Technology Day 2023: Research from Above and Beyond: MIT in Space Faculty Presentations (continued)
Please welcome to the stage MIT Alumni Association President Steve Baker. Good morning, everyone. Welcome back to our Tech Day program.
Thank you all. I'm Steve Baker, and I'm honored to be entering my final month as MIT Alumni Association president. What a way to cap a great year.
Tech Day is one of the institute's most enduring traditions and a celebration of the desire of our MIT community to never stop learning and never stop problem solving. We all share that as alumni. Another tenant of our community, as you know, is the application of our knowledge in service to society. During the past few years, the MIT Alumni Association has introduced several outstanding new initiatives. And the creation of the MIT Alumni Better Service Award is among the most significant. Now in its second year, this award honors alumni who have proven an ability, passion, and unwavering commitment to the MIT ideal of working wisely, creatively, and effectively for the betterment of humankind.
The Service Award was created in compliment with the MIT Alumni Association's long standing leadership awards. While those recognized service to the MIT community, this new honor celebrates the service that our alumni provide to their communities around the world. And when the Alumni Association puts out the call for nominations for the Service Award, we are amazed to receive so many worthy submissions for consideration. This year, the Awards Committee for the Alumni Association Board of Directors decided to honor not one, not two, but three better [INAUDIBLE] award recipients. And I'm proud to share with you why all three have been risen to the top of the nominations.
Please join me in congratulating Vanessa Feliberti Bautista from the class of 1991, Oluwasegun Ige, who holds an SM and PhD from MIT, and Donald Rea, who also holds a PhD. Donald is watching-- I'm sorry. [APPLAUSE] Donald is watching with us online. Vanessa and Segun, would you please join me on stage? [APPLAUSE] Congratulations. Congratulations. Stand over here while I read your citation.
Vanessa is an outstanding leader who has committed herself to the cause of enabling equal access for technological jobs for underrepresented populations. Her work in creating, leading, and supporting programs for education, job training, and career development has enabled hundreds of racial and ethnic minorities and economically disadvantaged individuals to find life changing opportunities to achieve their career and life goals. She has inspired countless young technologists to find their place and their worth in their work. As a lead for the women's community within the workplace, Vanessa has organized early in career activities, mentorship rings, and even argued with architects to include nursing facilities that new mothers need when they return to work. Vanessa has focused her service-related efforts on equity and inclusion, creating opportunities and working tirelessly to promote diversity, equity, and inclusion. Please join me in congratulating Vanessa.
[APPLAUSE] Congratulations. Let's step forward and get a photo. Congratulations.
Well done. Well deserved. We also have an award for you [INAUDIBLE]..
And now Segun. Segun has performed sustained innovative and impactful community service in Africa for more than 14 years. His desire to expand African educational opportunities led him to found the Anike Foundation in 2007 with one clear purpose, making education accessible to improve the livelihoods of individuals in Africa. Anike is a small nonprofit that uses its limited resources through its partnership. It now has a network over of over 200 partners in 20 countries across the continent, touching thousands of lives through its funding of essential programs. The foundation is 100% volunteer based.
And he has grown his diverse team of volunteers to over 70 individuals in 12 countries around the world. Segun's effort to bridge the education gap in Africa-- the education gap between Africa and the developed world is exemplary. Please join me in congratulating Segun. [APPLAUSE] Congratulations. Well deserved.
Finally, watching on the live stream, Donald Rea. Donald's vision was to pair retired or semi-retired STEM professionals with K-12 educators to enable those educators to have a rich resource for their classroom studies across STEM topics. To that end, he founded the American Association for Advancement of Science STEM volunteers program in concert with the AAAS leadership in 2004. Serving just one single school district in that first year, the program has grown to encompass five school districts in the greater DC metro area and includes more than 180 volunteers serving more than 6,000 students.
Through the foundation, Donald has made a deep impact on the community with his excellent training and delegation skills and his dedicated spirit. Please join me in congratulating him. I'm going to wave at him at home. And let's give him around of applause too.
[APPLAUSE] Vanessa, Segun, and Donald, on behalf of the MIT Alumni community in the audience today and those watching around the world, we feel a profound sense of pride knowing that you are part of the MIT Alumni community. And we thank you for your service in helping to create a better world. [APPLAUSE] And now back to our Tech Day program. Please welcome to the stage MIT Professor Taylor Perron.
