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Interviewer: Hi, everyone welcome to Stargazing, my name is Jeff Stanger and I'm a Science teacher at Sydney Girls High School and
an Astronomy Educator at Sydney Observatory.
And let's say hello to our guests today, another pair of passionate astronomers, Dr Fred Watson is Astronomer-in-Charge at the
Anglo-Australian Observatory near Coonabarabran.
Fred, could you tell me a bit about your interests and your work?
Fred Watson: I could, I'll be delighted to do that Jeff.
Because I spend my life thinking about usually things that aren't really that much to do with life here on the Earth which makes me like
many other astronomers, a very strange person.
But my, as David nods sagely in agreement.
My work is concerned as it has been for many years with trying to observe very large numbers of objects in space.
So, my sort of professional astronomical work is about survey astronomy and what that means is looking at objects, whether they're
stars or galaxies or even quasars and doing it in very large numbers so that you can start to build up a picture of what patterns these
objects are revealing when you analyse them and I do that with a telescope that has a thing called a spectrograph attached to it
which breaks the light up into its rainbow barcode of colours and gives you the information that's needed about that.
So, that's my professional life, I manage a project at the moment which is analysing a million stars using the United Kingdom
Schmidt Telescope which is part of the Anglo-Australian Observatory.
But I'm also very heavily involved with things like making sure that people know, first of all that it's a bad thing to have lots of light
going up into the sky, so that the work of observatories like ours is compromised by skies that are too bright.
And so that's part, that has basically transferred a lot of my energy into education because it starts with persuading people that good
lighting is light that goes downwards and not upwards into the sky and then goes from there to telling people what it is that astronomers
are so passionate about finding from using these dark skies.
And so astronomy education and outreach is something that has taken up more and more of my time over the last decade or so.
Interviewer: Now, David could you tell us a little bit about your work and interests?
David Malin: Yes, well I'm retired but my life continues, my professional and academic life continues.
For many years I was a photographic scientist at the Anglo-Australian Observatory.
There I supported visiting observers, made plenty of observations using the telescope myself.
Most of the photographic in those days I invented some ways extracting more information from the photographic images I made.
And as part of the way through that process I evolved a system of making true colour images from the black and white glass photographic negatives that we had.
Now, that also produced some interesting scientific results.
So, my life is in two sections, in a way that Fred's is really.
There was a serious scientific career built in there as well but I'm best known for the colour photographs I made which are really useful
tools for explaining the complicated intricacies of astronomy to audiences that are ready to soak up the quality of a really good picture.
So, the pictures are very strong, they carry a really interesting message and a few words with them can make them really superb.
In my life now I'm still managing many of the images I made at the observatory but now it can all be done on the internet in a way that it couldn't be done a decade ago.
I'm still writing books, I'm still doing talks, I'm still doing this kind of thing which I like very much and Fred's got this aspect to his life
as well, this kind of PR side of his life, this outreach side of his life.
We both find it really stimulating especially talking to schools.
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Interviewer: Now, I have to ask you two both though, how do two guys with such similar English accents end up working in astronomy here in Australia?
David Malin: Let me, let me address this.
If you have a good ear our accents are certainly Northern English but they're different as Fred is from Yorkshire, and he's having treatment,
and I'm from Lancashire and so my accent is rather more refined I think.
The answer to your question though is that we were both offered good jobs.
My background is in Chemistry and you might wonder why how a chemist gets to do astronomy.
My background is in Chemistry and I was very interested in the way photography worked and by the time I'd been doing this for quite a
few years I could call myself a photographic scientist and when an advert appeared in the press for a photographic scientist to join
the Anglo-Australian Observatory in 1975, I was ready, ready for that job it would suit me perfectly well.
What I didn't know much about at that time was astronomy, so I kind of learned it on the job.
So, I took a job, well was to my surprise really in Australia while happily working in the North of England in a chemical environment.
But, its been rather successful, I've thoroughly enjoyed it.
