National Science Foundation/EHT Press Conference Revealing First Image of Black Hole

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Amanda Hallberg Greenwell: Okay.
Welcome to today's press conference brought to you
by the National Science Foundation
and the Event Horizon Telescope Project.
Thank you all for joining us today.
My name is Amanda Hallberg Greenwell,
I am the head of the National Science Foundation's
Office of Legislative and Public Affairs.
I would like to introduce today's distinguished panel.
Dr. France Cordova, Director of the National Science Foundation.
Sheperd Doeleman,
is the Event Horizon Telescope Project Director
of the Center for Astrophysics, Harvard and Smithsonian.
Dan Marrone is an Event Horizon Telescope
Science council member
and an Associate Professor of Astronomy
at the University of Arizona.
Avery Broderick is a member of the Event Horizon Telescope
Board and Wheeler Chair of Theoretical Physics
at the Perimeter Institute and Associate Professor
at the University of Waterloo. And Sera Markoff is a member
of the Event Horizon Telescope Council,
a professor of theoretical physics
at the University of Amsterdam
and she coordinates the EHT multi-wavelength workshop.
We will have time for questions after the panel concludes
so please hold all questions until that time.
I will now turn it over to Dr. Cordova.
Dr. France Cordova: Good morning.
Thank you for joining us at this historic moment.
I would like to give a special welcome
to the Director of the White House
Office of Science and Technology Policy,
Dr. Kelvin Droegemeier.
And from the National Science Board,
the current chair, Diane Souvaine and former chair,
Maria Zuber.
Today, the Event Horizon Telescope Project
will announce findings that will transform
and enhance our understanding of black holes.
As an astrophysicist, this is a thrilling day for me.
Black holes have captivated the imaginations of scientists
and the public for decades.
In fact, we have been studying black holes so long,
that sometimes it is easy to forget
that none of us have actually seen one.
Yes, we have simulations and illustrations.
Thanks to instruments
supported by the National Science Foundation,
we have detected binary black holes,
merging deep in space.
We have observed the episodic transfer of matter
from companion stars onto black holes.
Some massive black holes create jets of particles and radiation.
We have spotted the subatomic neutrinos
those jets can fling across billions of light-years.
But we have never actually seen the event horizon,
that point of no return after which nothing,
not even light can escape a black hole.
How did we get here?
Through the imagination and dedication of scientists
around the world willing to collaborate
to achieve a huge goal.
Through a large pool of international facilities,
and through long-term financial commitments from NSF
and other funders willing to take a risk
and pursuits of an enormous potential payoff.
Without international collaboration among facilities,
the contributions of dozens of scientists and engineers
and sustained funding,
the event horizon project would have been impossible.
No single telescope on earth has the sharpness to create
an un-blurred definitive image of a black hole's event horizon.
So this team did what all good researchers do, they innovated.
More than five decades ago,
other NSF funded researchers helped lead the development
of very long baseline interferometry,
which links telescopes
computationally to increase their capabilities.
This team took that concept to a global scale.
Connecting telescopes to create a virtual array,
the size of the Earth itself. This was a Herculean task,
one that involved overcoming numerous technical difficulties.
It was an endeavor so remarkable
that NSF has invested $28 million
in more than a decade,
joined by many other organizations in our support,
as these researchers shaped their idea into reality.
I believe what you are about to see
will demonstrate an imprint on people's memories.
The event horizon project shows the power of collaboration,
convergence, and shared resources,
allowing us to tackle the universes biggest mysteries.
Now I'm going to hand over this to our distinguished panel
starting with Dr. Shep Doeleman, EHT's Director.
[Applause]
Dr. Sheperd Doeleman: Thank you assembled guests,
black hole enthusiasts.
Black holes are the most mysterious objects
in the universe,
they are cloaked by an event horizon
where their gravity prevents even light from escaping,
and yet the matter that falls onto the event horizon
is superheated so that before it passes through,
it shines very brightly.
We now believe that super massive black holes, millions,
even billions in times the mass of our sun,
exist in the centers of most galaxies.
And because they are so small that we have never seen one,
they are though that they can outshine the combined starlight
of all the constituent stars in those galaxies.
The best idea we have of what they can look like come
from simulations like this.
The infalling gas that is superheated lights
up a ring of light where photons orbit the black hole,
and interior of that is a dark patch
where the event horizon itself prevents light from escaping.
The event horizon telescope project is dedicated to the idea
that we can make an image of this black hole.
That we can set a ruler across this shadow feature,
measure the photon ring and test Einstein's theory
where they might break down.
It also allows access to a region of the universe
we can study precisely the energetics
and how black holes dominate the cores of galaxies.
To do this, we worked for over a decade
to link telescopes around the globe
to make an Earth-sized virtual dish.
The event horizon telescope
achieves the highest angle resolution
possible from the surface of the earth,
it is equivalent of being able to read the date
on a quarter in Los Angeles
when we are standing here in Washington DC.
In April 2017, all the dishes in the event horizon telescope
swiveled, turned, and stared at a galaxy
55 million light-years away, it is called Messier 87 or M87.
There is a super massive black hole at its core,
and we are delighted to be able to report to you today
that we have seen what we thought was unseeable.
We have seen and taken a picture of a black hole.
Here it is.
[Applause]
This is a remarkable achievement.
What you are seeing here is the last photon orbit,
what you are seeing is evidence of an event horizon,
by laying a ruler across this black hole,
we now have visual evidence for a black hole.