[APPLAUSE] Good morning, everyone. I want to start with no pictures and a question for you. Do you ever wonder what your life would be like if a few key details were different? What if you'd chosen a different career? What if you were born a generation earlier? What if you'd never come to MIT? Now, would have turned out fine, but we wouldn't be here together today. We'll never the answers to any of these questions. We only get one reality. And that is what I think is so cool about Earth and planets.
They actually give you glimpses of alternate realities. Let me give you a few examples to illustrate what I mean. I'm an Earth scientist. But sometimes I wonder, what would Earth be like, what would the landscapes be like if there was no life on land? Sounds kind of dystopian science fiction, right? But as some of you may know, that was actually the case for the first 90% of Earth's history. And now geologists can use ancient rocks to try to reconstruct what landscapes were like before there were plants or animals on the continents.
Some of my MIT colleagues discover planets that are orbiting other stars. Every single one of those planetary systems is an alternate reality. And some of them are wildly different from our own. And how about this one? What would the landscapes on Earth be like if gravity was seven times weaker and if you replaced all the water in the hydrologic cycle with liquid natural gas? Now, the MIT lab safety people are watching this and thinking, what is he going to try to do? But they don't have to worry. I'm not going to do that experiment because the solar system has already done it for us. This is Saturn's moon Titan, my alternate reality of choice.
It looks like a big orange ball because it's the only moon in the solar system that has a thick atmosphere. And that atmosphere contains organic compounds like methane that block light. You know how it's hard to see the horizon in a city with smog? Well, Titan has smog that would make 1970s Los Angeles proud. And so for a long time, we had no idea what the surface looked like.
We knew that it was cold, minus 290 degrees Fahrenheit. We knew that it's made of ice instead of rock. But beyond that, there were few details.
So at this point, you're thinking, wait a minute. This title was Earth's Twin. That doesn't sound like Earth's twin. Let me show you what we saw when we finally got a glimpse of Titan's surface. The reason we finally got a glimpse of Titan's surface was the Cassini-Huygens spacecraft mission, which went into orbit around Saturn in 2004. And as it was flying past Titan in early 2005, it dropped the Huygens probe, which is the little gold dome you see on the left hand side of the spacecraft down through Titan's atmosphere.
Here's an animation that was pieced together from pictures that were taken by the Huygens probe as it was parachuting down to Titan's surface. And you can see that the first thing we saw when we finally got a close-up look at Titan's surface was networks of river valleys carved into hills made of ice. It turns out Titan has weather a lot like Earth's. But the clouds, the raindrops, the liquid flowing through the rivers is methane, liquid natural gas, instead of water. Titan has mountains, but the mountains are made of ice and organic compounds instead of rock.
Titan also has lakes. And its biggest lakes are as big as Earth's biggest lakes. But they're filled with liquid methane and ethane instead of water. So this is what I mean with my title. In terms of weather and in terms of landscapes, Titan is Earth's twin.
And this is more exciting and more useful than any experiment that I could do in a lab. So what have we learned by studying this experiment that the solar system has given us? One of the most obvious lessons, which is especially interesting for us here on Earth, is that clearly, there's more than one way to make a stable climate. There's more than one way to make hydrologic cycle even if there's no hydro in it. In my group, we've been piecing together the details of the climate and environment of Titan's surface to try to understand what that stable climate is like.
We study the mechanics of landscapes. We study rivers, coasts, mountains. We use a variety of techniques, including laboratory experiments. We go out in the field to some pretty ugly places, and we use numerical simulations. And one of our specialties is in taking the knowledge that we gain about landscapes here on Earth and translating them to planetary environments and accounting for the differences in gravity, atmosphere, materials, so we can learn something about the environments of other worlds.
One of the challenges in our Titan research is that we can't always see these landscapes up close. And so sometimes, we have to get creative and invent techniques that we would never bother to use on Earth where we can actually go and stand on the landscape and do fieldwork. As an example, we've developed a technique that allows us to measure the rate of flow through rivers on Titan or other worlds just with measurements of the width of the channel and how steep the river is.
And both of those are things that we can actually observe remotely. Now, we have to test these ideas on Earth to make sure we get the right answer in a place where we know what that answer is before we apply them to other worlds. And once we do that, we've learned that Titan's largest rivers might have flow rates as large as the Mississippi River on Earth, even though Titan is a smaller world. And it is also useful because it allows us to estimate the rate of rainfall that's feeding those rivers. And so we've estimated that rainfall rates on Titan may be comparable to what you get during storms in dry regions on Earth. We've also studied coasts.
