Focus 580; The Hubble Telescope and The Space Telescope Program

The Hubble Space Telescope has now over the last 14 years provided us with a ever greater understanding of the universe. However the future of the telescope now is in some doubt if mission to do some repairs and refurbishing is an accomplished stratum or say that sometime within the next couple of years the Hubble will be nearing the end of its useful life and there are a lot of people in the field of astronomy that things of that would be too bad. But there's no reason that the instrument shouldn't continue to add to our knowledge about the universe providing that it is maintained. We'll be talking a little bit about the Hubble about more generally perhaps about space telescopes and the advantages they present and also about another instrument that sort of the next generation space telescope and we'll get people who are listening the opportunity to call in and ask questions we have two guests with us this morning in this part of the show. Mario Livio is adjunct professor in the Department of Physics and Astronomy of the Johns Hopkins University he is also an astronomer at the Space Telescope Science Institute. John

Bacall is part of the Institute for Advanced Study at Princeton University where he is also professor of natural. Science and both of them have been following the issues connected with Hubble for some time now. Questions are certainly welcome from people who are listening. If you'd like to be a part of the conversation all you need to do is call us here in Champaign Urbana 3 3 3 9 4 5 5 is the number we do also have a toll free line. That means no matter where you're listening if it would be a long distance call you can use that number and calls on us. That's 800 to 2 2 9 4 5 5 3 3 3 WRAL and toll free 800 to 2 to WLM. Well Professor Liviu Hello. Hi and Professor Bacall. Hello. Thank you both very much for talking with us today. I certainly appreciate it. You know. I want to ask some fairly basic questions about Hubble. One thing that I'm sure that people who are interested in astronomy will understand is the advantages

that a space based instrument gives you. However people who don't might not really know the difference. We do indeed have and continue to use ground based telescopes. But maybe you could talk a little bit one or the other of you could talk a little bit about why it is that having the instrument in space above the atmosphere of the earth gives you an edge over what you can do with a ground based telescope. Well maybe I'll give you just an energy option to that. When we were working first to sell the space telescope we used to say that the telescope would be placed out beyond where the stars twinkle. That indicates that the interference from the atmosphere of the Earth does not make the images lower. You see things much more clearly from space and you can from the ground. And in addition you can see colors from studies that you cannot see

from the ground because some of the colors of astronomical objects cannot penetrate thier sadness fear. It was that initially a difficult argument to make that we should spend the money to put it up there in the first place. It initially looked like mission impossible. We got started with a small group of people mainly interested in space astronomy but as time went on the larger community of astronomers became convinced that this was a great thing to do for our entire science. However people that now were not so convinced and in fact the NASA's administrator at the time James Fletcher went to President Nixon and told him that he needed a new shuttle orbiter.

And the price that the Office of Management and Budget should put up on the new orbiter was such that he would have to choose between either the orbiter or the Space Telescope. And he made that decision without consultation with any of the scientists in the program. He chose an extra orbiter and he fought and initially the efforts of the astronomers to lobby the Congress to overturn that decision. Is that a reflection of what has been perhaps a continuing sort of tension between groups who are interested in different things. That is between people who are interested in what you might argue would be pure science that is simply learning trying to learn more about the universe and its history and how its put together. And those people whose interest in space may be commercial may

be defense oriented. And both of those kinds of interests are competing for money they have different sorts of constituencies. It seems that that kind of argument if you had to use the term argument has been going on for some time now and maybe we expect that will thats never going to go away. I dont think its groups of people with particular interests. I think there are individuals with particular points of view and I think people on all sides of the spectrum are in awe of what the Space Telescope has done and are very appreciative of the science and of the prestige that its brought to our nation. It can you can one of you talk a little bit about obviously there there has been a lot of knowledge generated by Hubble but maybe can you pick up one or two things that you think are particularly interesting or particularly important things that we've learned

because the Hubble is there that we didn't know before. Sure. Let me give you a few examples. So one thing that we have known for a long time in fact since the 1920s was that our universe is expanding. It is not standing still. But what we have all assumed for a long time is that these expansion should be slowing down in the same way that you know if I throw my keys up on art they're slowing down because of the Earth's gravity. We thought that under the gravity of all the mass within the universe the expansion should be slowing down. Now what we have found not just by Hubble by a combination of Hubble and ground based telescopes and other space telescopes we have found just in the past few years since 1998 is that these six. Tension is in fact speeding up and we now know that this expansion is being pushed by