We now know that a black hole that weighs 6.5 billion times
what our sun does exists in the center of M87
and this is the strongest evidence that we have to date
for the existence of black holes.
It is also consistent, the shape of the shadow,
to the precision
of our measurements with Einstein's predictions.
The bright patch in the south that you see tells us
that the material moving around the black hole
is moving at light speeds,
which is also consistent with our simulations and predictions.
This image forges a clear link
now between super massive black holes
and the engines of bright galaxies.
We now know clearly that black holes
drive large scale structure in the universe
from their home in these galaxies.
We now have an entirely new way of studying general relativity
and black holes that we never had before
and as with all great discoveries,
this is just the beginning.
The imaging of a black hole doesn't come easily,
I can tell you that from personal experience
as can many people here in the audience.
It has required long-term developments, a committed team,
but it also required some very interesting cosmic coincidences.
Take for example the maelstrom you see before you,
the hot gas swirling around the black hole.
A photon has to leave from close to the event horizon,
travel through the hot gas infalling to the black hole,
and light rays of a millimeter length,
radio waves can make that journey.
Not all of them can.
Then that radio wave has to propagate 60,000 years
through the M87 galaxy, and then another
55 million years through intergalactic space.
Then it winds up in the Earth's atmosphere
where it's greatest enemy, the greatest danger,
is that it'll be absorbed by water vapor
in our own atmosphere.
So the event horizon telescope uses telescopes at high,
dry sites so that we can see allows us
to see the photons that have traveled to us so far.
So far so good, we have the photons.
But the M87 shadow is very, very small
compared to the galaxy that surrounds it.
So in order to see it, we needed to build a telescope
as large as the Earth itself given the wavelength of light
we were trying to observe.
And to do that, we use a technique
called very long baseline interferometery
which you can see a schematic of here.
Radio waves from the black hole hit radio telescopes,
where they are recorded with the precision of atomic clocks
that lose only one second every 10 million years.
When you've registered these radio waves so precisely,
you can then store them on hard disk drives,
send them to a central facility
where they can be combined precisely.
It's exactly the same way that a mirror
used in an optical telescope
reflects light perfectly and in synchronicity to a single focus.
When we do this, we can synthesize a telescope
that has the resolving power as though we had
one the size of the distance between these telescopes,
truly turning the earth into a virtual telescope.
All of the sites that we used can be seen here.
We have telescopes from Hawaii to Arizona to Mexico to Chile,
the South Pole, and in Spain.
But even these, even this broad global network
is not enough by itself to make an image.
You can think of them being silvered spots
in a large global mirror.
The key is that the earth turns. During a night of observing,
we are able to sweep out more baselines,
more coverage of this virtual mirror to make our image.
So on the left, you will see the earth turning.
Every pair of telescopes
provides us with one point on the center panel,
which fills in the Earth-size virtual lens and
on the right you see the evolving image.
The more and more data we get,
the more we fill in this virtual mirror,
the sharper our view of the black hole becomes
until you wind up
seeing what we have as the final image there.
So we have taken advantage of a cosmic opportunity,
it is remarkable when you think about it.
Light that left near the event horizon
traveled all the way through intergalactic space,
it hit our telescopes.
The earth just happens to be the right size
so we get resolving power
so that we can see the black hole and M87,
whose mass and distance let us observe it.
And then the earth turns to fill in our mirror
so that we can make this image. It is truly remarkable,
it is almost humbling in a certain way.
We are four members of a large collaboration
and it is our distinct honor
to be here to represent that collaboration.
We are 200 members strong, we are 60 institutes,
and we are working in over 20 countries and regions.
We consider ourselves really to be explorers,
through international cooperation and innovation,
we have exposed part of the universe
that we thought was invisible to us before.
It is our responsibility to report these findings
and we are doing that today to the National Science Foundation,
to our funding agencies, international and foundations,
and to all people who support pioneering research,
and also to the taxpayers.
Nature has conspired to let us see
something that we thought was invisible.
This is a long sought goal for us and we find it tremendous,
and we hope that you will be inspired by it, too.
Thank you, and now let me introduce Dan Marrone
who has literally gone to the ends of the earth
to collect some of the data we've seen here today.
[Applause]
Dan Marrone: Thanks Shep.
So the heart of our measurement is, of course, the EHT array.
It would have been an expensive
and enormous undertaking to build a dedicated array
just to do this experiment, so we didn't do that.
Instead we built an international partnership
that allowed us to use submillimeter telescopes
are over the world,
in fact we used basically all of the submillimeter telescopes
in the world to make this measurement.
One that none of them could have done on their own.
When you take a heterogeneous collection of telescopes
and build them into one giant telescope,
it provides a lot of technical challenges.
So In the years leading up to our 2017 experiment,
we went telescope by telescope all over the world,
installing the specialized hardware we needed to do this.
Most had detectors we could use,
but almost none of them had the atomic clocks we need,
and certainly none of them had the very fast data recorders
that we use.
Some places, we had to do even more.
A good example is the ALMA telescope in Chile,
It's a 66 telescope array,
it's by far our most sensitive telescope
and its sensitivity is transformational
for our experiment. But in order to use it,
we didn't just need the basic hardware,
we also needed a special piece of hardware
that can sum the light from all the telescopes
before we send it to our reporters.
This alone was a many year project
using an international collaboration of people
from the EHT and also from the ALMA project.
Another good example is the South Pole telescope.
The South Pole is a special place in our array.
