Welcome to the public lecture of the
General Assembly of the RASC, 2015.
I'd like to welcome all our members who are here
from across Canada, I'd like to welcome any
any of the public that have come, and I know there a number of people here as well
from the Halifax Astronomy Meet-Up group,  so welcome to coming out to this event.
thanks for coming and I hope you enjoy the
evening. My name is Paul Grey, I'm the
center president the Halifax RASC. I have a few housecleaning items to attend to first.
First of all, the entrances you came in at the right and the left of the auditorium are primary exits.
Other either side of the curtain
straight through the back,
there are two emergency exits shall we have to them. Washroom, are again, back out the hallways that you came in.
My left side is the men's, the opposite side is the female.
That's most of the
house cleaning duties.
I'm going to introduce James Edgar, he is
the national president of the RASC. He will
give you a bit of a background on who we
are what we do, as well as the lecture
you about hear tonight, and that is who
it is named after and why we do this
memorial lecture every second year. And with that I will pass it on to my good friend and
President: James Edgar
Wow. Good evening. What a nice looking
Crowd. For the members of the public who
are here, this is a public lecture, so I
want to tell you a little bit about the
Royal Astronomical Society of Canada. We were
founded in 1868 in Toronto and we are... we
consider ourselves Canada's leading
astronomy organization, bringing together
over 4,900 enthusiastic amateurs,
educators and professionals. In addition
to many national services are 28 centers
offer local programs all the way across Canada
Our vision is to be Canada's
premier organization of amateur and
professional astronomers, promoting
astronomy to all. Our long history has
been enriched through the hard work of
hundreds of volunteers and professionals
and one such person was Ruth Josephine
Northcott, who unfortunately died young
at the age of 56 in 1969. She was one of those women
who were called computers in the old days.
She graduated from the University
of Toronto in 1934, followed by her
master's degree in 1935, whereupon she
was promptly appointed to the staff of
the David Dunlap Observatory in Toronto. Her primary work was in
radial velocity measurements of stars
and spectroscopic binary orbits.
In 1983 minor planet 3670 was named "Northcott",
commemorating her significant
contributions to astronomy and science.
Obviously tireless, Ruth Northcott was
assistant editor of the journal and the
assistant editor of the handbook at the
same time. She eventually succeed
Doctor Clarence Chant as a handbook editor in
1952
and her last press-run for the
nineteen seventy edition was
twelve thousand handbooks. In addition to all
that she was the RASC president from
1963 to 1965 and truly an inspiration to
all who knew her. It is small wonder
then that the society honors her with
the Ruth Northcott Memorial Lectures
held in odd number of years
alternating with the Canadian
Astronomical Society and the HoG Lectures. 
This year we are indeed honored to have
professor Rob Thacker as our guest speaker
and with that I'll turn it over to the
Dean Stephen Smith to introduce Rob.
I would like to start by welcoming everybody here tonight. Its fantastic to see so many people here on campus, so welcome on behalf of the University.
We're very pleased to have the
RASC General Assembly here as well as to
host the lecture  tonight. I'm just here to
introduce Dr. Thacker who is Canada
Research Chair in computational
astrophysics here in the astronomy
and physics department, as well as the former Chair. He maintains an internationally
recognized research portfolio related to
large-scale structure and galaxy
formation. I understand the second part
of that but I'm a psychologist so there's
always a lot I don't get [audience laughter]. He's a very
accomplished science communicator and as
as I'm sure you're gonna see tonight, has
the ability to take stunningly complex
matter and explain it in such a way that
really captivates people and gets their
imagination going, so you're in for a
treat tonight.
He is frequent subject expert. He's done... I don't
think we could even count the number of
media interviews he's done... TV and radio,
as well as popular books in chapters. In
addition to that he's got forty
scholarly publications with over 4,000
citations as well as over a hundred
conference presentations, proceedings,
book chapters, all those sorts of things.
He also has obtained over the years
1.7 million dollars in research funding
and that's why he's a Canada Research
Chair -- one of the best in the country. As
chair of the department, he was chair
just after I started as Dean,
great colleague to work with, very
pleased to be able to work with him. He is
always looking out for the students but
also looking to better the University.
I'm sure as many of you know we have a
new Ralph M. Medjuck telescope here on campus,
which is the second largest telescope in
the country on a university campus and
the largest in the Atlantic region and
that's really because of the leadership
Dr. Thacker. He is a subject matter expert for
local media. He's a talented teacher,
mentor, and of course is a member of the
Royal Astronomical Society. His passionate
extensive knowledge of the universe's
mysteries has ignited the imagination of
thousands of Canadians and like I said
you're in for a treat tonight. Please
join me in welcoming Doctor Rob Thacker [audience applauses]
OK. I have to do one thing. Everything is being carefully recorded
so before we start I have to start
recording. Great. Alright! Hi everyone! [some audience laughter and "Hi" returned]
Everyone doing OK? Chilling out, right?
science is not like eating your greens
science is meant to be fun, right, so if
anyone gets bored, in fact I'm freaked
out that Paul started with "the exit are there"...
