Interview with the 2006 Nobel Prize laureates in physics, John C. Mather and George F. Smoot on 6 December 2006. The interviewer is Adam Smith, Editor-in-Chief of Nobelprize.org.

John Mather, George Smoot, welcome to Stockholm.

John Mather: Thank you.

George Smoot: Thank you very much.

When you very kindly spoke to me just after you had heard the news that you had been awarded the prize, George Smoot, you mentioned that you had 170 students in California who were expecting you to be there this week.

George Smoot: That’s correct. My superior and chairman at the department is teaching my lecture later today and my alarm already went off saying so to my lecture but there’s now a time difference, so she still has three more hours.

So the students have been understanding, do you think?

George Smoot: Yes, though they were disrupted by photographers and other things that went on.

Teaching is a very important part of your research career?

George Smoot: I see my job as both doing research and preparing the next generation. I like teaching. This semester I am teaching freshman physics, the second semester of freshman physics, it’s the thermophysics and electromagnetism. It’s a hard course for the students, but it is for all those who are going to become scientists years later.

Is it unusual for somebody at your level to continue to teach undergraduates?

George Smoot: It may be unusual, but the university requires us to teach, so unless you can pull the strings to teach upper division or graduate courses all the time – which some people do – your … will easily go between lower division which is the first and second year and the upper and graduate courses. I go between those.

Is undergraduate teaching a big part of your life as well?

John Mather: No, since I am a full time NASA employee my job is primarily to conceive and build new space projects. I do a lot of public speaking now, especially now since the prize announcement, but my main job is working on the project. In my case now is the James Webb Space Telescope, which is the successor planned for the Hubble Space Telescope. It would go up in 2013, so that’s my main job.

Do you pull graduate students into …

John Mather: We can, but we don’t usually, because it is hard for a student to compete with the professionals and get a thesis project from working on something that is being built. Mostly the graduate students work with missions that have already been launched.

It would be interesting to explore the difference between choosing students, graduate students to work on projects, and professionals to work on NASA projects. What do you look for when you look for those people?

George Smoot: It’s very different because with professionals on a big project like John’s project or the space project we are doing, you have to meet a deadline, you are meeting other people who are well trained and experienced are there and everyone has to work together as a team and meet the deadlines. With the students you are bringing them on because they show promise, and they need to learn and experience how to do science. It is very good to get them involved part time in a big project so they can learn about that later, but you have a small project that they are responsible for. If they get in trouble, you’ll have to bail them out in the big project. If they get in trouble on their own project, you can let them flounder until they find their way and it is very different. Right now I have five graduate students, one, … from Korea; one Daniels from Mexico; there’s two Americans, Mia Emm and Michelle Delinski who are Americans, and then I have one Italian student, Sarah … They are all doing different things, Sarah is working on the next generation cosmic background satellite, but she is working on how to separate the foregrounds from nearby galaxies’ signals from the distant signals.

So, microcosm of the international space center really.

George Smoot: For me there is sort of a sequence, you’re not only working in projects that are going on, the way that John is really focusing on, major projects, the James Webb is one of the biggest projects there is. I am sort of on intermedia projects, this Planck with European Space Agency and with some NASA … and I have also some other projects going on, so you have postdocs you’re training there, in the transition between being students and being fulltime researchers. Then graduate students and then I have undergraduates studying research projects with. I even take on high school teachers and students and so. We have an outreach thing which I would show you, just to explain the different paces of the universe. We have high school teachers and undergraduates involved and putting this together on the website, to make it available to high school students. It’s this pipeline where you start training them and until they eventually turn out to be in John’s area where they are doing the work.

You are looking for people who are just fully fledged, ready to go?

John Mather: Yes, we look also for young people that have promise and we hope to bring them in and let them learn the trade of space engineering and space science by working with people that have been doing it before, because there is a special discipline and knowledge about things that are very strange and things you would never think of worrying about for space missions. The fact that you can’t go and fix them ordinarily is a very special challenge for people because it is exactly the opposite of a graduate student project. On a graduate student project is working, you take data and publish your paper, and then you are on to the next one. With the space mission you get it working and then you have to make it work for quite a few months and before you trust it to send it up at the space where there is no hope of repair, usually, so it is a completely different discipline, but one well worth mastering because of the things that one can get only in space.

