Mapping Humanity From Space: NASA’s Black Marble with Dr. Miguel Román

How can a weather satellite see Ramadan, Christmas and a blackout? Dr. Miguel Román joins Krishna Choudhary to explain NASA's Black Marble: nightly maps of the lights on Earth, from a single band on the VIIRS instrument, processed to account for moonlight, airglow, clouds and atmospheric effects. It began as a calibration job on a brand-new satellite and an "anomaly" that followed the lunar calendar. Román traces how a small NASA team turned it into open data now used for energy access, disaster response and urban growth: Puerto Rico before and after Hurricane Maria, why LEDs can make satellite maps look darker, the 30-meter Black Marble HD, and a John Deere tractor seen from space. Recorded in Washington, D. C., on September 28, 2026, before the Golden Goose Awards ceremony. Román is Deputy Director for Atmospheres and Data Systems at NASA Goddard Space Flight Center and a member of the Black Marble team, recognized with a 2026 Golden Goose Award. Part of our Golden Goose series. CHAPTERS 00:00 Cold open: three moments from the interview 00:49 A NASA intern's question and a new weather satellite 02:38 Calibrating the night band: the Moon and the desert 04:09 The anomaly: Ramadan seen from space 05:39 Christmas lights, and home in Puerto Rico 06:48 A new pair of glasses: all of humanity at night 08:32 From calibration to a Black Marble team 11:51 Opening the data to the world 12:58 Keeping the data honest: moonlight and airglow 14:36 One band, and why LEDs look like dimming 15:57 Why the satellite can't see blue: one instrument, many jobs 18:20 Light from every angle, and building heights 22:14 Puerto Rico: the 2016 blackout and Hurricane Maria 27:29 A Golden Goose story: Adjuntas, La Perla and resilience 30:21 From 500 m to 30 m: Black Marble HD 34:55 Ground truth, and a tractor seen from space 36:50 Electrifying Africa: the darkest places on Earth 40:58 What the Golden Goose Award means 44:49 Thank you, and why showing the method matters 47:46 Outro RESEARCH & FURTHER READING Holidays in lights: Ramadan and Christmas (2015): https://doi.org/10.1002/2014EF000285 NASA's Black Marble product suite (2018): https://doi.org/10.1016/j.rse.2018.03.017 Puerto Rico after Hurricane Maria (2019): https://doi.org/10.1371/journal.pone.0218883 Uncertainty and viewing angle in night lights (2021): https://doi.org/10.1016/j.rse.2021.112557 Multiangle night-light composites (2022): https://doi.org/10.1109/LGRS.2022.3176616 Volatility in human night-time activity, Nature (2026): https://doi.org/10.1038/s41586-026-10260-w NASA Black Marble data: https://www.earthdata.nasa.gov/data/projects/black-marble Tracking SDG7: The Energy Progress Report 2025: https://www.worldbank.org/en/topic/energy/publication/tracking-sdg-7-the-energy-progress-report-2025 EDITORIAL NOTES 15:12: White LED streetlights often use blue emitters near 450 nm, outside the VIIRS day-night band's roughly 500-900 nm sensitivity. A change in lighting technology can change what the satellite detects. 22:50: NASA dates the island-wide outage to late on September 21, 2016, following a power-plant fire; nearly 1.5 million customers lost power. 30:21: The 30-meter Black Marble HD maps are downscaled using additional land-surface information, not native 30-meter night-light measurements. Miguel explains this distinction later in the section. 36:50: About 666 million people lacked electricity in 2023, including 565 million in sub-Saharan Africa (Tracking SDG7 2025). Statements reflect the September 2026 recording. WATCH & LISTEN Episode notes and research: https://ffppod.com/episodes/ep67 Golden Goose science rundown (EP59): https://ffppod.com/episodes/ep59 Watch and listen: https://ffppod.com Subscribe: https://www.youtube.com/@FromFirstPrinciplesPod?sub_confirmation=1 Support the show: https://ffppod.com/donate Follow @FFPPod on Instagram, TikTok, X and Facebook. Breaking down science news so it makes sense to curious people everywhere. #BlackMarble #GoldenGooseAward #SciencePodcast

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

  For a lot of people, it meant that you could track things like energy access.

• 0:03Krishna Choudhary?

  Right.

• 0:04Speaker 00

  You can track disasters. And at the time, we didn't know how powerful this tool was gonna be uh for many different organizations. And I put Puerto Rico on, just like I do every day. I drink my cafecito and I'm gonna look at Puerto Rico and I have to look three times.

• 0:22Krishna Choudhary?

  Hmm.

• 0:23Speaker 00

  And my hard job, because it had disappeared, made me go on a John Deere tractor, turn on the lights, and they detected the lights from space.

• 0:32Krishna Choudhary?

  No way.

• 0:33Speaker 00

  I can show you. Guess where?

• 0:49Krishna Choudhary?

  So you've already noticed the photograph that was um that's over here. This is one of the first photos on the Earth Observatory on the NASA website that sort of caught everyone's attention, this potential to study human activity at nighttime using satellite imagery. Were you looking to do this? Or how did you even stumble upon this story? Tell me, tell me what the the story is.

• 1:18Speaker 00

  Yeah, so for the record, there's no NASA department dedicated to studying how lights from space.

• 1:24Krishna Choudhary?

  Yeah, good.

• 1:26Speaker 00

  Not even today, even though I think we should probably have one.

• 1:28Krishna Choudhary?

  For sure.

• 1:29Speaker 00

  But.

• 1:29Krishna Choudhary?

  We get an intern on that.

• 1:31Speaker 00

  I did.

• 1:32Krishna Choudhary?

  Oh, okay.

• 1:33Speaker 00

  And that's that's the wonderful thing about NASA interns.

• 1:35Krishna Choudhary?

  Okay.

