio
waves will all be coming
from maybe better stars than our
sun, ones that are more violent
and that was the model that
prevailed for almost a decade.
As you will see it
was completely wrong.
They got two steps wrong.
The unresolved emission wasn't
the stars and the one star
that they had studied
well, which was the sun,
was not an example of any of
the things that were to come.
Now the story of what was to
come next involves an expedition
by another group that was
working in CSIR in Australia.
And they had been looking
not at the sun but at some
of these radio sources to
measure their accurate position
so that they could try and
work out what is it out there
in space that's making
all these radio signals.
But with just one
cliff at Dover Heights,
they could only get one
piece of information
from the interference pattern
so they went to New Zealand.
And New Zealand
has wonderful cliffs
and it has them
on both the east
and the west coast.
Here is a little portable
antenna that was shipped
across to New Zealand.
John Bolton who was my
supervisor, by the way,
later after this and
Gordon Stanley set this
up in New Zealand on a
place called Pakiri Hill,
which is on a cliff above Lee.
That's kind of famous because of
"The Piano" the film was filmed
on the beach just
below that cliff.
That's got nothing to do
with the story of course.
[laughter] So what happens?
They've drawn one
line in the sky
from the Australian observations
and saying those radio sources
lie somewhere along that line.
The New Zealand expedition,
which was completely
successful, drew another line.
Now you look where the two
lines cross and if you look
at that point up in space,
that's where you
should find something.
And the four strongest sources
in the sky they could see,
the one in Cygnus, I
already told you about,
it was a strong source in
the constellation of Taurus,
one in the constellation of
Virgo and one in Centaurus.
They measured four positions
and they got the
surprise of their life.
The one in Taurus
turned out to be pointing
at something that's
called the crab nebula.
There's a beautiful new
image made with a VLA,
which I'm showing rather than
of course the very crude image
that they had at the time.
And that is in the position
where the Chinese saw a
star explode in 1054 A.D.
And this star was so bright
that it was easily visible.
When we get the next
supernova that close
in our galaxy everybody will
see a bright star appear
but it only happens every 3 or
400 years so who knows when.
But the Chinese recorded
this one as a gas star.
We are now looking at
things much further away.
The light from this one left
when the pyramids were
being built 6000 years ago.
So I've taken a pretty
big jump already.
We've gone from the
nearest stars
and we don't find an interesting
radio source until we get
out to 6000 light years away.
So we're jumping out in space
in huge steps and this is one
of the brightest radio
sources in the sky.
Let's put the Hubble space
telescope and point it at it
and that's what we
see in optical light
with the Hubble telescope.
It all matches up beautifully.
But this object you could
have an entire lecture about.
In the middle of that, this is
a telescope which takes pictures
in the X-ray and has produced
this incredible picture,
something swirling around in
the centre and in fact something
that is indeed a jet
poking out of it.
You point a radio telescope at
it, connect it to the earphones
or even connect it
to a loudspeaker
if you're a radio astronomer
and when you point at it,
[noise] they're the
radio pulses coming
from the centre of this object.
And that is an object which
is rotating once every beat
in that sound and I won't tell
you much about that story,
but -- but it's a thing
called a neutron star.
As I said it's an
entirely different lecture.
So there you can see
that this detection
of this particular radio source
just led to such a wealth
of phenomena and just think
for a moment something the mass
of our sun spinning at the rate
at which you could hear
that -- that pulse.
All right.
Let's go to the next
one they measured.
The brightest source in the
constellation of Centaurus,
low and behold there's
this incredibly beautiful
but rather strange
galaxy and you see 5128.
Now we have, assuming that's
a galaxy, moved totally
out of our entire galaxy.
That light left 10
million light years ago.
For that object, we are back
at when the first humans
were evolving on earth.
And the radio emission in a
modern image looks like this.
There's a spot in the middle
and the radio plasma seems
to be funnelled out
from the centre.
But it's way more dramatic
even than that because --
let's try and get the
scale right and I've got
to shrink this image way down.
This is an object the size
of our entire galaxy and then
when we do a modern radio
image, this is what we see.
So there's an object out
there generating radio waves,
which is hundreds of times
bigger than our entire galaxy.