It is so far south that it doubles
the resolution of EHT for sources it can see.
But the SBT was designed
to do a completely different kind of measurement,
it studies the cosmic microwave background,
so its detectors are not the detectors we need.
So in addition to bringing down an atomic clock
and all of the tens of crates of hardware that we needed,
we had to build a special receiver
that would detect the light the way we needed it detected,
special optics to relay the light,
and install it and get it to work in the cold
and sometimes harsh Antarctic environment.
This was many years of work for many of us,
many trips down for myself and graduate students
and post doc and other engineers in the EHT team,
but at the end of it, we had a South Pole telescope
that could be an EHT station.
Now getting the sites to work isn't the end of the process.
We also had to test them all because in VLBI
you really only get one shot, everything has to be working
exactly right when the script starts.
So we spent years taking site by site, pairing them up
and making sure that our VLBI observations would work.
The last of these observations was in January 2017.
By March 2017, we knew that test had worked,
and we were ready to go.
The image that Shep showed was from April 2017,
from that campaign,
we sent our team to the telescopes all over the world,
their job was to turn everything on, do very extensive testing,
and then be there to do the observations.
But even with all of that in place,
we still had to wait for weather.
And my experience with ten years of doing these observations
is that the weather is usually the place where we fail,
we have to have good weather in Hawaii and Spain
at the same time, in Arizona and in the South Pole.
That is a lot to ask.
But in 2017, we were very lucky.
Our first three days of observations
were some of the best weather we have ever seen.
For a ten day campaign, we were done in only seven,
taking all of the data that we wanted.
At the end of that we had five petabytes of data recorded.
It was recorded on more than 100 of these modules,
and it amounts to more than half a ton of hard drives.
Five petabytes is a lot of data.
It is equivalent to 5000 years of MP3 files,
or according to one story I read,
the entire selfie collection
over a lifetime for 40,000 people.
The image you saw though isn't five petabytes in size,
it is a few hundred kilobytes,
so our data analysis has to collapse
this five petabytes of data into an image
that is more than a billion times smaller.
We do that in many steps, the first of those steps
is to get these modules to our correlators in Westford,
Massachusetts and Bonn, Germany.
The fastest way to do that is not over the internet
it's actually to put them on planes,
there is no Internet
that can compete with petabytes of data on the plane.
Once they are there, the correlators job is to find
the exact same wave front of light
arriving from the black hole at each telescope.
Once it's found,
small timing corrections that line up those waves,
we can condense our data, we can average it,
and we reduce the volume by 1000.
Now we're at terabytes, a much more familiar unit.
But we have a lot more work to do,
the data still has imperfections at that point,
both from the instruments themselves,
and from the atmosphere above the telescopes.
And so we do something called fringe fitting,
we do this in the cloud with cloud
computing which lets us do it in days, instead of weeks.
We calibrate the data
so that we know exactly how bright our sources are.
And I'm speaking of this as though it is just computer work,
but this was actually a very significant project
for a subset of our team,
primarily junior people, postdocs and graduate students
and they deserve an enormous amount of credit
for their diligence and dedication
because without it we couldn't have made an image.
Once we are done with that,
we can finally go to the imaging stage.
Now, imaging with an interferometer
isn't as simple as downloading a picture from your camera.
Fortunately, the math that we use for it
has been around for more than 200 years,
the principle is well understood.
The methods though, as with everything with this project
are a little tricky for our data,
so in order to get the image,
there has been years of image algorithm development
that has been essential to our results.
At this point in history,
we have many different image algorithms to choose from,
they have different strengths and weaknesses,
it just depends on the character of the data.
And so the way we approached the imaging stage,
is we set up four teams all over the world,
they were collaborating,
each team is representing many parts of the world,
and we told them, don't talk to each other or anyone else,
choose with whichever algorithms you think are best
and make images of these data.
Then, in the summer of 2018,
we brought everyone back together.
Had a very exciting meeting at the EHT imaging workshop
in Cambridge, Massachusetts. If you couldn't be there,
you certainly called in from the Internet
because you wanted to see the presentation.
And in a very exciting presentation
we revealed to the other teams
and to ourselves what we'd found.
And what we saw in those images were four very similar pictures,
looking almost exactly like the one you see today.
An emissive ring surrounding the shadow of a black hole.
It was a wonderful day of science
and I'm glad that after a few more months
of very careful checking and paper writing,
that we are finally able to share with you today.
I would like to hand off to my colleague,
Avery Broderick, to talk about the interpretation.
[applause]
Avery Broderick: Thank you Dan.
It is an enormous pleasure to be with you this morning
to share in this extraordinary moment.
As Shep said, we have now seen the unseeable,
now what does it all mean?
Every photon in these first EHT images
began its journey in a churning maelstrom
embedded in the most extreme environment
in the known universe, the vicinity of a black hole.
And M87 the crucible in which these photons were born,
was empowered by the black hole in two distinct
but related ways.
First, via necretion flow. A violent disc of orbiting gas
driven inextricably toward the event horizon.
By the time the material was making its final plunge
it is crashing into itself at nearly light speed,
transforming the gas into 100 billion degree plasma.
Second, through astrophysical jets.
Narrow beams of outflowing material speeding away
from the black hole at nearly the speed of light.
These jets are powered by black hole spin,
rotating black holes drag everything,
gas, magnetic fields and photons about themselves,
driving these paradoxical structures
whose cosmic importance will be discussed by my colleague,
Sera Markoff.
In M87, one of these jets is pointed very nearly toward us.