• 1:36Speaker 00

  They had to ask amazing questions. And that was one of the questions that came my to our office after we were doing what our job was, which is we just started a new mission back in two thousand and eleven, launched in twenty eleven, data started coming in early two thousand and twelve, called the Swami National Power Orbiting Partnership, which is our nation's next generation weather sensor. Large system took years to build. And we needed a preparatory mission

• 2:15Speaker 00

  to make sure we're testing everything before we go into this new program that is gonna be generating all sorts of measurements to track our weather, to track all different trends, very important things like ozone, surface radiation.

• 2:28Krishna Choudhary?

  Okay.

• 2:29Speaker 00

  Through the twenty forty's. So this was that at the moment, the US were was looking under the hood of this new instrument. And they were recruiting people fresh out of college like me, saying, hey, calibrate this thing, which is, is the data coming out of this new instrument correct? Is the integrity, everything about this instrument working? And I was in, I was, I trained as an engineer, then I switched over to science. So I was always kind of working around the integrity of the data.

• 3:02Krishna Choudhary?

  Yeah.

• 3:03Speaker 00

  Working with the instrument teams, working with the science teams and trying to be a bridge. And they asked me, is the instrument stable? The visible infrared imaging radiometer sweep? Figure it out. They gave me two years. So first thing you do is you ask the spacecraft team to look at the moon. Cause the moon is very stable. So if they, if you look at the moon every month and the moon starts looking dark, you got a problem with yours.

• 3:32Krishna Choudhary?

  Fair enough, yeah.

• 3:33Speaker 00

  So we started doing that.

• 3:36Krishna Choudhary?

  And this is literally, you just point the thing at the moon, okay?

• 3:39Speaker 00

  Right. Very stable. Problem is, there's a lot of variability, even though it's stable. So we needed more data. So what is the next most boring, stable place on Earth? Just look at any desert where there's not been any kind of source of civilization. So we picked the Sahara Desert. And so this picture you showed a section of the Sinai Desert next to Cairo, up there's, you know, all these places, Jordan, Israel. And we're, we're tracking how the data changes in a place where there's no clouds, where the moon goes up and down, up and down, and suddenly, so you, it doesn't reach a peak.

• 4:23Speaker 00

  And suddenly, boom, and we had to look at it like three or four times. We're seeing pics over like the bright lights in all major metropolitan districts in this region. Why? That every research article that we had read since then told us that, yes, lights do increase gradually from year to year, but it takes time. It shouldn't be from one season to the next.

• 4:49Krishna Choudhary?

  Mm hmm.

• 4:50Speaker 00

  And we thought the instrument was broken.

• 4:53Krishna Choudhary?

  Okay, interesting.

• 4:54Speaker 00

  We thought, okay, the low gain stage is so fine, the high gain stage detects very small, chintz signals was broken. Wasn't broken. And we knew because we had corrected two data sets and the anomaly was following the lunar calendar, not the Gregori calendar. And who uses the lunar calendar?

• 5:13Krishna Choudhary?

  Right.

• 5:13Speaker 00

  Muslims.

• 5:14Krishna Choudhary?

  Uh huh.

• 5:15Speaker 00

  And so when we looked at two thousand and thirteen and two thousand and fourteen, the anomaly had perfectly matched against the last day of Ramadan, the A A. So we were mapping Ramadan from space. The instrument was fine, but it had given us a gift. They had given us a capability to monitor humanity from space and literally culture from space. And so the next thing is like, whoa, we're US agency, let's go and get Christmas. Also found Christmas lights.

• 5:45Krishna Choudhary?

  Okay.

• 5:47Speaker 00

  And that brought me back to my home of Puerto Rico because we're very part of Puerto Rico, if you don't know, but we, our Christmas are the best Christmas. Longest Christmas hour.

• 5:57Krishna Choudhary?

  Yeah, get in the comments if you disagree.

• 5:59Speaker 00

  Yes. Let me say, you know, starts with Black Fridays, ends in January twenty with the San Sebastian festivities. And I felt that this was an opportunity to connect with these communities. And, and that was amazing. I mean, the other thing is, we knew that we needed to do data filtering elsewhere because snow, if you think about the snow at night, very bright too. So Puerto Rico doesn't have snow, but it still have Christmas. So again, just like the desk, find an easy case study.

• 6:35Speaker 00

  Turned out beautifully. So this map, you could, there's a Puerto Rican map also.

• 6:39Krishna Choudhary?

  Right.

• 6:40Speaker 00

  And, and at the time, it began to sink in that we were looking at a gold mine. But it was, like I told you, it wasn't, that wasn't our job. I, I, and that's where a lot of our science staff began to ask questions about, hey, these are very bright lights. But if it's like they've given, you've given us a new pair of glasses and now we can see not just that activity, but we're also seeing these low light pieces of our geography at night.

• 7:15Krishna Choudhary?

  Mm hmm.

• 7:16Speaker 00

  These places that before were being, you know, in a way, these bright lights were shadowing over the smaller light, rural communities, communities living outside the city. That's where the big reveal was. The fact that we can see all of humanity, not just the metropolitan areas that were being, that were occluding due to contamination of the the lights, occluding these other pieces of society. And that's where the data became very powerful. For a lot of people, it meant that you could track things like energy access.

• 7:51Krishna Choudhary?

  Right.

• 7:52Speaker 00

  You can track disasters. And at the time, we didn't know how powerful this tool was gonna be uh for many different organizations. And we were just, I mean, we were building on our research to do that.

• 8:06Krishna Choudhary?

  Yeah, that is, that is an incredible like starting story. Um, that you were effectively just trying to calibrate this thing. And then you look like to the side and then there's just like these random high frequency events that are happening. That's, that's pretty cool. And then from there, you know, this is sort of the first sojourn of of the team. This is before even the team of um Black Marble was found, was was formed, right?

• 8:31Speaker 00

  We were just two at the time.

• 8:32Krishna Choudhary?

  Yeah, so how do you transition from like, okay, there's like random people doing calibration? To now like there's, you get like a consortium of of scientists and you and your colleagues who are now being recognized for the Golden Goose Awards? Like, how do you, how do you, how do you start convincing um, you know, people that this is something that's worth full-time scientists to work on?