[laughter]
But seriously! Let's have some fun tonight.
This is good stuff. And in fact Steve said
I'm really an astrophysicist. I
consider myself a completely amateur
astronomer. In fact I'm convinced that
everyone in the Halifax Chapter of the RASC  knows the sky better than I do.
I come from a physics
background and I'm I'm slowly learning
more and more about astronomy. And so
what I'm going to talk about tonight is
it something new for me. This is fun for
me to learn all this stuff I mean I know
there are people in the audience who
know more about spectroscopy, that's
something technical, but there are people
out there who know more than I do so I'm
learning as well which is great
place to be. Alright, so this is a
difficult for me to give because I know
that there are some members of the RASC
who have quite a lot of knowledge about
astronomy and at the same time this is a
public lecture too, so I've got a talk
that's kind of at a low level but every now and again there are few things
where I do go into technical details, for
members of the audience who can
appreciate that, but if anyone has at any
time "what you talking about?" just put your hand up and ask. I'll probably go "I have no idea"
[laughter] but its OK. Alright so in the style
of the famous Richard Feynman who was a
famous physicist who you either love or you hate: three easy pieces tonight. The WHY. I'm a big
believer in explaining the WHY because
when I go and talk to politicians about
funding astronomy they go "Why are we
gonna do this?"
So I'm going to start with WHY and
then we'll start with HOW. Now at the moment
those words probably won't mean anything
but I hope that in half an hour they'll mean something to you.
And then we'll finish off with the "WHAT"
And the WHAT is how we gonna do this. Really what is
astronomy, it's not astrophysics in this
case, and the new telescopes we're going
to be building hopefully in the next few years
Right well. My wife's mother-in-law is actually
a paleontologist and she said "it
shouldn't be called galactic archaeology
should be called paleontology" but I'm
gonna start with the definition of
archaeology and then maybe some people
in the audience who have an interest in
archaeology... and traditionally
archaeology has been the study of human
history
prehistory through the excavation of
sites in the analysis of artifacts and
physical remains and really what does
that mean? That means getting down and
dirty. And well galactical archeology isn't like that.
It is completely
different. We think of archaeology as
brushing the mud off, troweling stuff out
and so on
whereas what I'm gonna be talking about
tonight is very different. I'm not
digging beneath the feet. We're digging
in the sky. So this is completely
different and we are going to be using things
like this: a giant telescopes. This is Canada France Hawaii Telescope
really beautiful piece of equipment
although it's forty years old.
This is the kind of equipment we're going to be using.
And I've got a joke. I got one joke about
archaeology. And.... I searched so hard,
right, but the problem with archaeology is,  all the jokes are dirty!
[audience laughs] At least you laughed! Alright! So
I'll start with the big picture.
and it's so ironic that this morning as
part of the conference, we had Dr. Roy Bishop say:
" I don't know about that dark matter
and dark energy stuff", so I'm actually
going to start with dark matter and dark energy. It's what I study and ironically, having worked in very very high polluting
fields of theoretical physics where there is
stuff where I'm really.... "Ohhhh I don't believe in any of that", this I
actually do have strong confidence in
being true. So what am I showing you? This
is a beautiful image, and this
represents about 120th the size of the
total observable universe. Why do I say
observable? Because light travels at a
certain speed and we think the universe
has a finite age. 13.7 billion years. So this is just this weird stuff called Dark Matter.
It's really
embarrassing to stand up and say that
the universe is full...
...eighty-five percent of all the matter in
the universe in some form we don't know
what it is. But we know it's there.
We can see it influencing stuff. Either that
or what we know about the laws of
physics is really really wrong. Right, so
this isn't just an image. This is a movie. So in fact this
is taken from a simulation and we can
create these virtual universes and
solve equations of the laws of physics
and now you can see that this is a
beautiful three-dimensional structure
very complicated but all of the physics
that is being solved in there basically
comes out of the Big Bang and gravity
and we know this to really quite
exquisite precision and now when we go and
observe the universe with telescopes to see where galaxies are, they have
this kind of structure. This isn't an
exact representation of what the
universe is. This has all of the
properties of the universe but its
simulated within a computer. So that's
the general kind of structures that we see.
But what I want to do is now
show you how incredibly detailed that
structure is
it's not just on that scale that you're
seeing there. I'm going to go out now, this
is about a quarter to a third the size
of the observable universe so if you put
a few more over there and a couple more over there,  then you get the whole observable universe.
We will zoom in.
This was, again, simulated in a super computer, part of a big research program I was involved in few years ago.
So now we can zoom in and
you'll see more and more structure as you zoom in.
Again this is just the
Dark Matter. It's colored in a different way.
We play lots of fun games with coloring
dark matter because it really has no color.
We just put that on there too to make the
pictures look pretty and have everyone go "oooooh"
So, this would be a cluster of galaxies.