I imagine people have enormous self-confidence once they are ready for this.

John Mather: I don’t think so, I think we have to have accommodation of confidence and caution. The person who is too confident is dangerous and the person who has no ambition is dangerous. We have to have a mix of the things that are beyond what we can do but can still be proven. This is what we do.

From the perspective of the people who come to work for you, what do you think they look for from you, from your experience of your own scientific evolutions? What do you think makes a good mentor?

John Mather: I think that for me the people that have been mentored are the ones that have a creative process and have some knowledge of a wide variety of fields because the things that we have to do are usually spanning many disciplines. To get something to work in space you have to know a little bit of mechanical engineering, … engineering, electronic engineering, optical engineering, kinetic engineering, communications and to be sufficiently afraid of the environment out there to make sure that you think about all the things that could go wrong with your idea before you proceed. That is what I am looking for, people that have that combination.

George Smoot: It varies with the level, we have graduate students who are looking for their first research experience and get a chance to see what doing science is like and just go forward so they can get recommendations to go to graduate school, it is learning now plus preparing for the next job. With graduate students it is a much more personal and intense experience where they have to come in and learn techniques from you and then take it in their own hands and handle it themselves. Then you have to prepare them to write papers and give talks and go out and find their next job and in fact even the job after that because usually the first job is the … job which is a transition job and then they go into permanent jobs. For postdocs, they are looking for a chance to do research that they can get their name on, give presentations and then go on to the next job, go to a permanent job, so it depends on what level you are on and what’s going on. Sometimes they come because they are very excited about the science, and they don’t even realise that the process is an educational process and a launching into the next phase process.

I suppose that there is a lot more to it than the science, especially with a project like COBE which involves thousands of people, you have a lot of administration and management to do as well. Is that increasingly the case with physics research, do you think, that these skills have to be learned alongside the scientific skills?

John Mather: I think so, although it is hard to learn those in school, one has to learn in a crucible of ‘trial by fire’, I think, you develop them by learning, on a job. Some things I think people learn when they are young, to play as team members and other things you don’t learn until you are actually there.

How did you learn?

John Mather: I learned it by actually being there. No one hands you an instruction book and says ‘This is how you are a leader of a space project’. You are 28 years old and you have never done this before, but this is your job, so you do it.

George Smoot: You could say the same thing of the Nobel Prize. It would be handy if the Nobel Prize announcement also came with a handbook – of what to do, what is going to happen next and so forth. You have to learn and be flexible in these kinds of situations, but in fact it is all about learning, and teaching people how to think and how to react and how to behave. I think that we inherited an era which came from … who was the preses really, with the beginning of big science where you put teams together to solve certain problems that were so challenging and so interesting that many people would want to do. And it comes down to everyone agreeing that the objective is very important, and that was so important for us for COBE, was to do that and part of my job as … to go and give talks to the team and keep them enthusiastic, going to the Vandenberg site, giving talks to the air force people and … people just to make sure that they were motivated. It wasn’t just another job for them, they were going to put the rocket right. We were both very nervous at the time of the launch because it was one of the last rockets and there were rusty parts …

John Mather: Yes, it was quite a job to get the rocket ready.

Because it ended going up on a Delta rocket.

John Mather: It was indeed.

It wasn’t intended that way.

George Smoot: That was not. The fact that Delta line had been discontinued for a while, and there were just parts lying in a warehouse rusting. They dusted them off and assembled the rocket for us – it gives you a lot of confidence.

You must have a lot of power to make that happen as well.

George Smoot: It’s power persuasion, it’s the power that it’s such an exciting attempt and path of adventure to follow. It was the crew who got excited about the fact that we might learn about the Universe, even that we didn’t know what we were going to learn. That’s the challenge and the fact that the scientists were so thrilled about it.

John Mather: They really worked beyond what they ordinarily would be called on because they knew how important it was to so many people.