• 8:54Speaker 00

  Yes. We were very blessed with a very multi-talented team that brought unique skills and different questions to, to our group. Cause if it weren't for me, we will be just focusing on data filtering. To me, the most important job of an NASA scientist is to create highly pristine science measurements of the Earth system. And, and at the time, this has changed a lot, but at the time, we would just generate the gold standard product, throw it over the fence and allow the science community to ask those questions.

• 9:34Speaker 00

  So in a way, years later, we, we then evolve as an agency, as an organization, and now NASA scientists are doing a lot of work that crosses these boundaries, crosses the boundaries around nature, technology and society. So in a way, we were pioneers in that new mindset of developing our science to action. And we brought urban scientists to our team very early.

• 10:02Krishna Choudhary?

  Oh, okay, cool.

• 10:02Speaker 00

  We brought people who were, who had degrees from Yale in, you know, understanding urbanization as a process. And instead of giving them maps of land cover to show where are the cities and where are the non-urban areas, now they had something that helped describe the function of these places. Cause you can see a building, if the lights are off, the building is there during the day. And so this gave a lot of versatility to how, what kind of questions you can ask from an urban development, from an infrastructure point of view, that we would never be able to do before, unless you had a lot of money to literally manually count buildings and how much energy they use and everything.

• 10:47Speaker 00

  And we understood that we had to be careful about what we were really seeing. We've seen lights at night. And yes, it's been used as a proxy of many different things. But we were always very cautious in approaching that with integrity. Like we weren't overselling the capability and saying, this is a good way to replace estimates of total electricity.

• 11:09Krishna Choudhary?

  Right.

• 11:09Speaker 00

  No.

• 11:10Krishna Choudhary?

  Yeah.

• 11:10Speaker 00

  No, this is a piece that gives you better insights globally, geographically. And I think the part that we began to coalesce was when we hired someone who was entirely focused on applied science. And that's where the community became broader because we were doing things like light pollution, so monitoring dark skies, but we were also doing disaster response. So we were covering the entire gamut of energy conservation, wildlife preservation, and then emergency preparedness, resilience and all these things. And we, by then, we were just a team of four or five people.

• 11:49Krishna Choudhary?

  Yeah, that's, that's pretty incredible.

• 11:51Speaker 00

  And so we went back to, you can't just run such an amazing capability with five people. And our NASA leaders pushed us to make it fully open to the, to the world. That happened eight years after this, after this discovery. And that in fact was our biggest contribution. We, we made, we really embraced open science. And that meant that the data was not just in a webpage. You know, you can find it, you can access it, you can reproduce it from start to, from, from scratch. And that's what it has attracted so many people from around the world. That before they were just like, just a handful of teams.

• 12:37Speaker 00

  The majority of the research produced now is produced by outside organizations. NASA still published, we still publish, but we are seen as, as the folks that preserve the integrity of the data, right? That's our main, that's still is why they come to NASA and ask us.

• 12:58Krishna Choudhary?

  Well, uh, so speaking of like, you know, preserving the data and presenting pristine data, that's a big passion of yours. So I wanted to ask you just how difficult it is, actually. If you don't mind, we, we, we like getting technical on this podcast because, um, you know, the name is from first principles. So we try to develop the process of how science is done rather than just the answers. I think the answers are certainly really cool, right? The fact that you can see Muslim cities of Cairo and Oman fluctuating in brightness during Ramadan. And it like coincides with Eid.

• 13:33Speaker 00

  But I know where you're getting with this. Do you know what it takes to get?

• 13:36Krishna Choudhary?

  Exactly, like it's a lot of work, a lot of work goes into convincing yourself that you're not being fooled because the easiest person to fool is yourself. So what I wanted to ask you, um, with this, this is a figure from, I think it's the first paper.

• 13:50Speaker 00

  Theoretical basis document.

• 13:52Krishna Choudhary?

  Exactly.

• 13:52Speaker 00

  So which is NASA's speech for no one had written the theory on understanding how lights interact with the sky at night since 2018. We had to create a theory from scratch.

• 14:03Krishna Choudhary?

  Exactly. So, so I wanted to ask you, like, so there's moonlight, obviously in this figure.

• 14:08Speaker 00

  There's airglow?

• 14:09Krishna Choudhary?

  Yeah, airglow is just the atmosphere glowing.

• 14:13Speaker 00

  Yes, from, from precipitation electrons from the heliosphere.

• 14:18Krishna Choudhary?

  Oh, wow. So interacting with.

• 14:19Speaker 00

  Yes, hydroxys and atmospheric chemistry happening. So every time there's a storm event, you see Aurora. And that becomes noise for us, but heliophysics is love to go get those maps to do early warnings for potential impacts to infrastructure, like our power grid. This is the same data set.

• 14:36Krishna Choudhary?

  Oh, it's this, wait, so, hold on, so let's start from just the satellite, okay? What are the, what are the wavelengths that it's sensitive to?

• 14:44Speaker 00

  So it does only one band.

• 14:46Krishna Choudhary?

  There's only one band.

• 14:47Speaker 00

  There's only one, panchromatic one from point five to nine hundred nanometers. And it captures all the infrared, visible and infrared light in that. And.

• 14:57Krishna Choudhary?

  So it's just brightness?

• 14:58Speaker 00

  It's just brightness.

• 14:59Krishna Choudhary?

  Okay, that's crazy, actually. So.

• 15:02Speaker 00

  And, and because had it been designed by someone with expertise in night time nights, would have been done completely different, including the LED pump or 20, which a lot of the lights that we see now are transitioning to LEDs, we can't see that. Why? Because it was not built to do that. It was built to measure clouds at night for weather. This is a leather sound.

• 15:23Krishna Choudhary?

  Wait, so wait, no, now I'm jumping the gun because like, so the last paper that I wanted to, uh, we're just going for it. So the last, the last figure I have is this one, this is the very recent, um, nature paper. And there you see Europe dimming, but that's because of the, it's just outside the band.