And one of the frustrating things about Titan's coasts is that we can't see them up close. We can't even tell if there are waves on the surface of the lakes or if its mirror smooth like the Charles Basin on a really calm day. So we've developed a technique that lets us take the shape of a coastline and reconstruct whether there's been wave erosion taking place and even whether there's a dominant wind direction. And we see evidence that some of Titan's coasts are consistent with the presence of waves.
One thing I want to point out too is that studying planetary landscapes also has some benefits for us back here on Earth. If you're in the business of building theories to try to predict what's going to happen to landforms on other planets and you have to be able to apply those theories, regardless of differences in gravity, atmospheres, or materials, you have to make them really robust and flexible. And if you can do that, it makes it more likely that those theories and models will hold up under the full range of conditions that we see here on Earth, even if those conditions involve natural hazards, even if those conditions involve engineered landscapes.
So studying planetary landscapes helps us build better theories for Earth. Some of the results we've obtained for Titan are still predictions, and they'll have to wait for future spacecraft missions to be able to test them. So if any of this has piqued your interest, stay tuned because the Dragonfly mission to Titan, which by the way, is led by an MIT alum, is scheduled to land on Titan surface in 2034 and continue to explore there. And given how much we learned when the Huygens probe touched down on the surface of Titan almost 20 years ago, Dragonfly is guaranteed to surprise us. So stay tuned, thank you, and I'll see you in 2034. [APPLAUSE] Please welcome to the stage MIT assistant Professor Erin Kara.
[APPLAUSE] Good morning. All right. I'd like you to take a listen with me. [BLACK HOLE SOUND] The sound that you just heard is what a black hole sounds like. And I'll tell you the first time that I heard that sound, I got shivers down my spine.
And it's not because it's kind of spooky sounding, which it is. But it's because I could hear the general relativity in that sound. So what I want to tell you about today is how we use these echoes to understand black holes and how they grow. And I hope by the end of this talk, you too will be able to hear the general relativity. OK, so let's start with this beautiful image taken with the James Webb Space Telescope, our newest biggest toy in astronomy. And when this image first came out, a lot of people were looking at that beautiful spiral galaxy that you see in the foreground.
But what I was looking at and what a lot of astronomers are looking at are not the foreground galaxies, but the background galaxies. Look at all of those galaxies, those smudges there in the background. All of those are galaxies. Some of them are in the nearby universe.
That means something like 100 million light years away. And some of them are from the very beginnings of the universe when the universe was a few hundred million years old. And what really gets me is that at the center of each one of those galaxies is a supermassive black hole at the center that's a million or a billion times the mass of the sun. And one of the things that we astronomers want to understand is how did they get so big in the first place? How do you form a black hole and have it grow so big to become a million or a billion times the mass of the sun? One of the ways that they do grow that we know of is that material falls into them. Gas, dust, stars are falling into black holes.
And they grow from that accretion of matter. And we know that they're growing because we have observations like this. Is 3C273, a galaxy and a black hole in that galaxy that's a million times further away from that star that you see in the bottom right hand panel. But what's amazing is that this Black hole is even brighter than the star that's a million times closer. And so maybe you remember from 802, electricity and magnetism that the luminosity goes as the distance squared. And so what that means is that 3C273 is actually a trillion times more luminous than that foreground star.
And the only thing in the universe that can create that amazing amount of luminosity is the accretion of gas onto a black hole. Gas funnels towards the black hole, it loses its gravitational potential energy, and that energy is released in the form of radiation, so much radiation, that it totally outshines all of the stars in the galaxy. And what we want to understand is how does this process work in detail? How do you go from matter falling in to this incredible amount of radiation coming out? And to answer that question, we really need to zoom in to the innermost regions around black holes to the event horizon scales where most of the energy is being released.
And so what's awesome is now when I say we need to zoom in to event horizon scales around black holes, you all have an image of what that looks like. This image taken by the Event Horizon Telescope is an amazing feat of engineering. And what we've done here, what this Event Horizon Telescope collaboration has done, is to directly image the very close environments, the event horizon scales around this black hole M87, that's about a billion times the mass of the sun. So what's key, though, is that the Event Horizon Telescope can only work on black holes that are not actively growing, on black holes where the amount of matter that's falling into it is not very much.
It only works because the density of that gas is low. But how about those black holes like 3C273 that were so bright, that we're actively growing? What do they look like? Well, that's what they look like. Any telescope out there, no current telescope, no future telescope is going to be able to directly image the event horizon scales around a black hole. And so that's why we need to get a little bit more creative and use echoes of light to reconstruct what we think it looks like around a black hole. And so that's what my research is about and what I want to tell you about today.