We see very very rich clusters of
galaxies with three or four hundred galaxies in them.
And this would be the dark
matter that's actually in that cluster of galaxies.
Now just as we get in to the next one, we will be able to see lots and lots of points. And all of those points would be
the dark matter that surrounds
individual gasses. There we go. Now each of
those points you can basically associate
with an individual galaxy.
And we are just going to stop zooming in. But if we kept on zooming in, we'd see the same kind of thing again.
And now we'll stop and go all the way out again.
But that's like, the incredible structure you have. From the large scale all the way down to the small scale. It doesn't stop there of course.
It keeps on going down, and smaller and smaller and smaller, so you have things, within things, within things...
... and we call that idea
hierarchical clustering. That's a very
well insituted theory of the overall structure
of the universe, and it seems to be really good.
And in fact those of you who are
interested in science, and probably heard something  called fractals, the idea is that this thing, you blow it and you can see the same structure again
and blow it up again. We kind
of have a bit of the universe but it's
not perfect
there's a scale at which it doesn't work above, and a scale of which doesn't work below.
but there's one in the middle where it's
just right
and if you keep on zooming in you see
kind of similar structures again. alright so
that's how things look now in the dark
matter. How did things get to be the way
they are? And that's really what galactic
archaeology is all about. Tt's not about
what things look like now, its about what were
things like in the past. So now I'm gonna
do another movie . I'm gonna show you
how things evolve in time and so some of you
may say "well, doesn't universe expand? Why am I not seeing this expansion in your movie?"
we actually take the expansion out,
so you can see what's happening. In fact
when we start the movie it would be a
hundred times smaller than when it
finishes, so you wouldn't get to see anything. So I'm
taking all of that scaling out and you can
just see whats happening.
So immediately you see that the first things to form are small things. And what else do you see? A lot of merging going on. Things banging together.
More merges going on. and you see things floating around
outside other things. Again astronomers are probably thinking "satellite galaxies". That's exactly right.
We have this beautiful structure where you
have a central region and then surrounding
that you have a halo of dark matter. So
we call these things  dark matter halos. Nothing to do with angels.
kind of beautiful structure. You want to see it again? Yeah? OK. Again. First things to form: small. Merge together to form bigger things. Keep on merging together to form yet bigger things.
So that is in fact the time sequence of
what happens in hierarchical cluster. and we think this is
really really very accurate if we look back
with telescopes we can actually see a
lot of evidence for this. Especially with
Hubble, and other ground-based telescopes
you may be wondering what this
particular simulation was. The entire simulation goes
on far far larger scale than this but
this was actually meant to be the dark
matter in the Andromeda galaxy in the Milky
Way and eventually the two of them will merge together but
we did this UC-berkeley a while ago now
and in fact the mass of Andromeda was
estimated to be wrong then. So this simulation
isn't quite right but it still looks
cool. So I just want to summarize that for you. This is hierarchical clustering in a nutshell
and this really matters because this is
something we're going to be looking at
in detail in galactical archeology. but you form the smallest galaxies early on. those small galaxies
very quickly emerge into bigger galaxies.
and those bigger galaxies don't survive
for too long before they merged into yet
larger galaxies. and so that process as I said
it supported by observations very well
the farther back we look in time, the
earliest galaxies we see: really small.
Its smaller than we thought it was.
I actually think its even less than that now. They are almost the same. Its come down a lot. In fact what happened when we did all of that work back then,
with all of the things that are around, because we made the galaxies so big, everything was moving too fast. Because we thought it was too big.
Lastly, what have I done up there in the
last one, I've put a disc right in the middle.
Why have I done that? Because I'm want to show
you that the galactic disks
that we actually see, which are made of the stars, are much
much smaller than the halos.
A 10th or 20th the size. So galaxies extend in terms of their halo much much further out. I've got another
picture of andromeda
CFHT that goes very deep and you can see
that. That's in a few slides.
So that's how we think dark matter comes together and how it impacts the formation of the galaxy.
But of course we don't see dark matter. All we see are interstellar media, the gas
between galaxies that glows and so on.
So we want to understand how that evolves as well.  And, of course, we can simulate that, too.
It's actually very difficult to do. The physics of how dark matter interacts is just gravity.
The physics of how gas evolves is something called hydrodynamics
which is much more complicated much how
much harder to do, much bigger supercomputers to do it.
But you get amazing movies like this. This is a
disk galaxy. Don't worry about that funny little bit at the beginning.
That's just the person
behind the curtain. Just kidding.
So, this is a simulated disk galaxy, And you can see the color coding just represents how dense the gas is.
The more yellow it's
denser. And so where the gas is very dense,
that would be clouds of gas that are
forming stars. In fact there are
literally thousands of these very very dense
knots of gas
and in fact we see thousands of clusters of
stars in the disk of the milky way. so we think this is actually a
reasonably that good representation. And look it's doing something really weird.