So right away, these
radio waves were picking
up some absolutely
remarkable things
out there in the universe.
Here are the three people that
were involved in that paper
which measured the
first positions.
John Bolton, Gordon
Stanley, and Bruce Slee.
They had just discovered
a couple
of the most important
discoveries in astronomy.
The crab nebula, they nailed it.
They got it right.
But this Centaurus A hundreds
of times more luminous
than our galaxy.
Hundreds of times
bigger than our galaxy.
Who's ever going
to believe this?
This -- this maybe
can't be real.
John Bolton told me
when I was a student
and this is an example also
of how people can misremember,
they had problems with
the referees so they had
to put this statement
in the paper
that says it's a
pretty weird galaxy.
It's got this funny dust laying
across it so maybe it's really
in our galaxy after all and the
optical astronomers have got
it wrong.
That's the statement
in the paper.
John says, just had to
do that for the referees.
Of course we knew
what was going on.
But in those days people
wrote letters and some
of those letters still
exist and you can find them
and my colleague,
Milligauss in particular,
has been doing the research
in the archives and came
across this little gem, which
was written just at the time --
a few months after that paper
was submitted by John Bolton
and he's writing to somebody
called Rudolph Minkowski
at Cal Tech, one of the top
scientists working on galaxies
in the world and what it says
is, "In a letter to "Nature",
written before I had a
chance to consult with you,
I have suggested that
these objects may be
within our own galaxy.
On the basis that a close
freak is more probable
than a large collection of
freaks at great distance."
You see, as soon as
they acknowledged it was
at great distance all the
others were going to be
at great distance too.
And this was a step too far.
They weren't at that point
willing to make that step,
but who did he have to talk to?
He says, this galaxy
looks weird to me.
He's a radio engineer.
He's not even an astronomer.
So you say, oh well you
talked to somebody next door
who knows about galaxies.
In 1949 in Australia,
there wasn't anybody
who knew about galaxies.
Close to 0.
So he's got nobody to tell
him, that's a real galaxy.
It's not going to be -- it's
not going to be in our galaxy
and Minkowski replied
immediately, saying come on,
you have found the galaxy and
this is way more incredible
than what you even
said in "Nature".
So the message here was, you
need to have this network
of connections to people who
know about all kinds of things.
That group in Australia
had worked on the sun
and they did know a bit
about supernova remnants
and exploding stars, but
there was nobody in the group
who new anything about galaxies
and so they missed, in fact,
in terms of the paper,
they missed this
incredible discovery.
Everybody who knew about
galaxies it was within months
that the original
story was changed.
Everybody knew that galaxies
were detected perhaps
with the exception of Martin
Rile, he hung on a bit longer.
Our Cambridge friends.
So by five years later,
these things are being
called radio galaxies
and they are being
found by the dozens.
And every time you measure
an accurate position,
you find a big galaxy
often with these lobes
like the ones shown
here outside.
And finally, in 1954 the
brightest one in the sky
which is this one called
Cygnus A was discovered
and as you see it's a bit
like the picture I showed you
of Centaurus A. Now these
things are another factor
of 10 further away.
We are now back to
the light living
in the age of the dinosaurs.
So if you're thinking
back in time, we have gown
that much further
out in the universe
and we're seeing all
of these objects.
Here is Walter Barter
and Minkowski, both the
experts in what galaxies were
and the people who were
using the great 200-inch
and 100-inch telescopes
at Palma to study them.
What they saw in the middle here
in the photograph here taken
with the 200-inch, Minkowski --
well Barter first and Minkowski
together they thought it looked
like two galaxies had banged
Into each other and they came
up with a theory that they were
colliding galaxies and that's
when two entire galaxies
crash into each other.
That's what provides
all the energy
to make these incredibly
luminous sources.
So now they knew that the radio
could pick up these things
so the next step was people
want to see things further
and further away
so the idea was,
find really small radio
sources and they're going to be
at even greater distance because
the further away things are,
the smaller they're going to be.
So there was a huge team
of people started measuring
the sizes of radio sources.