So when my friends and family ask me, Erin, what is it that you actually do all day? And I try to explain these light echoes. I find myself often using the analogy of sound. Sound echoes or something that we all can appreciate. Here's a little demonstration.
I will clap my hands. You hear the sound of my clapping directly, that flash of sound. But you also hear the echoes off of the walls, right? And if you could map out all of those echoes in time, you take that time delay, those echoes.
You multiply it by the speed of sound. And then you can perfectly map out this room that we're in without directly imaging it with your eyes. So this is what we're trying to do with black holes and what we do do with these accreting growing black holes.
So the schematic that you're seeing here-- we'll go back and play it again-- is a schematic that the NASA Press Office put together for me. So what you see here is a Black hole on the bottom right hand corner. And gas, this orange bit on the bottom is gas that's funneling into the black hole. And you're seeing a cross-section of that gas that's funneling in.
And what we see in these systems are that they are very abundant in X-ray emission. X-rays are coming from this hot plasma around the black hole that we call the X-ray corona because it's around the black hole. And the blue there is that shining source of X-ray light. In the sound analogy, it's that clap. We see a flash of light from the X-ray corona. But we also see that corona shines back down onto that in flowing gas, that accretion disk.
And that disk then echoes the light. And since we can measure those echoes, that light that is being reprocessed off of that accretion disk, and because we know that light travels at the speed of light, then we can use that to reconstruct what that looks like around that black hole, how gas funnels into the black hole. So it's not totally as simple as what I've described to you just now. It's not quite so simple. One of the things that we have to account for is the fact that we are around a black hole, that the spacetime around that black hole is very curved.
And so the light that is echoing off of this accretion disk, this in flowing gas, is distorted from the strong gravitational effects around the black hole. So for instance, if we had a ray of light, this blue wavelength here traveling through space, we would see it as a blue light ray. But since that light is coming from around a black hole and is traveling through the very curved spacetime of black hole, as that light escapes from the strong potential well of the black hole, its wavelength gets stretched. This is what we call the gravitational redshift because the wavelength of the light gets stretched to redder wavelengths as it climbs out of the potential well of the black hole. And that's one of the things that we have to account for when we want to reconstruct these echoes into an image of the black hole. So that takes me to getting back to the sound that you just heard.
During the pandemic, we were all alone. And I was in my apartment. I was like, I need to communicate.
I need to reach out with some people. And I thought this project is kind of a fun side project that I always wanted to do. Let's take our light echoe simulations, our general relativistic light ray tracing simulations and convert them into sound and see what that sounds like.
And what you can see here on the top-- whoops. Not yet. On the top here is that echo of sound that I told you about originally. On the bottom is a simulation of the light echoes from around the black hole.
And it's actually amazing that they even look anything like each other. We have this primary flash of radiation from the corona. And then it echoes out and reprocesses off of the accretion disk over time.
So what we did with colleagues at MIT in the music and anthropology department-- that's one of the things I love about MIT is that even the musicians and the anthropologists are tech nerds, and they love black holes. We converted these light echoes into sound. So we took the pitch of the frequency of the photon, the wavelength of the photon. And we translated that into the pitch of the sound that you're going to hear. So let's play that sound again.
This is an image of the black hole. The circle there is the event horizon. And you're going to hear now the reprocessing, the echo, off of that irradiated accretion disk. And I want you to listen for the whoo. That's the gravitational redshift. That's those photons that are escaping close to the potential well of the black hole that are being stretched to longer wavelengths.
[BLACK HOLE SOUND] Did you hear the general relativity? You got it? OK, that's all I have for you today. I just want to thank my research group and MIT School of Science. Thank you.
[APPLAUSE] Please welcome to the stage MIT vise president for research Maria Zuber. [APPLAUSE] OK, thanks, everybody. We're back.
And we're going to start right away with the second panel. So I'm going to call Taylor and Aaron to come out and start the questioning. So get your questions in. If you're streaming in, there's a Slido box beneath the stream.
And if you're here in the audience, you can scan the QR code and give us the same kind of interesting questions that you gave us in the last session. OK, so I have to start with Erin. [INAUDIBLE] On my cell phone, my ringtone for text messages is the 2015 Ligo black hole collision. And I'm going to try to play it for you, OK? [SMALL DRIP NOISE] Don't we live in an amazing world where-- now, don't start texting me, OK? Or else, we're going to be in trouble here. So I would always say in terms of why we explore space, you go out, you look at things you've never seen before, and then you go back.
