Science Friday - Event Horizon Telescope, Biosphere 2. April 12, 2019, Part 1

Episode Date: April 12, 2019

“As I like to say, it’s never a good idea to bet against Einstein,” astrophysicist Shep Doeleman told Science Friday back in 2016, when the Event Horizon Telescope project was just getting underway. At an illuminating press conference on Wednesday, April 10th, scientists shared the image for the first time: a slightly blurry lopsided ring of light encircling a dark shadow. But even as the image confirms current ideas about gravity, it also raises new questions about galaxy formation and quantum physics. Event Horizon Telescope Director Shep Doelemen and Feryal Özel, professor of astrophysics at the University of Arizona and EHT study scientist, help us wrap our minds around the image. And Julie Hlavacek-Larrondo, assistant professor of physics and Canada research chair at the University of Montreal joins the conversation to talk about what scientists would like to discover next. Plus: A project aims to use the artificial sea of Biosphere 2 as a testing ground for bringing back coral reefs affected by climate change. Christopher Conover from Arizona Public Media reports in this edition of The State Of Science. And the image of a black hole isn't the only space news that came out this week. Umair Irfan, staff writer at Vox, joins Ira to talk about the crash of the Israeli lunar lander Beresheet and other stories from the week in science in this week’s News Roundup. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I'm Ira Flato. A bit later in the hour, we're going to be talking about the big space news, that black hole, actually. Did you see that? Isn't that an amazing, amazing photo? If you have questions, you'd like to ask the experts, well, you can, if you make the call, our number 844-724-8255, or tweet us at sci-fi. We'll get to that right after our news roundup. And it has been a busy week in space, including the unveiling of that historic image. last night's launch of SpaceX Falcon Heavy rocket and an attempted moon landing by the Israeli spacecraft beretsheet. Spacecraft failed in the final minutes and probably crash landed. That's what they think, on the surface of the moon. Tony me now to talk about that and other selected short stories in science is Umer Erfhan, staff writer for Vox. Welcome to Science Friday.

Welcome back. Thanks, Ira. Let's talk about this. Let's look at the moon landing attempt. What was it? Who was behind it? What happened to it? Well, it was done by an Israeli nonprofit called Space I.L. And what was particularly significant about it was that this mission was one of the first privately financed missions to the moon. This cost about $100 million. It was launched aboard a SpaceX rocket.

And it was carrying some instruments to measure the moon's magnetic field. But, of course, yesterday, as you mentioned, they lost contact on its way down, and the mission controllers presumed that the spacecraft has crashed. So we don't know why it probably crashed. It's a little early to tell right now. Moving on, you have another story in Vox, moon-related story about human waste. Yeah, that's right. My colleague at Vox, Brian Resnick, did a pretty thorough investigation of what the Apollo astronauts left behind. Now, they took a lot of stuff to the moon and they took a lot of stuff back,

but what in particular was interesting was these 96 jet bags or bags that were jettisoned, and in them were human waste, including features. Now, that's actually of a particular interest to a small group of scientists because human feces contain, or about 50% by weight, bacteria. And it could give us some important lessons about what we can expect when it comes to living in space and about life on other planets. So we could understand more about the survivability of microorganisms? Yeah, that's right.

I mean, on Earth we find microorganisms at the bottom of the ocean and thermal vents. We find them in glaciers, and past NASA emissions have tested that bacteria can survive outside of spacecraft. Now, it's been 50 years since the Apollo missions, and the moon is a very harsh and desolate place. So it's very unlikely that something has survived, but if something had survived, it could have a pretty interesting mutation or could have gone dormant, and there are some lessons we could learn for a longer-term space mission, say, a manned mission to Mars. I would look at it as lunar composting. Potentially, maybe for a future lunar colony.

Okay, so what is the possibility that someone will actually retrieve these and bring them back? Well, it's very low. I mean, the likelihood of another manned mission to the moon is still pretty far-fetched right now just because of the financing. But it is a priority for future missions. They do want to know about how life can survive in the farther reaches of the universe. And this is a really good inadvertent scientific experiment that they've set up for themselves. Yeah, it'd be interesting to see what's going on there. Back on Earth, a little closer to home, there is another kind of microorganism in the news,

and that's a fungus among us. Yes, that's right. The New York Times did a pretty interesting investigation into a new drug-resistant fungus that's been spreading all over the world for the past five years. It's called Candida Aris, and there was a pretty alarming case of a patient who died of it last year in New York. It was so persistent that the hospital workers had to remove ceiling and floor tiles in the patient's room because it was just that hard to eradicate. Wow.

