Black Holes, Hubble & the Cosmos - An Amazing Journey with Astrophysicist Dr. Smriti Mahajan

[00:00:05]How much of the universe now we truly truly understand scientifically and what part of it is like still a mystery?

[00:00:15]>> I think the fact that we are living on a planet which is one among eight others [music] going around a very normal star which is just one among 400 billion others in our galaxy [music] and that too a galaxy which has nothing special about it. It is one among two trillion others in the part of the universe that we can see. Just after 8:00 p.m. if you are looking towards northeast, you will see a bright star rise and that is Vega. It is the fifth brightest star in the night sky. And let again the fact sink in that it has taken 25 years for the light from that star to reach my eyes. So if anything has happened to that star in the last 25 [music] years, I will not see it until next 25 years. Imagine the Hubble >> [music] >> Deep Field is something that most people have heard about. It's a >> tiny patch of sky and all Hubble did was to stare at that tiny patch of sky [music] which didn't really seem to have any significant objects. And what it found was [music] thousands of galaxies each having hundreds of billions of stars. For Hubble, I would give the credit to the dark energy bit. We knew that there were evidence and there were theories that universe is expanding but to confirm that using observational data [music] that it's not just expanding, it's accelerating. I think it took a long time even for the scientific community to get their head around.

[00:01:27]>> So black hole is not as sinister as >> It's not a villain actually. It's an absolutely not a villain as it is being portrayed. So quantitatively speaking, we understand about 5% of it. 5% which is actually ordinary matter. Matter that you, me, everything that we see around us, the stars are made up of. The other 27% is what we call as dark matter because this matter, it does not interact with light. So we do not see it but we can feel its presence because just like ordinary matter, this matter also exerts gravity hence the name dark matter. The rest of 68% of the universe, that's where things get tricky. That is what we refer to as >> Hi, welcome to Talking Through.

[00:02:11]We look at the sky, we see stars.

[00:02:14]Sometimes you also see planets, sometimes we see meteors.

[00:02:18]And it's an absolutely amazing world of space. Today we have Dr. Smriti Mahajan with us and we will ask her some really interesting questions about the cosmos.

[00:02:27]So without wasting any time, let's talk to her. Welcome Dr. Smriti.

[00:02:32]First of all, tell me out of everything else you could have done in life, why be an astrophysicist?

[00:02:39]>> To be honest, I don't really have an answer to that. I was I always wanted to become an astronomer.

[00:02:45]My dad tells me that on my third birthday he asked me what do I want to become because he got me a book with, you know, different kind of occupations people are following and of all things I said I want to study stars.

[00:02:58]So maybe I was born to do this and I find myself very fortunate actually that I was actually for able to follow my passion as well. So I did my graduation in physics from Delhi University, then found a scholarship to go and do PhD at University of Birmingham in England which followed up with several other research positions in the US, in the UK, you know, worked with people in Europe, did a job in Australia, finally when I decided to come back to India. So it's been a long journey.

[00:03:28]Now I work as a science communicator and an astronomy educator to be to be specific with Starscapes experiences and yeah, life has been fun doing all of this.

[00:03:39]>> I [laughter] mean, you've also gone around the world doing what you do, right?

[00:03:42]>> Yes.

[00:03:43]>> So I mean what I would like to start with is say if someone doesn't know anything about astronomy, >> Yeah.

[00:03:52]>> what is the one fact of the universe that could completely blow their mind?

[00:03:58]Like, they wouldn't know about it.

[00:04:00]>> I think the fact that we are living on a planet which is one among eight others going around a very normal star which is just one among 400 billion others in our galaxy. And that too a galaxy which has nothing special about it. It is one among 2 trillion others in the part of the universe that we can see. 2 trillion. The one cut that is two followed by 12 zeros.

[00:04:23]Right? And I think for me that is mind-boggling.

[00:04:26]>> Yeah, of course. Yeah.

[00:04:27]>> Yeah.

[00:04:27]>> So, I mean, us being here is probably the biggest >> Yeah. Yeah.

[00:04:32]>> surprise.

[00:04:32]>> Yeah. As I heard Carl [clears throat] Sagan say, you know, we are just a collection of atoms which just fell into place to understand the rest of the atoms in the universe. And I think that is a fact that we forget in our everyday life, but that is something we should think about more often.

[00:04:48]>> And I'm very glad that you're here because I've always wanted to do this topic on on our podcast.

[00:04:55]And one question I wanted to ask was about black holes.

[00:05:00]>> Okay.

[00:05:01]>> Because everywhere you see a movie or you you go into pop culture of astronomy, so black holes are like very popular.

[00:05:09]>> Yeah.