Should have included
they're doing this
on the famous Lovell
Telescope at Jodrell Bank
and they're finding
the really small ones,
they're measuring
accurate positions of some
of those small objects
because if you're trying
to find something
very small like a star
and your position is only as
good as that, you've got lots
of choices and to
study all of them
with a 200-inch telescope
is actually impossible
because it takes sometimes all
night to get a spectrum of each
of them so they had to
get much better positions.
They were doing that
with an interferometer
at the Owens Valley
in California.
An interferometer built by no
less than the same John Bolton
who discovered the
radio galaxies.
See the Americans after the war
didn't go into radio astronomy
and they fell behind the
UK, Europe and Australia
so they actually got John
Bolton to come to Cal Tech
to build a radio astronomy
observatory there for them.
So that's also interesting
in case you imagine
that Australia's the underdog.
Sometimes yes but sometimes no.
So John Bolton built that
and one of the ideas were
to use those two telescopes to
get the interference pattern
to measure the accurate
positions
and as John Bolton again and one
of his students Tom
Matthews got the position
for object number 48 in the
Cambridge catalog and this turns
out to be a pretty
interesting object.
So once they had nailed which
star-like object it was,
they got a spectrum of
it with the 200-inch
and across the bottom are
three of the luminaries
in measuring light from --
from objects in -- out in --
in astronomy out in
space Jesse Greenstein,
Guido Munch was involved in
this and here's Allan Sandage,
famous for the cosmology you
could do with a 200-inch.
So they got a spectrum of 3C48.
It had lots and lots of
what we call emission lines.
You analyse the light
from a star.
You can tell what kind
of elements are in it
because they make
what's called lines
in the spectrum I guess I'll
show you one in a minute.
And you can tell what
kind of elements they are
and if the object is moving, you
can measure the Doppler shift
and see how fast it's moving.
So they measured -- there were
lots of lines in the spectrum.
They couldn't work out
what they were and in 1960,
Allan Sandage here as a paper
to the double American
astronomical meeting saying
there's this weird
object with weird lines.
Possibly it could be a
remote galaxy of stars
with some strange red
shift but it's most likely
that this really is
a star in our galaxy.
So here they go they're
actually heading
down exactly the same
path and the same trap
that we had already seen before.
And furthermore this
object was variable.
Like in the beginning of
my talk the one in Cygnus
and if something varies,
then it can't be very big
and this thing was changing
in its optical brightness
from night to night.
So the thinking was
if it was distant
as a galaxy then it would
have -- and you can see it --
it would have to have
as much light as all
of the stars in an
entire galaxy.
So here's the object
3C48; if they imagine --
this is a very distant version
of this galaxy -- oh
that's what I did.
Good. Then if it varies in a
week that means that every star
in the galaxy would
have to vary in a week
and of course that's nonsense.
How that possibly happen?
They can't possibly
know about each other.
They are thousands
of light years apart.
So the view was because of the
variability this cannot be an
extra galactic object it
has to be something nearby.
And so that was the situation
in 1960 and it was considered
to be the first radio star.
Greenstein, one of the most
famous spectroscopists an expert
in analysing what the
light means, how you can go
from the light to what kind
of elements and what kind
of conditions there
were that made it
and he had written a paper
for the Astrophysical Journal
with totally weird kinds of
elements in a very weird kind
of star that he thought
might be some offshoot
of the stellar revolution
process.
So -- and the paper had
been accepted by ApJ
but hadn't come out yet.
By the way, from this point on,
things are happening
really fast.
And even though there's no
email in this era just think
about that also a little bit
people are writing era grams
back and forth on a time
scale of about a week.
The groups in Cal
Tech, Manchester,
Australia are all
talking to each other
and there's a lot going on and
you'll see there's a lot packed
in to the next five
minutes of my talk.
A hell of a lot happens
really fast now.
Well this John Bolton who
had gone to Cal Tech to build
that Owens Valley Observatory
had decided to return
to Australia, which he did.
And in a history, which
John wrote in 1989,
he made a statement saying that
this 3C48 could have been fit
with a red shift of .37.
Now I already gave you one
example of the same John Bolton,
in fact telling us what he --
a change he made in a
paper because of a referee
and that was -- maybe the
referee was tough as well
but it was a small mis-remembery
of what had happened.
