(upbeat music)
(audience applauds)
- So our next gig is a tiny little bar
in North Lansing this coming weekend.
So pretty lucky.
So I decided to talk about
supermassive black holes,
and I wanted to make a
direct connection to you.
It's a bit of a long chain of reasoning,
so that's why I invited
you to sit down for it.
(audience laughs)
So the connection between
supermassive black holes
and you starts with,
talking about what the
ingredients for life are,
and life needs elements,
they need carbon, oxygen, iron.
So I have a couple of
pictures from Frankenstein,
various movies from Frankenstein here,
you have elements.
Also needs energy.
Doctor Frankenstein knew that
to animate his monster he
needed to infuse it with energy.
So life needs elements and energy.
So the first event in the universe,
and yeah, it is a long story
so we have to start at the beginning.
The first event in the
universe was the Big Bang,
and about five minutes after the Big Bang
the periodic table had
begun to be assembled,
but it was still pretty small,
and only has the elements
of hydrogen and helium
and trace amounts of lithium,
beryllium and boron.
And that's not enough for life,
you need more complex atoms to have life,
so we really owe the Big Bang a lot.
After all, it gave us space, and time,
and matter and energy, so that's good.
- So I got that going for me,
which is nice.
- So you can't really hear,
but Bill Murray says,
"So I got that going
for me, which is nice."
He was talking about,
let's see what was it?
Total consciousness,
which is also nice.
The Sun.
Which is good.
It provides us energy today.
But the Sun doesn't provide
us the elements that we need,
the Sun was born at the
same time as the Earth was,
and so whatever the Sun
has and the Earth has,
all those elements were generated before
the Sun was even a thing.
So the Sun is about
five billion years ago,
so the elements that make up
the Earth and the Sun and everything
had to be made before five billion years.
So billions of years ago
many generations of stars died
to make you some oxygen.
And I'm gonna play a little video.
This is from NASA,
we're zooming into the core
of a red supergiant star,
so we're going away down into the core
where the nuclear furnace
is that's assembling
the elements from hydrogen and helium
and making the more massive
elements like carbon,
oxygen, and eventually iron.
Iron is sort of a dead end
when it comes to nuclear fusion,
you can't get any more energy from that,
so stars that start to
build a core of iron,
eventually explode,
and that redistributes
those elements back into
the rest of the universe
in a supernova explosion.
It leaves behind a black
hole or a neutron star.
Some of those black holes then
merge,
that's what's gonna make you some gold.
(light music)
So this is an animation
that was created by the
European Space Agency
to show what happens during
the merger of a neutron star.
What you're seeing there
illustrated by the artist
is the gravitational waves that
are sent out by that event.
Gravitational waves that
have been detected by the LIGO Observatory
recently of an asteroid
captured by astronomers.
And there's a nova event has evidence that
the heavier elements (words
drowned out by music).
So maybe that will be Nobel
Prize number two for LIGO,
the first Nobel prize went
to that team and others
for the discovery of gravitational waves
from two merging black holes,
which has no electromagnetic signature.
So stars and their remnants
like neutron stars,
detonating white dwarfs make most of
the elements heavier
than hydrogen and helium,
those are the elements necessary for life.
And this is a depiction
of the periodic table,
and it's color-coded,
the elements on the top,
the lightest element
is hydrogen and helium
are created mostly in the Big Bang.
Stars make some of the
helium but not much of it.
The elements coded in blue are made
by supernova and various types,
even massive stars blowing up,
our white dwarfs that
blow up after merging.
Or exceeding the mass that
they can support themselves.
The orange is coated,
because late stage red giant
and red supergiant stars
also assemble heavier elements.
In fact most of the carbon in your body's
were probably made in the
late stages of red giant stars
called carbon stars.
Yellow is coded to indicate the elements
that are likely created
in neutron star mergers.
And a lot of this color
coding happened in the last
I would say few years
or so before that time
we were suspicious that
maybe neutron star mergers
could create these heavy elements,
but I think with the direct detection
of a neutron star merger,
plus the afterglow,
it really is seeming like it's
a more certain declaration.