Fred Watson: You see this Lancashire/Yorkshire thing Jeff, the Wars of the Roses ended in was it, 1280 or something like that but it's still
going on and there's this saying that they have in Lancashire, he's from Lancashire and they say 'Ah, the best thing that came out of
Yorkshire was the road to Lancashire.'
David: Certainly true.
Fred: But it's carried on in a rather light-hearted fashion I have to say.
But, yes my story's very similar to David's in that I was actually an astronomer already but working at the Royal Observatory in Edinburgh.
And if you think rivalry between Yorkshire and Lancashire is something, you should try the rivalry between Scotland and England
and Edinburgh of course is the capital of Scotland and I was an Englishman and they said 'Oh, we canne take any notice of him, he's English.'
But, so I did my PhD there and I worked at the Royal Observatory in Edinburgh but the Royal Observatory then had an outstation which
was right next door to the Anglo-Australian Telescope where David was working in Coonabarabran in rural New South Wales.
And one of the sort of penances that astronomers at the Royal Observatory in Edinburgh had to do was a three year tour of duty at
this little country town in north western New South Wales.
And I did my three year tour of duty which started in 1982 and hasn't yet finished actually it's still going ...
David: This little country town had the best astronomical camera in the world.
Fred:Absolutely.
David: That's why you were there.
Fred: That's why I was there because the telescope which was then run from the Royal Observatory in Edinburgh was as David says it was
the best camera of its kind in the world, it could photograph a huge area of sky with exquisite detail and basically that project was run from Edinburgh.
The idea was to make an atlas, a photographic atlas of the whole sky, this is back in the 70s and 80s we're talking about now.
And I came out to do my stint as an observer on the telescope and take my share of the 19 000 photographs that we ended up taking.
But I also had some slightly other balmy ideas about using fibre optics on the telescope which is now what it does full time.
The photography era is over.
So, I came kind of fired by the fact that here was a country with a wonderful astronomical heritage and a wonderful astronomical
facility that I was being let loose on in a very similar way to David and had a ball.
David: And a very dark sky, that was the key thing about Australia it was dark, it still is dark.
It's fantastic.
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Student: Modern optics have many adaptations that counter interference due to atmosphere.
Could you explain what adaptive optics are and what improvements they can have by the quality of their images?
Fred Watson: One of the problems with the telescopes that we have available today, the biggest telescopes are the ones that clearly sit
on ground level, we know that there's the Hubble Telescope in orbit.
The Hubble's one of a kind though, it cost two billion dollars to build it and launch it and that's money that most astronomers don't have at
their disposal or most astronomical fund raising agencies.
Whereas ground-based telescopes are much cheaper to build and you can build much bigger ones which have the capacity of seeing further into space and seeing more detail.
However, the problem with the telescope built on the ground is that it sits at the bottom of the Earth's atmosphere.
The Earth's atmosphere is a very turbulent and agitated place and what that does is to essentially spoil the images that these telescopes can see.
So, what should be a tiny, tiny point of light in the image of a star becomes this kind of trembling blob of light and that's caused
entirely by the effect of the Earth's atmosphere.
It's the same thing that causes twinkling when we look at the sky the twinkling is caused by this turbulence in the atmosphere.
So, what you want to do is get rid of that and modern technology has evolved a way of being able to sense the way the light is being distorted by the atmosphere.
You can sense that by using a thing called a wavefront sensor and that will then tell you what the atmosphere is doing to the light that comes in.
And if you're really clever and you've got enough computing power at your disposal you can feed that information back to a mirror whose
surface can bend in sympathy with these distortions of the atmosphere.
And the idea is that one cancels out the other.
The bending mirror cancels out the distortions of the atmosphere and that way removes, not entirely but to a large extent the deleterious,
the bad effect of the Earth's atmosphere.
So, it's a way of trying to turn telescopes here on the Earth's surface into their equivalents in space where there is no atmosphere.
It doesn't succeed entirely but it's a very promising technology and hopefully it will bring many new results.
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Student: In terms of what we have learnt and what we can achieve in the future in space science and astronomy, do space telescopes really offer value for money?
David Malin: Yes, they do.
It's a lot of money and happily most of it isn't our money but it is very good value for money.