So where is it now found? Where is it spreading? Well, right now it's spreading in hospitals. Potentially anybody could get sick from it, but of course the people that are most vulnerable are the elderly, the very young, and also people who are already sick, which is why you find these kinds of drug-resistant infections in hospitals. And the big concern, though, is that hospitals aren't necessarily required to tell the general public about it if there is an outbreak. The Centers for Disease Control, in fact, is not allowed to disclose which hospitals have reported infections. And they say it's because they don't want to start a panic and they also don't want people to. get treatment if, you know, they think they have this, these are showing symptoms. But

it is alarming for the general public that there could be some of these spreading infections and they may not know about it. I wonder if you, you know, if you call up and ask a hospital where you're having elective surgery this week or next or whatever. Hey, you got any cases of that fungus around there? Whether they will tell you anything. Well, that's been a big concern. I mean, there were patients who were reported to be ill or may have been infected with these drug-resistant bacteria or funguses. And they were, some people have alleged that they were mistreated or they were given substandard care because the hospital staff was too afraid to interact with them. And so that's also another concern.

All right. Let's move out to something a little more pleasing to talk about spring, spring, flowers. They're blooming. And some people, the bad part, are really feeling the allergies. And there is a climate connection this time, is there not? Yeah, there's actually been a growing climate connection. And even more research keeps coming out showing the links. There was a recent paper in the Lancet, Planetary Health that showed that in about a dozen different sites all over the world. They found that the amount of pollen and the duration of pollen being produced by some plants has been increasing as temperatures have gone up.

You may have seen some images this year of giant yellow clouds floating over North Carolina of pollen, and it's a trend that we're likely to see getting worse in the coming years. And it's becoming more severe, not just because of warmer weather, but what, the CO2 levels are making plants produce more pollen. Yeah, that's right. The warmer weather, of course, makes the growing season longer for, plants, warmer winters makes it so they bloom earlier in the year. But carbon dioxide is, of course, plant food. And what it does is it does encourage the plant to produce more pollen.

It's not just at a planetary scale. We see plants like ragweed near highways, for example. They grow and produce more pollen because they're exposed to more CO2 from cars. So it's a very small scale effect as well as a very large scale effect. Okay. Well, thank you very much for talking with us today, Mayor. My pleasure. Amarfon is a staff writer for Vox. And now it's time to check in on the State of Science. This is KERNNO.

St. Louis Public Radio News. Iowa Public Radio News. Important local stories of national significance that you should be following along with us, and here's one. It's a story about Biosphere 2. Once upon a time, the Biosphere 2 project

was going to create a sealed ecosystem that could model what's going on in the larger world. That project eventually failed, but the dome itself and its enclosed Model C, There's a sea in there. That sea lived on. About 20 years ago, researchers raised the concentration of carbon dioxide in the dome to 400 parts per million,

and that is close to what it is in the real world today. You know what happened? The corals in the biosphere two reef died from the acidity being water level, you know, CO2 bubbles in there, gets a higher acidic condition. Joining me to talk about the project, hoping to revive the biosphere two reef. It's Christopher Conover reporter for Arizona Public Media in Tucson. And full disclosure, I should note that I'm an informal advisor for a biosphere two. Welcome to Science Friday, Christopher.

Thanks, Ira. So let's talk about that. What does the artificial sea in biosphere to look like? To the casual observer or the tourist who goes in, it's a million gallons. It's probably 60 yards long, 20. 20 or 30 yards wide. And from the top, it looks pretty good. There's a wave machine, so it's got some movement to it.

And from the top, it looks pretty good. It's once you get inside that you see the problems. Now, you did get inside. You're a scuba diver, and you actually been diving into the Biosphere 2 ocean? I have. I've done it twice now, both times for stories about six years apart. The most recent one was a few weeks ago. and the difference is pretty stark.

First of all, there are very few fish in it. I saw four or five total, and some of those that may have been repeats. But what you really notice is everything is now covered in algae, and it's long, hair-like algae, dark green, probably. Some of the strands are up to a foot long, and it's just this thick mat of algae all over everything. So there used to be a real reef there, but then something happened.