So everybody said, ah
John is making it up.
Nobody knew that it
had that red shift.
Well guess what's been found
in the archive of letters?
And my God what are we going
to do in the email age?
Who's going to actually find
these gems among the millions
of worthless bits of information
[laughter] that plug up all
of our databases well
think about that too.
Here's John Bolton.
He's actually left and I
think he was in Hu Wei,
and he was on a boat
to Australia
and he's written this letter
to Joe Pawsey who would --
it would be his boss when
he arrives in Australia.
"I thought we had a star
but it is not a star.
Measurements on high
dispersion spectrum suggests
that these various lines neon,
argon need a red shift of .367.
The absolute magnitude
is then minus 24
which is two magnitudes
brighter than anything known."
So he did do it and
he wrote it down.
This is -- this is 60
so this actually is --
is three years before
the discovery of Quasars.
This was a Quasar
no doubt about it,
but one month later he
writes another letter --
that's right, this letter
he was still at Cal Tech.
A month later he writes saying,
"No, the experts have told me
that these lines are not
possible it can't have this kind
of ionisation.
Such an object cannot exist.
I was wrong.
So must be a star after all."
So that was the effect of
having the most expert person
in the world saying
what that spectrum was.
So this is an example
of too much knowledge
becomes a problem.
Previously we had the problem
with the galaxy it was
too little knowledge.
Here clearly, there was
too much knowledge and now,
let's proceed into
the next step.
This is the Parkes
Radio Telescope
and we were actually
observing the moon
when this beautiful paragraph
was taken by Seth Shostak.
I was inside so I'm
very proud of it.
We were looking for very
high-energy neutrinos
but that's something
totally different.
It's got
the telescope and the moon.
Now if a radio source
goes behind the moon then
if you time very exactly when
the radio source disappears
and when it reappears you
can measure an incredibly
accurate position.
So this was an alternate
way of being able to pin
down the identifications of
some of these radio sources
and thank you Diviar, I stole
that from your Power Point
presentation the other day.
Cyril Hazard had
become the master
of doing these occultation's.
He was doing it at Jodrell Bank
using what's now called the
Lovell Telescope but he had come
to Australia and he was aware
of the fact that a
source called number 273
in the third Cambridge catalog
was going to be occulted
by the moon and that would
be visible from Australia,
not from the northern
hemisphere.
So he asked if he could get
access to CSRO's radio telescope
to observe this occultation
and it was --
there were actually a sequence
of occultations throughout 1962.
Here is one of about 6.
In this case, the radio source
is emerging from the side
of the moon down here you see
nothing then you see an increase
then you see a little step
which turns out to be real
and that's part of
what I'll show you next
and then it continues
to increase
and then you get this
beautiful diffraction pattern.
It is an absolute classic
knife-edge frenal diffraction.
It's the radio waves
being diffracted
because they're half blocked
by the moon and half not
so it's a classic
diffraction pattern.
That tells you straight away
that the thing that's being
occulted by the moon has got
to be extremely small
to make this pattern
and it also tells you it's
got another lump in it
and that lump doesn't
come with a pattern
so that other lump has
got to be not small.
So they pull all these
observations together.
They can draw this
little picture.
So in this direction of the
sky there is a point source,
which is making this pattern and
down here there's another blob,
which has to be a
little bit elongated.
Here's the photograph taken with
a 200-inch and now by the way,
this is happening in
February by now '63 and lots
of things are happening
very quickly.
They knew this source
was going to be occulted
so they already got a
good quality photograph
with the 200-inch but
this is what they found.
Previously they thought
this source was identified
with a completely
different object.
This very point like
object is that star
and see a little faint wisp.
That's exactly where the
other thing has to land.
The first thing the
optical astronomers thought
of when they saw this was,
well, we've got a mixture here.
This must be a background very
faint galaxy and this is going
to be another one -- whoops,
where's my pointer going?
And this is going to be another
one of these galactic stars
and that's just a
chance coincidence.
That was the first reaction.
August '62 Martin Schmidt gets
the photograph I showed you.
Martin Schmidt had come from
the Netherlands and by the way,
that is absolute typical Martin
Schmidt any time you meet him it
will be looking elegant
with a bow tie.