some form of energy that you know for lack of a better name we call dark energy which is 73 percent of the energy of the universe and which we don't have a conduit. The moment was easy and you can imagine I mean you know the surface of the earth these covered 70 percent with water. Imagine that we had no idea what water was. This is one of the things that Hubble has afforded us. Another thing is how Bill is given us the deepest view of the universe in the type of light that we can see with our eyes our universe is now about thirteen point seven billion years old. How cool is given us a view in the combination of optical and heat to light infrared light has given us a view of the universe when the universe was less than a billion years old. So it's like you know looking at you think a

person that 70 years all day and you know you look at it 20 it's just a small shot. Given the first two most Year of the planet outside the solar system the composition of that atmosphere because there is so doing there there is hydrogen there there is carbon and oxygen. You know primates outside our solar system. And just you know a few examples from the many many things that probably is not. I'm sure that people will remember when Hubble was launched there were some problems with it that were then corrected by a mission that went up. We sent astronauts that went up and did some repairs and from that point forward it continued to perform where Whelan and give us lots of useful information. People I'm sure tho will remember there were a lot of jokes made about Hubble and its problems initially. Can you can one of you talk about and

maybe again this would be John talk a little bit about what caused the initial problems with Hubble. Hubble's mirror was ground perfectly to the wrong prescription. It's like you had your glasses but somebody else's prescription so it didn't fit the telescope and and the instruments that we had what was necessary was to put an extra an extra optical device inside the telescope or inside the instruments so that to correct the imperfect curvature of the mirror. Now the mirror is better than we had with the correction is better than we had interests of painted before the telescope was launched. Yeah you're right about the business. They know that there have been a nice jokes about these. They even featured in one of the Naked Gun movies you know is a

disaster and so on. But what is more important is that through the ingenuity of scientists and engineers and you know the work of the astronauts I mean that the mission of error has been turned into one of the biggest successes of science ever. So I mean to some extent even that the initial error actually adds to the drama that you know has been surrounding the start of school. You take something that was supposed to be the biggest scientific failure and turned it into the biggest scientific success. Well many people think that the caller's scope is indeed the most successful large science project ever conducted. What's been the price tag so far what it cost us to to build Hubble and to put it up. Well that depends on what items you include but roughly a

billion dollars. Then it was the nice show cost and of course you know if you start including from that you know what the cars cost good scenes. Then in terms of you know everything that is going into it to a few billion dollars. And how does that compare. I'm just curious about the cost of other things that we've done in space for example how much we've spent so far on the International Space Station. Tiny I think. We think and much more on the I think it means on the international space. Yeah I think the international space station was initially there was an agreement that it would never exceed eight the dollars. I think it's around somewhere very crudely around 40 billion dollars. And if the current NOW IT'S A plans are really carried out and it's completed it may double not price. So our space telescope is tiny compared to the International Space Station.

We have two guests with us this morning in the first hour focus and probably I should introduce once again the two of them. Last person you heard is John Bull call from the Institute for Advanced Study at Princeton University where he's also Professor of Natural Sciences. Also joining us is Mario Livio. He's adjunct professor in the Department of Physics at astronomy of the Johns Hopkins University. He's also astronomer at the Space Telescope Science Institute. And we're talking this morning obit about space telescopes we've been talking here about the Hubble and we'll also be talking about the next generation space telescope the James Webb Space Telescope questions certainly are welcome if you'd like to call in. 3 3 3 9 4 5 5 that's the champagne Urbana number we do also have a toll free line. That one's good anywhere that you can hear us and that is 800 to 2 2 9 4 5 5. You're talking just a little bit earlier about the fact that there are many people who would consider the Hubble to be the most successful big science project ever if not the most successful I'm sure that

