 Over the past few days, we've been flooded with images of space, images from the James Webb Space Telescope, images from even billions of years ago. Now many of us have been wishing that we paid more attention to our physics textbooks. Some of us have been going to Wikipedia, other media sources for more information on what these images really mean. So today we decided to take a look at some of these questions. What are these images? Why is the James Webb Telescope special? And more importantly, maybe what is the point of all this? Why are all of us actually excited about this? Why is humanity even doing this? To talk more about this, we have with us Bapa Sinha. Bapa, thank you for joining us once again. So you've been following this very closely. You've been writing about it. So I think to ask a larger question first in the sense that what is all the excitement really about? Why is this set of images special? We've been seeing many images from space for a long time. NASA, other space agencies captured all kinds of images. So why is the James Webb Space Telescope images special? These images are special because we have just sent this brand new telescope. It's the most powerful telescope we have sent to space. And this is kind of the successor to the Hubble Telescope. So when the Hubble was sent to space in 1990, since then we have got amazing pictures of the images of the universe. And that led to a whole burst of expansion of our knowledge and our understanding of the universe. Now this telescope is far more powerful than the Hubble Telescope. And the hope and expectation is that with this we would get to know far more about the most distant parts of the universe. And also we will be able to look back in time and look back to the first stars and galaxies which were created after the big bang. So that's really what the excitement is about. What we have seen already with the first five set of images which were sent is that the detail that we are getting is at a much higher level of resolution than we could see in the Hubble. So as you know, the Hubble was a telescope which really operates in primarily in the visible light region, a little bit on the infrared spectrum also. The James Webb Telescope is focused on the infrared spectrum. Also it has a much bigger mirror than the Hubble so it can capture images from with far more clarity and for distant objects. So I think that kind of tells us that's what the excitement is about. Right. So could you also maybe quickly take us through these images and what really they're about. We'll go into some of the more deeper concepts about the big bang, the infrared concept, the mirror, etc. But before that, a quick look at the first five images. The first of the five images is an image of the S-Max 0723 Galaxy. And the bright objects in the foreground of that image are the Galaxy. So S-Max 0723 is not a galaxy, it's a galaxy cluster. And the bright objects in the front are really the galaxies of that galaxy cluster. And that galaxy cluster is about 4.6 billion light-years away. While in the background, there are tiny dots. And each of those dots is a galaxy. And one of those tiny dots, the light from that galaxy took 13.1 billion years to reach us. So effectively, we are looking at 13.1 billion years in the past, almost within one billion years of the big bang. Because the big bang, as we know, happened about 13.8 billion years back. So this is about, let's say, 700 million years after the big bang. Right. So there are also, of course, images of it. Yeah, so that was the first of the images. Then there is an image of an exoplanet that's a planet outside of our solar system. It's the vast 96B planet. It's a gaseous planet. What is interesting about the planet is that they have detected water or water molecules in that planet. There are two images of nebulas. One, they are calling it the cosmic cliff, which is from the Kareena nebula. And they're calling that as a nursery of stars. So this is like a huge cloud of gas and dust from which stars emerge. And then there is another nebula of the certain ring nebula. And that is of a dying star. So as one of these stars, there are two stars which are orbiting each other. And one of the stars is dying. And that's like throwing out this huge cloud of gas and dust. The fifth one is from the Stephen squinted. These are five galaxies, about 290 million light years away. And four of these galaxies are very close to each other and they're colliding. And when galaxies collide, spectacular things happen. Stars get ripped apart. Huge clouds of dust and gas get sucked in. New black holes emerge. So those are the five images. And all of them are spectacular. And hopefully, we will see far more spectacular images from the web and get to learn much more about the universe and also about laws of physics and astronomy. Absolutely. So Bapa, coming back to the James Webb Space Telescope itself, you already mentioned Hubble. But this is quite a unique instrument. We know that it's located quite far away from Earth. This was basically this big instrument. How did it really get there? It's a question a lot of people are interested in. Also, what's really unique about the James Webb Space Telescope that maybe nobody, no other instrument has achieved so far, say telescopes on Earth or Hubble. What really distinguishes the James Webb Space Telescope? So look, like I said, it is by far the most powerful space telescope we have. So the leading space telescope before this was Hubble, which has been in operation since 1990. And