Into the Impossible With Brian Keating - Shep Doeleman: How the Event Horizon Telescope caught the Milky Way’s MONSTER Black Hole! (#229)

Episode Date: May 15, 2022

European Southern Observatory (ESO) released groundbreaking new Milky Way results from the Event Horizon Telescope Collaboration (EHT). Today I speak to Shep Doeleman Founding Director of the Event Horizon Telescope about. what it all means! You can watch the press conference on ESO's YouTube channel https://youtu.be/rIQLA6lo6R0 and watch my breakdown of everything you need to know! Astronomers have unveiled the first image of the supermassive black hole at the center of our own Milky Way galaxy. This result provides overwhelming evidence that the object is indeed a black hole and yields valuable clues about the workings of such giants, which are thought to reside at the center of most galaxies. The image was produced by a global research team called the Event Horizon Telescope (EHT) Collaboration, using observations from a worldwide network of radio telescopes. The image is a long-anticipated look at the massive object that sits at the very center of our galaxy. Scientists had previously seen stars orbiting around something invisible, compact, and very massive at the center of the Milky Way. This strongly suggested that this object—known as Sagittarius A* (Sgr A*, pronounced "sadge-ay-star")—is a black hole, and today’s image provides the first direct visual evidence of it. Although we cannot see the black hole itself, because it is completely dark, glowing gas around it reveals a telltale signature: a dark central region (called a “shadow”) surrounded by a bright ring-like structure. The new view captures light bent by the powerful gravity of the black hole, which is four million times more massive than our Sun. Please Visit our Sponsors: LinkedIn: LinkedIn.com/impossible to post a job for FREE Athletic Greens, makers of AG1 which I take every day. Get an exclusive offer when you visit https://athleticgreens.com/impossible AG1 is made from the highest quality ingredients, in accordance with the strictest standards and obsessively improved based on the latest science. Learn more about your ad choices. Visit megaphone.fm/adchoices

Hey friends, welcome to another special episode of the Into the Impossible podcast featuring my friend Shep Dolman, the founding director of the Event Horizon Telescope. And I'm sure you have heard the exciting news that this phenomenal collaboration has detected and imaged the event horizon around the black hole known as Sagittarius A Star or Saj A Star for the cognoscenti that dwells the behemoth that lurks at the heart of darkness inside of our own Milky Way galaxy. This has been sort of a holy grail for Shep for 25 years. And in addition to some technical nerding out that you'll hear about, I cannot resist as an experiment, the astrophysicist, from delving deep into some of the things that get me all revved up. But we also talked about the emotional side of doing science at the highest level. And some are whispering that Shep may someday win that coveted, gilded,

graven image of Alfred Nobel. We'll see about that. He's a great guy. Have a great conversation. And he's really just a delightful person to talk to. full of humility and good cheer, and love having him on. So I hope you'll take away from this episode the challenges, but also the rewards of being an experimental astrophysicist, and studying the most enigmatic, mysterious behemoths that cause our universe to be so delightfully arranged.

So for now, sit back and relax and enjoy this ride deep across the galaxy. 33,000 parsecs away, we go into the impossible inside the event horizon of Sajjar. Come along, let's go. Any sufficiently advanced technology is indistinguishable from magic. Open the bud-bay doors, please help. I'm here live with Dr. Shep Dolman, who is a friend of the show, past guest on the show, talking about the previous phenomenal discovery by the Event Horizon Telescope. Today's announcement really shook up my universe,

the universe of those who care about monsters and incredible gravitational discoveries. But Shep, take it away. What did your team announce today? This is so phenomenal. It was a pretty incredible day, Brian. But today we announced the first image of the supermassive black hole in the center of our galaxy, Sagittarius A-Star. it's at the same time very similar, but also quite different from the black hole we imaged in 2019.