people would consider it among the the most successful. But now the future of the Hubble there's some question about the future of the Hubble and whether it can be continue it can be repaired and kept going at least for a few more years and generating more more information. What what exactly is the problem with the Hubble now or what is it that that if we're going to keep it going. Needs to be done well. The uses gyroscopes which he uses to point and beat also uses a batteries that give each power the gyroscopes you know have a certain failure rate. Hubble can operate fully on three gyroscopes. There are no plans to make it operate even on. But the problem is that if you look to the past and the rate that to each gyroscope you know have been become defunct. You find

that some time in the time frame Wolf around 2007 or thereabouts it will be down to one gyroscope which would not allow you to continue with science program. Similarly if you look at the batteries those are going to run out also around maybe two thousand eight or so time frame. So the point these that the telescope will be from the beginning to be serviced and indeed has been serviced four times by shuttle astronauts. And in every one of these service NGs they both do maintenance work you know like replacing bed gyroscopes and so on. And also they install new instruments which make essentially almost to be a new telescope. We current. I have two such new instruments on the ground ready to be put up and the maintenance work. You know that needs to be done. The problem here being that in January 0 the CDR

the NASS administrator made the announcement that because of the Columbia disaster there will be no more visits by the shock to Hubble since then many things have happened including an important study by a committee chaired by by John on a study by the National Academy of Sciences and so on and great support from the public and the idea now iis that the telescope may be serviced or robotic. He is not by the shocked a lot by human Ostrov but by a robotic commission that will perhaps do all of these and this is currently under study. Well do you is the thinking that this this robotic repair mission that we're talking now I think about a robot that was that's built in Canada. Do

you think that that's actually up to the job. Because apparently the kind of tolerances and the precision that we're talking about to do these repairs are pretty tight. Well I think there are demonstrations that there are so far no showstoppers that is to say the things that have been tried seem to work seem to indicate that their robotic mission is possible in principle but any new space mission especially with an untested technology is very risky. You never know whether it's going to work until you try it in space. Professor Liviu was just talking about the fact that there there had all along that the idea was that periodically that Hubble would repairs maintenance would be done and that would be a way of extending its life and it had been done in the past by astronauts but when the shuttle fleet was grounded after the disaster the Columbia

disaster in February of last year 2003. Then after that the NASS administrator said Well we're we're not going to be able to do this anymore and then in response to that that many people in the scientific community astronomers and so forth said hey wait a minute this is this would be a this would be a real loss. So we ought to find some way to deal with this and that's what we're talking about now. If if it had if the Columbia disaster hadn't occurred last year would there. Would we be having the discussion that we're having now or would we have had this discussion about should Hubble be allowed to die or were would just continued with this kind of periodic maintenance and what before the Columbia disaster what were people thinking of in terms of the expected life. Well you know one of the planned servicing mission already is they say there are you know ready instruments and that's and that servicing mission should have happened. In the coming year and that would have done precisely what was needed in

terms of both maintenance and putting in new instruments. In fact one of the things that the committee that John chaired was looking at was even the possibility to have yet another servicing mission beyond that one to extend the life of the telescope even further. But there was no question about you know the existing servicing mission taking place and thereby extending the life of the telescope at least to the planned date which was 2010. So even at the beginning nobody was thinking that Hubble would be would be there forever but that it would have a useful life in and then at a certain point it would be it would be decommissioned and it would be allowed to come down. That's right. One always needs to turn off even productive instruments in order to be able to afford the new generation of instruments and devices.

When you have a finite budget as we do in science well if the kind of repairs that we've been talking about can be accomplished. No assuming that that could be done. Now what does that mean for the life expectancy of Hubble. Well you know that of course that would not if it were to be a robot decommissioned it would not happen immediately because of course as John say that has never been tried before it would take a few years to prepare such a mission. But if that commission were to happen let's say in the 2000 seven or eight timeframe then that the idea was that that would extend the life of the telescope and in fact would continue with a telescope for another five years. Is this is the question here the primary questions about whether or not this repair mission can be can be mounted. Are the primary questions here technical. That is can we make it work. Or is