That's called a bar instability and this
simulation is rather unique, because most bar
instabilities exist for a very long time
and this one is very transitory and it
will go in a couple more rotations. If you're thinking "Why is it slowing
down?" That's completely
unrealistic. That's just something that
comes out of the simulation. That's not actually what would happen in real life. It's just the way we made the movie.
And then at the end you get something that looks like
the eye of Sauron from Lord of the Rings. but can you see it
looks like it's still rotating around. It is a really good optical illusion.
so what do I want you to take away from
that? I want you to take away the fact
that how everything is moving in the disc of
the galaxy is really complicated. Things
are also bumping into one another within the
plane of the Milky Way. Happens. And also
you can imagine, if things that
complicated once you form something,
how long is it going to survive. It's a good question. How long
did that represent? That's a few billion
years of evolution. It takes about two hundred and
twenty-five million years for the Sun to
go around the center of the galaxy.
so this is a beautiful picture of NGC 35
72 (credit to ESA). I am showing you this is because this a stellar nursery.
It is twenty million years old -- there are
probably slightly better estimates now --
and what you're seeing is thousands of
stars that have been born together from the same cloud of gas.
And as and these thoughts
again slowly dispersed over time
we see this happening -- we see what we call open
clusters (there are thousands of open clusters in the plane of the Milky Way) -- So we know this is how stars form.
In time things are going to start moving
apart. Their only very very loosely bound
by their forces of gravity. All of the red:
some of the astronomers will recognize exactly what that is.
And thats from the giant molecular cloud, basically all the gas being lit up
by all the stars inside. Also pushing on it, pushing it around with winds.
There's beautiful structures down here in the
bottom right. I love these images --just fantastic -- Physics!
Looks beautiful and has got amazing physics. We also got little
sort of like rings in there, things that
are being lit up as well. So much detail in that.
ok. Lets have some fun.
What I'm trying to convince you all, is that 
the galaxy formation and galaxy evolution
is one gigantic blender.  That
seems like a weird analogy but it's
completely true. You've taken all of
those things that have merged together
and you've mixed them around, stripped them apart... etc. So I'm gonna show you how
you blend a galaxy. It's a Galaxy phone. Anyone seen some of these? The "Will It Blend" series?
This is absolutely crazy. I just
have to check my sound levels on this....
Do not try this at home please.
I'm gonna press the
starting bell button
So, I'm having just a complete amount of fun by that, but I think you will now always remember that galaxy formation is a blender. So what we're really trying to do
when we look at the galaxy now, is to put it back into t he  same initial condition and figure out all of the bits that went in. That's what we're really trying to understand when we do galactic archeology.
So I said I would have a picture of what the halo looks like.
And we can do this very straightforwardly, it takes a lot of telescope time but the idea is straightforward.
And we can do this with the nearby galaxy Andromeda: M31
And so this was a project, and I am please to say this is a Canadian project lead by Dr. Alan McConnachie, at the RASC at Victoria.
They looked at a very very deep, low brightness regions around M31 and I said you can see how big the
disc of the galaxy is relative to the halo
And there you can see. There's the
disc in the middle and there's the halo all around.
So the halo is BIG -- seriously big. But
there's still a lot of structure.
ok so you have a stream of stars here
there's another one here and there are
others around here close to the galaxy as well. We know
there's some of these structures around
the Milky Way, too. They are very
difficult to see around the Milky way for reasons I'll get into.
You can also see M33. Actual galaxies are really small compared to thier dark matter. So there's a lot of
stuff to see out there beyond just what
we see in the disc. And if you're
wondering, it would be like 3 or 4 full moons across that disk probably, maybe a bit more than that.
So this is quite a big patch of the sky: several
degrees. But nonetheless there's a lot of
amazing structures here. And so...
that's what we see. And this is the kind
of thing that theory predicts: this is taken from a paper by Starkenberg in 2009.
And she said: look
if we could look at all of the galaxies
that came together and merged, what would that look like? So we'll
color-code each galaxy as it comes in and merge
And we'll see what kind of picture
we get at the end. And this is what she
got along with her collaborators. Now this is probably .... ahhh... sorry I'm going to get all 'professional'... It
is probably not a really good model for
the galaxy. Is a bit too smooth and the
way they did things meant things stay
together longer than they should. But all
of this you would expect to be filled by
stars that have been stripped apart and
torn apart as they merge into the galaxy. So we think
nonetheless that something like this is
just sitting around outside the Milky Way.
The problem is how do we go about figuring out what
belongs with what and what came from what. That's the real challenge
And the other thing with this is the sky
is big. It's not like you're looking
through a telescope at really small
patch of sky. You've got to look at the whole sky to see the
halo around the Milky Way. So here is a
movie that some of the members of the local RASC chapter may know.
This is Jerry Black's
time-lapse of Peggy's Cove.
And this...is the plane of the Milky Way and even
that is big. I'll run it again.
and we've got to look at the whole sky to do this kind of stuff. This is a real challenge.
So. There's a couple of ways that we can do this. We can go look for these structures.