That was M87, which weighs 6.5 billion solar masses. So let's first talk about why they're the same. No matter how you light up the space time around a black hole, the intense gravity dictates what the image is going to look like. So these black holes are surrounded by an ultra-hot plasma, radiating light cross-electromagnetic, and it's bent by Einstein's gravity into this ring shape. So the fact that we saw a ring in M87 and we saw one in Sagittary Star, which are different in mass by about a factor of a thousand, is another confirmation of Einstein's theory of gravity,

that these black holes all bend light in exactly the same way and appear the same. Now they're different because M87 is a monster. M87 is one of the biggest black holes we know of in the universe, and it has a jet that is powered by the black coal piercing the entire galaxy. Whereas Sajah Star is the timidest of eaters. It is just eating a tiny, tiny amount. At the press conference today, Michael Johnson said that if Sajah Star were a human, it would be eating one grain of rice every million years or so.

That's the rate at which Sagittarius A Star is delicately consuming the gas around it. So it's not a monster. What makes it so special is it's our monster. And we can use its proximity to study it in a way that we can't necessarily study M807. So it's a great day for black holes that they're the same, but also that we have a completely different black hole to study it. And the shape of the black hole, it looks, you know, I was kind of anticipating this would be about the black hole, the Milky Way galaxy. But the shape and the morphology looks so radically different from the M87 black hole. Is that purely attributable to its mass?

Well, it's partially the mass, but also mostly at this point, it's due to the fact that Sagittarius A-Star weighs a thousand times less. So that means that the dynamical time scale, the rate at which it changes is a thousand times faster. So while we're observing Sagittarius A-Star, it's changing while we're trying to capture its image. That means that the quality of the image is poorer. It's like trying to capture a running person in a time exposure, a long time exposure. It gets very blurry. So the fact that it looks a little different, but there are blobs around the ring is mostly a consequence of the fact that it's changing while we're looking at it. And not so much that it's intrinsically much, much different.

Now, this is a good thing, right? because this tells us that when we talk about making movies of black holes, we now have our leading actor. Sagittary Sastar is the one that we want to make a movie of because it changes on these very, very short time scales. For M87, we would take snapshots every few weeks and tie years of observation into a time-lapse movie. With Sajer Star, we can see evolve in real time.

So again, the images are a little bit different. a little bit the same, and it all speaks to the fundamental physics around black holes. Will we also expect to get more information in the coming years from this black hole? Are you still taking data with the E.H.T. currently on this object? It's peak pollination season, and my business is scaling fast. To keep the nectar flowing, I need a phone plan with top priority data speeds. That's why I chose GoogleFi wireless. My connections stay strong even when the hive is buzzing.

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This is the strongest evidence for the existence of the supermassive black hole in the center of our galaxy. Full stop. In 2020, Reinhard Gensel and Andrea Gilles won the Nobel Prize for determining that there was a compact object at the Galactic Center. But the Nobel Prize Committee stopped short of saying it was a black hole. Now we have the proof, the long-sought proof, that the object at the center of our galaxy is indeed a black hole. There's no other way for us to get that particular ring that matches the mass derived by Gensel and Gensel and Gez at four million solar masses. Everything fits together now. It paints a wonderful picture.

But you asked about what comes next and what we're learning. So, for example, looking at the simulations of black holes, we can now say that there are likely strong magnetic fields operating close to Sagittary, say, We can say that the temperature of the electrons is probably pretty high compared to the temperature of the ions. It's something that people who study accretion are very interested in. And we can also say that the time variability seems to match generally what we might expect. It's actually, Sagittary's A-star seems to be a little quieter than all of our computer models might suggest. So when you run these computer models on banks of CPUs, they predict that Sagittary Statistar would be a little more jumping,

a little more frantic, a little more puppyish. And the Sagittar object that we actually observed seems to be a little calmer. So that's something for us to really dig into over the coming years. And we have data in the can from a couple of other epics, and we're building the instrument out all the time. and the next generation, PhD will make true movies of Sajahe Star.