I've never not seen
Martin with his bow tie.
He'd come -- Minkowski had
just retired and he was taking
over the program in the 200-inch
to measure faint galaxies
and so his job would really
be to try and see what
that faint wispy thing was.
But it was immediately
obvious from the occultation
that there was radio emission
from the star and from the wisp.
Martin said he took the
spectrum of the star first
because he wanted to
get that out of the way
and then he'd do the difficult
job of trying to get the wisp
but when we took the spectrum of
the star, this is the spectrum
down here, it's now
February the 5th.
He's actually taken the
spectrum in December.
He looks at it straight away.
All of these black bands are
these emission lines I told
you about.
There's something in the
star, which is some elements,
which are making these lines.
They didn't make any sense.
They didn't make any
sense to Martin Schmidt
but he straight away said
it's another thing like 3C48
which doesn't make
sense but he didn't know
about the high red
shift of 3C48.
And then in -- he was
then writing the paper
up to put together with
the occultation paper,
put it in "Nature" and he
went back and he looked
at the spectrum again and he
suddenly saw that this line,
this line, this line and a
faint one you can't see in here
but you can see on a different
spectrum were in a certain ratio
and it suddenly realised
it was the Balmer sequence
of hydrogen lines if you
multiply them by 1.16.
So if you gave them a huge red
shift they all fell into place.
And not only that, this is now
science making predictions.
Here is a hypothesis.
If that thing was going at this
incredible velocity then the
lines would all fall
in that place.
A guy called Baboak had
an infrared spectrograph
and then you could predict
that the strongest line of all
which is H alpha would
be in the infrared.
He looked spot on.
So there's almost no
doubt at that point.
They have found the red
shift of this thing.
Next door is Greenstein's
office.
So Martin says, "Hey look at
this, this thing looks a bit
like your 3C48 but I know
what its red shift is."
and Jesse Greenstein
says, "Oh shit."
Canceled his paper in ApJ
and within days had
written another paper
on the second Quasar 3C48 which
indeed have a red shift of .37,
which was what John
Bolton had said
but was talked out
of 3 years ago.
So the bizarre twists and turns.
Now, these Quasars,
they are really bright
and if the red shift is part
of the expanding universe,
then our -- so many billion
light years away we are actually
talking about the first life
-- evidence of life on earth.
So we're now out to
about 10% of the age
of the earth and the universe.
So we have suddenly gone to
these vast distances in space.
That's a summary
and furthermore,
this thing wasn't just as bright
as the galaxy it was
100 times brighter
than the most luminous
galaxy known.
And of course that is what
triggered my opening slide
and the enormous
excitement about the Quasars.
There's a bit of a problem.
This is one of the
major discoveries.
There's no Nobel Prize
for discovering Quasars
but if you've been listening
to my story, you can see,
it's a very confused story.
Who discovered 3C273?
And in fact, we've
been trying to find
who was actually the
first person that said,
looked at that 200-inch
photograph
and said the star
in the jet line up.
Martin Schmidt says
this was not me.
I just observed the thing that
you guys told me to look at.
Tom Matthews who he says did it.
Tom Matthews said no
I didn't do it at all.
So did Cyril Hazard do it?
But Cyril Hazard
there's no evidence
but he almost certainly
didn't and so on.
And perhaps -- probably
I think John Bolton did,
Benkowski was in Australia.
He had a copy of
that picture with him
but I'm not sure we're
ever going to find
out who actually identified it.
But as you can see, there's
so many people involved
in so many steps.
The Noble Committee doesn't
handle that very well
when giving out Nobel's.
To move from there to the
future, here's a sketch
of what they thought the
radio emission looked
like based on that occultation.
Small thing up here and down
here a more extended object
and the other piece
of the sketch,
which is actually being done by
Jan Auton in the Netherlands.
Oh by the way, there's people in
Australia talking to the people
at Cal Tech, talking to people
at Manchester, here talking
to Jan Auton of the Netherlands.
This is international game.
This is a world game.
This is not played by any
one group and the information
to sort this out is spread
over all these places
around the world.
This is international science,
which is my other thing I love
and working very well.
So this is what they measured.