[00:05:09]>> And there is this sense that everything will be sucked inside a black hole, right? So, is that scientifically is it a accurate thing to know about or it's not?

[00:05:23]>> Not at all. So, I think in this sense black hole is probably the the name itself is a is a misnomer. There is no hole as such. So, this comes basically from the diagram. So, we have in in in Einstein's framework you the space and the time are dimensions which are interchangeable. And inside a black hole what happens is that the space and time interchange themselves. So, otherwise what are the properties of space? Space can be three-dimensional. You can go in three directions. Time is one-dimensional. Time flows only forward, right? But, inside a black hole, these two things reverse, and that's why when you see the diagram of that grid, if you remember, the space-time diagram, in a black hole, it appears like a tunnel.

[00:06:06]So, that is where the whole idea of black hole comes in, and then people think about it like a cosmic vacuum cleaner, which it absolutely is not. For example, if tomorrow our sun is going to turn into a black hole. It is not going to, but let's assume it will.

[00:06:21]The size of the sun will be about 3 km, which is the size of a small town, right? But, nothing will happen to the Earth's motion around it, because the orbital motion of the Earth only depends upon the mass of the sun, which will still remain the same. Only its volume is decreasing to a very dense mass. Of course, everything will become dark, because the sunlight is gone, and then, of course, we will not survive. But, those are other questions. But, nothing will actually happen to the Earth, or we will experience anything in terms of the motion itself.

[00:06:49]>> Right. So, black hole is not as sinister as people think.

[00:06:52]>> a villain, actually. It's absolutely not a villain as it is being portrayed.

[00:06:56]>> But, um just that I understand and and the audience understand, what is the purpose? Like, what is it doing in the cosmic universe, a black hole?

[00:07:06]>> So, it's nothing. So, there are two different main kinds of black holes we can talk about. So, stellar black holes, so a star which has, you know, so stars just like people has a life cycle, and very massive stars at some point, the outer shell blows away, and the inner core that remains, it keeps collapsing under its own gravity, and it turns into a stellar black hole. Those are tiny black holes. They're not doing anything.

[00:07:29]It's just tiny mass, and it's uh you know, part of an evolution. They're just like you will ask, you know, what is an 80-year-old doing? It's not He's not or she is not doing anything.

[00:07:38]>> Yeah.

[00:07:39]>> They are just there.

[00:07:40]>> Yeah. Uh the same is the case for bigger galactic black holes, which we now believe are at the center of every big galaxy, including our own. And again, this is just an aggregation of very dense mass, which is there.

[00:07:53]>> Right. And since um Thank you for clarifying that, and black hole is not sinister.

[00:07:59]>> No, no, no.

[00:08:00]>> So, since now we have so many researches going on uh in astronomy, uh there have been spaceships sent, and so much has happened. Um How much of the universe now we truly, truly understand scientifically?

[00:08:20]And what part of it is like still a mystery?

[00:08:25]>> Okay. So, I'll answer that question quantitatively like a physicist, okay?

[00:08:28]So, quantitatively speaking, we understand about 5% of the universe. 5%, which is actually ordinary matter.

[00:08:35]Matter that you, me, everything that we see around us, the stars, are made up of. Matter that we can see. That is 5%.

[00:08:44]Okay? The other 27% is what we call as dark matter.

[00:08:48]Dark because this matter, whatever it is, it does not interact with light. So, we do not see it like ordinary matter, but we can feel its presence because just like ordinary matter, this matter also exerts gravity.

[00:09:03]Okay? Hence the name dark matter.

[00:09:05]The rest of 68% of the universe, that's where things get tricky. That is what we refer to as the dark energy.

[00:09:13]Okay? Dark, again, because we don't really know what this force is.

[00:09:18]And energy because in Einstein's framework, energy and matter are interchangeable. Right? E = mc² if anybody knows uh physics a little bit.

[00:09:29]So, energy and matter are interchangeable, and this 68% of the energy-matter content is something we do not understand. And all of these numbers and that I've talked about are true as long as our observations continue to be in, you know, um they continue to agree with Einstein's framework. Which they so far have. But the day that changes, we basically don't know. So I think the more humbling thing to remember from this discussion would be that we really don't know how much we don't know.

[00:10:02]>> Right. Yeah. So basically, um we are still to evolve so much scientifically that we get to know how much actually we have to know rather than how much we know.

[00:10:13]>> Yes.

[00:10:13]>> Um but asking you about this dark energy thing, >> Mhm.

[00:10:18]>> why haven't we made progress in knowing more about it?