Exactly. As you mentioned about 20, 25 years ago, as part of an experiment, Columbia University was running the Biosphere 2 at the time. They increased the carbon dioxide level inside. There's also a rainforest in the Biosphere 2, so they wanted to see how all of that reacted. One of the reactions was the corals that were in the Biosphere 2 ocean at the time died,

and what we're looking at today in the biosphere two ocean is what scientists believe could possibly happen to the world's oceans. Let's listen to a little bit from Joaquin Ruiz for the past 20-something years of why there were no coral reefs there. When the CO2 concentration inside the biosphere was ramped up to about 400 ppm, this was about 25 years ago when the concentration of CO2 in our atmosphere, was about 360, and it was clearly shown that the 400 ppm, the ocean acidified, the corals just will die. That's pretty scary when you think of our oceans, right? It is, especially as someone who scuba dives. I know what a healthy or a healthy coral reef looks like, but with climate change and overfishing

loss of herbivores, this type of thing is a definite issue, and that's what the scientists are now trying to figure out is how to remediate it so they can expand it out to real oceans because this is big enough. It's a million gallons. It's not just a tank and a laugh. So they want to take some actions to rehabilitate the reef? That is their hope. They began this month as part of Earth Month releasing some new animals into the biosphere ocean. They've done hermit crabs. They've done Emerald Crabbs and this weekend, I believe they are doing sea urchins. All of those are herbivores and the hope is that they will help to get rid of the algae. Eventually, they want to add new corals in and see how the corals do under various conditions because they can control that ocean so carefully with temperature and light and things like that to try and mimic what's going on in the real world now, but also what could be going on in the future and ways that they could fix problems potentially as they come up in the real

ocean. Well, as someone who had a coral reef ravaged by algae, I can sympathize with the problem there. And as a scuba diver like you, I have gone back to sites in the Caribbean that I used to dive in that are all dead now. Exactly. Yeah. Thank you, Christopher. Thank you.

Christopher Conover, a reporter at Arizona Public Media in Tucson. We're going to take a break on when we come back, we're going to take you through the biggest science news of the week, the first ever image of a supermassive black hole. I know you got questions. You know, this raises so many questions about what you're actually seeing. So you'll get a chance to actually interview some of the scientists who worked on the project 844-7248255. Also, you can tweet us at SciFri. Stay with us.

We'll be right back. This is Science Friday. I'm Ira Flato. I want to take you to a special historic news. conference this week. You said in your opening that this was seeing the unseeable, and it's been a good long time to prove this concept out, and I'm just wondering for a moment as a scientist, what you, what your team members, just what it felt like to see that image for the first time. That's a great question. We've made out this for so long, and there's been such a build-up.

There was a great sense of relief to see this, 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 have 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. And it was just astonishment, I think, and wonder.

And I think that 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 us. When that happens, it's an extraordinary feeling. Those were the words of astrophysicist Chef Dolman sharing groundbreaking news at a press conference held this week, describing the moment he saw what the Event Horizon Telescope team had been working towards for over three years, the first ever image of a supermassive black hole.

And on Wednesday, the public was able to join him in that feeling of wonder when the image were shared for the first time. A slightly blurry, lopsided ring of light and circling a dark shadow. I'm sure you have seen it by now. But as they say, there is more than meets the eye here and joining me to try and help us wrap our minds around what we have seen for the very first time

and what it means are my guests. Shep Dolomyn is director of the Event Horizon Telescope Project. Welcome back, Shep. Hi, great to be here. And also joining us this time was another E.H.T. Study scientist, Dr. Fariel Ozel, Professor of Astronomy at the University of Arizona. Welcome to Science Friday, Dr. Ozil. Are you there? Yes, I'm here. Ah, okay. I think our line dropped. I think your line dropped. Okay, we got it back. Let me ask you first, Farrell. First off, congratulations to both of you on this.

Thank you very much. There was so much excitement this week around seeing the first picture of a black hole. Why was it deserving of so much excitement, Ferial? I think part of it is that it's a new frontier. It's something we haven't seen before. It's something that we didn't even think we could see. And it's been so long in the making, both the technological development and the theoretical understanding to interpret the data.

So I'm really happy that everybody is excited to see this image. Shep, you said in the press conference and even here on our program that black holes are essentially unseeable. So how do you explain what we're seeing that? We are seeing one now. Yeah, they're unseeable if they're naked, if there's nothing around them. But black holes attract just everything around them because they're intense gravity. And they're trying to get it in such a small volume that it's like when you rub your hands together, they get hot. All the friction heats that gas to hundreds of billions of degrees.