For those of you who
study radio emission
from AGM this is
the paradigm AGM.
They measured the spectrum.
They had a number
of frequencies.
Compact one is flat.
This thing down here is steep.
That was the first time that
was found in a radio source.
This is where it started
with that occultation.
There is a modern image
taken with the VLA
and so you see they
got it pretty good
in the old occultation record.
So 30 years later with
a big fancy telescope,
you got perhaps a better
picture and then you look at it
with a Hubble Space Telescope
and this is what you see.
Beautiful picture with
very bright Quasar up here
and here is the optical jet
broken out into a whole string
of knots and today we still try
to understand exactly what's
going on especially in the jet.
But we will mostly now talk
about what's going
on in the stars.
Today we call them Quasars.
The astronomers didn't
introduce that term.
It was a populariser
of science writing
in physics today got sick
of writing quasi stellar radio
sources and called them Quasars
but the journal,
ApJ in particular,
refused to use the word Quasar
and there's a little story here
which comes from Martin Schmidt.
He then decided that they
were optically loud --
optically radio loud
radio quiet Quasars
and they needed different names
and he wanted a term to apply
to everything so he
wrote a paper to ApJ
and said we really got to use
this term and here's the reply
by Chandrasekhar pointing
out that this very reputable
journal hadn't used this popular
term but they feel that it
can no longer be ignored.
So that's when Quasars
came into the literature.
These things were bright.
They were relatively
easy to observe.
You didn't even need a 200-inch
and look what happened
immediately after 1963.
This thing called
Z is proportional
to how far away they are and
so there was a race basically
of people all over the world
trying to find an object
at the greatest distance.
So there was a huge amount
of activity and going up to
as you can see red shifts of
7, which we believe is the time
in the universe when Quasars
were probably first made.
None have been found
beyond that and beyond
that we now have other
things gamma Ray bursts
but I won't talk about that.
This same Quasar, I had
a few other surprises
and I just wanted to show
you this one quickly.
If you look at this picture,
it shows images taken
of this Quasar with
its -- with its jet.
It's a very central part of
it and pictures are taken
about once every
year and the sizes
in light years are written on.
Does anybody see that there's
something pretty unusual,
amazing about this photograph?
In a time scale of roughly a
year, this thing keeps changing
in size by 5 or 6 light years.
That means it's been
expanding at 5
or 6 times the speed of light.
That was always observed.
Is this a problem or not
for special relativity?
The answer is not
because you can do it
with an optical illusion and I
think you either know about this
or else I don't have
time to explain it
but because the objects are
moving apart at about the speed
of light and the light is
coming to us at the speed
of light you can
make an illusion
in which you get this
apparent expansion
but of course there's
another "Nature" paper
and a whole business
of measuring what's called now
the superluminal expansions
in AGN.
But I wanted to look
at a deferent aspect
of the discovery of Quasars.
So just recapitulating,
Parkes did the occultation,
Schmidt got the spectrum and I
am actually sitting at Cal Tech
at about this point in time
and I was watching what I
thought was an incredible
collision of two cultures.
Astronomers all of a
sudden had to get in bed
with general relativity
theorists.
A kind of theorists and normal
astronomer would not even think
about talking to because you
have no idea what they were
talking about.
These were the theorists who
work on Einstein's Theory
of General Relativity
and space-time
and coordinate transformations
and what was generally thought
to be pretty weird stuff.
But the Quasars caused
something enormously interesting
to happen.
Because how did you get
this much energy not now
from an entire galaxy
but from a small region?
Remember. It fluctuated
night to night.
It's only a few light
days across.
You got to get this energy
not from an entire galaxy
but from a very small region.
And if you think about that,
there's only one source
of energy, which
works and it's gravity
by having an incredibly
massive object
in the nucleus of the galaxy.
By December in that same year a
symposium had been convened only
you can't work this fast.
It was the first Texas symposium
on relativistic astrophysics.
If you're interested in history
and excitement you read this
and it bubbles with the
excitement that's going
on in that year 1963.
And here's a statement, a quote,
which was attributed
to Fred Hoyle.
I assume it is.
"So relativists with their
sophisticated work were not only
magnificent cultural ornaments
but might actually be
useful to science."