there still some question about money and how much is going to cost and where that money will come from. Well of the money is not fixed yet because the one thing that has been made clear by the in years and years of experience with Nassa development is that you can't predict how much your project will cost until you complete it. At least for the innovative new projects and this is one such project one could control the cost for a future shuttle mission. And in fact if you church shuttle mission was endorsed by 40 x astronauts who no longer work for NASA's I think the astronaut community have joined with the scientific community and in fact with school children throughout this country and saying we ought not to let Hubble die and the astronauts are eager to service the

telescope with a shuttle mission if allowed to do so. Yeah. You must realize that it does not. Hope that the talk is not that Ostrogoths would not fly at all. I mean not to steal plans or order 25 missions to complete the space station with the shuttle so you know what John was just saying is that many scientists former astronauts and the public in general say you know one extra mission to hobble is definitely worth it. And the difference in the safety between going to Hubble and going to the space station is a matter of debate Admiral Geymann and his person who chaired the committee about the Columbia disaster in his testimony before the National Academy Committee said that he had read an interesting and convincing analyses on both sides of the question which was it more dangerous to do to go to the space

station or to the Hubble. But he said in any event the difference was very small it was measured in tens of a percent. Just as a server really meaningful at that level. So it's clear that if you have two almost equivalent missions if you send one to space station and one does shuttle a one to Hubble then it's much more dangerous to go twenty five times the space station than once the Hubble. But I guess with just one thing we do need to keep in mind is that going to space is dangerous full stop. That's And you know it's going to space station is dangerous doing this is dangerous. Any any time you go into space is dangerous. So the danger is pretty much equal. I've talked to feel very strongly that if they're going to into space and risking their lives they'd like to do it for something that changes human history like the Hubble Space Telescope. We have a caller to talk with let us do that. Someone listening this morning in Indiana

on our toll free line 1 4 0 0 0. I must have my history confused but my understanding was when Bush announced that he wanted to plant a man on Mars. That's when NASA's said well that's the end of the shuttle program. And forget about Hubble telescope for repairs. Is that not true or is it been mistaken all along. There was a coincidence in time but the President's Bush's initiative which is almost identical to his father's initiative many years before but which is not as well funded as his father's initiative was. His initiative was announced and slightly below before that the decision had been taken that in order to reorient the agency and to save money and for various other

reasons none of which have ever been made crystal clear to the scientific community. The decision was made to not go to hobble but still to send 25 space station 25 shuttle flights to the space station. One of the things that has been argued is that if we are indeed going to return to the moon and have some long term. Human presence on the moon or if we're going to think about something like Going to Mars that there's much more we need to learn and know about living in space for long periods of time. And that is one of the things the space station will do for us. I wonder is do you buy that argument is that true. And you know how do you make the argument for spending as much money on the space station as it's going to cost.

Well look Space Station is primarily I think regarded as a technological achievement. I mean it would be very D.C. cooks to argue that space station is scientific could be a very important instrument. I mean if you think NO lot you could achieve man that you are able to be in space and work in space and be that relatively complex structures in space. But you know with one point you have to decide that if you like the clear success or victory and that you have achieved that and that is eat it. Absolutely true that if humans were to go to Mars you would need to overcome many many problems associated with the exposure of humans to a very very long drapes in space. And this in fact is going to be probably the biggest challenge to

any such program I mean even more so perhaps than the than the technological challenge involved whether a space station ease is precisely the right two way of doing that. I think I'm clear. And in any case I mean you know we have current robots on Mars and they are doing an absolutely fabulous job. If you have seen the pictures that come from there. So you know we could continue to do that for a long time. Well given the fact that. That again I say we're talking about going to Mars we're talking about very large technical problems that need to be solved and it's going to be very expensive if we decide that we're going to do that. And since there is only so much money going around that means that if we decided to do that maybe there were some other things that we would not do. What do you think generally about this and perhaps in a sense Professor Levy you've already answered this question but about doing

what it would take so that we could have a human being standing on the surface of Mars and it is as far as science goes is that is that something that's important to do. I'd like to answer that. As an American citizen and as a member of the human rights I think it's something that we would all be thrilled and enormously proud to have a human do. I think it's inspirational. I think the challenge to do that would invigorate our our science and our technology. And it would provide a focus and a unity in a coherent far space program. Whether it's going to be obtainable on the time scale that's been set and whether we're whether the this is the right time to do it.