• 15:40Speaker 00

  Poor, it's not dimming because there's some power, it's dimming because all of Europe decided to switch to LED lights in three years.

• 15:47Krishna Choudhary?

  Right. So the brightness could remain the same.

• 15:49Speaker 00

  Yes.

• 15:49Krishna Choudhary?

  Right? It's not that the brightness.

• 15:50Speaker 00

  The brightness is getting worse.

• 15:52Krishna Choudhary?

  Yeah, yeah.

• 15:52Speaker 00

  But in our data, it looks like it's going down because we don't see the blue.

• 15:56Krishna Choudhary?

  Yeah, that was unclear to me. So before this, before we did this interview, um, we did like a deep dive on five papers that you were co-author on. And that was the last one. And it was, it was kind of unclear to me why the brightness would go, I mean, the, the explanation was in the paper that, you know, there's policy changes and there's different types of lights, but now it's very clear that it's just a single band and the thing is outside the band.

• 16:19Speaker 00

  And it is not only a single band, it's a single band with a narrow aperture in wavelength that

• 16:29Speaker 00

  we made trades at the time, we needed to be more in the infrared because I, I sacrificed the blue, but I gained infrared light to monitor fires and flaring.

• 16:40Krishna Choudhary?

  Okay, fair enough. Yeah.

• 16:41Speaker 00

  So that's always the trade when you build an instrument. What do you give off and what do you gain? And at NASA, we've had to do that many, many times to help address the needs and priorities of broader science communities. You know, when we built this same instrument was built to measure clouds, to measure ocean color, to measure fires, to measure forests. So by the time you build those requirements, you're talking about a $700 million instrument.

• 17:12Speaker 00

  And so at the end, you add, oh, and I want to add blue LEDs. Okay, that's going to be another $2 million. Like at some point you gotta stop, you know, so that's.

• 17:20Krishna Choudhary?

  You can't just, you can't, what's the, what's the technical reason why the band has to be like a certain width? Why can't it be a little, like, why, why is it more expensive so much?

• 17:29Speaker 00

  It's driven by requirements. It's not, it's not just this one decision. It's decisions going back to the requirements of a large swath of stakeholders across the federal community.

• 17:41Krishna Choudhary?

  Yeah.

• 17:42Speaker 00

  The OD, NOAA and NASA, they all have different customers. They all have different stakeholders. You've got folks who need to support weather, you know, you got, and so at the time, the requirement was we need to be able to see low fog and cloud in Alaska. And these are the bands that allows us to optimize again that Christmas lights was not a factor.

• 18:06Krishna Choudhary?

  Yeah, yeah. And it's about, it's about weather at the end of the day.

• 18:09Speaker 00

  It's all about, this is our nation's weather workforce.

• 18:12Krishna Choudhary?

  Yeah.

• 18:13Speaker 00

  And so the priority is, let's try the five day forecast. If there's science that comes out of that, we'll revisit it later.

• 18:20Krishna Choudhary?

  Right, okay. And so, okay, so back to the figure, you've got moonlight that that, um, that penetrates our atmosphere, hits the ground, goes back. Sometimes it goes back into the ground and then comes back. Cause there's like, just photons are doing weird things. Um, there's the, the airglow from the atmosphere. Then there's clouds, there's all sorts of like random crap that, that photons are hitting.

• 18:46Speaker 00

  Yes.

• 18:47Krishna Choudhary?

  Before it hits your sensor.

• 18:48Speaker 00

  Even before we did this, we didn't know how difficult it was. So here's another problem. The lights from buildings also vary by angle. So it matters a lot, and that's where we accounted for that in this paper.

• 19:00Krishna Choudhary?

  Oh, wow, okay.

• 19:01Speaker 00

  If you're in New York City, Times Square, and your spacecraft is looking obliquely at forty-five degrees, you're not seeing the lights.

• 19:10Krishna Choudhary?

  The billboard.

• 19:11Speaker 00

  The billboard.

• 19:12Krishna Choudhary?

  Ah, okay.

• 19:12Speaker 00

  So you have to be looking from really at across the the the Laios site, so what we call Nader. And so we realized that this instrument had a lot of structure in the data. If you understand the directional signature, the multi-angular signature, because you have natural variation, but you also have anthropogenic radiation going on in the map.

• 19:36Krishna Choudhary?

  Wow.

• 19:36Speaker 00

  So the biggest bait to between this paper and this paper was the fact that we understood that the world, the light in the world, also vary a lot angularly. And we couldn't, we didn't even account for that when we did.

• 19:49Krishna Choudhary?

  Right, here you have angle from the moon.

• 19:51Speaker 00

  Yes.

• 19:51Krishna Choudhary?

  You've accounted for that.

• 19:52Speaker 00

  Yes, that we can for that, and we basically use atmospheric correction routines from daytime, and we just basically plot the sun on the moon. That's that's all we did.

• 20:00Krishna Choudhary?

  Ah, okay, yeah, fair enough.

• 20:01Speaker 00

  Yes, because the inherent optical properties of the atmosphere is really the same. You have aerosols, you have molecules. So you can make some approximations, and those approximations have hold now for twelve years. The biggest state of the art now is trying to figure out the angular structure of artificial light. And that is very fascinating, because you could relate those different modes. So even though we don't have colors, we have a lot of understanding of the architecture of the lights. And that is how we started looking at the volatility of lights. Because the fact that the dark, that it's dark at this angle and it's bright at this angle, what does it mean? I have something, I have building height.

• 20:44Krishna Choudhary?

  Right.

• 20:45Speaker 00

  So it's literally, I can extract building heights from the lights there.

• 20:49Krishna Choudhary?

  Yeah, yeah, yeah, yeah, that that's that's that's pretty cool.

• 20:52Speaker 00

  And if I can, if I can track building lights over a forty-year period, I know how your country is growing. China urbanized in twenty years. They built up, and they ran out of space. Who's next? India. So India is gonna be the next civilization that is still building horizontally, and now they're building up. Then when you, Eleanor Stok, he's our, she's our expert in urbanization. She came out of Karen Seles' Go Back Yale. They're the experts, they're the ones informing mayors on how to build cities sustainably, where you don't end up in a situation where you're building so fast that you're not gaining benefits from building, building cities that are more accessible, more.