So black holes are surrounded by these 3D flashlights of this hot luminous plasma. And then their gravity warps the light from that plasma into these distinct shapes. You're really seeing Einstein's geometrical gravity laid bare. You're seeing just how light moves along spacetime. Yet Einstein, even though he came up with the theory about warping space, did he not, well, he wasn't really convinced that black holes might exist? Yeah, he struggled. Go ahead.

Veryl, go ahead. He did struggle with that for a while. The theory, I mean, practically breaks down at the center of a black hole. It predicts a singularity, an infinite space-time curvature and energy density. So he was very unhappy with that, and he thought maybe there's a reason why nature would not form these objects. Let's talk a little bit, Farrell, about the image itself so we can explain to folks, because it's not, quite what it appears to be. There's a lot more stuff going on there. And let's get right into the reddish ring of light. Where is that coming from? That is coming from right from the inner part

of the accretion flow and the base of the jet. So as Shep was saying, as this plasma that the black hole gets from the stars around it, swirls around and makes its way down to the black hole, it heats up, and the emission that we are seeing at this particular wavelength of light is coming from right outside of the point of no return. So there is the event horizon, outside of that is the photon ring, and outside of that is the part that truncates the disk, and where we think jets form. So the source of the light is right in the vicinity of that point of no return, and it is being lensed into the circular shape.

Well, that's the question. I'll continue with that, because if it's a three-dimensional image, shouldn't it be surrounded by that glowing red, so we should not be seeing into it as we look straight? That's a very good question, and it's something that we've worked out 20 years ago. So part of the reason we're seeing it is because it's tourist shaped, so it's not really completely spherical. But even if it were, we have to pick a wavelength of light that satisfies two things. One is we wanted it to be emitted right near the horizon, so it lights it up. We didn't want something that comes from farther away. But it's a double-edged sword, as you're saying. If there's

too much of that light, too much of that gas, then it will interfere with our ability to see down to the horizon. By picking the 1.3 millimeter wavelength of light, we are, we are walking that tight rope. There is light that is lighting up the black hole, but it is not so much that it is actually obscuring our view to the black hole. And Shep, actually, is it not true that light that is heading toward the black hole will be bent around the back of it and come forward towards us? So it still stays black that way.

Yeah, it's never a good idea to try to hide behind a black hole because the light from you will always be bent around. In 1919, when they looked at the deflection of light during a solar eclipse of stars to verify Einstein at first, the deflection was one-two-thousandth of a degree. And now we're looking at light that does loop-to-loops. So it's a completely different ballgame from that perspective. And, you know, Farial said it very well.

You have this flashlight, this light that's close to the event horizon, but not in the event horizon, of course. And what that means is that the light gets lensed around this last photon orbit. All the light grazes this last photon orbit. If it goes a little bit inside there, it's lost forever in the event horizon. And what that means is that we see a ring, which is a projection on this three-dimensional flashlight. But then, for example, if there were another civilization elsewhere in the Milky Way, they would also see a ring. Or in M87, they would see that ring too.

So everybody gets to see a ring because of the lensing. in Einstein's gravity. Why then is some of the ring whiteish, right? So he seems brighter than red. Well, it's a phenomenon that it goes from what Ferial was saying. The gas is moving around

so quickly, it's at near light speeds. So when it descends all the way into this gravitational well, it's really moving quickly. And when material moves that fast when it emits light, the light is boosted in energy in the direction that it's moving. So you're seeing some of

gas coming towards us from underneath the black hole. It seems like it orbits clockwise around what you see there. And so it's bright on one side and dim on the other. So is it like a candle? It's hotter on that side? So it glows brighter? It's more, it's brighter. It's not so much hotter. Fairail? That's right. So the color map that we've chosen is a good representation of how bright it is. So the parts that you're seeing in a lighter color, are actually the brighter parts. And the reason is this swirling plasma. So the half of it, roughly, the half that's approaching us,

is this brighter emission, and the part receding from us is slightly dimmer. Shep, you talked about that there is still light inside the black hole. What happens to that light in there? Well, there's no light coming to us within the event horizon. But as Ferial said, you have gas always falling into the black hole at all levels, and it emits. You're really not seeing anything too much interior to the last orbit, which is that ring that you see. Everything that is in there tends to go through the event horizon, and we don't see it anymore.