[00:10:23]>> No, it's I won't say we've not made progress because it's something we we are not used to, right? It's very difficult, for example, even to conceptualize the idea of a four-dimensional space because what we see around us is a three-dimensional space. So taking on that fourth dimension of time, for instance, takes a while.

[00:10:39]Uh and there have been many many theories in a field of astronomy, if you like, which is called cosmology. And there have been theoretical models. But think about something which is going against gravity.

[00:10:51]Right? So we do not really understand what can go against gravity. Now, people have tried to uh tell you this could be a particular kind of uh you know, a particle. It could be a kind of a force field. And there are many theories that people are testing. Um and I don't think your audience would want to know the details.

[00:11:11]And these models, there are about 50 coming out every week.

[00:11:15]Um and there are some tests being done together with the, you know, even particle physics uh people could be involved. And we get into a branch where we call astro astroparticle physics. Um or or quantum gravity and all of these domains which are in tuned to each other. Um but we we really don't understand it fully yet.

[00:11:36]>> Mhm.

[00:11:36]>> Right. Um which uh which is fascinating, all of this, and obviously I would want to know more about it, but I want to understand also about this um thing about we have about aliens, right? So um say if tomorrow we assume that we find a biosignature >> Mhm.

[00:12:00]>> on some other planet.

[00:12:01]>> Mhm.

[00:12:03]>> Like what level of evidence do scientists need to say, "Oh, there is life available here." Like how does that work?

[00:12:11]>> So first of all, let's understand what are biosignatures, right? Biosignatures are basically elements that telescopes like the James Webb Space Telescope can detect in the atmosphere of other planets.

[00:12:25]>> Mhm.

[00:12:25]>> Okay?

[00:12:26]For example, carbon dioxide, methane, water, oxygen, ozone. These are some of the things we know as we understand life on Earth requires to live or for biology to function. So if biology exists, then you need some of these material in particular ratios.

[00:12:47]The existence of any of these biosignatures by itself does not tell you that life is there for sure.

[00:12:52]>> Mhm.

[00:12:53]>> But there are certain combinations which can be very difficult to explain. For example, carbon dioxide and methane can also be produced by volcanoes.

[00:13:00]>> Mhm.

[00:13:01]>> Right?

[00:13:01]>> Right.

[00:13:01]>> But if you find methane and oxygen together, and both of these things destroy each other very quickly because they react, but you find both of them, it is very hard to explain their presence unless something is replenishing it.

[00:13:15]>> Mhm.

[00:13:16]>> Now, from the way we understand life, that something can only be biology.

[00:13:21]>> Mhm.

[00:13:22]>> [clears throat] >> Right? But you need other concrete evidence, so you need to go there, wherever this is happening, or find other ways to confirm that it is actually life.

[00:13:32]Biosignatures by themselves are not enough.

[00:13:34]>> So, I mean, a lot of evidence is required to say, "Oh, there is some viable life living out in some planet."

[00:13:42]And obviously, without going there physically or sending a mission over there, I mean, that evidence which can bring back some some evidence.

[00:13:50]Um and just another question, even if we bring back some evidence from there, do we have the technology to actually, you know, assess all of that? A lot of things might be unknown, right? Yeah.

[00:14:05]So, that's what That's why I said the first thing is we are looking for life as we understand it here.

[00:14:10]Right? We think life needs oxygen.

[00:14:13]Whereas, even on Earth, we have found species which do not need oxygen to survive.

[00:14:18]So, isn't it possible somewhere else? Of course, it is. And aliens, especially in the movies, they show, you know, these fancy creatures who are still standing on their two legs. That may not be the kind of life. The kind of life that, you know, when scientists talk about life, they're talking about the simpler form of life, bacteria, viruses, and stuff like that. So, that is more probable.

[00:14:37]And I think why we are doing it is because the odds that we can find it in mine and your lifetime is more The odds are much better than they were in our parents' lifetime.

[00:14:48]>> Exactly. Exactly.

[00:14:50]But yeah, I mean, there is this pop culture around aliens and how they're looking. Are they going to be friendly? Are they going to be hostile?

[00:14:59]>> [laughter] >> This is just, you know, movie movie stuff that we know. But obviously, scientists look at it in a very different light, right?

[00:15:06]Um so, since you spoke about the James Webb telescope, and then we also have the Hubble space telescope, people think telescopes are on Earth.

[00:15:18]>> Yeah.

[00:15:19]>> You have to look through them and you look into the sky and look at the cosmology, right?

[00:15:23]>> Yeah.

[00:15:24]>> But they are different. So, can you please explain them how they are different and what difference are they making?

[00:15:29]>> Okay. So, let's start with the Hubble Space Telescope first. So, what is happening is if you have a telescope on the ground, whatever light is coming to you from other objects, it's coming through atmosphere.