• 21:37Speaker 00

  Those are the questions this data set in needs.

• 21:39Krishna Choudhary?

  Yeah, yeah, hopefully Los Angeles also takes note. Because um, I I would love to to have more housing in Los Angeles.

• 21:48Speaker 00

  So in order to do that, you need to understand the makeup of transportation, commercial, you know, housing. Understanding how those functions change over time. For the first time, we have data sets that can help you understand that variation. And you can now understand the volatility of those sectors as a result of disasters. So that's another factor that that's very unique to this.

• 22:13Krishna Choudhary?

  Yeah, yeah, actually, so one of the things that I wanted to ask you about was the big Puerto Rico paper. So first of all, this must have been um, personally, a very big deal for you, right? Um, how how'd you, how'd you come across like doing this?

• 22:31Speaker 00

  Yeah, so I remember the day I was a garter. Have my monitor, twenty sixteen, September twenty. The first major outage, like of an entire area, was a power outage that happened at the Aguirre Power Plant in Guayama that day. And with this is early Black Marble, we were still manually downloading data. No, we weren't in the cloud, like, and I put Puerto Rico on, just like I do every day. I drink my cafecito, and I'm gonna look at Puerto Rico, and I have to look three times.

• 23:09Krishna Choudhary?

  Hmm.

• 23:10Speaker 00

  And my hard job, because it had disappeared.

• 23:13Krishna Choudhary?

  Yeah, this is just after the hurricane.

• 23:16Speaker 00

  Before the hurricane, a year before the hurricane.

• 23:18Krishna Choudhary?

  Oh, before the hurricane.

• 23:20Speaker 00

  That was kind of a warning sign.

• 23:22Krishna Choudhary?

  Interesting, okay.

• 23:23Speaker 00

  Electricity system of Puerto Rico was already very vulnerable, and sending us an early signal of what became the largest power outage in Puerto Rico's in US history at the time, which is Hurricane Irma and Maria, that followed each other within two weeks. And the project changed forever after that. We knew what was going on. We weren't, you know, our height didn't skip at that time. And rather than having a concern, it was, you know, we had a sense of urgency as an agency, not just our team. I mean, I remember being part of NASA's Disaster Response Coordination Team.

• 24:08Speaker 00

  We were in meetings at the White House with all our partners and other federal agencies, helping understand the situation in Puerto Rico from us.

• 24:16Krishna Choudhary?

  Wow.

• 24:17Speaker 00

  And everything we had done prior to this was curiosity-driven. It was understanding the night, understanding how to protect the night, you know, the natural patrimony that is to be able to have dark skies.

• 24:35Speaker 00

  Puerto Rico changed that. We, we started asking different questions because of this. And it wasn't not enough to just coming up with a power outage map and putting it in the front cover of Washington Post. We used to do that a lot.

• 24:50Krishna Choudhary?

  Yeah.

• 24:50Speaker 00

  But after this, it wasn't enough. We we had to stay and monitor which communities were still without power for how long. And the entire project became a focus on recovery and resilience. And, yeah, so we were, I remember being on in calls with the Army Northern Command in Puerto Rico, and they were moving diesel power generators around the island.

• 25:18Speaker 00

  And I got a call from a captain, it's like, sir, like, we're gonna move, we wanna go to this town, Baranquitas.

• 25:24Krishna Choudhary?

  Uh huh.

• 25:25Speaker 00

  And I was like, yeah, they've been without power for sixty days, based on the DOE report and our nighttime nets. And we we were part of the search capacity force, the federal-wide search capacity force that had not been activated since Katrina.

• 25:40Krishna Choudhary?

  Wow.

• 25:41Speaker 00

  Long days. There were, there were folks, there were a lot of female folks in Puerto Rico eating MREs for weeks. And, you know, and that taught us something very important, because we were here, we were in DC.

• 25:55Speaker 00

  It taught us that you can look at all this stuff from space, but if you can't connect with those communities and people with that knowledge,

• 26:04Speaker 00

  and that's where Black Marble evolved, thanks to Puerto Rico. Because we began to realize that you can't do earth action, earth science to action, without involving the local expertise.

• 26:17Speaker 00

  And, you know, at the time, like, I've grown now, you know, since then, so it's been nine years.

• 26:22Krishna Choudhary?

  Yeah.

• 26:23Speaker 00

  It it really, it, that personal connection at the time was very hard. But now, I've sort of seen how much we've learned from from these events. And the world has learned. You know, the the world has become more resilient in a way, because we know what happens when you have these large-scale events. And what, how can that impact centralized electricities? And you go to Puerto Rico, everybody has, you know, domestically, you know, every home now has batteries and solar power.

• 27:00Krishna Choudhary?

  Nice.

• 27:01Speaker 00

  Right? And so, and there was both local investment, federal investment going into restoring that, and you can see that in the in the data too.

• 27:10Krishna Choudhary?

  Right, really?

• 27:11Speaker 00

  Yeah, you can see that, you see Mount, like, the coffee-ground mountain region of Puerto Rico, Aljuntas. They're, they're now fully electrified with solar. And every time there's an outage, they're still on.

• 27:23Krishna Choudhary?

  They're still on.

• 27:24Speaker 00

  And you can see that in our anomaly scores. Years later, eight years later.

• 27:28Krishna Choudhary?

  Yeah, so so that's like significant changes at the ground level because of um, you know, I mean, this is like a classic Golden Goose story, right? You're chasing uh, random holiday lights, and it turns into this incredible um, story where communities are changed forever.

• 27:48Speaker 00

  You know, now that I'm forty, I love salsa music more than I'm used to when I was a kid.

• 27:53Krishna Choudhary?

  Okay.

• 27:53Speaker 00

  And there's this amazing singer-songwriter, his name is Ismaili Wada.