And you look with a different set of eyes. And now you can look with a different set of ears. And we're really getting into the age of not only the optical and far reaching wavelengths and very short wavelengths, but also acoustics. And so could you reflect upon that in terms of not just your own X-ray area, but the broader area of black holes and just what looking with all these different kind of sensors has meant for progress here? Yeah, that's a great question. I think it is an amazing time to be a black hole astrophysicist right now.
Not only are we seeing electromagnetic light, but we're also seeing the bending of space time from black holes that are merging together. And as we go out and we find more of these bending of space time and we have just telescopes that are not just pointing at one single black hole that we know about, but just looking for just exotic objects that are just going flash in the sky, we are constantly learning and being surprised. And it's just the universe is blowing our mind every day. And I think it's kind of an exciting time because we have all of these telescopes that are coming online at the same time that are just finding things that we never thought possible that the universe can do.
And the biggest thing going forward, I think, is what we call multi-messenger astronomy is not just measuring the light, but simultaneously measuring your cell phone during the gravitational waves, the rippling of space time. Ligo, which was largely built here at MIT-- and Ray Weiss received the Nobel Prize for his developments building this gravitational wave network. They are just starting up operations again, and we're all just waiting for the next big thing. It's exciting. Great Thank you.
So Taylor, I didn't want you to feel acoustically disadvantaged here. And so we had the audio team put together sound from this solar system. And we're going to play that now. But everybody, be quiet because it's low frequency. [WIND] Any idea what that is? A quiz.
[LAUGHTER] Was it derived from Huygens? No. I don't know. Wrong planet. That is an actual audio of the Ingenuity helicopter flying on Mars. It turns out, on the Perseverance Rover, there are two microphones. And we heard the first two actual measured sounds, not converted sounds, of something [INAUDIBLE] one spacecraft listening to another spacecraft on another planet.
Thank you for including me. But I have another question too. So the Titan analogy is really interesting.
And actually, Titan is the only other planetary body in our solar system that has a nitrogen atmosphere like Earth. Far more common atmospheres are carbon dioxide. And of course, we're worried a lot about the accumulation of carbon dioxide in the atmosphere of our planet. And in your talk, you just really nicely laid out the idea of nature doing another experiment for us in some other part of the solar system.
So two other planets that have carbon dioxide atmospheres are one, Mars, which lost most of its atmosphere, and then Venus, which has had a runaway greenhouse. So maybe reflect upon if there's anything to be learned about what's happening on our own Earth with the accumulation of CO2 from these two other natural experiments that we have bookending the Earth in our journey around the sun. Yeah, that's a great question. And that is probably one of the first big atmospheric natural experiments in the solar system that we became acutely aware of is that the trajectories of Mars and Venus, even though there are a lot of similarities to Earth, have been so different and have turned out so differently now, obviously, Mars now, very cold, Venus, rather, uncomfortably hot and high pressure. And so one of the things I mentioned when I was speaking to you earlier is that it's interesting that we see that Titan, at least, right now, has a stable climate.
And Venus and Mars, in terms of their CO2 greenhouse, have taught us that that's not a given. Things can kind of go in different direction. So this is a major goal of those of us who pay attention to terrestrial planets, rocky planets to try to understand their climates.
And one of the things that we've been trying to do, at least, on Mars and the Mars community in general, is to understand what the early climate was using some clues on the surface to maybe tell us what was happening through time in terms of that atmospheric evolution. How long did the CO2 greenhouse effect on Mars stick around and maybe keep the surface, if not, as warm as on Earth, maybe warmer than it is now? And then on Venus, what happened to put all of that CO2 in the atmosphere with no way of being recycled kind of it is on Earth? And so the geologists get in on this too because we try to understand what regulates the concentration of CO2 in our atmosphere. Plate tectonics probably plays a big role in that.
And so we'd like to understand what about Mars and Venus prevented a regulatory system like that. Great. Thank you. All right.
We're going to now move to our questions from our alumni friends. Erin, let's start with you. There's question asking you to describe the three-dimensional shape of the accretion disk. Does it look like a bagel? Is it stable? Is it unstable? Clue us in here.
Yeah. So you'll remember now from 801, conservation of angular momentum. Sometimes I get asked, why isn't everything just sucked into the black hole? And it's because of conservation of angular momentum. Imagine you have a black hole here and you're trying to throw a particle of gas into that black hole.
You'd have to have impossibly precise aim to hit it directly. And more likely, what's going to happen is that particle of gas is going to get whipped around the black hole. And it's not just one particle of gas.