Given the budgetary constraints that we have because of the many obligations internationally and and within the country that's another question. But I think all of us would be proud and thrilled if we could put a presence a human presence on Mars. We're a little bit past a midpoint here we have another call we'll get right to. Let me get introduce our guests. John call with the Institute for Advanced Study at Princeton University he's also a Professor of Natural Sciences there. Mario Livio is adjunct professor in the Department of Physics and Astronomy of the Johns Hopkins University he is also astronomer at the Space Telescope Science Institute. Questions are welcome 3 3 3 9 4 5 5. Toll free 800 to 2 2 9 4 5 5. We have a caller in Bloomington Indiana. There Indiana listener here line number four. Oh hi I have two questions. Do you know how time is allocated on the Hubble telescope. What astronomers get to use the Hubble and how is it determined what they will study. OK I can answer that.

We have a very it to elaborate process of determining that every year as you did by my wife. It was all we had reveal any confidential conflict of interest there. Every year there is a call for proposals for astronomers from all over the world. And they propose to use the telescope to solve very specific scientific. Problems so when they submit proposals in which they describe in great detail what scientific problem they want to study how the telescope is going to be used to study that problem they specify precisely what observations they need to do and in particular they have to demonstrate that the solution to these problem absolutely requires the use of the Hubble Space Telescope in that it cannot be used. Done say from the ground. Then the

institute that which I am the Space Telescope Science Institute convenes order Tempero xover experts in different fields of astronomy and these these people. Study the different proposals because we get off order a thousand to twelve hundred proposals every year so they study first affording the different the Supremes these proposals and rank them really to rather rank them you know best to worst then we have a large time a location Committee which is composed of experts from all the fields and that time a location committee looks at what was done in the different panels and also looks at the large proposals that have been proposed and so on and the net result of all of these is a rank through Least of all the proposals. We then know exactly how much time is available for observation in every year you know given the efficiency of observations. So this of course marks a line as to which

programs are going to be a. Cute. That's very interesting. I have one more question. I assume that the Hubble telescope has about a 90 minute orbit time around the Earth about 96. OK. And for more than half of that time the Hubble is in sunshine. Can the Hubble be used when it's exposed to Sunshine is it any good. Yeah exposed to Sunshine is not the problem of course you cannot observe anything that's very near the sun public and let the open serve the sun or a kennel to observe things like mercury which are too close to the sun. What these more important is that the reason for a part of the aura beat the reason earth Oku basin where the Earth of course so called parts of the sky. So that is the part that is lost in terms of observations I guess the reason that our telescopes are no good on earth during daylight daylight is because we have an atmosphere and the atmosphere is a is reflecting light all over the place and it is

right. That's right. OK with that thank you very much. Thanks for the call other questions are certainly welcome 3 3 3 9 4 5 5. That's the one to use if you're here in Champaign Urbana where we are. We do also have the toll free line that's good anywhere that you can hear us and that is eight hundred to 2 2 9 4 5 5. We talked a bit earlier about the fact that astronomers always knew that Hubble would have a certain expected life and that a point would come when it would no longer be functional and it would come down and that even if the repair mission that we discussed earlier even if that happens well the same thing is true with that that's going to extend the life of Hubble for a few more years but then again it will come to the end of its life. One of the things that I wanted to make sure that we talked about was that what sometimes referred to as the next generation space telescope the James Webb Space Telescope and this was something that actually astronomers began planning for even before Hubble

was launched back in 1909 I believe if it can one of your preps both of you say something about this telescope and in in in what way or in what ways it's different from Hubble the James Webb Space Telescope is a very different telescope from Hubble. First of all open primary infrared or keep ready a sun if you like. It's a little beat in the infrared but mostly in the type of light that we see. And in ultraviolet light the James Webb will observe entirely in the infrared or heat radiation. It would be a much larger telescope the Hubble used the main mirror is two point four meters or about eight feet in diameter. The James Webb Space Telescope will be about six and a half meters