• 27:59Speaker 00

  And now, every time I go to God or I have, you know, Amazon Music on, I'm listening to Maero. And he talks about this little chantita off of San Juan called La Perla. If you've ever seen the video, music video, Despacito, that's La Perla, right?

• 28:16Krishna Choudhary?

  Oh, okay. All right. And Sorry, I do, I have seen the video, yes.

• 28:22Speaker 00

  And they talk about this down outside the walls, the old walls of Old San Juan. About, he talks about this community with dignity, you know? And it's funny, like, it took me, I had to come work at NASA to understand some of the things this man was saying. That a lot of what we have learned from Black Marble are just basic things about protecting a community, right? Not everything that's important in life is the thing that shines the brightest. It's hard for me to translate.

• 29:00Krishna Choudhary?

  Yeah, yeah, okay.

• 29:01Speaker 00

  Um, people can get hit really hard and they get up. That's a very American thing. You see it everywhere in Hurricane torn regions, in tornado torn regions. People just feel bad better. They just get up. And again, the credit comes by understanding that community at a personal level. And we just came back from Puerto Rico last week. We opened a North Information Center at the local science museum.

• 29:30Krishna Choudhary?

  Okay, nice.

• 29:31Speaker 00

  And we, it was a small event, so we had to, we had fifty registrations every hour. So we did two hundred people, right?

• 29:44Speaker 00

  People from over the island wanting to learn about Black Marble, wanting to learn about how can NASA data help their communities?

• 29:54Speaker 00

  I would have never thought, you know, we would be able to reach communities from Puerto Rico, learning about what we're doing at NASA. It's just

• 30:04Krishna Choudhary?

  That's, that is, that is really cool. And that must have been so meaningful for you to go back to that community and

• 30:09Speaker 00

  And going back to a community where you see the outages that, of places that you know, streets that you have not.

• 30:17Krishna Choudhary?

  Right, right.

• 30:19Speaker 00

  Yeah, it's

• 30:21Krishna Choudhary?

  That's, that's pretty cool. I, I did wanna, um, one of the, one of the innovations, I think, at least from what I read in this paper, um, that was kind of like, it sounded miraculous to me when I first read it. It's this figure where it shows the resolution of the, of the Black Marble standard product, which is like five hundred meters, so half a kilometer by half a kilometer. Which, okay, fine, that's believable to me, right? That it's like nighttime, you don't get a lot of photons.

• 30:51Speaker 00

  Yeah, but how did, how did we get there?

• 30:53Krishna Choudhary?

  But then it's, it's completely unclear to me what data magic happened to get you the thirty meter resolution.

• 31:00Speaker 00

  I can explain.

• 31:01Krishna Choudhary?

  Yes, that's, that's why, um,

• 31:03Speaker 00

  This came out of a need.

• 31:04Krishna Choudhary?

  Yeah.

• 31:04Speaker 00

  This came out of a need.

• 31:05Krishna Choudhary?

  Yeah.

• 31:06Speaker 00

  When we were talking to FEMA

• 31:08Krishna Choudhary?

  Mm-hmm.

• 31:10Speaker 00

  and local communities, they're saying, we love this, you're telling us where the lights have gone down, but your dataset is so coarse, I need to get down to the house lab. And I'm like, I can't help you.

• 31:23Krishna Choudhary?

  Yeah.

• 31:23Speaker 00

  I can't help you. I only have

• 31:25Krishna Choudhary?

  The fraction limit, yeah.

• 31:26Speaker 00

  Right? So, but then, one of our team members said, but, but we have Landsat. And Landsat, another NOAA, USGS NASA mission, can look at buildings at the hectare scale, right? You could see streetlights, the streets. You don't know where this, where those streets have streetlights or not. Why didn't we merge those two datasets? The Landsat archive, which is the, like, the crown jewel of, like, our science, isn't it?

• 31:55Krishna Choudhary?

  Yeah, it's, it's an amazing

• 31:57Speaker 00

  Going in, and we're like, well, we know we can count on Landsat being good.

• 32:02Krishna Choudhary?

  Yeah, because there's other guys like you and Landsat team

• 32:05Speaker 00

  Yeah, there are other big girls at Landsat who know, like, oh, they can get down the quality of the data down to

• 32:10Krishna Choudhary?

  Yeah, their whole thing is quality of data, so.

• 32:12Speaker 00

  So we know that if we, if we can get in previous area from NASA, meaning anywhere that there's cement. And you make this assumption, the more cement, the more likes.

• 32:25Krishna Choudhary?

  Okay, I think it's a fair assumption.

• 32:28Speaker 00

  Fair assumption? Then now you can create a fused image between, in that pixel, anywhere where there's cement, they attribute the lights of that valley over, that area over that region. This came out of a need because we don't have a Black Marble satellite at ten meter resolution. We do now, thanks to NASA's, uh, commercial satellite data acquisition program. So we, I can now, this is the awesome thing about industry being part of NASA, I can now, as a company, to take a picture at night and buy the data for research. And it, they go through a, an award, and then they make their satellite system available to researchers.

• 33:13Speaker 00

  So we have done, as of last year, there was a major power outage in Mississippi, and our disaster response system was I want high resolution images. And we detected power outages with real, real nighttime nights. But between now and then, we had, we were basically creating a, you know, a, a simulated map.

• 33:36Krishna Choudhary?

  Yeah.

• 33:36Speaker 00

  And that, that map does, is not SI Trezo.

• 33:40Krishna Choudhary?

  Mm-hmm. What does that mean?

• 33:42Speaker 00

  It means you can visualize it, but you don't know what the values mean. It's just for situational awareness only. Nothing replaces a physical measurement. So every time, that's why these maps, you can see them in museum displays, you can see them, but analysis, you still use the fire in your brain. Okay, need something of high integrity and you cannot use that assumption in previous area lights and assume that that's gonna apply everywhere.

• 34:12Krishna Choudhary?

  Right.

• 34:12Speaker 00

  That's not the case. In the, across the world, different countries use lights differently. It, that assumption only holds visually.