But anyway.
So we should be thankful to
stars for making those elements.
So multiple generations of stars,
mostly long dead,
billions of years ago long dead
made the elements that are
inside you right now today.
But you need more than just
stars floating out there
in space to make elements,
you needed a galaxy.
And you need a galaxy because galaxies
are places where stars form,
it takes a galaxy of stars
to make enough elements
so you can get rocky planets and people.
The universe is full of galaxies,
about 100 billion galaxies
in the observable universe,
each with about 100 billion stars.
This is a picture taken with
the Hubble Space Telescope
of the Andromeda Galaxy, so I can zoom in.
And these galaxies are full of stars.
Each major galaxy has about
100 billion stars in it.
So galaxies provide the
environment that you need
for these repeat generations
of star formation.
So over on the right
hand part of this slide
I'm looping through a movie
showing you how tiny fluctuations
in density grow to make
larger densities,
whoops that should have worked.
So again on the right
what you're seeing is tiny
fluctuations of density,
where there's over densities,
the over densities get bigger with time,
the under densities also get bigger,
so the difference between the two grow,
it's sort of like the rich get
richer the poor get poorer,
like a nasty economic
system it just happens.
But gravity works like
that naturally enhances
small density fluctuations
and makes them bigger
density fluctuations.
Galaxies are where most of
the matter will collect,
they are the sites of the highest
matter densities in the universe.
When stars form, when they blowup,
winds blow, that tends to push gas away,
so if the stars were just isolated
floating out there in space
you would have one generation of stars,
it would push the gas away
and there would be no
more elements forming.
So for life to really
happen you need to have
a concentration of stars forming
one generation after another
to build up the heavy element abundances
that is necessary to make rocks.
You need rocks to have surfaces,
you need surfaces to collect water,
you need water for chemistry.
You need chemistry for life.
So these repeat cycles of star formation
and star death are necessary
and you're only gonna
get that in a galaxy.
So, galaxies don't just hold together on
the basis of stars alone.
You need gravity, you need
matter, and you need a lot of it.
And probably some of you have
been coming to these talks for a well,
you know that the universe
has a mass energy budget,
and much of it is matter,
but most of it is this
stuff called dark energy
that Professor Everett
mentioned in my introduction.
Galaxies themselves don't have
a lot of dark energy inside them,
dark energy likes big empty spaces,
it's related to the size of things.
Some people think it's got something
to do with the vacuum
energy of the universe,
so the more vacuum there is,
the more dark energy there is.
So galaxies really internally
are not affected much by dark energy,
the universe sure is.
But galaxies are where
matter is concentrating.
So the universe mass energy budget isn't
the same as the galaxies
mass energy budget.
The galaxy's mass energy
budget is mostly mass.
So we're gonna look at
this part of the wedge
where it's dark matter, gas and stars.
And then just look at that budget.
So you have mostly dark matter,
about 80, 85% dark matter.
15% gas.
Only 2% stars.
So that's why I was saying stars
aren't enough to hold
the galaxies together,
you need a lot more matter,
gas alone also isn't sufficient.
You need a lot of dark matter.
There is an audit alert in this chart,
and a typical galaxy we only know
about where 10% of the gas is,
and we don't know exactly what
dark matter is made out of.
All we know is that it's not
made out of the usual stuff
like protons, neutrons and electrons that
the rest of matter is accounted for.
So there's a whole other
talk that we could give
about the search for dark matter
and what it's made out of.
What we do know though
is how much there is,
and that's why we can
make a chart like this.
Gravity has a way of affecting
the orbits of stars and so forth,
and we can tell how much matter
there is from studying that.
So dark matter holds
the galaxies together.
So a little gratitude for the dark side.
Okay.
(audience laughs)
So things to be grateful for,
you know we're approaching Thanksgiving.
So we could be grateful
for a lot of things,
we can be grateful for the Big Bang,
we can be grateful for the
stars that formed the elements,
we can be grateful for the galaxies
as birthplaces of multiple
generations of stars.