You can achieve things with telescopes in space that you simply cannot achieve from the ground.
The Hubble Space Telescope is a terrific example, it's only two metres, a bit more than two metres in diameter, it's a small telescope by any modern standard.
But because it's above the atmosphere, as Fred pointed out before, there isn't the atmospheric trembling and the telescope can see at all,
an enormous variety of wavelengths that never reached the ground.
Because there's no trembling and because the optics are so good now they've been fixed and because it can see it all wavelengths it can
see right back to the beginning of the universe almost.
And the images its made and the observations its made of galaxies and happenings right at the edge of the universe have really
increased our understanding of the universe enormously.
If you value this knowledge you can't put a money value on it, it's really for society to say whether spending this vast amount of money
on telescopes like Hubble is worthwhile.
It's not for the scientists to say that, they can make the case but really society pays for this instrument and it's for them to say no more or carry on.
Fred Watson: Can I add to that if I may?
One of the issues of course with the Hubble because it's an expensive project, it's an expensive telescope there is only one of them
whereas ground-based telescopes can be built much more cheaply.
So, you can have for the price of one Hubble for example you can have twenty of the world's largest current class of ground-based telescopes.
And so that's why people are putting effort and energy into this idea of adaptive optics to try and do as well, nearly as well from the ground as you can from space.
But there are still going to be things that you can only do from space and that's why it's worthwhile putting telescopes up there.
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Student: Why is it advantageous to take many long-exposure photographs of the same part of the sky?
David Malin: Yes, there's something called a signal to noise issue basically.
When you point your camera, your big telescope camera at the sky, now the sky is never completely dark and because it's not completely
dark, if you make a long-exposure, your film or your CCD or your digital camera, it fogs, you get a level of fog coming up, as though
you're looking through a faint but luminous haze to the distant sky.
If you make many such pictures and stack them together you can minimize the effect of that haze.
In other words you improve the signal and minimize the noise so you can see ever fainter objects.
It used to work in photography but it works much better with digital imagery which you can handle inside a computer without any kind of information losses.
So you can actually stack the information up in a linear fashion, so the longer you expose for, the fainter the object you see.
That's basically why you do it, to improve the signal to noise.
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Student: We know that the universe is ever expanding at an accelerated rate and the galaxies are moving away from each other.
But the Gravitation Law state that the galaxies should be moving towards each other.
How is this contradiction explained?
Fred Watson: You're saying that the universe we know is expanding but galaxies gravitationally attract one another, is this a contradiction?
I think that's the right question.
Would you like me to try that one David?
David Malin: Well, you certainly can, yes.
Fred: Thank you. I'll have a stab at it.
The fact that the universe was, or is expanding was a great surprise when it was discovered back in 1929 by Edwin Hubble.
He recognised that the further you look into space at distant galaxies, the faster they are moving away from us.
And it was Hubble and people like Georges Lemaitre and a man called Alexander Friedman who was a Russian physicist, they worked
out that this basically means that the universe itself is getting bigger and it turns out when Einstein went back to his equations of general
relativity, yes the equations of general relativity say that the universe will probably get bigger as well.
So, it was a very self consistent picture but you're absolutely right in your question that galaxies and stars which are what make up
galaxies or at least one of the constituent parts of galaxies actually have a gravitational attraction.
Everything in the universe attracts everything else by gravity.
Even David and me are attracting one another at the moment and it's terrible.
David: Speak for yourself, Fred.
Fred: So, there's this mutual gravitational attraction of everything.
Now, what that does is to provide a breaking effect on the expansion.
And back in the 1970s and 80s when people were looking at the universe and trying to measure the contents of the universe by looking
at the speeds at which objects were moving away from us it was thought by everybody that the mutual gravity of all these galaxies
would slow down the expansion so that it would, the universe would decelerate and perhaps would even stop expanding sometime in the future and then collapse back in on itself.
So, it was a very great surprise in 1998 when two groups of scientists, one of which is here in Australia discovered that actually the
universe's expansion is accelerating, it's getting faster and faster.
