 For 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 why, 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 image 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 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, this is a telescope which really operates in primarily in the visible light region a little bit on the infrared spectrum also while 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 right so effectively we are looking at 13.1 billion years in the past almost within 1 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 yeah so this is this was that was the first of the images then there is an image of an exoplanet that's a planet outside of a solar system it's the vast 96 b planet it's a gaseous planet what is interesting about the planet is that they have detected water or water molecules in that planet right the 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 which from which stars emerge and then there is another nebula which is of a of the certain ring nebula and that is of a dying star so as 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 right the fifth one is from the stefan squinted these are five galaxies about 290 a million light years away and four of these galaxies are very close to each other and they're colliding and when galaxies collide like spectacular things happen stars get ripped apart huge clouds of dust and gas gets sucked in new black holes emerge so 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 Bappa 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 you know this big instrument how do you 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 you know that maybe nobody no other instrument has achieved so far say telescopes on earth or Hubble what's really what really distinguishes the James Webb space telescope so look it is like I said it's it is by far the most powerful space telescope we have right so the the leading space telescope before this was Hubble which which has been in operation since the 1990 and now the first thing about this telescope is that its mirror is much bigger than the Hubble's mirror right so this has a mirror which is 21 sorry which is about six and a half meters in diameter while the Hubble was only about two and a half meters in diameter so much bigger mirror which which means that it can it captures far more light and electromagnetic radiation which can then be focused to the to its imaging sensors now because it has such a big mirror well one of the things is also this this is special because like I said the Hubble operates in the visible light spectrum while this one operates in the primarily in the infrared spectrum now one of the so so I'll come to that but one of the things about operating in the infrared spectrum is that any object which is which has like 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's earth's radiation would not become noise to the to this telescope also it has to be kept very cold right and so the this mirror had a giant sun shield and the sun shield is about the size of a of a of a tennis court right now this huge apparatus cannot just be launched into space right 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 sun shield put it in place unfurl the mirrors put all the things in place so that it can start actually capturing the universe right and the the the telescope operates at around eight degrees kelvin which is like zero kelvin is the absolute minimum temperature we can achieve like on the on the negative side right the lowest temperature we can achieve this operates at eight kelvin which is roughly in in like 270 minus 270 degrees celsius and so so all this makes it a enormously complicated operation right and like i said because there are multiple steps of deployment there were more than 300 steps of deployment of the sun shield 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 right so this was a huge technological feat to even just send it out and and and it goes out to what is called langage point two which is about 1.5 million kilometers away from the earth right um it's it's a place where the kind of 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 um and and the other thing special about the mirror about this telescope is that it operates in the like i said in the infrared spectrum so um and 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 the we need to observe it in the infrared spectrum right but 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 kind of things but in this context what is really its relevance in the sense that why do we say that uh why is an infrared telescope or why is an infrared telescope really required as opposed to just getting light what's the science behind right so um see the the visible light right which is how we see each other uh that's really a very small part of the entire electromagnetic spectrum the electromagnetic spectrum ranges from radio waves uh to microwaves to visible light and then on the other side uh well um after microwave we have the infrared then visible light ultra violet and then the other side um the x-rays and the gamma rays right now like i said we see each other in visible light uh but um the light from distant galaxies when they come to us they get shifted so so even though the light starts off as visible light over as it's traveling towards it gets shifted towards the towards the infrared spectrum so now what that effectively means is that their wavelength increases okay now the then the question is why do their wavelengths increase um so this is something which is called the redshift right and um it's 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 um so this was a very important discovery and an understanding and um now why that happens it's i think it's best explained through an analogy which we understand right so if you if you see if you like a hair a car with a siren or an ambulance with a siren coming coming towards you then we'll we'll experience that the sound of that siren its pitch uh is uh increases when the car moves towards you while when it passes you and leaves you the the pitch reduces right so so so what is effectively happening is when the when the car is moving towards you the frequency is more which means the wavelengths are smaller and then when it when an object is moving away from you its wavelengths its wavelengths get stretched and the frequency decreases uh now there is an analogy of this in light light is also just like sound is a wave light is also a wave and so when things are moving away from you the their wavelength the the wavelength of that light increases right and so uh infrared the infrared spectrum is basically electromagnetic radiation with uh longer wavelengths so so the wavelength of the light which starts off as visible light uh for objects which are moving away from us at a very rapid speed they are kind of uh get shifted to the uh infrared infrared spectrum and and