Yeah, I want to get to that in a bit. I notice you have a new button on your lapel. You had a previous one last time. So if people can find their lapel manufacturer, then they'll be able to get data, you know, in real time. Just kidding. But in seriousness, when we look at the, when we look at the black hole image from M87,

and we look at the black hole now image that you've produced with your team from the Sajjah star, we see, you know, there's no scale. There's no way to tell just from the lapel pin, you know, are they the same size? Of course they're not. This one is, you know, maybe 500 times less massive. But what do we learn about the sense of scale and perhaps the orientation? Because the black hole, you know, could be in any orientation. And was it just fortuitous that they seem to present the same general?

morphology and they're circular. Obviously, there's a shadow. There's a dark spot. Was that fortuitous? Or is that something else? Yeah. So, you've hit the nail on the head there, Brian. So it turns out that because the ring seems to be roughly uniform or the north of the ring is as bright as the south part of the ring, there are lumps, but there's no clear asymmetry from one side to another of the Sagitt star result. That tells us. that we're probably looking at it face on. And that is very interesting because consider for a moment that we live in an outer arm of the Milky Way galaxy. So if the spin of the black hole was aligned with the rotation of the Milky Way,

we would be looking at Sagittary Say Star edge on. It does not look like we are seeing an edge on black hole. That means that the black hole for some reason seems to be pointed not far from our line of sight. Now, that's a mystery, and that's what we're going to have to resolve over the coming years. Like, why is that? There's a little bit of evidence from the optical and infrared groups that suggest also that we should be seeing it face on. So this is consistent with that. But another mystery, like, why are we in this preferred direction from the galactic center?

So that just speaks to your question about why it kind of looks the way it does. But in terms of scale, now let's talk monsters, Brian. The M87 black hole is 6.5 billion solar masses. It's the size of the entire solar system. Our entire solar system could fit many times over in the shadow of that black hole. So to keep that in your mind for a moment, Sagittarius A Star, though it appears the same size on the sky, because it's closer, is actually about 1,500 times less massive.

The event horizon and shadow of Sagittet Star would fit well within the orbit of mercury in our own solar system. Right? So you're looking at something that snugly fits close to the sun versus something that can swallow the solar system many times over. And the fact that we're seeing these black holes that appear the same size reinforces the idea that black holes are the same no matter what size they are, no matter what mass they are. The ones that are discovered by LIGO, there are 10 solar masses seem to be the same as the ones

the Sadjee Star, which is of four million solar masses, and one that's six and a half billion. There's no other object in the universe that exists in a single form at all those different scales. If you took a mouse and you tried to scale a mouse up a billion times, it would collapse under its own weight, right? A mouse can't be a billion times the size of a mouse. It's skeleton doesn't scale properly, right? But a black hole is perfectly at home no matter what mass it is. That's incredible. Yeah, they are the biggest objects, single objects in the universe.

They've been around for a long time. I made a video on my channel today, or I talked about, you know, could they make up for the dark matter in the universe? And before we get to that, I want to ask, behind me is a picture of M51, which is the Whirlpool Galaxy. It's a galaxy not unlike the Milky Way. way, but M87 is an irregular elliptical galaxy. It's very different. Could that be in part why we see these blobs? Are these the, you know, the blobs that Andrea and Reinhardt call, you know, these

A2 and are those blobs that we're seeing in the image? Are they any way related to the clumps of gas and dust and star-forming and star-dying regions in our galaxy? Are they completely different? They are very different. It also helps to make a jump to the scale here. So the, the, the tremendous tinering work by Andrea Gess and Reinhardt Gensel show the orbits of stars around an unseen mass, that compact object that we talked about earlier. And the closest point of approach of those stars is still about a thousand times bigger than the shadow we observe today. In other words, if Newton saw the motion of these stars around the black hole, he would not be surprised. You have to look very, very carefully at the motions of those stars to discern any hint of eye. time and general relativity.