We can be grateful to our Sun
for giving us free energy.
You came to this talk though,
it's like what is our connection
to supermassive black holes?
So here we go.
In the center of every galaxy apparently
there is a supermassive black hole.
Now the supermassive black hole
doesn't hold the galaxy together,
but I'm gonna explain why
that supermassive black hole
is important to galaxies,
and our story about how
galaxies evolve and make stars.
So in our own galaxy this is
a picture of the Milky Way,
an whole sky picture,
no one telescope can capture this picture,
it lets you see both
the Northern Hemisphere and
the Southern Hemisphere.
So this is made from a
compilation of pictures.
And I'm going to zoom into the center
using this is all real data,
and I'm gonna acknowledge Mark Vogt
for my husband for assembling this series,
this was all very, very precisely
aligned and put together.
So what you're seeing is a zoom in.
You see the little
rectangle in the center?
We're gonna zoom into that rectangle now.
Okay, we're still seeing more,
but now as we get close to
the center of the Milky Way,
we need infrared light
to really peer through
the dust and gas set between us
and the center of the Milky Way.
So I'm gonna start
showing a scale bar here,
so that's 250 light-years,
a light year is a distance
that light takes to travel in one year,
it's about 10 trillion kilometers.
This is the radio view of that same area.
We're gonna zoom in to this rectangle.
And we're seeing a lot of the red,
is the hydrogen gas that's towards
the center of the bright little spot on
the right-hand side that's
labeled Sagittarius A,
that's where the center is.
We have the scale bar on
the left again showing
where 50 light-years is.
And this is the radio
image superimposed on that.
Okay, now we're gonna zoom in on
that box over Sagittarius A.
Okay.
Sagittarius A has a
lot higher star density
than our local neighborhood.
I would imagine that the night sky
if you were on a planet
around one of these stars,
your night sky would be pretty
well contaminated by light.
You wouldn't be worried about star leak.
Five light, so that's five light-years.
So for a little bit of scale,
our nearest star to us
is four light-years.
So this neighborhood is pretty packed.
Okay, this is the radio,
a bit of the radio image.
All right, zooming in again.
Closer to the center.
One light year,
okay so we are starting to zero in.
Okay, this is very, very
close to the center,
this is a map of the
locations of stars separated
by periods of one year.
As they move around a very dark object.
So each of these orbits is
orbiting a central object
using Kepler's laws what
you might be familiar
from your Astro 101 course
that says that every object is an ellipse,
every orbit is an ellipse,
and the focus of one of the focus points
is the point of the central position,
so each of these ellipses
has a common focus
and it's right there in the center,
and all of these stars are orbiting.
So we can tell from these orbits
what the mass is in the center.
There we go.
So hopefully this works.
And we have to click one more time.
All right.
So these are observations taken
with interferometric techniques
by Andrea Gascon and her group at UCLA.
And we'll circle around, there we go.
Okay.
So did you see that one that
almost came in radially,
and then took a left turn
and back out up to the right?
That very precisely locates
the dark object that
is being orbited here.
And that dark object is an object
that has four million solar masses.
And it's clearly not glowing.
So this is some of our best evidence
that the dark object in
the center of our Milky Way
is a four million solar mass object,
supermassive black hole.
And this is the picture of Andrea Gascon,
if you are on the Nobel prize committee.
She's a good candidate,
I would vote for her.
Just in case.
I don't know if there's
any Nobel prize community
candidates in the audience,
but that's my plug.
So very recently,
you probably remember last spring
that there was an announcement from
the event Horizon telescope
of the discovery of a picture,
they made a picture of the event horizon
of the black hole in M-87,
M-87 is 1000 times further away,
it's also about 1000 times,
the black hole is about
1000 times more massive.
So the event horizon in M-87 is about
the same size on this sky as
the event horizon for the
center of the Milky Way.
So I would predict that barring
any technical difficulties
that the black hole in the
center of our own Galaxy
will bee the next target from
the Event Horizon telescope.
But the first one was M-87.
Because of reasons of transparency
to M-87 versus to the
center of our galaxy,
it was actually the easier target.