The EHT images are influenced both
by these bright emitting regions,
the rotating accretion disk and outflowing jets
and by gravity itself.
In general relativity, radio waves fall just as apples do,
typically this effect is exceedingly small,
but black holes are gravity run amok.
The radio waves we see in these first images
orbited the black hole
before beginning their 55 million year journey towards us.
This results in the dark shadow or silhouette
cast by the black hole's event horizon upon the emission
from the accretion flow in the jet.
Importantly, the size and shape of the shadow
is determined by gravity alone.
General relativity makes a clear prediction
for both of these features.
To within 10%, the shadow should be circular.
With the diameter determined solely by mass,
multiplied only by fundamental constants.
However, as with all voyages of discovery,
when we began this expedition of the mind,
we did not know what we would find.
Were Einstein wrong,
were the heart of the M87 not a black hole,
its silhouette could have been very different, misshapen,
mis-sized, like those seen here, or even simply missing.
Changing gravity changes how light bends,
and thereby changes the shape of the shadow.
In April, 2017, this was the dog that did not bark.
The shadow exists, is nearly circular,
and the inferred mass matches estimates
due to the dynamics of stars 100,000 times farther away.
Today general relativity has passed another crucial test.
This one spanning from horizons to the stars.
The shadow is surrounded
by a bright ring of enhanced emission,
those photons that just escaped the black hole's clutches.
The properties of this ring like feature result
from the astrophysical drama that unfolds on gravity's stage.
To understand these dramas, over the past three years,
the EHT collaboration has undertaken an unprecedented
simulation effort at research institutions across the globe.
This has generated the largest collection of simulations
ever assembled of the accretion flow
and jet launching region in M87.
The southern brightness excess arises directly from near
light speed rotational motions near the black hole.
Regions that move toward us
at nearly the speed of light are bright.
Those that are moving more slowly or away are dim.
From these,
we have inferred the sense of rotation of the black hole.
In M87, the black hole spins clockwise.
Moreover, the excellent quantitative agreement
between the EHT images and generic theoretical expectations
of a bright crescent like feature
with a dark interior provide significant confidence
in our interpretation. The object of the heart of M87,
the object that powers M87's jets,
is a black hole like those described by general relativity.
Importantly in combination with infrared
and optical flux measurements,
we can now rule out a dim but otherwise visible surface.
That is, this does appear to have the defining feature
of a black hole,
the event horizon, that point of no return.
Today, several complementary windows
have opened upon black holes,
science fiction has become science fact.
Together, two of these windows, the EHT and LIGO,
which reported the first detection of gravitational waves
a short three years ago,
have verified another key prediction
of Einstein's theory of gravity.
Despite varying across of factor of billion en masse,
known black holes
are all consistent with a single description.
Black holes big and small are analogous in important ways.
What we learn
from one necessarily applies to the other.
At this point, I would like to hand the story off
to Sera Markoff,
who will describe the broader astrophysical implications
of these first EHT images. Thank you.
[Applause]
Sera Markoff: Thank you Avery.
So black holes may be the most exotic consequence
of general relativity but these bizarre sinkholes
in the actual fabric of space-time turn out to be,
have a lot of consequences of their own,
which I'm going to talk about today.
That is because black holes
are major disruptors of the cosmic order
on the largest scales in the universe,
they are helping mold to the shape of galaxies
and clusters of galaxies.
What we've now confirmed, as Avery was saying,
that general relativity itself does not change
when we look at different black hole masses,
it turns out the impact of a black hole
will actually change a lot. And so if we want to understand
the role of black holes in the universe,
then we need to have accurate determinations
of the black hole masses.
This has been a problem up until now.
So, our mass determination
by just directly looking at the shadow has helped resolve
a long-standing controversy in measuring the mass of M87.
There's been two independent methods,
one, both, basically looking at the motion of either
gas or stars,
but they ended up giving different answers.
Our determination of 6.5 billion solar masses lands
right on top of
the heavier mass determination from stellar motions
so this will also help resolve the discrepancy
that can lead to better mass determinations
for other more distant black holes
when we can actually see the shadow.
So getting to the impact of this is important because
M87's huge black hole mass makes it really a monster,
even by super massive black hole standards.
So you're basically looking at a super massive black hole
that is almost the size of our entire solar system.
And in fact that's part of the reason why we can see it,
even though it is so far away.
But now if we zoom back out to the more cosmic perspective
of the host galaxy of this black hole,
the galaxy is made of billions of solar systems,
so on those scales the black hole itself is minimally small,
it is about 100 million times smaller than the galaxy.
And if it were a dormant black hole
like the super massive black hole
in the center of our own galaxy, Sagittarius A*,
then the galaxy would have no way of knowing it is there,
it would basically be like a pebble in a shoe.
But when the black hole is activated
by gravitationally capturing material,
it starts to convert that fuel into other forms of energy,
with the efficiency that can be almost 100 times better
than nuclear fusion that powers stars like our Sun.
So when that happens in these active phases,
black holes temporarily become
the most powerful engines in the universe,
and they go very quickly from being a pebble in a shoe
to a thorn in the side of the galaxy, literally.
And the thorns in this case being the jets
that Avery was mentioning.
In the most extreme cases, these jets can actually
penetrate into the entire galaxy and well beyond.
But the power that is coming out,
we can't see with our own eyes, so if we want to understand them
we have to look in other wavelengths,
so we look with telescopes
across the electromagnetic spectrum.