Was the challenge a disaster and the set back that resulted from that the most challenging part of the project? Was that the bit where you needed the greatest confidence to continue?

John Mather: I think so, because when that happened we didn’t know that we would ever getting a chance to launch the vehicle, so we were dependent on finding a completely different alternative. We were very fortunate that our engineering team found a way to do that and we had to lose half the mass of the pay load in order to get it onto the Delta rocket. We were very fortunate there was a different design that was possible, because the Delta rocket is different from the space shuttle, so was able to do that directly.

George Smoot: What happened, we almost had it all assembled. I still have the pieces, the framework from one of the – my instrument came in three pieces – from one of the three receiver pairs. I still have the framework for what was going to find the Delta, because we had to lose weight and shrink in size, we had to rebuild everything. We took the sensitive instruments out of it, and I saved the pieces and reassembled it in. A student and I reassembled them in the lab late one night, so I still have them in my office.

I think it is interesting to think about how one keeps the motivation going through a disaster like that. I can see that individually you can keep your focus, but you have got this enormous team of people who you need to bring with you. How did you go about making sure that people …

John Mather: I think we depended really on our project management which worked so diligently to find a way, and as soon as there was a hope that there was a launch vehicle people were so thrilled that we could actually go again. As soon as that happened there was no problem, and in the meantime we just thought we were doing our job, we will find a way, so I don’t think we lost a lot of momentum on that.

George Smoot: That was exactly … investigators, you have to believe, you have to keep working, show enthusiasm, and there was a core of the teams, they saw you working, they kept working and the other people kept working although you could see their enthusiasm was down a bit because everybody was nervous. It’s not the only chance but that was the one that affected the whole team, hundreds of people at the same time, and the fact that we were going for it and that we would say the same: We’re going to find a way. Then NASA said: Look, we have to show we can go back in the business and if you guys are willing to push this hard you could be the first. And that was …

John Mather: That was a tremendous boost for us, because we went from not having priority to having top priority. At that point it was possible to finish this job which we had looked so daunting before that.

George Smoot: But then they worked night day. We were running three shifts during that, … scientists had the third shift because they wanted the people who were actually working on the space craft to be there during the day light hours and the people who were checking would be there and then whatever what was left were us.

So you went into a reversed cycle. Preparation for coming to Stockholm.

John Mather: Yes.

George Smoot: Yes

Once you got up there and you measured the cosmic microwave background radiation you, in the telephone interview we conducted in October, described that as “the accumulated trace of everything” which I think that was a lovely way of thinking of it. Could you tell us in more detail what it is that you are actually are looking at?

John Mather: We are looking at what is the remains of the cosmic explosion itself. The heat radiation from the Big Bang is still filling the Universe and it’s still not so faint as all that. It’s about a microwatt per square meter of heat radiation coming at us, but it is equivalent to a temperature of only 2.725º Kelvin, so it’s very cold. Nevertheless, quite right on a cosmic scale. This is the radiation we are looking at, it is the Big Bang itself, and it might have traces in it added later, of things that happened from galaxy formation or any kind of strange things that might have occurred. One of our results was that there wasn’t any surprise, the Universe was simple after the first year, until galaxies formed. That was a primary result that we get from the spectrum and it showed that he Big Bang really was the right picture for the whole story. Then there was a whole other second major results that came from the hot and cold spots that George can tell more about.

Sure. Just focusing on that Big Bang result, the CMB is always with us, so in a sense looking at it, could it be described as looking back in time as a way of travelling in time?

John Mather: Yes, we see the radiation as it was when it was last bumped into a meta particle, so we can see the spatial distribution that way, but the colour of the radiation is much older than that. We see the colour of the radiation as it was established one year after the Big Bang. Although the Universe was still a … it wasn’t changing the colour of the radiation, so we see that particular phase as the earliest we can see with this radiation.

It’s extraordinary to think that one has this window into the past. The observations that you made come from considerably later, form about 300 million years after the formation?

George Smoot: 370 000 years.

Sorry.