The first thing we can do is just say how are things moving. I have two slides with graphs. This is ONE. And I'm gonna do
Arnold Schwarzenegger impression as well. Anyway so this is velocity against velocity. What does this tell you? It tells you how things are moving.
So if we find things  that are moving kind of  together, we think that they're
probably associated with one another. So we can do this in around the Sun we've been doing
it for a while and we find a couple of
notable structures
There's something called the Hercules stream. It's in the Hercules
region of the sky right and that may or
may not be associated with itself. The MilkyWay is mean. It will do
what's called orbital resonances. it will
put things together and movethem  around
together, even though they have no
association with one another. Its really
difficult to figure out whether things
started together or whether they've just
been put together by the Milky Way's
overall motion. But there is another bit on here called
HR 16-14. And we know that that
really does seem to be associated. It's
all moving, and probably was one
star cluster along time ago. But these
are very rare. There aren't very many of
these. It's tough to do this in the disc
of the Milky Way. You need something better. If you want to find
groups that used to be in the disk of the Milky Way. it's good for the halo, though. It works in the halo quite well.
So, we need something better if we want to understand how the disk evolved.
Remember I showed you that movie of
the disk evolving and everything was so complicated. And...any CSI fans? Fingerprints. You need a fingerprint if you want to find the culprit.
So we need some kind of thing that we can use to actually traceback
stars to where they came from.
So this is our fingerprint. It doesn't look
much like a fingerprint. Here is the 2nd graph.
My Arnold impersonation is coming. So what am
I showing you? This is basically how much
on this axis, and then this is the atomic
number. It basically gives you a really
nice way of writing down all the
elements. And then just basically how
much of each element do I have? That's the one
thing that we're going to  use. This is actually for the sun. We can do this precisely for a nearby star.
It's difficult to do, and I'll just talk about that very quickly in a couple moments.
But this is a real thumbprint for a star. How much of a given element does it have?
Now those of you who know a bit about stars will know...
stars are constantly changing one element into another. They are giant nuclear reactors, so we gotta pick
the right kind of elements if we're
going to do this. So let's pick the right elements.
This is the periodic table of elements in a
form that some of you may have seen
before, most people have never seen it
this way before. This is really cool! Where are atoms formed?
Where do we form atoms? So those of
you who have done a bit pf physics will know that hydrogen and
helium, they form in the Big Bang. But things like Lithium, Beryllium, Boron, they are actually
actually created in space, a little bit made in the Big Bang but not very much.
They are mostly created in space itself by
believe it or not...
high-energy cosmic rays coming along and
banging into hydrogen and helium nuclei.
But carbon, nitrogen, oxygen, sulphur, neon,  all
of those elements and made in smaller stars
And then if  you go to really big
stars, the bigger the star the more energetic it is, the hotter it gets
the more energy it can
put into create bigger and bigger elements.
So by the time you get large stars, look anything with green on you can make in a large star.
But there's a
few things you still can't make in a large star.
and there's a few elements that are just
made in supernovae. They are these ones here.
A few down here as well. And basically about
twenty five elements that are kind of
unique in terms of once you form the
star they're pretty much the same throught the lifetime of the star. And so
these are our sort of like holy
grail elements to use in working out abundances. Right so I just
sort of said I would say something about
how we make these measurements. We do
this was something called spectroscopy. All atoms have thier own
energy levels and will absorb or emit
light at specific wavelengths of light. So astronomers will know this very well. But 
here is a spectrum. This spectrum is really
weird. Anyone see what's wrong with this? Its not the colors, but thats a great guess. Its a technical thing.
There should be a Delta line there but it's missing. This is meant to be hydrogen. Anyway so we have the
color and then you can see these dark
lines and those correspond to the points
in wavelength where the atom will absorb the light. So if we turned
it around said where does it emit? You'd have red over here, this is of course H alpha, H Beta, H gama and so on... that's just for the people who can understand this stuff.
But we can turn that into a graph. And
here's my Arnold impersonation. You know I said there'd be two graphs....
I lied [audience laughter].
There's gonna be
three. Ok so here is the intensity of the
radiation and here is the wavelength. So we make
this graph , but really it's just a
colorful spectrum and we're putting it
as a graphing instead. So for the sum,
of course we can do this in incredible
detail. Here is just a tiny tiny tiny patch of the Sun.
And there are lots and lots of lines. Iron, titanium. More iron lines. Chromium...
magnesium... This is all really  useful informaiton
And you can build up
an idea of what the precise  state of the
atmosphere around the star is. Because that is what you are measuring.
measuring the outside of the star. And basically, my
colleague Dr. Ian Short, who is an expert on this...
...I'm certainly not an expert on this,
basically the depth and the width of
these lines are what you use to
calculate how much of a given element is in the star's atmosphere.
So that's what we do. It's very complicated
but the idea is now come to be known as
Chemical Tagging and really a lot of
people think of this... nowadays things
rarely are sort of like one person's idea,
you often  hear that several people had the same idea at once.