It just disappears from our causal existence. But where does it go? Well, that's the $60 million dollar question. Well, it goes into the singularity, you're right. Yeah, if anyone tells you they know, don't believe them. Stephen Hawking spent his life trying to figure that out, didn't he? He did, and many others, yeah. Yeah, I do want to say, I think for many people in our collaboration, it was bittersweet.

We lost Stephen Hawking just a little while before we made this discovery. We had a chance to describe it to him a little bit, which was great, and I wish that he'd been alive to see it. Our number 844-8255, we have so many phone calls, I'm going to get to them, after I ask a couple of more questions that a lot of people have been asking. Can you explain the difference between the event horizon? And you touched on a bit. The event horizon, the black hole, and the black hole's shadow. Sure, I can do that.

So general relativity not only predicts this point of no return, which we call the event horizon, but it also predicts the existence of a few other special distances from a black. hole. The first one is when matter starts plunging in. We call it the innermost stable circular orbits. I know it's a mouthful, but it's basically the last point that matter can be in actual orbits around the black hole. If it's interior to that, it's just going to start plunging in. Next up, closer to the black hole is the photon ring, the point where the light does the loop to loops and makes a really bright image that we're able to see as a as a circle in the sky. sky. And interior to that is the event horizon. And that's where basically the everything is moving

toward the singularity. The space and time have switched signs, and that's where all hell breaks loose. So if we were falling into the black hole, we wouldn't know that we're going through these places. Maybe we would potentially notice the innermost stable circular orbit. But after that, we're just falling in, and we wouldn't necessarily know that we've crossed the horizon. It's for a distant observer like us that these things become important. 844-724-8255. Let me go to our first phone call to Mark in Durham, North Carolina. Hi, Mark.

Hi. Go ahead. So my question is whether a black hole has spin or rotation that compresses all the matter going into it into a flat disk, and if so, what difference would that make to a probe approaching either from the pole or the equator of the black hole? Okay. Oh, wow. Is it spinning?

That's a very good question. Yeah. There are actually two things there that we can break down. One is whether the black hole has spin, and the other is whether the gas swirling around it has spin, so to speak, like angular momentum. The black hole can have spin in the case of the image that we have seen from the black hole in M87. We can't measure it. The images themselves, the circularity and the size of the image is quite insensitive to the spin of the black hole.

We can say that the gas is rotating around it for the reasons that Shep talked about this Doppler boosting. And indeed, so gas does make a disc-like structure. But depending on how hot it is, it could be a flat disk or it could be more like a donut, a tourist-like object. And the particular nearby supermassive black holes we're dealing with are more tourist-like. Amira Flater, this is Science Friday from WNYC Studios. So are we looking down from like the North Pole down on the black hole? Or is there an up? Is there a down to it?

I mean, it looks like a disc, right? It looks like Saturn that we're looking at from heads on. Is that a correct interpretation? Does it have, or is it like a hurricane with an eye in it, with a big sidewall that red stuff is? Well, the interesting thing, springboarding off of what Farial said, we do think this black hole has spin. And one of the reasons we do is that not only do we see this ring of light

at one millimeter, which is where the event horizon telescope took its picture, But at longer wavelengths, we see these tremendous jet structure that comes out of the black hole. And it goes for over 100,000 light years. And the best idea we have is to the genesis of those jets is that there's a spinning black hole and that powers acceleration of charged particles that are in that plasma at near light speeds. And this jet is carrying away a huge amount of energy. So when we look at the energy of that jet, we can estimate what the spin. of this black hole must be.

Now, Ferial is absolutely correct. From what we've done, we can't really tell what the spin is just from the EHT data. But in the future, if we were able to see things move around the black hole, if we did measurements, let's say, every week, every month for a long time, we might be able to make a movie and see things rotate. And that would be able to tell us that the black hole was spinning just from the EHT data alone.

What direction is the jet in our picture going in? it's kind of coming out of that donut towards us and a little bit up to the right. If a jet is coming out, does that mean it's pushing the black hole someplace, action and reaction? No, so there are two jets coming out, actually. So there is one that's coming towards us, and there is one that we think is of equal power that is going in the opposite direction. So that doesn't really impact the black hole. but it impacts how we see the image forming. Quick question before the break.