or 21 feet in diameter. How bullies Ingin or beat very close orbits around Earth which allows the shuttle to go to eat and service it. The James Webb Space Telescope will be not serviceable and we will be at the point which is about a million miles from Mars. So they're very very different telescopes. The main focus off the James Webb Space Telescope is going to be the very distant universe. The point is that because the universe is expanding the farther you look light shifted more and more into infrared. I mean a lot like you see directed out to infrared. And so if you want to observe the most distant universe then you have to look in the infrared. So so on the one hand this is the continuation in the sense that this

is the next you know type of a general purpose space telescope on the other. They are very very different telescopes. Well sometimes we are asked Why do you astronomers need two space telescopes and I think the answer can be made clear. Certainly in this season I saying that if you're going to play the game of trying to figure out what nature is like you can't play the game with just a pitcher or just a catcher. You need both a pitcher and a catcher. You know a nice metaphor and so is that people should understand that this is not going to replace Hubble and when Hubble is gone the kind of things that we've been able to do with that we're simply not going to be able to do any more. This will do something different perhaps add to our knowledge in different sorts of ways but when when Hubble is gone that's gone and that's the end of that kind of observation. You're a very good steward here. It does. Does the fact that the Webb telescope

is going to be out further and that there is no possibility of sending a mission to repair if there's some problem with it does that make astronomers nervous at all that you got your one shot and if somehow something goes wrong or it goes wrong when it's out there then there's no way to go and fix it. Astronomers are always nervous very nervous when a new project gets started and every time any one of these very complicated very difficult. New developments of technology is placed in space. It's a miracle when it works. It's just that we've had repeated miracles. Let's talk with another caller someone I expect must be listening on the Internet because they're calling from San Francisco. Line number for our toll free line. Hello. Morning all. I had two different questions. I understand the Hubble will be crashing to earth at some time soon so in this case it's not necessarily germane but it has to do with salvaging

the product that we the taxpayers have paid for. So I'm wondering as privatization continues down here on earth we're essentially sending up a lot of very expensive items in some cases you know radioactive isotopes goal massive them for gold as I understand it and some other minerals that are pretty expensive. And and then the high tech that goes with it. And what is it you know in the case of the Hubble telescope it almost seems like it was high dollar to begin with and then made obsolete through some flaws and then. And then upgraded and then allowed to to be destroyed through lack of budgeting. And I'm just wondering about this. This aspect of privatization that will allow some of the some of our

products to be salvaged at rock bottom cost by somebody else who we don't necessarily want to give it to. And I had a second question also and this involves maybe something a little more insidious and that's that you know we've got a problem with. Well let's start with that one. Well that's a difficult one I don't think we know of anybody who has the technology to salvage the components of the Space Telescope. That's why does new mission is. So it's a pioneering challenging mission to develop a robotic way to do that and it will certainly cost much more than the salvage value of the components after all the technology for most of the telescope is technology that. More than two

decades will. Maybe I should mention that. I mean the Hubble can not just be left to fall bytes it is because its mirror is going to survive and the probability of heat actually hitting something is more than the threshold of knowledge for such missions and this is the reason that what one of the things that the robotic mission will also do is attach a propulsion module to Hubble that would have had a picture be directed into the sea when the mission is over. All right there really has to be some sort of an effort to reclaim it. I think the second question has a little more to do with theory and you know it's my understanding that string theory is not necessarily proven. Einstein's relatively relativity tends to be the norm

and that in certain aspects with Hubble it's being able to prove Einstein and somewhat disprove string theory. Now in in my understanding of Star Wars a lot of the Science of Star Wars is being proven to be a fraud. And so the very odd fact that Hubble is out there showing that that Star Wars is a fraud is of a danger to the military industrial complex so that they would want to to essentially allow this conflict of Sciences to go on and allow their budgets to go on if Hubble is to shut down. Then their their pseudo science can continue. And what I'm concerned with is whether or not they're there defunding the program is going to allow bad science to continue and and such.