[00:15:41]Okay? And atmosphere has atoms and molecules and also different layers with different densities, different thicknesses. So, some of these light can be absorbed by these species before it even reaches your detector. So, you have lost part of the light. That is one problem. The other thing that I mentioned about the layers, what they are doing is they are distorting this light.

[00:16:03]So, the image you get is very blurred.

[00:16:07]Or you don't get it at all. Right? And that becomes a problem if your object in the sky is very small or is very distant, so it appears very small.

[00:16:16]What is Hubble Space Telescope doing? It goes above the atmosphere. So, it sits at a distance of about 540 km from us.

[00:16:25]By escaping those atmospheric layers, Hubble can create images which are very sharp and it can get all the light from them, which allowed us to see very far.

[00:16:37]Okay? So, using Hubble data, we were able to pin down the age of the universe to be at 13.8 billion years.

[00:16:45]Using Hubble Space Telescope, we could see very far. I mean, imagine the Hubble deep field is something that most people have heard about. It's a tiny patch of sky and all Hubble did was to stare at that tiny patch of sky which didn't really seem to have any significant objects. And what it find was thousands of galaxies, each having hundreds of billions of stars.

[00:17:08]And I think that is the most beautiful image we've ever seen because then that helped us it gave us a new perspective to humanity's existence.

[00:17:18]So, besides telling us the age of the of the universe, the other So, this is a very It gave us a sense of wonder.

[00:17:26]The other important thing uh in terms of the discovery that came out of Hubble's data was that we understood that the universe is not just expanding, but that expansion is accelerating.

[00:17:38]So, those are the two scientific discoveries along with the sense of wonder that I will give credit to the Hubble Space Telescope. And to think about that all of this is done by a telescope which was sent into orbit in 1990 within my lifetime.

[00:17:53]That is something that is still mind-boggling for me.

[00:17:57]Right?

[00:17:58]Now, coming to the James Webb Space Telescope. So, the Webb was sent into the orbit in 19 in 2021.

[00:18:05]Okay, Webb was sent in the orbit in 2021.

[00:18:08]But Webb, unlike the Hubble Space Telescope which sees in the visible light, the light that our eyes can detect, the Webb is like a night night vision camera. It sees in the infrared.

[00:18:22]Okay? Why that is important? Because as the universe is expanding, the wavelength coming from very distant objects is also stretched.

[00:18:33]Which means even if the light was emitted from a very distant object as visible light, by the time it has reached me, it will be detected as an infrared wavelength.

[00:18:45]Which is longer than the visible light.

[00:18:47]Okay?

[00:18:49]So, Hubble's saw until a certain distance. To see beyond that, we needed the Webb Space Telescope.

[00:18:57]So, Hubble So, Webb is allowing us to see very close to the Big Bang. It has detected galaxies which formed just a few million years after the Big Bang.

[00:19:08]But besides the deep sky stuff, I think the other scientific impact of Webb is that it is allowing us to explore exoplanets. So, exoplanets we've discussed it before are extrasolar planets, planets which are going around stars other than the sun.

[00:19:25]Right? So, what Webb does is it has instrumentation on board where when a transient happens, what is a transient?

[00:19:34]As the planet is moving in front of its star, something like an eclipse, right?

[00:19:38]As it is moving in front of its own star, some of that star light gets filtered through the atmosphere of the planet and Webb can detect those fingerprints.

[00:19:48]Okay? And by detecting those species, it can look for biosignatures that you were mentioning earlier.

[00:19:54]>> Okay, right. And um both these telescopes are they were sent to orbit through satellites, right?

[00:20:02]>> Yes. So, they are complementary to each other. They are not competing with each other. So, whereas Hubble told us how big the universe is, I think Webb's most significant contribution is that it is trying to answer the other favorite question, are we there alone?

[00:20:17]>> Right. So, do we do we have evidence that our galaxy is the oldest or >> No. No. No.

[00:20:23]Our galaxy is definitely not the oldest.

[00:20:25]>> Okay, there So, there are other galaxies they are much older.

[00:20:28]>> The other thing is in astronomy, how do you define old? Something that formed earlier? Our galaxy definitely didn't because we've seen things that formed, as I said, very close to the Big Bang just a few million years after the Big Bang.

[00:20:42]And how what and there must be things which are even older.

[00:20:46]But because light has a finite speed, in 13.8 billion years, only light from so many objects can reach us. There may be others beyond that from which light has still not reached us.

[00:20:59]>> Right. Right. Right. So, it's a it's a very difficult thing to ascertain, right?

[00:21:05]>> Yeah. Yeah.