• 34:21Speaker 00

  And I, you know, from a NASA point of view, it's like, then why are you doing it? I'm doing it because I users need, because a lot of our users want a sixty percent solution.

• 34:30Krishna Choudhary?

  Uh-huh, and it's good enough.

• 34:31Speaker 00

  They're making are like in an hour, they can't wait three months for a science paper, you know, three years, to make a decision. So we, we were tailoring a solution. And that required a lot of technical skill, not just in building the algorithms, but figuring out the data pipelines to do this, because it's a lot of, it's, there's a lot of high volume in there.

• 34:55Krishna Choudhary?

  Yeah, okay, that makes a lot of sense, though. So it's with that assumption, and then you kind of do like a,

• 35:03Krishna Choudhary?

  you know, the Bayesian kind of analysis of like, okay, given this ground truth, what's the probability?

• 35:10Speaker 00

  It's probability, good old downscaling. And in the sciences, this is very common. Um, you measure flux, now, different kind of fluxes, um, and you have our collecting flux data. And then NASA satellites come in, give you a big perspective, and then you downscale it against that anchor. And you can come up with maps of like ozone, nitrogen oxide, everything, like, there is, it's just geostatistics. In this case, you do that, but we always say buyer beware. It is useful as a tool, if you do analysis, you need to get ground-based data and calculate it against the lights. And we're, we're also doing that.

• 35:52Speaker 00

  I just came from Cornell University, one of our partners, and they took me to an experimental agriculture site, made me go on a John Deere tractor, turn on the lights, and they detected the lights from space.

• 36:05Krishna Choudhary?

  No way.

• 36:06Speaker 00

  I can show you. Yes, wait. So imagine

• 36:10Krishna Choudhary?

  That's so few photons, that doesn't make it, what? Wow.

• 36:14Speaker 00

  Because, again, the sensitivity is not related to the actual support. A fire, a small fire can still be detected, but the scale at which is reported is broader, because you're, you're running a C D, right? So you can detect a twenty thousand lumen light, if you know how to shine it based on the geometry. So John Deere has lights this way, this way, that way. We, we got it. We had a Honda Civic next door, couldn't detect.

• 36:45Krishna Choudhary?

  Couldn't detect that, okay.

• 36:46Speaker 00

  The John Deere had so many conical lines.

• 36:48Krishna Choudhary?

  Yeah, the, yeah.

• 36:50Speaker 00

  The, the signal on it.

• 36:51Krishna Choudhary?

  Mm-hmm.

• 36:52Speaker 00

  Why does that mean to me? Well, if you care about electrifying Africa, where the light nighttime signal is three times smaller than the moon contaminated signal, that's ten percent of the human population, right there.

• 37:08Speaker 00

  So from a sustainability planning point of view, if you think about twenty-one hundred, demographically, Africa's gonna be a large, large contingent of human population. So if you wanna measure those trends and how that's gonna impact global economies at scale, you need to look at the darkest place in the world that are developing right now.

• 37:28Krishna Choudhary?

  Yeah, and that ten percent, so you're saying, because Africa, I'm guessing, is like near the equator, moon contamination is worse? Is that the idea?

• 37:36Speaker 00

  No, Africa is still the last mile in terms of energy. I'm saying that Africa is still in, there are countries that are still not electrified.

• 37:44Krishna Choudhary?

  Right, okay.

• 37:45Speaker 00

  And so, to, like, ten percent of the global population still has no electricity.

• 37:50Krishna Choudhary?

  Oh, okay, so I'm, I'm

• 37:51Speaker 00

  And so if you wanna detect those regions, your data has to be of high integrity, because those are very low signals.

• 37:59Krishna Choudhary?

  Uh huh.

• 37:59Speaker 00

  And so that's why NASA expands so much effort in validating these results and understanding where's the threshold that which you can make science because if you start if if the World Bank is gonna go to Africa and electrify Cote d'Ivoire, which they have, they can then use black marble to assess the effectiveness of those electrification programs over years and say, we made an investment of two hundred million dollars, we use black marble and now we're gonna look and it still looks dark. We got a problem here.

• 38:32Krishna Choudhary?

  Right.

• 38:33Speaker 00

  Right? Oh, it looks bright. Great. Cam, and then they begin to do assessments against, okay, why did it work in this city and why didn't it work? And so you can start making really good decisions about the future investments of countries that are very, you know, that don't have access to resource. We can do that too as a federal government. If I can tell you where are the places that are most frequently hit by disasters, that are constantly observing volatility, you can concentrate support, expertise, capital in those regions. That's, that's what earth observations offer you. We don't make the decisions, but we're

• 39:15Speaker 00

  giving you a very strong formation by which you can make decisions to help everyone.

• 39:20Krishna Choudhary?

  Yeah, and if the data can be trusted, then.

• 39:24Speaker 00

  The big if.

• 39:24Krishna Choudhary?

  Yeah.

• 39:25Speaker 00

  That's the big if, because that requires a lot of expertise and institutional muscle memory. You can't just calibrate an instrument like this and backfill it with somebody else. You need, you need a team of people that does that. That's where NASA steps in. Cause we made a commitment that data systems, data and integrity is a capability that must be sustained for our nation. Just in the same way, the US government has a vested interest type in the GPS network. Like, why? Because you cared, you couldn't find this place. If it weren't for GPS, well, it takes a lot of space hardware to run the GPS network. And

• 40:09Speaker 00

  many different federal agencies own the capabilities around position, radiation and timing. You know, about understanding, you know, and, you know, understanding changes in the atmosphere and how that impacts radiation signals. Like, everyone is involved in this. Black marble does nighttime lights, but we are not the only agency involved in asking energy-related questions or disaster-related questions. You know, so, but we've been given the distinct privilege to ask the weird question.

• 40:43Krishna Choudhary?

  Yeah.

• 40:44Speaker 00

  Think differently about these questions. And I think that's really the proudest thing about winning this award. That there were folks at NASA that believed in us, even though our leaders were crazy at the time.

• 40:57Krishna Choudhary?