So there was a transformation
occurring.
The other thing that
was happening,
this is in the nucleus
of a galaxy.
Well everybody now thinks
well of course the nucleus
of the galaxy that's where
the action's all going to be.
What's surprising about that?
Well the surprising thing is
that this was a big surprise.
Carl Seyfert perhaps one
of the best known
astronomers these days
because there's things called
Seyfert galaxies which are named
after him which are
hugely important.
In 1943 he made a catalog
of them, small catalog.
He had 6 of them.
For 16 years his paper
received not a single citation
and that's even worse than most
of the statistics
we worry about.
And furthermore when he
did get some citations,
none of them came from the west.
Not from all the people
working on galaxies in Europe
or the U.S. but from old Victor
Ambartsumian who said the nuclei
of galaxies aren't just the
place where they're brightest.
Maybe something important
is happening there.
And followed a few years
later by Vitaly Ginzburg
who got the Noble Prize by the
way for super conductivity.
Think broad look
at many subjects.
As far as I can tell he is
the first one that said,
gravity can supply the energy.
He's not normally
credited with it,
but I think you'll find
it was probably him.
So if you get into the nucleus
of galaxy and you've got a lot
of gravity you can
really make things happen.
Very quickly, all of the old
ideas of colliding galaxies
to provide the energy
disappeared within a year;
I would say they were gone.
One controversy lasted
for decades,
that was a rather strange one.
A subset of the scientists said,
objects cannot naturally
be that luminous.
This is unreasonable.
We would rather have
a red shift due
to some phenomena
we don't understand
so we'll invent something like
dark energy and say that's going
to explain away the
red shift and not have
to put them at great distance.
That persisted for
quite a long time.
It's interesting that theories
which were making good sense
were nevertheless so different
from what anybody was thinking
that they were considered
less credible than a theory
that you made up saying well we
don't understand what the red
shift is so that will be magic
and let's go on from there.
[laughter] Not surprisingly,
the magic theories failed
to predict much of anything.
Where as the gravitational
energy
from collapsed objects had
become a really big thing.
And in the years -- even
in '62-'62 there are papers
by a string of people saying
gravity can do wonderful things.
There could be accretion
disks around massive objects.
But notice I said,
what kind of object?
Nearly all these people are
saying really massive objects.
Maybe you can have a star,
which is a million times
more massive than our sun.
And then it could --
could accrete the stuff
and we could get all the energy.
What about the black holes?
You know all about
black holes now,
but black holes then were even
more esoteric than other bits
of general relativity and
it's also 50 years this week
since black holes
became credible.
Have a very quick look at
the black hole history.
We can go way back.
Chandrasekhar said -- this is
Chandrasekhar eventually the
editor of ApJ by the
way in 1931, young --
young -- young scientist.
"A star of a large mass cannot
pass into a white dwarf stage
when one is left speculating
on other possibilities.
The idea is if something
is so massive
that its gravity overcomes the
atomic repulse forces then what
happens to it?"
And so he's wondering
what happens.
The expert, here's the
authority steps in,
Eddington is basically saying
there's going to be something
in "Nature" to stop
crazy things happening.
It's not going to turn
into are black hole
or anything weird like this.
There'll be some law of "Nature"
because that would
be totally weird.
Oppenheimer more famous for
his role in the development
of the atomic bomb worked
for many years on the theory
of black holes and he called
it an exercise in abstraction.
And most of the theory was
there but was considered
to be irrelevant and
wildly speculative.
I also thought it
was interesting
when Chandrasekhar
eventually got his Noble Prize
and you read the citation.
The citation was for his work
on white dwarfs neutron stars
but included in the
citation is this statement
that he had predicted that
there would be a black hole
but in the noble
committee, they're still
so called black holes in '83.
Kavli Prize 2008 Schmidt
for the discovery of Quasars
and then they added
Donald Lyden-Bell.
Now when my friend Donald
added to the story was a couple
of rather interesting steps.
He wasn't the first one
to come up with the idea
that if you had a black
hole and things accreted
onto it you'd get lots of energy
but he did realise there was
so many of those things
out there in space
and the black hole all the
mass may have been used up,
you may have big black holes
which aren't doing anything.