now, the first thing about this telescope is that its mirror is much bigger than the Hubble's mirror. So this has a mirror, which is 21, sorry, which is about 6 and 1 half meters in diameter, while the Hubble was only about 2 and 1 half meters in diameter. So it's a much bigger mirror, which means that it captures far more light and electromagnetic radiation, which can then be focused to its imaging sensors. Now, because it has such a big mirror, well, one of the things is also this is special because, like I said, the Hubble operates in the visible light spectrum, while this one operates primarily in the infrared spectrum. Now, one of the, so I'll come to that, but one of the things about operating in the infrared spectrum is that any object which has some temperature is going to give out infrared radiation. So hence, this mirror, this telescope had to be sent far away from Earth, so that Earth's radiation would not become noise to this telescope. Also, it has to be kept very cold. And so this mirror had a giant sunsheet. And the sunsheet is about the size of a tennis court. Now, this huge apparatus cannot just be launched into space. So what had to happen was you had to fold it up and make it compact and then launch it in a spaceship. And once it was launched into the space, it would then go through the series of deployment steps to fully first unfurl the sunsheet, put it in place, unfurl the mirrors, put all the things in place so that it can start actually capturing the universe. And the telescope operates at around 8 degrees Kelvin, which is like 0 Kelvin is the absolute minimum temperature we can achieve on the negative side. The lowest temperature we can achieve. This operates at 8 Kelvin, which is roughly in like 270, minus 270 degrees Celsius. And so all this makes it an enormously complicated operation. And like I said, because there are multiple steps of deployment, there were more than 300 steps of deployment of the sunsheet, the mirrors, the telescope, the emitting sensors, and all that. And if any of these 300, even one of these 300 steps went wrong, the telescope wouldn't function. So this was a huge technological feat to even just send it out. And it goes out to what is called Langrange 0.2, which is about 1.5 million kilometers away from the Earth. It's at a place where the sun's gravitational pull and Earth's gravitational pull balance each other out so it can have a reasonably stable orbit at that point. And the other thing special about this telescope is that it operates, like I said, in the infrared spectrum. And that is required because light from very distant galaxies shift to the infrared spectrum. So if you want to see really far away, we need to observe it in the infrared spectrum. I'm going to push you on that a bit more because now I'm reminded of my physics classes in school, in infrared, ultraviolet, we read about all these kinds of things. But in this context, what is really its relevance? In the sense that why do we say that, why is an infrared telescope, or why is an infrared telescope really required as opposed to just getting light? What's the science behind it? So see, the visible light, which is how we see each other, that's really a very small part of the entire electromagnetic spectrum. The electromagnetic spectrum ranges from radio waves to microwaves, to visible light, and then on the other side, well, after microwaves, you have the infrared, then visible light, ultraviolet, and then the other side, the x-rays and the gamma rays. Now, like I said, we see each other in visible light. But the light from distant galaxies when they come to us, they get shifted. So even though the light starts off as visible light, as it's traveling towards, it gets shifted towards the infrared spectrum. So now what that effectively means is that their wavelength increases. Now, then the question is, why do their wavelengths increase? So this is something which is called the redshift. And there was a scientist called Hubble, after whom the Hubble's telescope is named. And so Hubble discovered that there is a redshift and objects in space all over, right? Distant objects are moving away from us. And the farther they are, the more they are moving away from us. So this was a very important discovery and an understanding. And now why that happens, I think it's best explained through an analogy which we understand. So if you see a hair, a car, with a siren, or an ambulance with a siren coming towards you, then we'll experience that the sound of that siren, its pitch, increases when the car moves towards you. While when it passes you and leaves you, the pitch reduces. So what is effectively happening is when the car is moving towards you, the frequency is more, which means the wavelengths are smaller. And then when an object is moving away from you, its wavelengths get stretched and the frequency decreases. Now, there is an analogy of this in light. Just like sound is a wave, light is also a wave. And so when things are moving away from you, their wavelength of that light increases. And so the infrared spectrum is basically electromagnetic radiation with longer wavelengths. So the wavelength of the light, which starts off as visible light for objects which are moving away from us at a very rapid speed, they get shifted to the infrared spectrum. And what we have noticed is that the farther the objects are from us, the more redshifted, they call redshifted, the more redshifted they are in the infrared spectrum. So basically, if you really want to understand far