It's many particles of gas that are interacting with each other and the black hole. And because of conservation of angular momentum, they start forming into a disk around the black-- orbiting around the black hole in a disk. It's kind of a donut or a flat disk. But what we see is actually something a lot more complex.
And that's because of the bending of light in the strong potential well of the black hole. So what's crazy about relativity is that light takes straight paths, but that space is curved. And so this accretion disk, this flat accretion disk that to you, if you're looking at it edge on, you maybe you wouldn't see the backside of that disk. But because some of those photons from the accretion disk, they get bent over the black hole, and we see them into our line of sight.
And so part of that image from the Event Horizon Telescope that you saw is light from the backside of the black hole that's being bent into our line of sight. And so it looks that flat disk then starts to appear kind of more bulbous shaped because of those relativistic effects. Great. Thank you. Taylor, there's a question here about how does Titan retain its atmosphere? Is there-- solar wind stripping did a number on Mars? What's going on out in the Saturnine system? Yeah.
So Titan's atmosphere, in fact, is more massive than Earth's, the only moon out of hundreds that seems to have managed to do that. And there are a bunch of mysteries about it, one of which is, well, why does it have all this methane? It breaks down in the atmosphere due to the sunlight, so there probably is a source replenishing it. But one possible answer to that question is that Titan spends enough time in the close embrace of Saturn and Saturn's magnetosphere that it might shield it from the stripping of its atmosphere. So between that and a source of gases, that apparently has helped it hang on to its atmosphere. OK.
Erin, back to you. What do you assume about the mass distribution inside the black hole and why? So we have no information from within the event horizon of the black hole. And so we assume that it's just once the matter goes into the black hole, it's just a point mass that grows larger and larger. Sometimes I think that that's a little bit disappointing to people from the perspective of an observational astrophysicist is what's the mass distribution? As far as I see is that matter just flows through that accretion disk.
Eventually, it'll go past the event horizon. And it just grows the black hole. And it has no distribution in space because it ends up in the singularity. And so what we can measure, even though we have no information from outside of the event horizon, we can see things. We can infer properties of the black hole, its mass, how fast it's rotating because all of that has an effect on the spacetime geometry around the event horizon.
So the larger or more massive your black hole, the larger your event horizon is going to be. And so if you can measure-- and the size of your accretion disk will also scale with the mass of the black hole. Stars orbiting around the inner regions around the black hole will travel at a particular velocity because of that particular mass of the black hole. And then we can infer also things like the spin of the black hole, which is one of the topics that I'm really excited about.
That's a little bit harder to measure than the mass of the black hole. But again, it changes the spacetime geometry that we can even observe outside of the event horizon. So we can infer those properties of the black hole itself even from outside of the event horizon. Cool. All right, back to Taylor.
If Dragonfly, if, when Dragonfly gets information from Titan in-- it says 2023, but it should be 2034-- how long will it take before the information is received and analyzed and the results reported? So people are eager. They are eager. Well, I'm glad to hear that.
The bad news is it takes a long time to get to Saturn. So the launch is scheduled for 2027. So it takes about seven years to get there. But it is still an if because we haven't launched yet. But hopefully, when the data come back, one thing we've learned from Cassini-Huygens, which was a very long lived mission, which was in orbit around Saturn from 2004 to 2017, is that it can sustain decades of research because almost everything we're learning is new. And this time, Dragonfly is planned to be able to move around the surface because it's an octocopter that can visit multiple locations.
So I would expect that after the landing happens that new results will start to come in within months. But I'm sure we'll learn for a long time after that. Is it going to carry a microphone? It has a seismometer, so it's actually going to be able to do some geophysics. Oh, yeah. That'll work.
Yeah. OK, Erin, when I was a student, we used the equation you referenced to use the luminosity to calculate distance of stars. How did the image you showed was a black hole that was both brighter and farther away? Yeah, this is one of those amazing discoveries that-- so this was back in 1963. Astronomers were starting to see these objects that they called quasi stellar objects.
And they called them that because they didn't know what they were. But they looked sort of stars. And so that's why they were called quasi stellar objects. And the major breakthrough came because they realized that no, it's not a star. It's a million times further away than that. And the way that they discovered that, Martin Schmidt saw emission lines in the spectrum, so transitions between photons being produced from hydrogen atoms and helium atoms.
And they produce emission lines at particular wavelengths. And we know very well what those wavelengths are. And when they made a spectrum, they saw these emission lines.