It's happening with Nobel
Prizes a lot now. "Oh I had that idea, that person had that idea, who do we give the prize to?" right.
But I'm going to single a couple of people who've really really
pushed this idea. Ken Freeman here who is 74 now but he
is like the energizer bunny, he just
keeps going and going going.
And Joss Bland-Hawthorn. Ken is an Australian, Joss was born 
in the UK but work in Australia now. So the two
of them have really really pushed this
idea and they're doing a lot of work on
this themselves. And so I'll just summarizes this again for you. The idea is stars form in groups And they
form from the same gas, that gas has the  same
distribution of elements through it.
So all of the stars that form in a group basically have the same fingerprint.
Over time because  we use specific elements that don't change, they
keep that fingerprint. But they disperse
through space. So what do you do? You go and look for
stars that have the same abundances.
That's it in a nutshell. Find the stars. Match them up. Easy, right? [audience laugh] You already know the answer to that one!
So why is this a little bit dangerous
for astronomers? Well because we get a
lot of mileage out of a really beautiful
pictures. Hubble Space Telescope has produced lots and lots of
beautiful pictures but we're now talking
about doing stuff where you are not
going to get a beautiful picture. You're
gonna get millions of graphs. How boring
is that? So, this is the Pleiades, and what
I'm trying to make clear to you is that
each of these stars is going to have its
own spectrum and we are going to actually put
fiber optic cable on each of those
stars in the focus of the telescope and
take a spectrum. No pretty pictures anymore! A bit dangerous if you want money from the government. I'm just kidding.
So instead of taking beautiful pictures
now the star is going to take literally
thousands of spectrum at at time. Not one slit. Literally thousands of fibers in the
focus. So no more fancy images from these particular telescopes that have
those instruments on them.
OK so I said in the in the abstract, I talked about
the pitfalls and because I was joking of
the time I said: oh, we don't have to worry
about people
coming along with whips and so on, right, Jones
references... right. There are a lot of
technical challenge and I'll try and
make these fun by giving you the finger
print analogy again.
So the first thing that's really
difficult is if things get spread too
much over the sky, then you literally
have to sample the entire sky at really really really
deep magnitudes and that's very hard to
do that would take so long to do.
so we want things to be kind of close to
go and so that's a bit like saying well
look if someone commited a crime in there
are no fingerprints at the crime scene
that messes you up, so we want the
fingerprints near the crime scene.
We want the stars to be somewhat close
together not to spread out. Second thing
is the stars have to be similar. That's
what I said about stars forming in a
group having the same elemental
abundances. If they don't it's a bit like
going to one crime scene one set of
fingerprints going to another crime scene,
and another, and they are all different. Than you can't relate the person who committed
the crime. And the last thing it's kind
of obvious but if you're taking
fingerprints with cellophane tape and
it's just messing up every time you take a fingerprint and you can't get a good one,
you can't compare one fingerprint to
another fingerprint. so we need telescopes that
take good enough abundance measurements.
That's about the best analysis I can
give you. Trust me I have condensed
literally a hundred and fifty pages of
journal articles into three boxes  [audiene chuckles] but I
think that gives you an idea.
Alright so what's going on now. Now we're
into the last part. How are we doing for time? Oh way overtime
already! I'm very sorry if anyone wants to go they can go now. Oh they are
running for the exits! Just teasing.
so right now the thing that's really
incredible something called the GAIA project
this is something that's been flown by
the European Space Agency and GAIA
truly incredible because it's taking
positions of stars to micro arc-seconds accuracy.
How does it do that? Very sophisticated plotting of orbits in space.
Very clever stuff. But it will
also get an incredibly large number of
proper motions, basically how things move
across the sky, not moving in and out of
the sky but how things move backwards and forwards, and
we'll get the true velocities of tens of
millions of stars. This is really amazing. So I wanted to give you what this is like. I'm just giving you words.
Well, you know Star Trek
Voyager? some of you probably know Star Treck Voyager. And they had the
astrometrics lab and they would going
there and they look around...
everything would be like  "ohhh this is a really interesting piece of space!" So GAIA is what we call an astrometry mission.
You would take the data from GAIA and put that into the astrometric lab, and you could
fly around inside it, and stuff like that.
This is all about measuring stuff
incredibly precisely. And we call that astrometry.
So Gaia is a fantastic astrometry mission. So that will just tell us where
things are though but it won't tell us
about thier fingerprints: elemental abundances. So there are
a number of projects doing this in fact
there is one on the Very Large Telescope
in Chile that's associated with Gaia, but
it won't talk about that I'll pick the
one that can Ken Freeman and Joss Bland-Hawthorn are running
on the anglo-australian telescope in the
southern hemisphere and this does 400 of
those spectra at any one time
sounds pretty good yeah? 400! We're going well!