A tweet coming in. We can't see in radio waves, so how can we see this image? Well, I think that's something that we deal with in all wavelengths of light. We make images in x-rays. We make images in the ultraviolet and infrared. So we get the spatial information and whether there are any changes in brightness. and we map it onto something we can see. So the color scale that we pick and the brightness scale that we pick

simply represents the true content of that electromagnetic radiation in another wavelength. Quick before the break, Shep, what surprised you most about this photo? Wow. I mean, I think everyone had their own private reaction to it. The whole team has been working for many years on it. For me, it was how pure it was. As I said in the remarks during the press conference, it could have been anything. We do a lot of measurements and we look at a lot of things that are uncertain.

To have something so clear, to have something so perfect like this, that that was a surprising thing for me. And it was wonderful. Okay, we're going to take a break and come back. Talk more with Shepdolliman and also Frajala Azel. Our number is 844724-8255. You can also tweet us at SciFRI. We'll be right back with your questions after the break. Stay with us.

This is Science Friday. I'm Ira Flato. We're talking this hour about the big science news of the week, the first ever image captured of a supermassive black hole. Joining me this hour are two members of the Event Horizon Telescope team. Shep Doloman, Harvard Research Fellow at the Harvard Smith-Sythony and Center for Astrophysics in Cambridge, and Friel Azale, Azzell, Professor of Astrophysics

in the Department of Astronomy at the University of Arizona. And astronomers and astrophysicists are celebrating this first-ever black hole image and yet more proof of Einstein's theory of general relativity. But even as the image confirms our ideas about gravity, it also raises new questions about galaxy formation and quantum physics that scientists want answers. two. So now that we can see this super

massive black hole, what more can we discover about it? Help us answer some of those what's next questions. I'd like to bring in my next guess. Giulia Lavacheck, Larando, is the sits professor of physics at Canada Research Chair at the University of

Montreal. Welcome to Science Friday. Thank you. It's great to be here. Now, I know that you were not part of the event horizon team, so you got to see the image along with the rest of us for the first time this week. Was it what you were expecting to see? It was incredible.

I have to say I was surprised at how clear the image was. It's just amazing to be able to see for the first time a black hole. And for me, this is so important because I've been studying these objects for the past 10 years. And my goal has been really to understand what supermassive black holes do on the scale of galaxies. what is their role in like a cosmological context, but I've never actually seen a black hole, although I've studied their impact for the last 10 years. So it was really tremendous for me,

and I'm going to remember this time for the rest of my career. I think we're all going to remember it, and I want to talk about something very interesting that you just brought up, and that is the fact that there are black holes in so many centers of galaxies. Do we know why that is? That is a very good question,

and I would say that we're still trying to understand how black holes form in the first place, especially supermassive black holes, how they grow with time, do they grow with their galaxies or not? It's still a very open question, and I'm sure that we're going to get some answers in the next couple of years. But the important part is you have to remember that we're pretty sure that every single galaxy now, at least the massive galaxies, has one of these supermassive black holes at its center. But the key point is that although very massive, the supermassive black hole is very compact. In fact, it's about a billion times smaller than the actual size of the galaxy. And what we're realizing is that although it's so small, it's such a powerful, incredible object

that it can have an impact on the scale of the galaxy, and it does end up reshaping completely the properties of the galaxy. Might it explain? I mean, we talk about dark energy. might there be, but we haven't found what it is yet, and dark matter. And we've talked about how dark matter helps shape, but keeps the shape in the form of a galaxy together. Could there be something going on between the black hole in the center and the dark matter that we don't know yet?

So there has been research, so scientists at least several years ago, try to determine is the dark matter that, present in galaxies that we don't see, could it be at least partially caused by black holes that are hidden in the galaxy and that are not actively feeding and therefore they're black and we can't see them? And so they do have some contribution, but it appears to be very minor. And so dark matter still seems to be a very mysterious substance that we don't know actually what it is. Shep, you also took data on the black hole at the center of our Galaxy, Sagittarius A-Star.

When are we going to see that picture? Well, you know, we're pretty tight-lipped. I think your other guests can attest to that. I talked to a lot of people, and they said we had no idea what you were going to show, and getting 200 people not to spill the beans was really quite a feat in and of itself. But I can say that we did take data on Sagittarius A-Star. That's the 4 million solar mass black hole in the center of our galaxy, the Milky Way. And by contrast, it's a very timid eater.