So I'm going to give you an example of this.
This is another very active black hole system,
and it is a combined image,
so you see in white from NASA's Hubble telescope,
the elliptical galaxy, Hercules A, in the center,
and then overlaid in blue is the radio waves
from the National Science Foundation's
very large array, and these radio waves
are basically tracing magnetic fields in space,
so that tells us that these jets are enormous fountains
of magnetized material
that are being sprayed out from the black hole,
not the black hole itself, but near the black hole,
nearly at the speed of light.
And these particular jets are 100 million times bigger
than the black hole that launches them.
Now if we add another layer, we are going to look
in the X-rays now from NASA's Chandra telescope,
and X-rays are probing extremely hot gas,
like billions of degrees
so we're seeing the entire system
is embedded in a halo of hot gas.
And we can use this information to calculate how much energy
the jets have to have to bore through all this material.
What we find is that the jets are carrying the equivalent
of 10 billion supernova in energy
deposited over one of these active cycles.
So this is,
these kinds of interactions are basically very important
because this tiny black hole on these scales
is somehow launching these structures
and also managing to heat the gas
to prevent stars from forming.
And since galaxies grow by forming more stars,
this has the effect of truncating galaxy growth
and we think it is through these types of interactions
that black holes help shape the largest structures,
galaxies, and clusters of galaxies
and make them look the way they do today.
Now M87 is in a much more modest active state but as you can see,
this is also from Hubble,
it is still managing to launch the magnificent jets,
these jets are emitting across the electromagnetic spectrum
as well, so we need this information
to be able to fully understand the system.
But if we zoom way out now to the cluster of galaxy scales,
this is another combined image where you see red
in radio and blue in X-ray,
you just see just a mess of structures,
and we think this is telling us
about M87's black hole's past interactions,
really affecting the cluster scales,
timescales on hundreds
or tens of hundreds of millions of years.
So until now we always thought that black holes were behind
these large structures driving these engines,
but we never knew. And now we with EHT
we have direct evidence of the root of these problems,
and we can look at this and we can now start to make,
to understand combining strong gravity, magnetic fields
and looking at atomic level processes to understand
how these processes interplay and conspire
to make these enormous structures
that are basically affecting the larger scales of the universe.
And so to capture all of this information,
we need to combine our observations
with those across the multi-wavelength spectrum.
As you heard from Dan, there are a lot of complexity
in these observations, and we added to that
by doing a complicated Sudoku of coordination
with many facilities across the globe and also in space.
This is similar to the campaign
that was run with LIGO for gravitational waves.
It's very important to combine signals
both from photons and particles,
so by doing this, we expect EHT is going to play an active role
in this new era of international multi-messenger astronomy.
So looking to the future, the same observations we took
in 2017 for M87 also included this dormant black hole
in our galactic center, Sagittarius A*.
And by looking at two black holes at opposite extremes
in activity range,
especially combining this with multi-wavelength information,
we can better understand
the ebb and flow of influence of black holes
in the long course of our history in the universe.
Anyway, thank you very much,
I'm going to hand this back over to Shep
who's going to say a few words.
[Applause]
Dr. Sheperd Doeleman: Thank you everyone,
I just want to point out that
when we first started the event horizon telescope project,
the group was small and I think it had to be small and nimble
to carry out precursor experiments
and develop the first kinds of techniques and instrumentation
that enabled us to move the field forward.
But, over the past decade,
the greatest accomplishment has been the building of a team,
and as I said before, we're more than 200 people strong,
many institutes, over 20 countries and regions.
If you want to reduce petabytes of data,
if you want to develop new imaging algorithms,
if you want to image a black hole,
then you need a large team.
It has included many early career scientists,
senior scientists, and many of them were here with us today.
So I would like to ask everyone who is associated
with the event horizon telescope
to please stand up so everybody in the media
can see who has done this work.
[Applause]
It is a true pleasure and privilege
to work with this crew.
I urge all the media to go seek them out
to learn how the sausage was actually made,
how the black holes were actually imaged.
I also want to say something in particular
about funding and support,
this has been a high risk but high payoff endeavor,
sometimes you have to kiss a lot of frogs
before you get to the Prince,
before you get to the black hole image.
You need supporters, you need funders who will stand by you
for long periods of time, who take the long view,
who understand that basic science,
never goes out of style.
and who also understand that basic science,
you never know when it is going to pay off,
but ultimately it usually does,
and you have to play the long game.
We have wonderful partners with the National Science Foundation,
with our international funding agencies and foundations
and our hat is off to them for sticking by us for so long,
and we look forward to greater things with EHT
as we continue to sharpen our focus on black holes.
Thank you.
[Applause]
Amanda Hallberg Greenwell: Thank you all very much.
One note before we take questions,
several of our panelists and many of their EHT collaborators
will appear this week in a documentary
which has followed efforts of the EHT for the past 2 years.
The film will show viewers how Shep Doeleman and his team
reached the groundbreaking moment.
The documentary is called Black Hole Hunters
and it will premiere this Friday,
April 12, at 9 PM Eastern on Smithsonian channel.
We will now take questions from the audience until 10 a.m.
Please raise your hand, wait for a microphone,
and identify yourself and who you are with you
before asking your question.
Seth Borenstein, The Associated Press:
Two part question, please.
First, this is M87, you have two targets initially.
Have you seen anything,
have you captured any images of Sagittarius A* yet
and have not released them for whatever reason?
Or have you not gotten those images?