Whereas we're so close that everything is governed by tens of billions of degree gases, emitting light is bent like taffy in the gravity of the black hole. So totally different origin of those blobs, much, much closer by a factor of about a thousand. Amazing. I want to ask a question that, you know, lay people want to know. Oftentimes people ask me, what do you, you know, hope to see? with the Simon's Observatory or any other project. And I always say, I don't like to think about what I hope to see, what I want to see,

because that can lead to confirmation bias, et cetera. In this case, you must have known for a long time that this was going to happen, and you must have been excited to see it in some sense. Talk about how did this emotionally resonate with you, if at all. We scientists are human beings, despite the stereotypes of the contrary. How did this culmination of your plan? with your colleagues for decades and fighting for funding and fighting for scarce resources. How does it feel to make this image of something that would blow the minds of someone as great

as Einstein or Newton or anybody? How does it feel just on a personal level? I'm curious. A lot of different emotions are running through us, like awe, humility, relief, and inspiration. You said something very interesting about Einstein and how his mind. would be blown. The more I've been in this game, and I've been chasing Sadie Star for over 25 years now, the more I think about it, the more it's about connections. We have a connection

historically. I call it the 100-year handshake with Einstein and Schwarzschild. We're continuing their tradition. And every day, we talk about the Einstein equations. Every day we talk about the Schwarzschild radius. It's not a fabric. It's not posturing. We dip into those deep traditional scientific wells every single day. And to be able to take the next step like this with this amazing team is a fulfillment not just of my personal dream, but also the dream of all scientists, that we will all build on the work of each other to address these big questions. So it's being part of a hundred year process that gives the debt.

of it, the richness of it, the texture of it. That's what I find most comforting and most incredible about this whole journey. That and being able to work with this team. I mean, the people involved in this project are just incredible. And you talked about the future. Let's go, before we get to the future for the next generation, which I'm thrilled to hear about. When we spoke last time, it was in between, I spoke to Haino Falca and others. about the polarization results.

Can we expect polarization results from the Milky Way galaxies, Black Hole, Sadgey Star, and if so, what will that tell us? Absolutely. We already know just from some of the brightness, not the polarization, but the brightness, that they are likely strong and ordered magnetic fields around Sagittarius A Star, but we haven't mapped them yet. That will be the next project for the E.H.T.

That and then looking at even more data, better array. So right now we have a hint that things are changing. In fact, we know they're changing. We can see from the raw data that things are jumping around. But we can't form a movie yet. We cannot make a movie of Sagittarius A Star. So it's like we know something is moving. Can't make it out. But in the future, we'll be able to advance our algorithms and build out the array to capture that motion. So over the coming years, we'll look at new data sets. look for polarization, but also look for this motion. And that's what differentiates M87 from Sajah A Star.

We'll be able to catch the black hole in motion with Sagittarius A Star. So that's really what motivates us to build the next generation in the H-D. Will that have more to teach us about astrophysics when these movies are made, or will it teach us more about gravity or all of the above? So it turns out both. both. What we're really after is kind of twofold. One is how do these black holes launch jets and how do they interact with the matter that's circling them? And understanding that will tell us how black holes feed, how they're in symbiosis with the galaxies that host them, and how they can

disrupt essentially star formation in those galaxies. In other words, how the large-scale structure do we see in the night sky evolves? At the same time, we know. know that these rings that we see have substructure. Some of the light is gently bent to us, but some does a U-turn, some does a full orbit around it. With the next generation instruments, we hope to be able to tease out that first ring. And that will be a much stronger test of gravity because the light that does a U-turn around the black hole spends more time in that highly curved space time. So the stuff, the photons that make it to us have a lot more information about whether that space time conforms to Einstein's theory or whether we have to find a new theory. Can we go back to what we talked about on your first visit on the end of the Impossible podcast?

I'll put a link to that conversation up here, over here somewhere. And that was about the next generation. Surely, you know, any reasonable funding agency would see these results, including the M-87 results from three years ago, and now these as harbingers of incredible new science that's uniquely capable by this instrument and this instrument alone. First of all, you know, I've been told the best thing in business is to have a monopoly. Do you guys have a monopoly? Is there any other team that can do what you guys do? And so is there, or is there not, an alternative for the NSF and the ESO and so forth to, upgrade and build a bigger, better version of NG EHT?

Well, so what I would say is that there are a lot of, there are some different views on how to proceed to enhance the EHT, but the one that has been, you know, endorsed by the National Science Foundation and the one that was written up in the Decatal Review, it just came out. This is this naval gazing exercise that all of U.S. astronomy engages in every 10 years. And they wrote that the next generation EHT concept that we put. forward is viable and should proceed. So we're damning the torpedoes. We're just full steam ahead to do this.