So it's eating about, you know, 10,000 or 100,000 times less than the black hole in the center of M87. So we wouldn't see it if it was at the distance of M87. That said, we are very excited to work on those data. Because for that source, we know the distance precisely from infrared work that shows stars orbiting the black hole. and we also know the distance as well as the mass. So we could do some better testing of Einstein if we were to see a ring around that source. If I may add to that a little bit,

Shep talked about how it's a more timid eater and its mass is a lot smaller. The timescale with which things happen around the black hole depends on its mass. The smaller, the mass, the more things happen. The more things change rapidly. So just based on its mass, we knew that it was going to be more of a problem child.

It's just more turbulent, and we need special imaging techniques to deal with that variability. So having said that, of course, we've been working on it, and we will look forward to sharing the results whenever we have them. Do we expect, do these black holes start out small, gobble up, you know, all kinds of stuff around it, and then grow either more dense or larger in size? Yeah, so this connects back to your conversation. with Julie just a few minutes ago, we now know of black holes in the centers

of all nearby galaxies and most galaxies that we can see. And we think based on their mass that these black holes must have started forming very honor in the age of the universe. So we're really looking at a coming-of-age story together between the galaxies themselves and the black holes at their centers. We think they started small.

But what is small? Is it 100 times the mass of our sun? Is it 10,000 times the mass of our sun? There are different scenarios in which we consider forming these baby supermassive black holes that we call seeds. And we don't have any direct evidence as far as which one of these is happening and how rapidly these black holes grow in the early universe. But one thing is for sure, even when they're small, they're having an impact on their host galaxies. and they're really, throughout the cosmic time, they're growing together. Let's go.

If I could maybe add something? Yes, Julie. So what's also intriguing about this is we now have evidence that very, very massive black holes. We're talking about almost the size of the black hole at the center of M87, so billions of times the massive of a sun. We have evidence that these black holes have existed for a very long time and that they seem to exist even only after a couple hundred, million years after the Big Bang. So they seem to form very quickly. And the question is, how? How can they do this? And we're still trying to answer that question. Absolutely, yeah. Something this image doesn't show that one, that we sort of touched on, Julie. I want to get more

into that. Are the Black Hole's jets? Can you explain a bit more why they're there, what they're doing? So that's a great question. I would say that we still don't fully understand how these structures form. but what we do know is that black holes can form them. They seem to be able to produce these very powerful jets of high-energy particles, and what's incredible about them is that they're propagating to just incredible distances. So just to remind you, black holes are very compact. They're about a billion times smaller than the size of their galaxy, yet the jets that they produce can extend to the size of the galaxy.

So it's gigantic. And what we're learning, especially in the last couple of years, is that these jets just inject a tremendous amount of energy into their surroundings. They heat up gas. They prevent the gas from forming further stars. They drag out lots of metals with them. So they do play a fundamental role in galaxy evolution. Shep, let me talk about the actual process of collecting the data that created this image. What was involved?

I know there were eight telescopes, eight radio telescopes involved, and what kind of algorithm, computer power, put this all together? That's a great question. We use this technique that's kind of a bit of magic when you think about it, called very long baseline interferometry. And a way to think about it is to take an optical mirror. We all know or have a feeling for the fact that it will reflect all the light to a focus what arrives at the same time where it can be combined,

and that's where you can put your camera. So imagine now taking that mirror and smashing it with a hammer and taking those little shards, those reflective shards all over the globe. You'd have a telescope kind of as big as the Earth, but you'd have to find a way to get all that light back to a focus. We do this in radio waves by recording the data at radio dishes spread out geographically across the Earth, and we record them with atomic clock so they can be played back with precision later.

and in the same way that the optical mirror shines light back up to a focus, a supercomputer aligns in time all of those recordings perfectly so they can be combined. And when you do that, then you have data as though you had a dish the size of the distance between these other radio dishes, which can be on different continents. And that gives you the angular resolution that you need. And so you need a supercomputer to combine all that data, and then you have to, of course, calibrate it and image it. and that's what has taken us the better part of two years to get right.

That's interesting. Let's go to the phones to David in Chicago. Hi, David. Hi, how are you? Go ahead. Okay. So I'm not a scientist. I've always struggled with conceptualizing this idea of gravity.

Is gravity a particle that emits from something, or is it like a depression in multidimensional space time? Hmm. Who wants to tackle that? I can try that. Yeah, sure. Right now our description of gravity is literally a distortion of space time. So we call that a geometric description. We don't have a quantum description of gravity, although many people are actively working on that.