In fact we'd like to put another zero on that: four thousand at a time. And this will
measure a million stars. Measure these
chemical fingerprints of a million stars
over five years. And you think "wow, that's a lot of stars". How many stars in the Milky Way? hundreds of billions. This is literally nothing!
in fact there was a paper just within
the last month that's come out that really
put a downer  on people because we realized a million isn't going to get us anywhere.
We need way more. Even a factor
of 10. We need a factor 50, probably more.
Four-memter class telescopes, which sound really
big, in fact comparatively small nowadays
but if you want to do things in the disc
of the galaxy
they're actually pretty good for that
because obviously things in the disc of
the galaxy are, comparatively speaking,
fairly close to us. The stars are still bright enough we can do with with 4m telescopes.
telescopes. But if you want to go out
into the halo, Remember I showed you
that picture of how big the halo was
relative to the disk? Then you need 8meter telescopes.
so there are a couple of projects coming
soon
VLT moons. Someone gets a prize for a fun name. And so that will have a
thousand fibes and that will
operate on the VLT telescope and then
PFS. Boring! Prime Focus Spectrograph on the Subaru telescope. Name of the telescope is better than the name of the instrument. So that will have 2400 fibres.
So really getting up there getting up there to
the four thousand that we want to get to.
Both of these will be operating around
2018/2019. Pretty pretty expensive to do.
We are talking about eighty million dollars to build the instrument.
This is because I meet with politicians... They always say "Why do you need more than one telescope?" [audience laughs]
So you're all laughing, because all of the amateur astronomers... who's got two telescopes? Put your hand up. Who's got more than two?
See? You understand! So you can't do everything with one telescope.
You really can't. and I'm trying to give you
an idea of how we do the best science.
I originally call this optimizing but it's
really how we do the best science.
And the size of the telescope, determines how much light you can get,
can get and how quickly you can do
things. Also the field of view does that
as well. How much of the sky do you see
any one time. And the only problem is, as
astronomers very well know, the bigger the aperature the more expensive the
telescope. Professionals haven't figured out a way to
break that yet. So it's always a cost problem.
But the other thing.... so these two factors
set how quickly we can do you want to do
things. Obviously you want to do things as fast as possible because we're
competing against other teams in the
countries. Science is competitive as well as collaborative. And then we have this box at the top:
Resolution and Wavelength. That's how
much of the spectrum we cover and how
well we cover it. And you can probably
guess you want to do as much as you can
with as much resolutions as you can. Costs. But those
two things determine the type of science
you can do and the quality of science you can do. Sometimes
you say, "ok we'll just do low resolution
across a big part of the spectrum", other times you want to do  high-resolution in just one part of the spectrum.
so it's not easy to build one telescope
that does everything. In fact it is basically
impossible. But you didn't need for me to
argue that! You can't have just one telescope!
So what is unique is that until now no
one has really considered building an
entire spectroscopy unit and an entire
telescope together to make them one
cohesive unit. And that's what we're
looking at doing in Canada right now
This is a project being led out of the
RASC in Victoria. A number of people there,
I'll just mention three:
Dr. Alan McConaghy, Dr. John Hutchings  and Dr. Patrick Cote have been
pushing very hard on this. There is a number of
other people as well.
Those are the people who I interact with most on this idea. So this is the
Canada-France-Hawaii telescope on Mauna Kea
and some of you may be aware of
there is considerable uncertainty of the
future of Mauna Kea right now, because it is considered sacred by a number of Native
Hawaiian groups. I don't want to say
anything about that I'm not an expert on
that at all and I do differ to the
people who are on Hawaii for that. But basically this is to replace the current 3.6m metre
with big honkin 11 meter telescope. And
its bigger -- how will it fit ? Well it just
turns out we completely over engineered
the CFHT when it was built for fourty years ago
The pier supports an equatorial mount but we don't
need to build an equatorial. We can build
an Altazimuth which is much lighter even
though telescope itself is much bigger
so you go from this, to this and it all
fits. And it has to fit, because one of the things that's
going to change in the Mauna Kea
management is that you cannot make an
observatory more than 5% bigger than it was in the past. So this is what
we're planning to do and this is a great
idea and in fact I'm leading a national
review of astronomy right now. We sat
down and basically have promoted this
as one of the projects that we think Canada 
should actively investing in. It won't just be
Canada, we are trying to get at
least five or even six possible other
countries involved, as well.
Oh! Something for the gear hounds.So what are
we looking at? Again sorry this is
technical for the astronomers, right, 
Cassegrain probably. There's a reason for
that, that we can actually... we worried about
how the center of mass of the telescope
moves. Sorry this is all technical stuff, just for one overhead. And so with the
Cassegrain alignment we can actually put
a lot of the heavy stuff here and that
will keep most of the weight over the pier
Its a little non-traditional but it will work.
12 metre nominal diameter. When you take
out the central destruction its about 11.64 and here's
the really incredible thing: that the field corrector will
have 1.4meter lenses in it!
Trust us the glass is strong enough for that!