Under the guise of top secrecy they're going to be able to have all sorts of pseudo science with fantastic but I don't think there's any connection in anybody's mind between the operational budget for the Hubble Space Telescope and programs to use missiles of missile defense. No I understand that I'm just talking about being at the Hubble is able to essentially prove or disprove string theory. Aaron an error in relativity right. No no. The predictions of string theory are not accessible to Hubble nor to any device that we know about. Practical device that we know about today. Saw that has nothing to do with with Hubble's operation or its achievements. Your By the way if I don't know if you have a GP s

system in your car but your car if it locates your position does depend upon an accurate use of M Stein's equations so your car can be said to be proving Einstein's equations every day. If you have a GPA system in it. I'm going to jump in here just because we're coming down to about the last five minutes or so and I'm just I'm curious again to follow up though on one of the points the caller made about salvaging the possibility of salvaging some pieces of. I mean is it is it the case that given the fact that it would be difficult and would be expensive and the fact that the technology now is a couple of decades old would just mean that there would be no point in doing that. Well at some point there was some discussion actually about the shuttle going up and trying to bring Hubble down intact to actually it for it to be put in the Smithsonian in the Air and Space

Museum. However this is not very easily achievable certainly shop those are not going to fly to Hubble again it's not going to happen. And in general I mean the feeling you get from Ostroff as John mentioned before is that astronauts are willing to risk their lives eager eager even to risk their lives for something that they see as you know the best scientific experiment of all time. They are really not that eager to risk their lives you know just to you know force some sort of show type thing or for it to put the Hubble out of its misery or things of that nature. We talked I did ask you a little bit earlier to talk about the James Webb Space Telescope and I think professor Leo did explain something of what it does and how it is different from Hubble. That is it's sees in a

different way. Can you could you talk about or one or both of you talk a little bit about some of the questions some of the scientific questions that we might use the James Webb telescope to investigate what sorts of what sorts of things will it tell us by the way that it sees. Well in particular it will actually show us the first generations of stars and galaxies in the universe. As I told you with the Hubble we can see when the universe was less than a billion years old. But we were ready see that there are God oxys out there. They are smaller than today and more disturbed looking. But we see that they are there with their James Webb. We will be able to look even farther back in time so that we would actually see probably the first generation of galaxies that have formed we would be thrilled to see you know how. Things like the milky way in which we leave have started

from their infancy. How the first star stars started to shine their light in the universe and how they could make it to form these you know island universes which we call God axes today. This is one of these these ideas that every time I say it it amazes me and yet I'm still not quite sure I understand it but at least I understand it well enough to know that the further away that you're looking the further away from the earth that you're looking. You're also looking further back in time. Absolutely. The telescopes are real time machines. It just it my mind is I guess easily boggled. It's a concept that I'm afraid boggles my mind. It's just the fact that the light takes a finite amount of time to get to us from where it's admitted. So if we receive it today it was admitted earlier. If we receive

it today from a source that is relatively nearby like in our own galaxy then it was emitted not too long ago. If it was omitted from a source which is as far away as we can see then it was amid billions and billions and billions of years ago right. The light that you see from the sun right now was a meet at about 8 minutes ago. The light that was you see from a galaxy that is a billion light years away was a meat that about a billion light years ago. So assuming that we had the the the way to do it. How far back in time do you think it's possible to look. Is it actually even boss able to answer a question like that. Well it does in some ways I mean the universe was completely opaque to read the ation when he was about four hundred thousand years old and there was actually a satellite called the W map that observed the

radiation that comes from there. That is what we called the COS make microwave background. You cannot see with light like you know the James Webb or Hubble he's looking beyond that point. I mean not even in principle. So in that sense we're not going to see beyond that. Now there are other ways to try to detect things that happen before that. By the structure that formed in things like these there would be other satellites like W map in particular one called Planck to be launched around 2007 that we'll look at even finer structures in the cosmic microwave background from which you may be able to tell even on things that happened when the universe was on the a fraction of a second all but the gain in directly. Well you know we're coming to the point where we're going to have to stop because we've used the time and simply want to thank both of you for having talked with us this morning. Professor Livio I want to thank you very

much for being with us. My pleasure. Mario Livio He's adjunct professor in the Department of Physics and Astronomy of the Johns Hopkins University and astronomer at the Space Telescope Science Institute and also joining us from Princeton. John Bacall from the Institute for Advanced Study there. Professor McCall thank you very much. It's always a thrill to talk about the Hubble telescope.