So if it is an interaction between particles and if we can ever write it as such as a field theory, we are not quite there yet. Einstein's description literally makes use of the geometry of space away from masses that is flat, and in the presence of mass or energy density, it gets bent. And all other objects just follow what they think are straight lines on that bent space time. So it's like an ant walking on a watermelon. It doesn't know that it's curved. It's just walking along.

So that's how we describe it right now. I'm Ira Flato. This is Science Friday from WNIC Studios. Talking about the great news this week about the discovery, you're actually seeing the first photos of this massive black hole. I imagine, Shep, there are going to be more black holes we're going to be seeing soon, hopefully. I mean, soon it could be a year or two or whatever. Is it going to become as commonplace as when Ligo gave us the first gravity wave burp? and then say, oh, well, we got another one now, you know.

Yeah, hopefully it won't become commonplace. Hopefully that seeing black holes will still be kind of a singular event. Well, the next one, as Farial described, is going to be Sagittarius A-Star, and that's a very different kind of black hole. So the nice thing about this is it will be a completely different flavor. It's a thousand times less massive. And as Ferial pointed out, the cool thing about it is that you can watch it evolve over the course of an evening. So one of the important things about this technique of very long baseline interferometry

is that you wait for the Earth to rotate and it sweeps your telescopes around, essentially increasing the coverage of that Earth-sized virtual mirror. For Sagittarius A Star, the challenge here is that the source can change while you're observing it. So we have to think about dynamically imaging it, making a movie. So that's challenging, but it's also hugely exciting. That's the one at the center of our Milky Way. Yeah, that's the 4 million solar mass black hole at the center of our galaxy. So it may be challenging, but the next very exciting thing may be a movie.

Are you saying that the black hole changes so quickly that one rotation of a day in Earth time will see a change when it comes around again? Yeah, basically when you're dealing with a black hole, you've got to just check your assumptions at the door. So this is a black hole that is kind of the size of maybe a third the orbit of Mercury, the one in the center of our galaxy. and light matter would orbit around it at the innermost stable circular orbit that Ferial described in about half an hour. It's extraordinary because things are moving it near the speed of light. Ferial, is that exciting to you? That is really exciting to me.

So on the one hand, it makes it more challenging to just do the imaging and to fit our models to it. On the other hand, we can actually see gas swirling in action. We have that potential, and that opens up different types of tests that we can do with it. So I think we're going to work actively on this dynamical imaging that Shep was describing, and once we get it to work to our satisfaction, then we will be able to not only answer gravity questions, which are, you know, the most important thing for us, but almost equally important is how does a gas behave around a black hole? It's a plasma that we just don't know of from our experience on Earth. So we really would like to understand if our models of it are correct.

Let me go to the phones to Jacob in Dayton Beach, Florida. Hi, Jacob. I go ahead. Hey. So what would happen when two black holes got near each other and like what happened? Julie? Very good question. So it would depend on the kind of black hole that you're looking at.

So as we've seen in the last couple of years with the detection of gravitational waves, if small black holes merge, then they produce a tremendous amount of gravitational waves, and we've been able to detectos. So we've actually been able to detect the merger of two small black holes. When we're talking about supermassive black holes, it's a bit different. The time scales are different. It takes much longer for the supermassive black holes because they're much bigger to actually merge. And we haven't been able to detect gravitational waves from that merger yet,

but that may be something that's coming up with future gravitational wave detectors. But for now, we will see. And we have so many people who have asked questions when we have run out of time. I want to point everybody to our website. at Science Friday.com, where we have all kinds of videos and stuff and explanations up there, because it is hair-hirting in a good way to talk about this. I want to thank all my guests, Farial Azel, Azo Professor of Astrophysics in the Department of Astronomy at the University of Arizona,

Shep Doloman, Harvard Research Fellow at the Harvard-Smithsonian Center for Astrophysics in Cambridge, and Julie Lavichek-Larindot, Assistant Professor of Physics and Canada Research Chair at the University of Montreal. So congratulations to all of you involved in this research. And we'll be back with the next one, okay? We'll all meet back here. You're welcome. One last thing before we go, we're headed to Boulder, Colorado.

We'll be putting on an evening of science conversations, live music, demos, and more at the Chautauqua Auditorium, right up there at the foot of the flat irons. Saturday night, June 15th. You won't want to miss it. More info and tickets at ScienceFriety.com slash Boulder. that is Saturday night, June 15th. It's not a Friday. It's a Saturday night. It's going to be a lot of fun.

You don't want to miss it. ScienceFriday.com slash Boulder. I'm Ira Flato in New York.