And this is a visualization,
a zoom in to M-87 that
was quickly assembled by Frank Summers
of Space Telescope Science Institute
to celebrate this discovery,
and he put some music to it.
(gentle music)
So this supermassive black hole in
the center of M-87 is a little more active
than the one in the
center of our own Galaxy.
So what has this radio jet
that is kicking out if it,
the Event Horizon telescope
is also a radio telescope,
so a lot of these images
that you are seeing
are taken at the radio wavelength.
So we are zooming into the jet,
the jet has a base with a red,
layer on the left-hand corner.
So a parsec is about three light-years.
So all of these pictures
that you see going forward
were taken with arrays of telescopes.
Spread across the planet to
act like a big telescope.
So this is the celebrated image,
there is the size of Neptune's orbit
if it were circling
around M-87's black hole.
So Twitter said this picture was blurry.
Screw Twitter man.
This is a simulated picture
that was prepared for
the movie "Interstellar",
they knew what it was going to look like,
they had help,
Kip Thorn, another Nobel prizewinner
helped with this particular movie.
So how was that accomplished?
That was accomplished
with radio telescopes
located on different parts of
the world thousands of miles apart,
and when the signal is combined
it can act like a telescope
that is much much bigger
than any individual
telescope in the network.
So it's almost like having
a planet-sized radio telescope looking at
the center of the Virgo cluster,
the center of its most massive galaxy
and directly imaging the event horizon,
that's the region from
which light cannot escape around M-87.
So people have been studying
these things for a very long time
and estimating their
masses in various ways.
Clearly imaging the event horizon is
the very toughest way to go,
but there's other ways
of measuring their masses
by measuring how fast gas
circles around the galaxy center,
or measuring how fast start moving
around the galaxy center.
And so people have assembled
estimates for masses
of the central black holes,
and what all those measurements
have been assembled into charts.
This is just an example
of one of those charts,
on the vertical axis is
the mass of the black hole,
as estimated by one of
these estimate methods.
And on the horizontal axis is
what we call a velocity
dispersion of a galaxy,
and that tracks with the
mass of the galaxy itself.
And what you can see is that there is
a correlation between
the mass of the galaxy
and the mass of the black hole.
And that circumstantial evidence
that the galaxy and the black hole
somehow know about each other.
Even though the black hole is
a tiny percentage of the
total mass of the galaxy,
and even though the black hole,
you saw those zoom ins,
it's a very, very tiny piece of the galaxy
the black hole actually
influences gravitationally.
Yet, somehow the black hole and the galaxy
when it's big, when the galaxy
is big the black hole is big,
and when the galaxy is small
the black hole a small.
And how that happens is
not particularly obvious.
But you remember those pictures
of M-87 showed this jet.
And here is an artist's conception of
a black hole that's erupting
as matter swirls around the black hole
and eventually falls into the black hole,
some of that matter is
ejected out in these jets,
this matter has to lose large
amounts of angular momentum
to actually settle into the black hole,
and jets are a way to take
some of that angular momentum
and get rid of it.
So jets seem to be a fairly common feature
of accretion discs around almost anything,
even proto-stars have jets forming,
and these supermassive black holes
have really, really big jets.
So this is a picture of a galaxy,
the center of fuzzy thing
that's a massive galaxy,
one of the biggest galaxies
in the local universe.
And the pink is the radio emission
coming from these giant thousands
of light years across jets
Coming out of the center of this galaxy.
And when you look all the way down
to the base of these jets,
it goes right down to the center
to that supermassive
black hole in the center.
So that's also circumstantial
evidence that says
the black hole doesn't
actually affect the orbits,
except very, very close to
the black hole of anything
like gas and stars,
but it's effecting something,
many, many thousands
of light years and tens
of thousands of light years away
from the black hole with these jets.
So this is a picture of Andromeda,
I'm labeling the body parts.
There's the disc of stars,
there is a central bulge of stars.
There is a halo that's a
little bit harder to see,
but stars are out there as well.
So this is the stellar distribution of
a typical spiral galaxy
like our Milky Way.