And, you know, observing at multiple frequencies, adding different colors to our palette when we image these black holes, winding the bandwidth with bigger sensitivity. You're doing all these things and building out new telescopes, that's going to, it's a very robust path ahead. and we already are working with private foundations and the NSF to do that. I really just see no showstopper here. I think that we should set our sites on 2030,

make high dynamic range images of M87 to show the energy extraction from the black hole through the jet, and on Sagittarius A-Star to capture the dynamics during a single night and test Einstein's theory by looking at orbits of matter. These are the questions that will motivate us, physics, astronomy, even history, philosophy, and mathematics for the coming decade. Oh, for certain.

What about adding new baselines? I mean, if you put one at the North Pole, if you put one in space, what are the limits to the resolution, both in space and time and frequency, of the current suite of instruments? And then think big 100 years from now. What could you imagine we could do with a next-next-generation E.H.T? Yeah. So I'll have to go after this because I'm being a rapture. I'm sure you had a busy day.

But so the magic of interferometry is that the number of baselines you can use, the number of connections between antennas, and each single pair gives you one data point. That that number of pairs goes as n-squared. So it's quadratic. So every time you add a new dish, you get many, more baselines. It grows very, very fast. So even by adding six new dishes, for example, we would triple the amount of data that we're going to get. And if we were to add, you know, many more

sites than that, we would again go up by a factor of three so that by 2030, we should be 10 times more capable than we are now. Now, that's a new telescope. Anytime you have an order of magnitude, you've broken through a certain barrier. So when you ask about new baselines, that really is the trick. You're filling in the earth-sized virtual lens. That'll take us to the next step. Your summer starts now with Memorial Day deals at the Home Depot. It's time to fire up summer cookouts with the next grill for burner gas grill on special buy for only $199.

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A hearty congratulations to you, your team, your friends in Europe and Asia all around the world. This is a worldwide effort. And we need it more than ever. I mean, you think about what unites people and what divides people. Who cannot fail to be just moved, blown away and excited about the future, the future of technology, human capital. and these resources that you and your team have spectacularly unlocked.

Thank you so much, Shep, for sharing your time. I know you've got a huge day ahead of you. Congratulations, my friend. We'll talk again soon. Okay, bye, Brian. Take care. Bye, my friend. Bye, bye, bye.

Well, that's a wrap. I hope you enjoyed this conversation with Shep Dolman, the founding director of the Event Horizon Telescope Project. Shepp's turning the new powerful eye of the Event Horizon Telescope to new targets, and I'm sure he'll be back many times on the podcast to come. I hope you will come back as well. And if you enjoy the podcast, please, please do me here. favor, give it a five-star review on Apple Podcasts, where you can also leave a review.

I just got an incredibly touching review from a listener, Beckinsby, who said, never disappoints, adding, I appreciate very much the fact that you have many females and people of color and LGBTQ and other science podcasts, many more than other podcasts have, according to Beckinsby. Just want to say that after listening to the one about Webb, she must be or he must be referring to the podcast I did with Hakim Alishai. to redeem the name of the namesake of the James Webb's base holoscope, where James Webb's name has been really dragged through some murky waters,

as Hakeem explained. I was gratified on my YouTube channel, which you should all subscribe to, Dr. Brian Keating, that Barbara Webb, one of James Webb's children, I believe, she left a comment about how much the video meant to her on that after this conversation that I had with Hakeem, who is African-American, but that's the least of his most interesting quality. As are all my guests, I don't have people on because of their pronouns or not lack of pronouns. I just enjoy having conversations with deep minds.

It really gets me through tough times and gives me inspiration to do big things and up my game. And I want to do better. So some of your suggestions, you can leave a review and put in there who you'd like me to see in the podcast, an Apple podcast. Or you can go to speakpipe.com slash impossible and leave me a voicemail, what you think about the podcast, what questions you have. And I'm thinking about doing an AMA and ask me anything. once I hit about 60,000 subscribers on YouTube. So let's make it happen, everybody. Thanks so much for going into The Impossible.

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