So he said maybe all
the galaxies may have
to have black holes in them.
Otherwise we can't
explain the number
of Quasars seen at
great distance.
And so that was when the
nuclei now will not only weird
occasionally when they have
these blasts of energy in AGN
but maybe all the nuclei maybe
even our galaxy has a black hole
in it.
I also thought it
relevant to pop this in.
This is the VLA, the -- one of
the largest radio telescopes
on earth at the moment.
And when you build a radio
telescope you have to make
up a story of what
you're building it for.
The VLA was built to observe
Quasars with optical resolution.
So if the Quasars
hadn't been discovered,
I guess we wouldn't
of had a VLA.
Now VLA did observe Quasars
with optical resolution
but it did a hell of a lot more.
Lyden-Bell said, hey, look
in the centre of our galaxy,
there might be a
black hole there.
Centre of our galaxy's
a pretty messy place.
Here's a picture of it, which
I was involved in making
but I don't have
time to talk about.
And at really high resolution
little white dot there
and when you do look at
the stars in the infrared
where you can see through the
dust and what this is showing,
the different dates is the way
these stars are all looping
around the galactic centre you
can apply Newtonian mechanics
and you can work out
there is indeed at exactly
that point there a black hole
with 3 million times
the mass of the sun.
And I was going to get the
movie of this but I didn't get
around to it which looks quite
dramatic but it reminded me
of these little black
hole machines
where you drop the coin, right,
and circles around and around
and around and goes
down the black hole.
And so that's a very
nice illustration
of just what's happening in
the galaxy and by the way,
all this gas you see is just
spiralling around the hole
as it goes down into
the black hole.
But when I looked up this image
or actually my wife found it
for me, there was an
amazing caption on it.
It said, "These things may
gather more money than any
of the other sponsorship
devices which are out there."
And so for the commercial
people here, here's a spin off
from black holes
and excuse the pun.
They are making money
because the shape
of that is designed
based on a black hole.
There's a beautiful picture of
a couple of galaxies colliding
with each other and swirling
off the stars and doing a kind
of dance before they
finally merge.
Well if each of these
have a nucleus and here
in this picture you can see
they do in the Hubble picture
and they each have black
holes then you're going
to have two black holes
in orbit about each other.
And if there are two
black holes in orbit
that gives interesting
possibilities.
Because they can generate
gravitational waves
and those gravitational waves
can be sensed by timing pulsars
and see the distortion
in space and time
as the gravity wave goes past.
And this is our now moving
quickly to the future
and here's a plot, which says
can we see these gravity waves?
Well of all the places
in Australia,
Perth in Western Australia,
is where much of the research
on detecting gravity
waves is being done.
There's a machine in Perth like
LIGO to try and detect them.
This has got to do
with the frequency
and big black holes have
a different frequency
than small black holes.
These pulsar and these are
the prediction all along here
and these little loopy
things are the limits.
None have been detected yet.
These are looking at pulsars
today and the best you can do
and the next one in here is what
this telescope called the SKA
will do and it should
get us to the point
where we'll see these
double black holes orbiting
around each other because of the
gravitational waves they make.
In order to do this
kind of experiment,
we now need telescopes which
are in order of magnitude bigger
than what we had before so
we need to go from the VLA
to things like the SKA and
here's an artist impression
of one part of the SKA as it may
look like in Western Australia.
And in conclusion let me just
comment on these new telescopes.
Of course there are
many things it can do.
I showed you just one tiny
example because it linked
into the black hole talk.
But like the VLA, it will
not just image Quasars,
these telescopes will test
the predictions we're making
but the exciting thing and
I think the exciting thing
about this story is it's
not the old questions
which we are answering,
but it's the new things
which they are going to find
to which we don't know
anything about yet.
And I think the Quasar story
has got this interesting twist
in the tail.
The power of science
is surely its ability
to make predictions
which you can test.
That's the foundation of
science and why it works,
but don't get confused.
Science itself evolves in
completely unpredictable ways
so we cannot predict what
the exciting science will be
in the future but we have
every reason to believe
that it will be just as exciting
as the period I've
just told you about.
Thank you.
[ Applause ]