away objects, you need a telescope which can sense basically infrared rays. So in this case now, let's move on to another point which, again, you mentioned. And I think a lot of it is connected to the first image that came out, one of the most iconic images. That is of the SMAX 0723 cluster. Now, one interesting bit of information that came out was that, like you said, there was one speck of light which was from 13 billion years ago. And now there was a lot of interest about it because, like you again said, it's close to the Big Bang. And 13 billion years ago is kind of incomprehensible for all of us. So could you really maybe take us a bit more into that concept and also in that process explain this idea of us moving away from them, which is what you said, because the universe is expanding. We are moving away, which is why the redshift happens. So in that case, why is it that could you explain it in the context of this object? Right. So see the thing is that we started off from a Big Bang. And so the Big Bang is really a point of singularity. So effectively, you can think of the entire universe being compressed to a single dot. And that's where we start and that explodes and the universe gets created. And so the universe has, ever since the Big Bang, the universe has been expanding. And now we have found out that it has been expanding at an increasing rate. Now, about this, and that is the reason that the distant objects are redshifted. Now, not only are things moving away, the other interesting part is that in any direction you look from the Earth, in every direction things are moving away. And the farther they are, the faster they seem to be moving away. So which is a very peculiar observation. I mean, why would that happen? So when these things are moving away, we are used to objects moving. But this expansion of the universe is not, we shouldn't think in terms of the motion which we are used to. Where when we are used to motion, it's like you are sitting here and either you or I or both of us move away. That is not this kind of motion. This is that it's almost like wherever we are, we continue to remain there. But the space between us expands. And that's what really is happening. As if that space itself is like a rubber band which you can pull. And obviously, then the two points in the rubber band would move away from each other. Now, if you take that rubber band and you let's say put markings on that, let's say you have a marking every centimeter. And you hold one end of the rubber band and you are marking at 1 centimeter, 2 centimeter, all the way to 10 centimeter. Now, let's say you very quickly in one second, you stretch the rubber band to double its size. Now, the 1 centimeter marking would move to 2 centimeter. So it would have from that one end, it would have moved away 1 centimeter in one second. So its speed from that end is 1 centimeter per second. But the 10 centimeter marking, since it would have doubled, it would have gone to 20 centimeters. So it would have moved 10 centimeters in one second. So the markings are really not moving in that sense. It's the rubber band, space itself is expanding. And that is what's happening. And that's why the further things away, the faster they move. Now, in context of going back to this image, in context of this image, that one speck of light, there are two interesting points about that, which they've identified as to be from 13 billion light years away. Well, I should correct myself. It is not 13 billion light years away. The light from that galaxy took 13.1 billion light years to reach us. Okay, 13.1 billion years. 13, sorry, 13.1 billion years to reach us. Now, that doesn't mean that that object is 13.1 billion light years away. That's a common mistake which people made and I kind of repeated that. So when that, we know the universe is expanding. So when that object emitted the light which is now reaching us, it was not 13.1 billion light years away. It was actually much closer to us. It was roughly, let's say, 2.5 billion light years away. However, once the light was emitted and it's, if everything was static, it would have taken two and a half billion light years to reach us. But while the light is traveling, space is expanding. And so, because the space is expanding, it took much longer to reach us. By now, see, that galaxy is probably long dead and it has maybe generated new galaxies in its place. So whatever was in its place, that by now is now like more than 30 billion light years away from us. So that's one interesting aspect to this. And so, it's incorrect. So you'll see in popular prayers, people say that's 13.1 billion light years away. It is not. That's an incorrect way to look at it. It's probably more correct to say that we are looking back 13.1 billion years in the past. Because that's, the light is coming from really that point in space and time. And so that's one aspect. The other interesting aspect of that is that the S-Max 0723 galaxy cluster is acting like a gravitational lens for that very distant galaxy. To explain that concept, this really takes us to Einstein's theory that gravity is created by a mass. Any mass distorts the space time around it. So this galaxy cluster, its combined mass is huge and so it kind of distorts the space time around it. And so for objects which are beyond it, light coming from them bend because of this galaxy cluster, right? And just like light from a magnifying glass bends and you get to see an enlarged image, the same processes happening here. So the very distant