[00:21:06]>> But um is there a specific discovery that James Webb or the Hubble has made which is which was completely unknown? Is Is there something very specific?

[00:21:19]>> So, I would give the For Hubble, I would give the credit to for this to to the dark energy bit because we didn't knew earlier. We knew that the They were evidence and there were theories that universe is expanding. But, to confirm that using observational data that it's not just expanding, it's accelerating. I think that it took a long time even for the scientific community to get their head around. With Webb, I think it's still to come. Of course, we found galaxies. We didn't expected galaxies to form so quickly after the Big Bang, but now we we are already detecting it. Similarly, we So, we at the time, I think we know a little over 6,000 exoplanets.

[00:21:58]But, some of them seem to be showing these biosignatures and the research is ongoing. So, because Webb just went into the orbit. So, we are just getting there.

[00:22:07]>> Right. So, it went in 2021, that's what >> 2021, yeah.

[00:22:10]>> Um So, um India sent Chandrayaan-3 mission which landed on the South Pole of the moon, right?

[00:22:22]And it was a big deal.

[00:22:24]So, in plain language, simply just explain us why was it a big deal?

[00:22:28]>> So, Chandrayaan-3 did a soft landing on the South Pole. First thing was it was a completely uncharted territory.

[00:22:37]Before them, the Before us, that is Americans, the Russians, the Chinese, everybody had landed very near to the equator. So, nobody had gone to the poles, especially the South Pole, because the terrain there is very rugged. The surface is very rugged, so it's very difficult to find a plain area to land on. So, that was one of the problems.

[00:22:59]The second problem was that the sun rays are inclined at the poles. So, even when at the time of the descent, the probe doesn't have ideal light, which creates problems.

[00:23:12]Because of the geometry, it's very hard also to find clear lines of communication with the ground station on Earth.

[00:23:20]>> Okay.

[00:23:21]>> So, all of those things put together, the fact that we made it and we did it successfully was a big deal. Right? And we became the first to do it.

[00:23:31]>> Right. [snorts] Um, and what would be the next step? Like, if what would be Chandrayaan-4? Is what I'm trying to ask. Like, uh, we've already landed on the South Pole. Then, what else is there to discover there?

[00:23:45]>> Um, so, we Chandrayaan-3 went there, but it's doing all sorts of experiments there itself. Chandrayaan-4, from what I understand so far, definitely has a module which will bring some of the samples back for analysis. And I think, uh, that probably is is one of the biggest things.

[00:24:02]>> Mhm.

[00:24:03]>> Right.

[00:24:03]>> Yeah.

[00:24:03]>> And, um, just for the ordinary citizen of this country any country for that matter, you know, why are these missions so important?

[00:24:15]People would say a lot of money is being spent on these things, and what do we really get from them? Just information or there is something tangible happening on Earth with that?

[00:24:24]>> So, I think space technology at every era, in every single era, has greatly benefited humankind. I can give you three examples to start with. You know, we [clears throat] all use mobile phone cameras. The CMOS image detection technology was first developed by an engineer at the Jet Propulsion Laboratory, the JPL, in the 1990s. Why?

[00:24:48]Because they wanted to miniaturize the cameras which will be put on interplanetary probes.

[00:24:52]>> Okay. Yeah.

[00:24:53]>> And then it found a spin-off, and today it's there practically in every palm on the planet. Millions of selfies being taken, images being taken and recorded by what?

[00:25:05]Which is something basically space tech.

[00:25:07]>> Space tech, yeah.

[00:25:08]>> Right? That's one example.

[00:25:10]The second is all of us whether we are planning a weekend trip or even our wardrobe for the next morning to go to office, we look at the weather forecast.

[00:25:19]>> Mhm.

[00:25:20]>> And people like me, millennials, you know, I I hope we are still called millennials, uh growing up in the '90s, right? Um we will agree that today a five-day forecast is much better than a one-day forecast in the '90s. Right?

[00:25:35]And how do we get there? We get there by send doing the space programs globally, not just in India, globally over and over again to pioneer the technology. And weather satellites are not just for planning your trips elsewhere. They are used to predict weather patterns which could, you know, like hurricanes or storms or floods and you're saving millions of lives and billions of dollars in the economy um just by predicting the weather patterns. So that is the second application for for satellites.

[00:26:07]The third and I think this will be most surprising for your listeners is memory foam.

[00:26:13]>> Okay.

[00:26:13]>> The mattress.

[00:26:14]>> The mattress industry um the insole of your running shoes, the bed padding for uh long-term patients, all of it uses memory foam. But memory foam is a modern version of a material which was developed by NASA in the 1960s to absorb G-forces for astronomer for astronauts while take off.