George Smoot: John was saying that we get a microwatt per square meter which is a lot of power compared to what you get from radio and tv signals that’s on that same scale. But if you ask how much radiation we’re getting from the Sun, direct sunlight is thousands of watts, it’s a factor of ten to nine billion in US, million I guess in European. The Earth is giving us the same. We had to reject the radiation from the atmosphere and from the Sun and from the Earth and from the Moon at a very high level. That was what I was mentioning to you before, that we had developed special antennas, the approach that I followed and the people was using my instruments which means this careful launching of the waves and the approach that John’s instruments followed, which was the sort of the trumpet horn view, where you smoothly, very carefully define what kind of radiation comes in by the fact that it has travelled all around this curve and come straight in.

Those were really key. It’s not quite as simple as it sounds. What John was seeing as this temperature, 2.72, it turns out that at the time we started thinking about the experiment the prediction from the theorists was that other part than a thousand of variations and those would be the seeds of galaxies and classes of galaxies. By the time COBE actually flew the predictions were down to a part than a …10,000. We found them at a part of 100,000. You can imagine, compared to the Sun and the Eart, these variations were just the answers to themselves. These variations are extremely tiny, it was all of being very careful and checking and that was the impressive thing that the team did – everyone was crosschecking and testing and the precision with which the spectrum was measured, that’s phenomenal and the way we measured the variations is just incredibly small.

The example I used to give is that the Universe is smoother than a billiard ball – you know what a billiard ball is? – it is smoother than a billiard ball, yet we saw the variations in that, that are the seeds for the formation, and we did it very much by using this radiation that if you should turn between the low frequency channels on your tv, you see the hash on the tv, some of that is a noisy receiver, some if that is from the … and some of that is this radiation from the Universe. They are all in the same scale, a rough scale, at the very low frequencies, but sorting all that out and measuring it to this position is a task that took these thousands of people working very hard for a long time and just being very careful. You have to give the team a tremendous amount of credit for the great job they did and the care they took.

Absolutely. And future generations of analysis are possibly going to find yet further information buried in the CMB?

George Smoot: It has already happened. As soon as the COBE made the announcements of the fluctuations there was a tremendous amount of public interest and a large number of … and people came into the field immediately, because they saw that … It was like somebody says There’s gold and amounts over there, there was this rush to go to this and at the time of the announcement I said We’re into the golden age of cosmology. A large number of people came and there have been several tens of experiments to make the measurements and the WMAP satellite and soon the Planck satellite coming up. The WMAP satellite has improved by making more measurements across the whole sky and verifying what COBE saw but also measuring with much greater angular resolution. COBE had these antennas, the beam width here is seven degrees, it’s about a tenth of a radiant, so seven degrees across. With WMAP it is around a quarter of a degree on the sky, so we went from 6,000 pixels to a million pixels. Now there’s a high resolution, so typically you show a picture of a person or of the globe with the continents on it. With COBE you can just see the continents, the five continents. With WMAP you can see the shape of the continents, you can see small islands – you can see Cuba – things like that. It’s just such a change and there’s so much more information there, we’re really learning about the cosmos already.

And that’s adding further refinement to the two main discoveries that you two made. Is there, do you think, a further discovery of the same level in cosmology to be made?

George Smoot: You never know for sure, because it’s a surprise. The one really major new discovery that’s happened since COBE was the discovery that the Universe’s expansion is increasing and it’s accelerating the Universe. We always knew that gravity’s attractive, and the Universe is slowing down and structure is forming and it had to happen that way. But now something has happened, it causes the Universe to speed up and pull apart faster. That accelerating Universe was kind of a surprise out of the blue although it makes our whole model of the Universe fit together much better because it makes the Universe older, because it is going faster now and is … back, you think it is younger. If you realise it had been going slower in the past then it started earlier and I guess time for the formation and the galaxies and the stars and our solar system.

John Mather: There’s more to come then as well, and there are many more things that people want to learn from this radiation. One major topic is called polarisation. We are beginning to measure the polarisation of the radiation and some parts of it come from the processes that happened after the radiation was let loose and the galaxies started to form. There’s another part that people are looking for, they may come from gravitational waves in the very earliest moments, so this is the next tremendous challenge, and the subject is to build an equipment that’s capable of discovering that.