Second, one of the keys I understand,
when you look at this distinct edge of the photon ring,
not being a scientist, this looks fairly fuzzy,
how distinct is this edge to you?
is it distinct enough to notice
the effect of gravity or not?
How close does it pass to whatever measurement you use
for sharpness of that edge?
Dr. Shep Doeleman: I will start off with the first part.
Sagittarius A* is also very interesting target,
we can see the event horizon, we should be able to resolve it.
It is complex. M87 was in some sense
the first source that we imaged so we went with that.
It is a little bit easier to image
because the timescales are such that it doesn't change much
during the course of an evening.
So we are very excited to work on Sagittarius A*.
We are doing that very shortly, we are not promising anything
but we hope to get that very soon.
On the point about the circularity of the image, NGR,
I would like to ask Avery answer that.
Avery Broderick: Your question
was on the sharpness of the edge.
So we have actually spent a considerable amount of time
trying to ascertain the particular details of this ring
like or crescent like feature.
And the sharpness, it falls off in less than 10% of the radius,
that's about the instrumental resolution
that we practically have.
So insofar as we can tell, it drops off nearly instantly
and does look then very much like a black hole shadow.
Seth Borenstein: So even though it looks fuzzy, it isn't.
Avery Broderick: That's right.
Alan Boyle, GeekWire: Hi, I'm Alan Boyle with GeekWire.
I wanted to ask, following up on that idea of the image,
are there things you might be doing
to enhance further the quality of the image?
Might there be more telescopes added to the network,
or are you using different data processing techniques
to get an even sharper image?
Dr. Sheperd Doeleman: I will answer the first part of that.
We think we can make the image
perhaps sharper through algorithms
and I'll leave that to Dan.
But we are embarking on a wonderful new series
of putting new telescopes in different places on the Earth,
so if you add more telescopes,
you build out that virtual Earth-sized mirror.
And it goes to N-squared,
so if 'n' is your number of stations,
then the number of points you get in your virtual mirror
goes to n-squared so even adding two or three more stations
in just the right places will increase
the fidelity of the image a lot. The other thing I would add is
that if you have higher frequencies,
which the EHT is going to do soon,
then you get an even higher angular resolution.
Dan Marrone: I think the biggest improvement
we'll make will be through adding new telescopes,
and the higher frequency observations
will be very exciting. As I said, in my section,
the methods of imaging are complicated.
So depending on what you are interested in,
if you're interested in the sharpness of the ring,
you can approach the imaging process slightly differently
and make a less blurry looking picture.
Tariq Malik, Space.com: Thank you very much.
Tariq Malik with Space.com. I think for Shep.
You said in your opening,
that this was seeing the unseeable,
and it's been a good long time to prove this concept out.
I'm just wondering for a moment, as a scientist,
what you, what your team members,
what it felt like to see that image for the first time.
Did you have a party? Did someone cry?
It is an amazing achievement, how would you relate that?
Dr. Sheperd Doeleman: That is a great question.
We have been at this for so long,
there was such a buildup,
there was a great sense of release, but also surprise.
When you work at this field for a long time,
you get a lot of intermediate results.
We could have seen a blob and we've seen blobs.
You could have seen something that was unexpected,
but we didn't see something that was unexpected.
We saw something so true,
we saw something that really had a ring to it.
If you can use that term of phrase
and I think it was just astonishment and wonder,
and I think any scientist in any field
would know what that feeling is,
to see something for the first time.
To know that you've uncovered part of the universe
that was off-limits to us.
When that happens, it is an extraordinary feeling.
I think for every one on the team.
Dr. France Cordova: I will just add,
as an astrophysicist,
this is the first time that I saw this image right now
because they wouldn't let NSF see it.
It did bring tears to my eyes so this is a very big deal,
I didn't really know what to expect.
It was so cool. It is an amazing image.
Congratulations.
Hi, Jay Bennett with Smithsonian Magazine.
You mentioned just now that this was kind of the perfect image,
there wasn't really any surprises to it,
it was the exact ring
that you expected from general relativity.
Was there anything about it at all
that was surprising or unexpected?
Or was it really just kind of what you were looking for?
Dr. Shep Doeleman: Well in broad brush, as Avery said,
it has verified Einstein's theories of gravity
in this most extreme laboratory.
But, there are some very interesting things
that we want to follow up with,
there are asymmetries around the ring,
the brightness in the southern part,
so there will be a lot of future work on this
to sharpen our focus on gravity.
Avery Broderick: So, first, I have to admit,
I was a little stunned that it matched
so closely the predictions that we had made.
It is gratifying, sometimes frustrating.
But this is the beginning, we are asked a moment ago
about how we felt and I think it was a cathartic release
that finally things are working,
but also the anticipation and the amazing science
that we are going to do by studying this image closely,
and by repeating the experiment.
In that sense, we will be able to improve the precision
with which we can probe general relativity, etcetera,
and there we may find these unanticipated surprises.
Chris Lintott, The Sky-At-Night: Chris Lintott
from BBCs The Sky at Night.
Thank you for releasing the papers
alongside the press images. The first image on the paper
there shows four different images from four different days,
and it seems to me there are hints of changes from day today,
are those real?
Can you say anything about time variability at this point?
Dan Marrone: There are two sets of four images,
the earliest image in the imaging paper
shows those four preliminary images that I spoke about.
The four different teams presenting their results.
Those differ slightly from the final answer
partially because that was still an engineering data release,
it wasn't the final data.