[00:26:38]>> Okay.

[00:26:39]>> Okay? So all of these things >> So it's a G-force absorber basically.

[00:26:43]>> Yeah, yeah. And and then it found a consumer market and just if I think about the medical industry, imagine how much of suffering this material has saved us over the decades. But for a, you know, somebody who's very skeptical from the money point of view, I don't think people actually look at the numbers. So, let me give you some numbers today.

[00:27:02]See, just for 2025-26, the Union Government of India, the expenditure budget is about 50.65 lakh crore.

[00:27:13]The budget, the total budget for the Department of Space is 13,000 crore, approximately.

[00:27:20]Which means for every 100 rupees that the Government of India is planning to spend on development and infrastructure, it is planning to spend 2.6 paisa on space programs.

[00:27:32]And at 2.6 paisa, we have planned the Chandrayaan-4, we have planned the Venus orbiter mission, we are planning to send our own astronauts into the low Earth orbit in a manned spacecraft. We are planning to have the Bharat Antariksh space station, which will be used for research and development besides other activities.

[00:27:51]We have sent the Mangalyaan at a cost, you know, which is much lower than making a Hollywood movie. So, even if you think about it in terms of the economy, I think the ROI is not bad at all.

[00:28:03]>> Yeah.

[00:28:04]Uh so, basically, this is not exactly accurate that too much money is being spent without any ROI, right?

[00:28:11]It's not just pomp and show. It's actually something tangible.

[00:28:14]>> And of course, then you the added advantage is that you end up, you know, inspiring the next generation to do STEM subjects, to to get interested in those, and it gives them a, you know, sense of wonder.

[00:28:27]Uh and unites the country. I mean, the recent uh events have been uh you know, are are evident for that. Everybody at all age groups was just glued to the screen when uh Captain Rakesh Sharma went to the ISS and when he came back.

[00:28:42]>> Yeah, of course.

[00:28:43]And safely.

[00:28:44]>> Yeah.

[00:28:44]>> Okay, since you talk about, you know, kids taking up STEM subjects and everything. So, say somebody a student today wants to do be an wants to be an astrophysicist >> Mhm.

[00:28:57]>> or some want to do something which is related to space exploration.

[00:29:03]Then what are the career paths available for them? Like, what are like what do they study? Like, what is the path really to do that?

[00:29:11]>> So, I think the great thing about astronomy is that you don't really need a particular path. Astronomy is wide and open to everybody. Right?

[00:29:20]Irrespective of where you start from.

[00:29:22]So, I'll give you some examples. For example, you know, ISRO people usually believe it's a space research organization. So, it has employed a lot of scientists who are astronomers and astrophysicists. That's absolutely not true. Because think about it, the main functionality of ISRO is to build space satellites and rockets. So, they will mostly be employing engineers. So, if you're doing mechanical engineering, system softwares, aerospace engineering, and maybe other branches. I'm not an engineer, so I I don't know the names.

[00:29:51]But, you will find a place in ISRO. And of course, these days people who are doing data analysis especially the application of artificial intelligence into analysis, you know, algorithms. So, you need all sorts of people. People who are doing testing of equipment. People who are doing quality control. These are all engineers.

[00:30:13]Then, people know about ISRO, but not many know about something called IN-SPACe, the Indian National space promotion and authorization, I think. Because 2020 2021, when Government of India decided that we can have privatized you know, private contribution to space sector, they created this IN-SPACe to regulate the space policy. So, we need people who understand policy, who understand law.

[00:30:39]And you know, there are things like satellite licensing, um, international treaties, orbital debris uh, stuff. So, you need people come So, there you will need people who understand law and policy framework.

[00:30:55]Then, of course, there are traditional paths like you can get into science communication, you can be writing, you know, for some media house, or you can be an astronomy educator working in a field of astrotourism or in a planetarium or in a science city.

[00:31:11]So, there are many different pathways, but the beautiful thing about astronomy is that just like it doesn't bind you how you get there, even if you you are a student of astronomy, you find career you you know, pathways going out. For example, many of my students went into finance just because of the skills they acquire.

[00:31:31]So, the skills you acquire you know, when you're doing a degree in astronomy is statistical tools. You understand how to do play with big data. You understand data analysis.

[00:31:42]And at the end of the day, the numbers you are playing with are the same irrespective of whether they are going to finance or they're coming from astronomy.

[00:31:49]Image processing, you know, again, a lot of the kids I've worked with find applications and built careers in medical image processing, the R&D there.

[00:32:01]So, astronomy allows you to do a lot of things, and a lot of what you are doing can allow you to come into astronomy in a nutshell.