If it is discovered, what will polarisation tell us, for instance?

John Mather: It will tell us about the quantum mechanical processes, what we imagine may have happened in that Big Bang itself.

So it takes us to an earlier point?

John Mather: Yes.

George Smoot: There have been observations of polarisation – you expect some of the polarisation just from the variations of the material – and that has been seen, although not measured very well yet, but then there is a next level which is a different mode. The kind of things thar are lumps of extra materia, they either have radiation flowing out of them or into them and the polarisation lines up that way. But if you have gravity waves, as John just has been mentioning, you can get a handiness because the gravity waves travel this way and is stretching space in this direction so it’s extra handy, you can have twist or rotation or … That mode would be an indicator that you’ve seen gravity waves and that could come from a very early part of the Universe. The ideas of inflation, that Universe had this rapid acceleration in an early part and that was what made the quantum mechanical … stretch them, so that their own galaxy was once a tiny fluctuation and now stretched to astronomical sizes. It’s a beautiful idea and we really like to know if inflation happened or something else happened and how did those variations in the Universe come to be and polarisation is one of the probes that we can use to find that.

John Mather: It’s one of the few that are left actually. We have measured everything that we can measure about some things on the background radiation at large scale. Our dependencies are already so well measured that you can’t measure it better. We’ve measured the spectrum very well although we think we could measure it a hundred times better if anyone cares, but the polarisation is something which could lead us to a new understanding of the forces of Nature. What is exciting for a physicist in the Big Bang is it’s the Nature’s laboratory, where we think all the forces were unified, and the great unified theories of physics would hope to explain how gravity, electromagnetic forces and the two kinds of nuclear forces are really all closely related and all quantised. So far that has not been accomplished, even at a theoretical level, but observationally we have a chance to go observe something about that, so this is one of the reasons that the Big Bang story is so important for physics.

That’s a goof point. The phrase you use ‘if anybody is interested’ makes the question if founding for this of research is improving or getting worse at the moment.

John Mather: In my opinion there’s plenty of funding for things that are really worth doing, but there’s always a competition in process for what is worth doing right now. Projects have to compete, worldwide we have these competitions. I think that the gravity wave and the idea that it would produce polarisation in the background radiation is an idea that is getting some funding and is expected to lead to a NASA mission at some point, maybe an international mission.

I just wanted to move to the question of the Nobel Prize itself and whether the notoriety that that will bring, the other notoriety as you have of course already received many other awards, will be useful to you, you think, in your future work. How do you think it will change things?

George Smoot: It will change things a lot and I have already been down talking to members of the congress and their staff about continuing support for sciences so forth. John and I will go – as a civil servant he is not allowed to talk to people without invitations – but we are going to arrange an invitation either in congress or at the Air and Space Museum to give presentations, so that the people in congress and the … staff will get to hear about what we are doing and how exciting it is and so forth. I think that we have a responsibility not only to attract new young people into science, but to make sure that science remains healthy and goes forward both for the good of our country, but also for the good of the world. That science is an international activity, and it is the situation if we have problems with global climate change or energy crisis we are going to have to have scientists in all the countries talk to their leaders and say Here is what the issue is and here is how we are get together to solve it, and then work it out. Without that scientific advice how are we going to go forward on global problems.

And the Nobel Prize puts you in a better position to be a spokesperson for that.

George Smoot: I already have hundreds of invitations and when I went to congress immediately the staffers wanted to meet with me and it’s clear John has …

John Mather: I get invitations every day.

So the students are going to be neglected a little longer.

George Smoot: They are not going to be neglected, we’ll take care of them, they are future scientists.

I am sure. This year for the first time we invited the public to submit some questions via the internet, and if I might, I was just going to ask you a couple of those questions that came in. Andreas Eriksson from Stockholm has asked how examining the largest scales highest energies longest time periods changed your view of everyday life. Does it?