what we have noticed is that the farther the uh objects are from us the more redshift they call red shifted the more redshifted they are um uh in the infrared spectrum right so basically if you really want to understand far away objects you need a infrared a telescope which can sense basically infrared rays cool so in this case now let's move on to another point which again you mentioned one is 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 s max 0 7 2 3 cluster now one interesting bit of information that came out was that like you said there was one spec of light which was from 13 billion years ago and now there was a lot of you know interest about it because like you again said it's close to the big bang and then 13 billion years ago is kind of incomprehensible for all of us so how could you really maybe take us a bit more into that concept and also in that process explain this idea of uh the you know us moving away from them which is what you said right because the universe is expanding we are moving away which is why the redshift happens so in that case why is it that could explain it in the context of this object right so so see the thing is that the like we started off from a big bang right and so the big bang is really a point of singularity right so so effectively you can think of like the entire universe been 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 a increasing rate right now the about this and and that is the reason that objects are the the distant objects are redshifted now the 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 right and the farther they are the faster they seem to be moving away so which is a which is a very peculiar observation right I mean why would that happen right so when these things are moving away we are used to objects moving right but this movie this expansion of the universe is not we shouldn't think in terms of like the motion which we are used to where things where when we are used to motion it's like I am you are sitting here and either you are I are both of us move away right that is not this kind of motion right this is that the it's almost like where wherever we are we continue to remain there but the space between us expands okay and and that's what really is happening right as if the that space itself is like a rubber band which you can pull and and obviously then the two points in the rubber band would move away from each other right now if you take that rubber band and you you let's say put markings on that right like let's say you have a marking every centimeter right and you hold one of the 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 the one 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 right 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 right so it would have moved 10 centimeters in one second so so but the markings are really not moving in that sense right it's the 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 faster they move right now in context of going back to this image in context of this image that one spec of flight there are two interest interesting points about that which they've identified as to be from 13 billion light years away well I should correct myself it's 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 the that object is 13.1 billion light years away right 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 right it was actually much closer to us right it was roughly let's say 2.5 billion light years away however once the light was emitted and it 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 right and so because the space is expanding it took much longer to reach us right 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 has now is now like more than 30 billion light years away from us right so that's one interesting aspect to this and so 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 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 right 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 the s max 0723 galaxy cluster is acting like a gravitational lens for that very distant galaxy and to explain that concept this really takes us to Einstein's theory that gravity is created by a mass like any mass distorts it's the space time around it right and so this gravity this galaxy cluster that it's 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 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 it's it that its image is getting enlarged by the s max huge galaxy 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 about actually finally a one final question on this which is that of course we're talking about you know 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've seen we've 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 you know we get these pictures of course they're exciting you know they provide quite a bit of say you know they add some drama we get some interesting factoids about the past 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 the like you said there's already 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 right 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 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 the our view of the world and the solar system changed radically about 500 years back with with what is called the Copernican revolution right before that for for like 2000 years or about 1500 years people used to believe in the ptolemic version of the 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 while the the sun is the center of the solar system and we are like revolving around the sun that leads to many things like it it it's first of all the church kind of totally looks down upon it and tries to suppress it and because it shakes the our our like 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 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 the orbits of planets so it had to be constantly refined and each refinement leads to a new discovery a new scientific achieve a new scientific progress right so you then had Kepler's laws which said no the objects are elliptical but Galileo come along and Galileo discovered the telescope right so 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 it we really the next massive discoveries come from Newton and 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 and so this is how science has always progressed and and for our generation we are seeing with the Hubble and now with the James Webb 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 Baba 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 James Webb space telescope it needs to be mentioned that a number of scientists have raised objection to the name itself that's James Webb now James Webb 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're called for renaming the telescope maybe to the Harriet Tubman space telescope in honor of the under 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