[00:32:09]>> Great, great. So, it's a very wide >> Yes, yes.

[00:32:12]>> Oh, great. So, um, one question I want to ask you and I think it would be criminal not to ask you this, is what is the role of AI, um, in astronomy now?

[00:32:23]Because this technology has entered our lives um, in every industry that we see. So, what is it doing in astronomy?

[00:32:32]>> So, in astronomy, I think it it existed before it entered anywhere else. So, astronomers have been training data set, which is the core of AI, since the 1950s.

[00:32:43]Because, you know, we are working with a certain set of observations, but we want to predict the entire universe. So, the application, okay, the data set could be small. The The way we trained could be more traditional, but astronomers have always been doing it. That you, for example, I have uh I fit I I want to find automatically what is the shape of different galaxies.

[00:33:08]Okay. And say I have a data set of 100 million galaxies. Of course, I'm not going to go through it one by one. So, what I do is I will choose the top 1,000 or whatever. I will give it a classification, and then I will feed it into a system. I'll write an algorithm and ask the algorithm that based on this, you go and tell me what what is, you know, how would you classify the rest of the samples? And astronomers have been doing this sort of stuff forever.

[00:33:34]>> So, for them it's not new.

[00:33:35]>> No, it's not new at all.

[00:33:37]>> Right. Okay. Um and say today um you want to take people out >> Mhm.

[00:33:47]>> to see the sky.

[00:33:48]>> Okay.

[00:33:50]>> What would you want to show them to observe?

[00:33:52]>> Okay.

[00:33:53]>> What what what's your first instinct there?

[00:33:56]>> Right. So, not in a city like the one which we are sitting in.

[00:33:59]But, uh say we are on a good dark sky location, like say Kausani or Mukteshwar, where Starscapes Observatory is. The first thing I would ask people to is just notice the sheer number of stars you see around.

[00:34:11]Right? On a clear night, when cloud-free, and say the moon is not very bright.

[00:34:17]And on an average, you can see about 3,000 stars with naked eyes.

[00:34:22]Right? Imagine this in Delhi or NCR, where you can see three to five.

[00:34:26]Right? So, the sheer number of stars, and I've seen that moves people so much.

[00:34:31]I've had people crying, just looking up and saying, "Is this for real?"

[00:34:35]That is an, you know, it it's extraordinary. And that moves something within you which is inexplicable in words. So, that is the first thing I will do.

[00:34:44]The second thing I'll ask them is to recognize a pattern, what we call as constellations. So, it's summer time now, say the Saptarishi. The thing that looks with seven stars looks like a spoon or a saucepan.

[00:34:57]Recognize that constellation, or if it's a winter sky, maybe the what we call as Kalpurush in Hindi, right?

[00:35:03]So, recognize those pattern and let the fact sink in that your grandparents and your their ancestors were standing under this same constellation, looking at it.

[00:35:15]And that's why there are so many stories about all these constellations. And in that context, the skies are our oldest and I believe most precious natural heritage. Let that fact sink in.

[00:35:28]And the third thing I would say is, you know, just focus on any object. So, any bright object. Summer sky these days, so just after 8:00 p.m. if you are looking towards northeast east direction, you will see a bright star rise, and that is Vega. It is the fifth brightest star in the night sky.

[00:35:46]>> [snorts] >> And let again the fact sink in that it has taken 25 years for the light from that star to reach my eyes.

[00:35:56]So, if anything has happened to that star in the last 25 years, I will not see it until next 25 years.

[00:36:02]>> Which is amazing.

[00:36:03]>> Yeah.

[00:36:04]>> Yeah. So, I mean, all these facts are so enlightening.

[00:36:09]>> And I think that's very important because that gives you a perspective of why we are special. The very fact that we are here and we are trying to understand the universe around us.

[00:36:18]Uh and try to make sense of it. And how vast is the universe.

[00:36:23]>> Right. And to be honest, I've had this experience where I could see thousands of stars and that moment I felt connected with the universe.

[00:36:34]>> Yeah.

[00:36:35]>> It really happened to me and I remember it very distinctly. It was many years ago, but I still remember because in the city you don't see it.

[00:36:43]>> You don't see it.

[00:36:44]>> So you don't realize what's around you.

[00:36:46]>> Why I decided to become an astro It's maybe not related, but I have a very vivid memory of me being 10 11 year old and uh my grandparents were living in Haridwar they had you know done with their social obligations and everything. And we used to sleep outside on the roof. And on a I just woke up randomly uh in the middle of the night.

[00:37:08]It may be 2:30 3:00 a.m. And I look up and I'm actually trying to touch the thing that you know is is this for real or is somebody put something on us. It was So there were more stars than the blackness.