So, it's overcoming this mutual gravitational pull of all the galaxies and we now put that down to perhaps one of the biggest mysteries
in the universe which is something we call dark energy.
It's a kind of springiness of space itself that makes space want to get bigger more rapidly.
So and it's clearly well able to overcome the effect of gravity.
The pull of gravity is still there between these galaxies but it's not strong enough to overcome the flow that the space itself is carrying them apart with.
David: Let me just add something to that.
The visual effect of it, the big effect of this is to make the galaxies tend to clump together but get strung out into long strings and strands and sheets of galaxies.
When you look at the universe on its largest scales as they do with the Anglo-Australian Observatory with a 2dF you can find there's a
structure there which reflects the attraction of the galaxies to themselves but also being pulled apart by the expansion of space.
And so the effect is in the end to get voids that are devoid of galaxies, sheets of galaxies and where the sheets overlap you get huge
clumps of galaxies, clusters of galaxies, that is the effect of expanding space and time and the gravitational interaction altogether.
That's about right, Fred?
Fred: Sounds grand, yep.
So the fact is that yes the universe is expanding and it's expanding evermore rapidly than we thought it was and that leads as I said
to this great mystery of 'What is dark energy?'
When we find out what it is it might be something that's quite useful, who knows?
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Student: How do we determine the age of the universe using the Doppler Effect and if it's with the Hubble Constant why is there such a big variation in it?
David Malin: Well, the age of the universe is actually the size of the universe as well because the light that we see at the edge of the
universe and it doesn't really have an edge and we're not really in the middle.
The light that we see as far as we can see began when the universe became transparent.
And that was about a third of a million years after the Big Bang, that light's been travelling to us ever since.
We now see that as the cosmic microwave background and that's as far as we can see.
We could measure the Redshift of that, we can measure how far away it is and it turns out to be thirteen point seven billion years away, a billion light years away.
The universe of course has been continuing to expand right from the beginning so the light is stretched out because the cosmic microwave
background we now see a two point five or two point seven degrees, well actually as hot as the sun when it's set out but the universe
is expanded, the radiation's been stretched out, we now see it as a very low temperature indeed.
Its variations on that low temperature sphere that give us some information about the universe at times before we can see it, and it's
those variations that led to the formation of the diverse universe we live in now.
The galaxies and structures we see around us now.
Fred Watson: Could I add something to that?
Your comment about the Doppler Effect is well made because the Doppler Effect of course is the effect of whether it's a source of sound
or a source of light as it moves away from you, its frequency decreases.
Or in the case of light waves the wavelength gets longer.
And we all know what the Doppler Effect sounds like when a fire engine goes past with its siren going because the fact that the note
changes in pitch is to do with the Doppler Effect.
And astronomers use that as well, we use it to measure the speeds of stars for example and back in the 1920s which we were talking
about a few minutes ago, it's what Hubble used to measure the speeds of galaxies moving away from him, he recognised that when you
looked at galaxies deep in space they seemed to have these velocities which he thought was due to the Doppler Effect, to these galaxies moving away.
But in fact today there's a slightly more subtle interpretation than that and it's basically we don't regard that as being due to the Doppler
Effect, we regard it being due as David has said to the fact that space is expanding, space is getting bigger all the time and so the further
away you look you're seeing objects whose light was emitted at an earlier period in the universe and in the intervening time between
that light being emitted, which might be millions or billions of years ago and today when we observe it, the light has been stretched by the expansion of the universe.
And so its wavelength has got longer and that means another way of saying that its frequency has reduced.
So, it's not really the Doppler Effect that allows us to measure this expansion of the universe.
But nevertheless it is that that tells us how old the universe is because if you can measure something called the Hubble Constant, which
is essentially the rate of expansion of the universe today, then one of the simplest things you can do is to actually invert the Hubble
Constant, you put it into a formula with one over the Hubble Constant and what you get out is a time, actually it comes out in seconds
which is a bit embarrassing because it's a long time.
But that gives you the age of the universe.
It's the easiest way of measuring the age of the universe.
It's not very accurate because it ignores things like the dark energy that I was talking about a few minutes ago, all this gravitational attraction of galaxies on themselves.