  Yeah. Yeah. So, I mean, I wanted to ask you, you know, now you're, we're about to go to the Library of Congress for the ceremony. What is, what does winning this award mean for, for you, for your team? You know, you've been working on this for what? Like, uh, ten, almost fifteen years now? Fifteen years since that, um, the Ramadan photo at least. It's been a long time. I'm sure you didn't start expecting to win an award. I don't think anyone does. Um, but, but what does it mean that, that you're, you're getting recognized like this?

• 41:33Speaker 00

  I think it validates something that our leaders at NASA have been saying for a long time, which is, we have given, we have produced a very amazing capabilities, not just black marble, but earth science in general, the fleet of NASA satellites. And we're going through this evolution because now, one of our leaders says, we're part of a broader ecosystem where, you know, there are many different actors. And the thing about being part of the ecosystem is you don't, no longer control the ecosystem. And it's a huge success

• 42:11Speaker 00

  story that our nation made a big bet around investing in earth observations back in the nineties and eighties. You know, and different administrations came in and said, let's do a big bet. Let's understand earth as a system. Let's build large observatories, the size of school buses. Let's deploy them. Let's try to get all the, and now we have all this data primed into the next chapter of US, if our, our next big bet, which is AI. And, and, and, you know, digital, digital modernization, all this. We have, we're one of the few countries

• 42:56Speaker 00

  in the world that has what matters in order to be able to have predictive, um, understandings of the future, which is gold, highly, pristinely maintained, highly integral product. Because with AI, you know how it works, garbage in, garbage out.

• 43:11Krishna Choudhary?

  Yeah, yeah, a hundred percent. Worst garbage art.

• 43:13Speaker 00

  Exactly. But with, but the fact that we have produced and we had the foresight to know that maybe AI wasn't a thing back then, but it is now. And.

• 43:25Krishna Choudhary?

  And data was gonna be everything.

• 43:26Speaker 00

  Building metrics, allowing people to create predictive understanding of risks. And I wish we had that fifteen years ago, but we didn't, but we had it now. I think that's what makes this award so special because it's really timed at a, at, at a moment where our agency has shown and produced a lot of public value for our nation.

• 43:52Krishna Choudhary?

  Uh huh. Certainly.

• 43:54Speaker 00

  And a lot of the times scientists don't get involved in that element of like, hey, how much, you know, we, we do, you know, we do certifications, we conduct reviews, we do all that due diligence. But to be able to represent our division in demonstrating the many thousands of times NASA earth science generates public value, it's, it's quite the privilege. Because we're not the only guys. There are people who are, who can monitor air quality at fine resolution, who can protect firefighters from the lines of fire using NASA satellites. There's so much going on. And they picked us, but let me tell you, for

• 44:37Speaker 00

  every black marble, there's a hundred other NASA earth scientists out there who are just doing crazy stuff, thinking differently and generating results that are directly impacting people's lives.

• 44:50Krishna Choudhary?

  Yeah, well, we're, we are huge fans of NASA at the podcast, and I think all of our viewers are huge fans. So I think you're doing, you're doing a great service for doing this kind of work. And AAAS and the Golden Goose Awards are just such a great way to recognize something like this. I hope, you know, we continue funding this kind of stuff. We continue doing this kind of stuff. It's, it's an incredible privilege to talk to you. Congratulations on the award to not just you, but also, uh, your co- recipients. Um, yeah, this was, this was really fun. I, I learned a lot. Um, I hope you don't mind the technical questions, but I don't think you did. I think you're an engineer at heart.

• 45:28Speaker 00

  You've enthused me. I, that's for sure.

• 45:30Krishna Choudhary?

  All right. Well, um, yeah, I'll be seeing you later today. It's gonna be a fun time.

• 45:34Speaker 00

  Thank you. Thank you again. Thank you for all the work you do. I mean, it means a lot to us to share how we do our work with integrity. Because it takes years.

• 45:47Krishna Choudhary?

  Yeah. And I think.

• 45:48Speaker 00

  And, and for you to deep dive on the algorithm, it, it means a lot because it shows that you're doing the due diligence that's required to build that credibility with your audience.

• 46:01Krishna Choudhary?

  Yeah, thank you.

• 46:02Speaker 00

  That's, um, a lot of the time folks, most of the folks tell me, I don't know what's gonna read that. It's like, people read it.

• 46:07Krishna Choudhary?

  No, I mean, you, you'll be surprised, you'll be surprised at how many people resonate to the methods of how you get the data, you know? Because as scientists, I think, you know, I'm just gonna go on a little tired, but like as scientists, um, convincing the public that what we're saying is not made up is, I think, as important as communicating what it is that we found.

• 46:30Speaker 00

  I think that's, that's a very important point because you're giving us the opportunity to show that we're not using a black box.

• 46:38Krishna Choudhary?

  Yeah, I know. Yeah, it's not, we're, we're, it's, it's not made up, right? This is, this is not just like.

• 46:42Speaker 00

  Neural network, that somehow it works. Like, this is actual.

• 46:45Krishna Choudhary?

  Yeah, this is, yeah, this is just physics being applied in a very reasonable way.

• 46:49Speaker 00

  Yeah.

• 46:49Krishna Choudhary?

  There's assumptions that are like open. You, you can see what the assumptions are.

• 46:53Speaker 00

  And most of, I mean, we, it was, it's almost destiny, but a lot of the physical processes and principles that the team, we learn as grad students. We learn from the real pioneers of earth observations that build those legacy systems that are now being retired. And so that legacy, I mean, we couldn't take, you know, we couldn't take full credit or re-bow. Like, weren't for those who, you know, were standing, standing on the shoulders from, people going back to the eighties, the seventies, were build the first radiator transfer model. Like, I mean, the science is just, if you really wanna start, you need to go all the way to P. Powers, you know, like, it's not a freaking way.

• 47:33Krishna Choudhary?

  Well, maybe we'll have you on the podcast for a much more lengthy conversation and we can start with at least radiative transfer. Um, but it was a pleasure talking to you. Um, and congratulations again.