But what they finally were able to do was realize, OK, they've all been shifted because the universe is expanding and the universe is moving away from us. And if light has traveled from a million light years away, it's traveling through this space that is expanding and accelerating away from us. And so as those photons travel to us, similar to the gravitational redshift effect, as those photons travel through this universe that's expanding, they will get shifted to longer and longer wavelengths. And because all of those emission lines were shifted by the same amount, then they could infer that that light must have been coming from very far away. And that really just broke open the entire field.
And yeah, it was a major breakthrough. Great. These are pretty technical questions. [INAUDIBLE] People are not taking the weekend off here intellectually. [INTERPOSING VOICES] All right.
And along those lines, Taylor, in your landform modeling, how do you account for the differences resulting from methane versus water and planetary gravity? Clearly, that must impact how the surfaces develop. Absolutely. And this is one of the tricky things about taking results from Earth and trying to apply them to other planets is that if you build your theory by fitting to a bunch of data for a particular place on Earth and you don't explicitly account for things like gravity, the density, and viscosity of the liquids, good luck when you try to apply that on Titan. So you really have to make sure that you include explicit dependence on gravity, material properties. There are a few things we can do.
We can account for the relative buoyancy of the sediment moving through a river, for example. So we know how to do that on Earth where it's rock and water. By analogy, we can figure out how to do that on Titan when it's either ice or organics in liquid methane or liquid ethane. And then in other cases, we can actually take the differences in gravity that are contained in the theories we develop and apply them as long as that appears in the equations. Another friend of ours is turbulence.
One thing that people always ask is, what if you have a difference in the viscosity of the liquids? And it turns out that liquid methane is less viscous. It's more runny than liquid water on Earth. But it turns out that once things become fully turbulent where you have lots of fluctuations in the speed of the flow, that some of these characteristics like resistance to flow in rivers become roughly constant. So you can actually, in some cases, neglect the difference in viscosity as long as you sure you have the right flow conditions. Technical question, technical answer, I guess. Yeah.
OK, and we're just about out of time. But we have the perfect closing question for you here, Erin. How does black hole research allow researchers to learn more about space itself? What information arises from the study of black holes? Whoa, that's a big question to answer in 19 seconds.
I think that what is amazing about black holes-- and the reason that I study black holes is that they are vitally important for understanding why the galaxy looks the way that it does. And that's actually a major puzzle. these black holes sit in the centers of galaxies that are 1,000 times more massive. So why should the galaxy care at all what that puny little black hole is doing? But it turns out that the black hole actually dictates how the galaxy evolves. And it's because that accretion of gas is releasing all of this energy that can affect the galaxy on large scales.
And so if we can understand how the growth of black holes leads to the production of this radiation, we can understand how galaxies evolve, why our Milky Way looks the way that it does. And I think that that's ultimately-- the big question is why are we here? Why does the solar system look the way that it does? And black holes are actually a very important piece of that puzzle. Great. Well, let's thank our panelists, Erin Taylor, [INAUDIBLE]..
[APPLAUSE] OK. We're having fun now. Well, the Alumni Society Leadership promised you a surprise, and the time has come to deliver. We've got two alums who really wanted to be with us today, but they just couldn't get the right connecting flights to work. So they're about 250 miles away. And I know that doesn't sound like too much.
But thinking about the topic of today's event, you're probably catching on by now that we're talking about 250 miles that way. And so a couple of weeks ago, I was out in Pasadena at the Jet Propulsion Laboratory helping out a little bit with the next Mars mission. And I had the distinct pleasure of interviewing Steve Bowen and Woody Hoberg, MIT alums who are currently on the International Space Station. So we're going to play now a video of that conversation. And Whitney and her team just had an awful lot of fun planning this presentation for you. And I hope you all enjoy it as much as the team enjoyed putting it together and bringing it to you.
So stay tuned. Station Houston. Are you ready for the event? Station, this is Professor Zuber. How do you hear me? Yeah, Professor Zuber, we hear you loud and clear. How do you hear us? I hear you just great.
So it's a real pleasure to see you again, Woody. Last time we met in person was on the MIT campus. And Steve, a pleasure to meet you for the first time.
So for you both, I'm the vice president for research at MIT and also a professor in the EAPS Department. And it's just fantastic to speak with you both today. OK, well, I'm actually broadcasting here from out on the West Coast with our partners at The Jet Propulsion Lab. So I know you both wanted to beam into our alumni reunion, especially because Tech Day this year is called Research from Above and Beyond-- MIT in Space. And I'm the moderator for this year's event.
And I thought we needed to include those who are physically closest to the work. And so you two were naturals to think about. Well, thank you, Professor Zuber. We certainly wish we could be there to experience the excitement in person.