It also has interstellar
gas that's full of dust,
so you see the dust lanes in
this particular galaxy picture.
And then the central black hole
is located in the middle of the bulge.
So where's most of the gas?
Most of the gas that is
associated with the galaxy
it is not inside where the stars are,
but is surrounding the galaxy itself
in this big, big gas cloud out there
doing what I would say
a Gen X person like I is familiar with,
it's slacking.
It's not forming stars,
it's just hanging out waiting its turn.
So most of the gas and heavy elements
that surround the galaxies is actually not
between the stars or inside the stars,
it's inside what we call this
what we call certain galactic gas.
So you look at a radio source like this,
it's clearly interacting with something,
and what it's interacting with is
this big gas cloud around these galaxies.
So we can directly study some of that gas,
especially if it's in a massive galaxy,
or in a cluster of galaxies using x-rays.
Because the gas is extremely hot.
So this picture is showing you
a picture that's assembled from
three different telescopes,
you see where the galaxies are,
you see the central galaxy in the white,
you see the radio in the blue
and you see the x-rays that
are here coded as purple.
So clearly x-rays are not purple,
you can't see x-rays,
but to visualize them
that's how we can do it.
So where are the purple is brighter
that's where the gas is denser.
So one of my primary topics of study
has been clusters of galaxies.
This is clusters of galaxies are aware
you can see all of this intergalactic
gas emitting in the x-rays,
because it's so hot.
And I've been very encouraged by
the things that we can study in the x-rays
Around massive galaxies
and clusters of galaxies
because what I can see
is not only the radio,
but I can also see how
the hot gas is affected
by the jets and the outbursts of
the central supermassive black hole.
So one of the most famous clusters
of galaxies is known as Perseus,
this is also a composite picture,
the blue is showing where the x-rays are,
the red is showing where
the radio plasma is
that's being ejected
by the central object.
The white is showing
you where the stars are.
And when I subtract off
the smooth component of the x-ray image
to show you where the wrinkles are,
you see evidence for many outbursts.
Not just one outburst,
but multiple episodes
of the central black hole popping off,
dumping energy into this gas,
and then those bubbles rising
like a mushroom cloud arising
from a nuclear explosion.
I know that's an unfortunate image,
I didn't mean to stress anybody out.
But it's the same sort of principle
that you dump some energy
and that bubble arises
and it expands when it moves out
into gas that's lower density.
So this is a simulation of that,
what you're gonna see is that in
the center of this orange stuff,
which is the gas in the simulation,
there is a rendition of
a supermassive black hole
dumping energy in the form of jets
into an atmosphere that is much like
the atmosphere around a massive galaxy.
So I'll show that.
And you see it turn on.
And as it turns on it generates
instabilities in the gas
that can cool,
and that cool gas can fall
back onto the black hole
and provides the fuel for more activity.
So it essentially can
create its own rainstorm,
and the rain from that the storm is
the fuel for more jet activity.
So here it goes, it's collecting
cold gas and then.
And this is some pictures I took of
the Hubble Space Telescope
of in the ultraviolet
that shows structures
much like what this
simulation from Juan Lee show.
In terms of the scale.
So our own galaxy has
had its own outburst,
and this is a picture
from the Fermi satellite,
which is a gamma ray satellite,
and this is again an all
sky picture on the right,
that the Fermi data, the gamma ray data,
and its color-coded so that
the blue and the black spots
are where there is very
little gamma ray radiation,
and then the white is where
the Fermi telescope sees gamma rays.
And you see two bubbles above
and below the galactic discs,
the disc runs right through the center,
that dark band through the center of
the all sky image is our galactic plane.
And so there's outbursts above
and below this galactic plane,
and over on the left-hand
part of this diagram
you see an artist rendition of that
where it's all been made nice
and smooth and symmetric by the artist.
But you see the Milky Way disc
running through the center,
and then the purple gamma
ray bubbles above and below.
So I wanted to just show you the data
and the artist's version
of what might be going on side-by-side.
So our own Milky Way
supermassive black hole
right now fairly quiet.