Yes it will be segmented as well. In fact the segmentation is the reason why we can't go any faster than that. Although for technical reasons going faster than that wouldn't be much help anyway.
And this comes back... the thing down here... so I'm trying to show you if you were to look through that telescope,
Here is the field of view of the
MSC telescope and here's the field view of the thirty meter telescope: TMT
I did a radio interview
with Rick Howe, and he said "well, you are getting 150 million dollars for the
thirty meter telescope , why can't you do that
with that" -- and it's right there. You just
don't see enough of the sky with TMT to use it efficiently. TMT is designed for seeing things that are
like way way way way off. So it is designed to see small things. MSC is designed to
see a lot of the sky at a time. Over two full moons.
So this is a big telescope, and it has a big
field of view. So it's it's a great idea
and I really really hope that we can
get enough money together and sell it well to the government government.
I'm now about to wind up
ok so the future, where we gonna figure
out more things other than just looking
at the sky? Because the fact of the
matter is I theoretician but I rely
upon working observers -- thier fun and quirky --
but we work really well together.
ok so I've got to up my game as well as them upping thier game, so I've gotta come up with
models that better explain how we get
stuff information. I've gotta come up with
high-resolution disc models cause those
ones I showed you really aren't that
good even though they look creally cool. There are a
number of things that are missing from
them. And we've also got a look at how
things are forming basically in the
entire universe, not just doing them
isolated from everything else. And that's
challenge. That needs a lot of cumputing to do. Right, but we know what we have to
do. Now it's just noses to the grindstone,
do the hard work, and at the same time,
the observers, well it'd be great for us
to know more about what's going on in the halo,
knowing more about those streams of
stars and so on and also where the first
stars are. Thats an important thing that could go into our models as well. So
everything works together. You can't just
do everything with a telescope. You can just do everything with theory.
The two of them have great interplay. so this is my last slide. Sorry! I
apologize, I hate it when people run over...
I'm very sorry. OK, so by 2030, that's
the one bad thing that I'm was accused of.
Everyone's always saying "oh it's almost 10 years away! but I think what we'll know by 2030 Its 15 years away!" But I think what we'll know by 2030 is
is really really incredible. The first
thing we gonna know the structure and
the origin of our Halo to incredible
precision. It won't just be... we'll probably
be making diagrams like that, but they'll be real diagrams with the data we have. We'll have found the oldes stars in the Milky Way. I can't
say that we'll have found the exact oldest one, but will have found
all of the oldest ones.
We'll also have found hundreds... and I put
a question mark on there because I'm
a scientist. I want to be honest about
uncertainties. There is a lot of
technical detail still to be worked out but
I'm fairly confident will find hundreds of stellar groups
that evolved in the disk of the galaxy. And from that we'll have an amazing knowledge, if we bring in all
of what we gonna learn from GAIA about
the dynamics of our Milky Way, and how everything is moving.
Mind-blowing. Absolutely incredible.
All right thank you to everyone in
Halifax chapter and the RASC for a great
General Assembly, not galactic
archaeology. thanks everyone!
I will ask you one quick question, before we say thank you, and this is: can you explain the shirt?
oh! I am terrible! Oh no! I am so embarrassed I didn't do that! Thank you Paul.
So this shirt was made by a lady called Elly Zupko, and it's a celebration of 50 brilliant female
scientists, technologists, engineers, and medical doctors -- right! [audience applause]
and I i dont wanna go into too much
detail, you can look it all up on the web, if you search #thatothershirt.
you'll see all the details. But astronomy in
particular is very male dominated and us as guys
need to act in a way that doesn't
discourage women from coming into
our field. I've grown up with two sisters. The person I was always fighting to best best with at school was a woman as well,
I've never had any thoughts that women were less capable... stupid, rubbish like that. So, I'm completely happy working with women
I want women there. I don't like it when I'm
sitting in a room full of guys. I'm thinking: there's a viewpoint we're missing here.
So I want more women in astronomy.
I'm going out talking to
people trying to encourage people and
I'm I'm really really happy to say that
we have a lot of women coming through
in our undergraduate program. The problem we
seem to have... I'm gonna get political on
you.... but the problem we seem to have is
that they get through undergrad, they get
into grad school, and then there's a
drop-off. And there's also a drop-off in
women in senior positions as well. And this is not good for us as a society, it is not good for science.  So we have to do
something about this we have to
understand why it happening. And it's not
clear that it's just guys being sexist,
there are some really weird biases that go on. Women can sometimes be biased against women. There are things
that we need to understand
to address this, but we will so. Yay shirt!
Thank you, Rob. On behalf of the RASC
nationally and our center here and the
General Assembly, we have a small token
of our appreciation for you. Its one of our fleeces
and one of the dreamcatchers from the Mi'kmaq who are presinting to us  tomorrow night with the
drumming at our banquets. Thank you again... [mic feedback]
and if anyone wants to ask me questions after, feel free.
Have fun! Science is fun! Its not like eating your greens. Science is awesome!