But just thinking about MIT, it's such a special place, really, one of the most amazing places on Earth. So Woody, you were the faculty advisor for the rocket club when you were a professor back at MIT. I'm sure we have some rocket club alums who are tuning in today. Do you want to give them a shout out? Yes, absolutely. Hello, MIT rocket team.
Rocketry was actually a big part of my early development. That's why as a young faculty member at MIT, it was an honor and a privilege to get to be their faculty mentor. And I'm just so proud of all the students that not only work on really hard classes at MIT, but also enjoy getting their hands dirty, playing with some real hardware. I learned a lot from doing that. And it's awesome to see students that are also excited about that.
I will also give two quick shoutouts to the MIT Outing Club and the MIT ski team. Both of those organizations taught me a lot about teamwork and appreciating the outdoors. And they certainly left a mark on me as an undergraduate. So for both of you, what was the biggest surprise about going into space? Obviously, you train, and you train, and you train, and you prepare. And then you get up there, and it's amazing, right? Yes, there is that. The thing that-- I say this every single time.
The thing that amazes me is how much doesn't surprise us when we get here because the training is so good and so intense. And then the opportunity to be able to work with people who have been here before really prepares you well for when you get here, what you're going to experience, the pleasant as well as the unpleasant. We kind of discussed it all. And certain things never get old.
For instance, floating just never gets old. The view out the window never gets old. I don't know.
What do you think, Woody? Yeah, for me, I think the single most amazing part has been watching how the human body evolves and adapts to new environments. That is truly remarkable. And it's everything from watching our vestibular system change to the fluid shifts in our body. It's a pretty extreme change in environment. And the body the human body just-- I grew about 3 inches up here, spinal elongation, just from the loading being different and all sorts of other changes that you definitely feel and notice. But it's just amazing watching the body adapt.
And it's also impressive mentally just how quickly you get used to new environments. I still remember-- this is my first flight, unlike Steve. But I remember the feeling of being on the ground and not knowing quite what it would be like to be always weightless and to be in space. It's a new experience.
And I have this amazing ride up on the rocket, eight minutes of excitement, flying uphill and then second engine cutoff, and you're weightless. And that was a little over 60 days ago for me. And I've been weightless ever since.
And it's amazing how quickly you get used to that being your new normal. So Woody, you talked about the influence of rocketry when you were growing up and how it got you interested, how interested you were. Steve, were you always interested in space, or did you develop that interest at a later time? Oh, no, I was always interested in space. I'm significantly older than Woody, shall I say. And so I actually watched Neil Armstrong step onto the moon in 1969.
And so as a very young child, it sort of set the bit in my brain. I never thought it was possible, though. I mean, I joined the submarine force after graduating from college. And it didn't seem like a career path option. But I applied, and I was accepted, which is like winning the lottery in my mind.
And it's been amazing ever since. But it was always back there. But it's one of those things you never think you can do. And so just sort of out there for everybody. The worst they could say is no, and that would have been OK. I would have been perfectly happy.
But this is just an amazing opportunity, an amazing experience. And I want add on to something that Woody was saying about how the body adapts. And this is not a fashion statement. This is actually part of the science we do up here. I don't usually wear a headbands.
But I actually have a whole suit with a suite of tools that are measuring part of my biometrics. And so we are our own experiments as well. So I know that you both have a message that you'd like to transmit to the surface here.
Welcome aboard. It's great to hear that you've got a tremendous position and tremendous responsibility for the school. That's incredible. Welcome to MIT and the amazing position you're taking on. We're really honored to welcome you aboard the International Space Station.
And we wish you very well with the mission you are continuing to forge ahead with back at MIT. It's near and dear to my heart, and we're so proud of the work you're doing every day. OK. Well, they're letting me know that we're coming to the end of our time. So I'd like to take this opportunity to thank both of you, to congratulate you for representing MIT in such a dramatic and hopeful way. And thank you for being a part of MIT's Tech Day.
Steve and Woody. Yeah, thank you. It's such a pleasure to get to talk with you, Professor Zuber, and to the MIT community.
The work that you are doing is so important. And whether you're a student learning and getting ready to contribute as a leader in science or technology, we need you. We need you for the challenges ahead. Or to the faculty members and other members of the MIT community, you're pushing the boundaries. And we're so proud of everything you're doing. Such a special place.
And it was just an honor to get to talk to you today. Station, this is Houston ACR. That concludes our event.
Thank you to all the participants from MIT and JPL. For the ISS, we'll resume normal operational audio communications.
2023-07-19 06:23