Apparently has had outbursts
millions of years ago.
So it's not always been quiet.
So all this together seems to be putting,
assembling a picture of a story
where central black holes are part
of how galaxies regulate their own growth.
So you have central black holes
that control how fast galaxies grow,
because it's regulating
the state of matter,
gas well outside where the stars are,
and it can limit how big the galaxies get,
and it also can limit how
big the black hole's get.
So central black holes don't
hold the galaxy together,
that's been grateful for dark matter,
we don't want to be grateful
to central black holes
for something they are not
doing, so just be clear.
It's the dark matter that's
holding the galaxies together.
But they act as the
central sources of energy
that can circulate heavy
elements that the stars make.
So this gas outside of these
galaxies is highly enriched,
but there's no stars at
their sharing the elements,
the stars are down here in the discs.
So supermassive black holes
are actually pulling the gas
that was formerly dead stars,
and distributing it and
circulating it like a giant mixer
to the surrounding gas.
And then it's also dumping energy,
and that energy can slow down
the formation of future stars,
and keep it from running a little too hot.
So if they weren't around,
our galaxies would actually
have even more stars
and more vigorous recent star formation.
And your thinking, why should
I be grateful for that,
because maybe if there were more stars
there would be even more
life, or more activity.
And I'll argue that maybe,
this is a lot more speculative right now.
Trust nothing I say at this point.
But since you've been
bearing with me so far,
I'd like to put this out there.
If our galaxy had more star formation
there would be more
explosions close to us.
And supernova explosions
close to us might be bad.
Not only might a very
nearby supernova explosion
might just blow away the atmospheres
of planets or something like that,
but also could dump a lot of
radioactive stuff onto planets,
or just cause problems in terms
of excessive mutations or what have you.
So more supernova might be more,
say gamma ray bursts or other things,
that could be hostile for life.
Another thing that could
be hostile for life,
if you had a richness of stars everywhere
and maybe you had more life everywhere,
more life might not be so great.
So maybe if there were more aliens
life wouldn't be so
good for us depending on
how we had our relationships
with the other aliens,
and given our relationships
with each other.
(audience laughs)
We don't need more.
It might be cool but we don't need more,
I don't think we need more
relationship challenges,
at least not right now okay.
All right, so things to be grateful for.
The Big Bang, the stars,
the galaxies as birthplaces
for those stars.
The Sun giving us free energy,
and central black holes
that circulate elements
and regulate how much gas turns
into stars and other black holes.
So my last slide is a
slide that is actually
a rendering from AVR thing,
that if you have one of those VR goggles
you can actually go to this guys website
and look at what it would be like
to fall into a supermassive black hole.
But I'm just gonna show you the rendering.
The 2D rendering.
But in VR you can look around.
So if you've got one of those goggles
and all that you should give this a go
and let me know how it went.
My son promised he was gonna try it,
and he has all the things, but I don't,
so I just have a lowly Mac.
So here we go.
("Enter Sandman")
The gravity of that black hole
is strong enough to stop life,
and that's one of the things
that continually happens.
♪ Say your prayers little one ♪
♪ Don't forget, my son ♪
♪ To include everyone ♪
♪ Tuck you in, warm within ♪
♪ Keep you free from sin ♪
♪ 'Till the sandman he comes ♪
♪ Sleep with one eye open ♪
♪ Gripping your pillow tight ♪
♪ Exit light ♪
♪ Enter night ♪
♪ Take my hand ♪
♪ We're off to never-never land ♪
♪ Somethings wrong, shut the light ♪
♪ Heavy thoughts tonight ♪
- This is an exact spinning black hole.
(music drowns out speech)
♪ Dreams of war, dreams of liars ♪
♪ Dreams of dragon's fire ♪
♪ And of things that will bite ♪
♪ Sleep with one eye open ♪
♪ Gripping your pillow tight ♪
♪ Exit, light ♪
♪ Enter, night ♪
♪ Take my hand ♪
♪ We're off to never-never land ♪
- So thank you.
(audience applauds)
(upbeat music)