George Smoot: Every now and then I think what difference will it make in a billion years? Because in the Universe a billion years is just an eye flick. We have had almost 14 billion years so far and we’re only a fraction of the way through what we think of as the normal life history in the Universe. We know it’s going to keep expanding at least for 150 billion years. The sun becomes a star and it dies away and that takes 10 billion years, that’s 7 % of the light. It changes your perspective, just to think that the time it takes light to get from Andromeda to here was the time from which it started out at the time when humans started to evolve. When you start to think about the light that came from far away, it gives you a different perspective of the history. How does it change my everyday life? It changes my perspective, but on the other hand I still like to get a good hot chocolate.

John Mather: I think I have similar reactions to George’s. When I look at physical things in the world, I know their history. I know where the hydrogen and helium came from, and it was not much of that around here, but the carbon and oxygen and nitrogen that we’re made out of came from stars that exploded. When I see nice woodwork or something I think to myself those carbon atoms were some place else in a giant cosmic explosion of a star not so long ago. It also reminds me that our own star is going to burn out itself in another two billion or so and we might find another place to live. Those are matters of scientific and personal perspective, but principally it says life is long, the Universe is long, and we need to take long term perspectives to manage our lives here on Earth. We’re like the gardeners here on the planet and we have to plan for a long future.

George Smoot: It’s a question you say if you understand how things work, like a rainbow or you have a little bit of oil on the ground and it rains and you get this nice colour scheme, does understanding how that works take away from the beauty or enhance it? Generally I think it enhances it. Knowing that a tree which looks like this wonderful mysterious thing hasn’t been there forever. That it came … you know, the planet hasn’t been here forever. That doesn’t take away from the fact that when you walk through the forest it’s an incredible experience. And hiking is just you feel a good home.

John Mather: I also feel that what we’re looking at is completely mysterious. Even though we have the stories of science about how this all happens, the individual expression of everything is not explainable. The fact that we look the way that we do is more or less accidental, the fact that particular chance encounters have led to our particular lives and discoveries that we’ve made. None of that is really explainable so life is just as mysterious now as it ever would have been.

Moving on to the unexplainable for the last question. Vijay Krishna Gryalaru from California wants to know what you tell curious kids if they ask you what happened before the Big Bang.

John Mather: I’d say that’s a really good question and science has not answered the question. We don’t know if it’s even a meaningful question because we don’t know whether there were any such things as space and time before the Big Bang. But on the other hand, mathematicians and physicists are working on the question and it’s a thing that we hope to be able to answer sometime, and George has had lots of interesting things to say about this too.

George Smoot: It’s a problem that I’ve been interested in because not surprisingly, many people have asked this question. One of the hardest things that people, they just can’t accept the fact there couldn’t be time before the beginning. The idea that time doesn’t go back forever is alienable. You try and give them examples like try and go past the North Pole, try and go north of the North Pole or something. You try and give those examples and it’s unsatisfying for people, even though you can understand that if you keep heading north, which is like going back in time, there comes a point where you’re going forward in time. You can construct the universe like that. But in fact, there are lots of alternatives out there where going back in time doesn’t mix, it’s like a random walk. There are a lot of people working on various models where there might have been something going on before our particular part of the universe bubbled into a Big Bang and you don’t know what the answer is and you know the Big Bang is going to confuse. It’s like somebody’s torched the place and set fire to it. The clues are very hidden after that, but occasionally when you’re experts on our sun, you can figure out whether it was burned by mistake or by accident. That’s what scientists are trying to do, they’re trying to pose the question in the most general way, even including making the most general laws of physics and see what kind of universes you get, and some of the things I think are quite successful, some of the things like you had in the early days of quantum mechanics and the Copenhagen School. Some of the stuff makes a lot of sense and they’re good rules, and some of it is just mysterious mumbo jumbo because nobody knows what’s going on, and it’ll sort itself out.

Unfortunately, time doesn’t go on forever either and we’ve come to the end of our time today, so it just remains for me to thank you very much indeed for taking the time to talk to us and to congratulate you both once again.

George Smoot: Thank you very much Adam, it’s a pleasure.

John Mather: Thank you. We appreciate it.

Watch the interview

Did you find any typos in this text? We would appreciate your assistance in identifying any errors and to let us know. Thank you for taking the time to report the errors by sending us an e-mail.