From day-to-day, we have tried to establish
how well we can trust the differences between the days,
they seem real but at the moment,
it is hard for us to interpret them.
So we hope, the timescale for variation from M87 is very slow,
so we hope that by looking at the data we got in 2018
we will be able to see if anything important has changed.
Dr. Shep Doeleman: Can I add to that?
I would also add that Sera pointed out,
the multi-wavelength is a key piece of the puzzle,
so when we observed with EHT on the very smallest scales,
we also want to observe the multi-wavelength,
x-rays and the longer waves of radios on the larger scales.
Sera, did you want to expand on that?
Sera Markoff: We actually didn't highlight that
in these first six papers.
We did use information from the x-rays
to help constrain some of the models
but we have an enormous amount of multi-wavelength data
that goes with these data sets
and so I think you can expect to see quite a lot of studies.
They'll help us understand some of the variability
that you're asking about as well.
M87, we're actually catching it in a quiet point.
We can tell this from historical multi-wavelength data
and compared it with what we've got.
So I think in a lot of ways it comes back
to the fact that we just got lucky.
Had it been flaring,
we might be seeing something a lot different.
It might have blocked the hole as well.
It was flaring even about seven years ago or so.
Arthur Friedman: My name is Arthur, [unclear] reporter.
I have a general question about black holes.
We are talking about the density and mass of the black holes,
do you have any sense of the general length
and width of the different black holes?
Are we talking like billions of light-years
across in terms of the width,
or is it billions of miles? What is the size?
And what keeps the density together in each black hole?
Do you think that larger black holes have a harder time
keeping the density intact versus smaller black holes?
Avery Broderick: The answer to your first part
of your question, how big is the black hole?
It is about 1 1/2 light days across.
So, not light-years, measured in a day.
That means that practically it appears
to evolve on week timescales,
so we see substantial changes in principle
in timescales of maybe two weeks, 1 1/2 weeks.
What holds it all together?
All black holes are the same in this regard.
It's all gravity. Black holes are all about gravity.
And, once you get that much mass
collected into that smaller region,
and how small depends on the mass, okay.
So if I make a black hole ten times more massive,
the region I have to reach it is ten times larger.
If I make it a billion times less massive,
the region is a billion times smaller.
Once you have gotten that much mass that close together,
gravity runs the show and there's no other force
that we know of that will stop it.
And everything collapses down in the center in principle
to a singularity but behind it, the horizon,
it is hard to reach.
When you go there, you don't get to come back
and tell us what you've seen.
Emilio Rodriguez, Nature Magazine: I'm just wondering
if these images can help us understand
how black holes produce jets and also,
do you see this thing evolving over time,
is it changing over time or do you just see it as fixed?
Sera Markoff: I think this comes back
to one of the earlier questions.
What we are seeing is effectively,
when you look in different wavelengths,
you're picking out different scales of the system
and then also the fact
that we are using a planet-sized telescope,
means we have the extreme precision
to see the route very close to the black hole.
That region is all magnetized plasma,
and we think that the jets are being launched
effectively by some sort of squeezing of the magnetic plasma
towards the black hole and then maybe an enhancement
from the spin of the black hole itself.
We are looking directly at this region,
so we do anticipate that this image,
we haven't really begun to see the full analysis
but we've done a lot of work so far, different groups
within the team have been doing simulations.
And the effect, the expectation of that
is that we will be making models
and comparing them again especially again
also to multi-wavelength data on the larger scales,
and looking for variability.
Looking for any hints at the underlying physics
that is really going on.
We have a pretty good idea in the broad
stroke of what is happening but there is a lot of debate
about the actual processes near the black hole.
And so that is going to be the next steps,
I think you can expect quite a lot coming out
in the coming period on that.
Anna Humphrey, TCWilliams High School: I was wondering,
this is obviously an incredible feat of global collaboration
in the scientific community,
and do you see this as being a model for science going forward?
If so, what are the challenges
and what are some of the things we can hope to accomplish?
Dr. Sheperd Doeleman: I'd like to say something about that.
That's a great question.
VLBI, Very Long Baseline Interferometry,
which as Dan explained is the whole technique that we use is,
by its very nature, a cross-border activity.
We don't pay attention to where the telescopes are,
just that they are high enough and above the water vapor.
And that they're manned by scientists
who share our common vision.
In that sense, we built this team,
this 200+ member team
by selecting experts from everywhere.
I think it is a really good model
for how we can do distributed science.
We spend a lot of time on video cons.
We have published papers with people
that we have never met before,
but we consider them our true and trusted colleagues.
That happens because we have the ability to reach out
and form a distributed network of scientists.
So I think it is a good model.
Question: Thank you for taking my question.
My name is...from NHK Japanese Public Broadcasting.
I have a question about international collaboration.
I understand this is the enormous work of collaboration,
but can you tell me more about the detail
of each country's contribution? Especially Japan.
Dr. Shep Doeleman: I can say something about that,
I work very closely with many people
at the National Astronomical Observatory of Japan and others.
Japan has played a very key role,
as have a number of countries.
Japan, for example, was one of the key members
for the project that phased up ALMA,
that took all the dishes in the ALMA array
in the high Atacama desert
and then made them essentially one dish,
that we can record on one set of equipment, that was huge.
They have been a key partner in the imaging techniques
and pushing that forward, too.
But, the key is that each country, each region,
each group, each institute brought something in kind
and they brought their expertise and they brought their work.
At the end of the day, you just need this stuff to get done.