galaxy, what we are saying, light took 13.1 billion years to come to us. Its light is getting enlarged by the, or its image is getting enlarged by the S-Max. This huge galaxy cluster. Galaxy cluster and that's why we are able to see that very distant galaxy. So I think those were the interesting points about that image. Right, right. So Bapa actually finally, one final question on this which is that of course we're talking about, like you said, it's almost a window into the past 13.1 billion years ago. We might get even clearer images and I believe that this is not the oldest image we have seen. Older images from other telescopes as well. But actually one important question here really is and I think a lot of people are also asking it in various ways is why is this really important because in the sense that we get these pictures, of course, they're exciting. They provide quite a bit of say, they add some drama, we get some interesting factoids about the past, about the origin of the universe. But on maybe say practical level or on a more utilitarian level, how really does this kind of research really matter for us? Right, so see that like you said, there's the philosophical aspect of it, right? We have always wondered where we came from, how the universe started, how everything started, right? And kind of this helps us to understand the beginnings of the universe, right? But there is a, at a more practical level, this is important because this is how science progresses, and so see the laws of physics are universal, right? So the laws of physics which hold billions of light years away also hold here. So when we look at distant objects, we discover new phenomena and that phenomena has to be explained with our existing laws of physics and we often find that our laws of physics don't explain that phenomena. So then we have to go back and either modify our laws of physics or once in a while come up with completely different laws, right? And so our understanding, our understanding of science and then in order to understand all this, we need to create new tools. So our knowledge of technology advances through this, right? Now, if you go back in history, if you think about it that our view of the world and the solar system changed radically about 500 years back with what is called the Copernican revolution, right? Before that for like 2000 years or about 1500 years, people used to believe in the Ptolemic version of the universe, right? Where Earth was the center and everything revolved around the Earth. Now, when Copernicus makes this discovery or rather his claim that we are not the center of the universe, the sun is the center of the solar system and we are like revolving around the sun, that leads to many things. Like it's first of all that the church kind of totally looks down upon it and tries to suppress it and because it shakes our worldview, right? But it also shakes up science, right? Because that then you need almost new physics to explain what you are seeing in the heavens, right? And so from Copernicus we... But the thing is when this model is suggested the Copernicus model, original model doesn't really explain how we see the planets revolving around us, right? It was by no means even close to predicting the orbits of planets. So it had to be constantly refined and each refinement leads to a new scientific progress. So you then had Kepler's laws, which said, no, the objects are elliptical. But Galileo come along and Galileo discovered the telescope, right? Through which we can look at distant objects and then looking at those objects we realized that there are many other things which are unexplained. Galileo's laws of inertia comes into being. After that we really... The next massive discoveries come from Newton and the Newton's laws of motion. They all come from really the Copernican revolution, right? They get initiated by that and these are all like interwoven processes. And I mean, for Newton you basically not only do you have massive advances in science you have advances in mathematics because in order to do the science you need to discover calculus, right? And so this is how science has always progressed. And for our generation we are seeing with the Hubble and now with the Gem's web like two fairly revolutionary new tools which we have got in a very short span of time. And hence the excitement that this will lead to major expansion of our knowledge of what's going around and then hopefully the science which follows and trying to explain what we are seeing. Absolutely. Thank you so much, Bapa, for telling us all that. So as we've seen the study of the stars is not at all a separate issue from the study of what happens around us from the science and technology of what happens around us. And the study of the stars is also not that separate from the struggles of people. While talking about the Gem's web space telescope it needs to be mentioned that a number of scientists have raised objection to the name itself, that's Gem's web. Now, Gem's web was at NASA administrator during whose term there was a lot of persecution against people from LGBTQ backgrounds. That is something many scientists have raised principal opposition to. They have called for renaming the telescope maybe to the Harriet Tubman space telescope in honor of the pioneer of the underground railroad. So these are also issues we need to think about while talking about the stars because the struggles of today are as important and will continue. That's all we have time for today. Keep watching People's Dispatch.