[00:37:20]And I still remember that image and even now when I think about it it gives me goosebumps.

[00:37:25]>> Right. Right. Right.

[00:37:27]>> And the other similar experience I had was much later when I for the first time I saw the Milky Way rise in the sky. First I thought it's it's smoke coming from somewhere because you know coming from Delhi that's what I I I felt. So this was in Spain. I I was there for observing and we were just sitting out on a mountain and it was like is this a cloud? It's a very linear cloud. You know maybe it's a smoke coming from the city downstairs.

[00:37:52]And then it suddenly occurred to me oh gosh this is the Milky Way. This is my galaxy. This is where we are.

[00:37:58]>> Yeah.

[00:37:58]>> So it's a very surreal experience.

[00:38:00]>> Yeah.

[00:38:00]>> And you've been to so many countries working studying.

[00:38:05]What are some of your very special memories from there?

[00:38:07]>> I think just working with people from different cultures understanding their you know there are certain behavioral nuances that we all have and exploring their cuisines. I'm a foodie so that uh and knowing that, you know, different parts of the world, even when they're looking at the same constellation, they have so many different beliefs, so many different stories related to them.

[00:38:32]Um that's been, I think, and how how um astronomy unites everybody. So, I've been part of the 30-m telescope team, the TMT, [clears throat] for example.

[00:38:43]And when I went to the TMT's office in California, uh there is this glass plate right outside the conference door, and this has TMT written in five different languages. And one of them is Hindi.

[00:38:56]Right? 30-m door beam.

[00:38:58]So, if I remember correctly, it's English, Spanish, um French, and then Hindi, and Chinese.

[00:39:07]And that that plate by itself tells you that, you know, 40% of humanity, if you think about it in terms of population, has come together to build this one instrument which we all believe will do us good.

[00:39:22]>> Right. Exactly. So, it is truly a global effort for you actually doing, which is fantastic. Um and what I find totally fascinating is it doesn't matter like how old the story is, how many generations have gone, there were no telescopes, there were no space probes, nothing, >> [snorts] >> but people were still very curious about what's happening in space. When they saw something, they wanted to make meaning of it.

[00:39:50]>> This is the science which is free to all. It's available to all. And especially, you know, when we didn't had electricity or when TVs were not that common, what people do? They just, you know, lie outside in the open and stared at the sky.

[00:40:04]And slowly that sky became so familiar that it became a part of our day-to-day life. When are you going to sow the seeds? When a particular constellation is up in the sky. When are the floods due? Because you knew that, you know, during monsoon season, you will start seeing a particular constellation or a particular star in certain direction. So, you knew there are there is going to be flood soon. So, you will move to higher lands. And all of that happened because people became familiarized with the sky. It was part of their everyday.

[00:40:31]>> Yeah, which is because it was very important to them. That was signals for their own survival sometimes.

[00:40:37]>> Yeah, and navigation of course.

[00:40:39]>> Yes, navigation. That's why we you know >> Sailors are still taught to do it.

[00:40:43]>> Exactly. That's what I was going to say.

[00:40:45]Like sailors still use the same thing, right? Your true north is what they say.

[00:40:50]We've discussed a lot of things.

[00:40:52]>> Yes.

[00:40:53]>> I can ask you 50 more questions. But things since this is a podcast it has to stop somewhere and start again at some point.

[00:41:02]Um one last question.

[00:41:05]Uh if there is one discovery that happens in your lifetime which will completely surprise you and you will jump out of the chair and say, "Oh, this is not what I thought it really was. This is something that it completely changes my worldview."

[00:41:23]What would that be?

[00:41:24]>> I think discovering life. I earlier used to say it's it's going to be discovering of gravitational waves, but we've already cracked it. So, now I'm very very hopeful that you know we will find some signature of life or at least move to the next step and say, "Okay, now we have to get there and confirm this." Um and that's that's what I'm I'm really hoping to to see happen.

[00:41:48]>> Very fascinating discussion that we've had today.

[00:41:51]>> Yeah, indeed.

[00:41:52]>> Um I hope you enjoyed it. We enjoyed it.

[00:41:55]>> Yes, thank you so much.

[00:41:57]>> Um so, for the audience, thank you very much for watching. Um we had Smithy with us today and we assure you we will have her back sometime again to discuss more on new things. Um if you want to learn more about this topic, read up. There is a lot of documentation, research available, books available. And whatever you think about the podcast, what if you have any questions, reach out to us.

[00:42:22]Uh put them in the comments and we will be happy to relate back to them and ask those answers. Uh but till next time, thank you very much for watching and take care.