Everyone came with a full heart really,
and the expertise and the energy to make this image
that we presented to you today.
Question: [unclear] from Wakefield High School:
I was wondering, if nothing travels
into the black hole
at the speed of light, other than light itself,
how does the black hole pull light into itself, I guess?
And also, you guys have mentioned how the M87
is 55 million light-years away,
then how does the time work from capturing the light
from here to itself?
Dr. Shep Doeleman: It just takes light 55 million years
to get here,
so when we see M87 and the image you saw,
that is what it looked like 55 million years ago.
That is the last part of your question.
The first part, anyone?
Avery Broderick: So light can't escape the horizon
because in some sense, space-time itself
is flowing through the horizon
at the speed of light at that point.
This is one of the beautiful elements
of Einstein's theory of gravity,
is that space is no longer a static stage
on which things happen but a dynamical participant.
And you can think about it moving and flowing,
and black holes drag it around when they spin
and flows through the horizon when they are,
even when they're static.
So those photons trying to climb
out of the gravitational potential well,
outside the horizon can do so because they can go faster.
But once you cross the horizon, they're dragged in,
just like sound waves across a waterfall.
Hi, Emily Converse, Science News: I was wondering
if you could talk
in just a little bit more detail in your future plans.
I know you mentioned adding some telescopes
and other frequencies.
Maybe you could just give some more detail
about when and what you are looking at.
Dr. Sheperd Doeleman: Well, I would point out that April,
2017 we had eight telescopes in six geographic locations.
And in 2018, we added another telescope,
the Greenland Telescope which dramatically increased
our coverage of the north of M87.
And we are going to add a new telescope in Dan's backyard,
the Kitt Peak Observatory in Arizona.
These will all increase the imaging fidelity.
They will fill out that virtual mirror
that we are trying to build.
That is important for something that Sera described,
which is the jets.
We see this ring, but it's difficult for us
to make the firm connection
to the larger scaled jets that Sera showed.
By adding more telescopes,
at intermediate and longer baselines
we'll be able to extend the image of that shadow out
to where it connects to that jet where we know it has to.
So that is one area that we are expanding into
and the increased frequency of observation.
We observed a one millimeter wavelength,
now we want to move to .87 millimeter wavelength.
It sounds like a small jump
but it increases your angular resolution,
the resolving power by over 30%, 50%.
So, you wind up sharpening your image
just by observing at higher frequencies.
And then of course, world domination is not enough for us,
we also want to go into space.
If we could put a space based radio telescope
in an orbit around the Earth,
it would sweep out even more of that virtual mirror
and do it much more quickly.
Amanda Hallberg Greenwell:
We only have time for a couple more.
Let's go right here.
Tom Costello, NBC News: Hello, Tom from NBC news,
congratulations for all of you.
I have a question for Sera or Avery.
Both of you being such devoted scientists
and having devoted your lives to this,
I'm wondering what are your thoughts about Einstein,
who predicted much of this so long ago.
I wonder what your thoughts are about his genius today
and what you verified.
Sera Markoff: Well, I do spend time thinking about how it is
that somebody could have sat down in a patent office
a hundred-something years ago
and come up with a theory that has turned into something.
I mean, it is great that we can see it
verified with black holes,
but in fact we use this everyday for satellite communication.
It's a very integral part of our understanding of the universe.
But to me, I feel like there are bigger mysteries afoot.
I'm fascinated by Einstein
and that level of understanding in the universe.
It doesn't happen in isolation, of course, there were many
other people also thinking that fed into this.
But I'm fascinated by the fact
that we're now at the threshold of understanding black holes
as maybe the best clues about quantum gravity,
and what's going on. How does gravity actually work?
Is this some emergent process coming out of space-time?
What is space-time?
I think there is a lot more, it is just the beginning for me.
Avery Broderick: Sometimes the math looks ugly but really,
there is a strong aesthetic in theoretical physics generally,
and the Einstein equations are beautiful.
So often in my experience, nature wants to be beautiful
and that's one of the striking elements
about the Einstein equations,
about Einstein's description of gravity
is it is fundamentally
one of the most beautiful series theories we have.
For that reason alone,
and the long history of Einstein being proven right here,
I suppose we are not terribly surprised.
But I can't, I can't lie to you,
the most exciting thing we could possibly do
would be to supplant Einstein,
to find that in this extreme gravitational laboratory
that there is something a little new.
And as Sera pointed out,
mysteries abound around black holes.
And we do know that there must be something more.
The problem of quantum gravity remains unsolved
with the current tools that we have and black holes
are one of the places to look for answers.
Amanda Hallberg Greenwell: Okay. Right here.
Michael Greshko, National Geographic: Hi,
Michael Greshko, National Geographic.
Shep, you mentioned seeing the unseeable
with regards to black holes, but I want to talk about
another aspect of our universe, dark matter.
Avery, you co-authored a paper in 2017,
pointing out that M87 in particular
with the event horizon telescope
would be a unique probe into dark matter,
the degree to which it annihilates its interactions
with other patterns.
Can you say anything at this point
about how this measurement changes or constrains
what we know about dark matter?
Avery Broderick: The quick answer is not yet.
We have been very focused on making the first interpretation
of this groundbreaking image,
so we have not yet gotten to that particular topic.
Amanda Hallberg Greenwell: Thank you all for attending,
if you have further questions,
staff from the National Science Foundation
are here to help, also you have an email address
inside your press packets for any follow-up questions,
thank you for joining us today, this concludes our live stream.
[Applause]