But it does give you an answer that's not too far off the best answer we have about thirteen and a half billion years for the age of the universe.
And it comes simply from this observation that galaxies seem to be receding from us.
Not really the Doppler Effect something called the Cosmological Redshift but rather closely related to the Doppler Effect.
Which is what David said but you know ...
David: In a garbled way.
Fred: A garbled way, that's right. We're both garbled.
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Student: I hear next year is the International Year of Astronomy.
What events can we expect?
David Malin: The International Year of Astronomy is going to be a fantastic year.
2009 is the four hundredth anniversary of Galileo's first turning his telescope to the sky and being able to see things that had never been seen before.
He wasn't the person who invented the telescope nor was he the first person to point it at the sky.
What Galileo did was to look through his telescope with scientific insight.
He observed the Moon and saw its mountains and made drawings of it.
He saw stars that had never been seen before.
He saw the phases of Venus.
But most importantly he saw moons going around the planet Jupiter and that confirmed his and other people's views that the Sun might be at the centre of the solar system.
He'd seen what looked like another solar system going around another planet.
That was probably the most important thing that Galileo did.
It's that Epoch making discovery that changed our view of the universe and of our place within it that we're celebrating in 2009.
There will be all kinds of outreach activities, all kinds of community activities as well.
There'll be art exhibitions, travelling shows, there'll be Fred and I talking endlessly, endlessly all through ...
Fred Watson: For weeks on end.
David: For weeks on end through 2009.
There'll be theatre performances etcetera, all sorts of wonderful, exciting things.
What are you going to do Fred?
Fred: Well, well I was just going to say that there's going to be an opening ceremony isn't there?
David: There'll be an opening ceremony, New Year's Eve at Christmas.
Fred: Which is going to be rather a clever thing, the fireworks display in Sydney Harbour will also have a dropping of the time ball at
Sydney Observatory and this is an ancient time signal that used to be used for mariners to set their chronometers.
So, that when they went off sailing around the sea they knew where they were.
But that time ball will fall at midnight on the 31st of December.
But instead of being driven by a clock, it's being driven by a thing called a pulsar which is the most accurate kind of clock in the universe.
So, the time signal's coming from space and it will kick off the International Year of Astronomy.
Then there are all sorts of events planned and something called a Hundred Hours of Astronomy.
David: That should be exciting. Everybody should be able to take part in that.
Fred: Yep.
David: That's in April.
Fred: In April. There will be events of quite unusual kind like cruises and things like that where David and I'll be telling people about the sky.
But there is a whole range of community activities.
The Amateur Astronomy Community is getting very highly mobilised.
They will have star parties, there'll be education weekends.
There is a thing called the Festival of the Stars in Coonabarabran which is where the Anglo-Australian Telescope is and that too will be
a special extended version for the International Year of Astronomy.
There's one of these Festival of the Stars every year or Festivals of the Stars every year but the IYA one, the 2009 one should be a big one.
And there is also going to be things like the celebration of the fortieth anniversary of the first human landing on the Moon when
Neil Armstrong set foot on the Moon that will be marked with some kind of party which I hope David and I will be invited to.
David: That's right. It might be at Parkes but certainly they'll be celebrating, Parkes and Tidbinbilla in fact we're celebrating all of that.
The Hundred Hours of Astronomy is a great thing it'll roll round the world for two or three days over a weekend in April and everybody,
literally you as well will be involved at some level since you're now able to connect to the world through this marvellous system you have here.
You'll certainly be involved.
There'll be, well there'll be a closing ceremony as well won't there Fred?
We haven't worked out that yet.
Yesterday, only yesterday I was talking to somebody about organising an event at Government House in Parramatta, Old Government House
in Parramatta, the old buildings there, there was an Observatory run by Sir Thomas Brisbane and many major discoveries were made there
and so we'd like to put on a musical event and an astronomy event and maybe a slideshow and a talk as well and that sort of thing will
be dotted all through the country throughout 2009.
We're going to be run off our feet and it's going to be fantastic.
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