Category: Podcasts

Dr. Charles and the ANU HDLT team. Image credit: ANU. Click to enlarge.
Listen to the interview: Plasma Thruster Prototype (5.5 MB)

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Fraser: Can you give me some background on the thrusting technology you’ve invented?

Dr. Christine Charles: Okay, this thruster is called the HDLT, which stands for Helicon Double Layer Thruster, and it’s a new type of plasma thruster application into deep space travel. And the background is our expertise in plasma technologies, space plasma, plasma processing for treating surfaces and a variety of other applications.

Fraser: So, the favourite engine of the space exploration set these days is the ion engine, which has demonstrated quite good performance as a fuel efficient engine. How does the engine you’re working on relate to an ion engine? Can you give people some context?

Dr. Charles: Yes, there are some common aspects and some very different aspects. So, first the ion engine has been successfully developed for the past – I don’t know – 50 years or so. It’s quite well developed now. But the HD thruster has some interesting advantages. First, it doesn’t use any electrodes. So in the ion engine, you have a series of grids to accelerate the ion. So our thruster doesn’t have electrodes, we have a new type of acceleration mechanism that we call the Double Layer. This is why we call it HDLT: Helicon Double Layer Thruster. It has no electrodes, so that means it has a long lifetime because you don’t have electrode erosion. And a second, really important aspect is if you look at devices like ion engines, they emit ions. So you need to have an external source of electrons to neutralize these ions, and that’s generally done by having a second device on the side of the thruster which is called a hollow cathode device. In fact you have two devices on an ion engine. And often because they’re afraid that these hollow cathode devices might fail, they put two of them on to increase the lifetime. But in the HDLT, we actually emit a plasma, which in itself contains a supersonic ion beam. So we have the supersonic ion beam, which is the main source of thrust as it exits the thruster, but we also have the plasma which emits just enough electrons to neutralize the beam. So we don’t need this external device which is the neutralizer. That’s very good because it can provide safety, and simplicity – there’s no moving parts – so it makes the HDLT quite attractive for very deep space travel; long lifetime. And another advantage is that because we use a second concept called helicon plasma, it’s a very efficient way of transferring electricity into the charged particles in the plasma. That means we can get really dense plasmas with a lot of ions and we can scale up in power. So, we can probably go up to 100 kilowatts. This hasn’t been done yet here in a prototype, because our first prototype was just 1 kilowatt. But other experiments have suggested that with our type of plasma, we can really scale up in power, and to do that with an ion engine, basically the main thing is that when you go above a few kilowatts, you have to have a cluster of thrusters.

So I would say that it’s really early days for the HDLT, but the main advantages are increased lifetime, simplicity, scalability, and safety. And it’s also quite fuel efficient, which is very good.

Fraser: In terms of performance, ion engines can put out the thrust of the weight of a piece of paper, but they can do it for years and years and build up thrust. You’re saying that you could put out more thrust?

Dr. Charles: At the moment, ion engines are definitely the best in terms of thrust, for kilowatt, at the moment. And the HDLT prototype, which is just a concept and under 1 kilowatt, it doesn’t match the thrust. If you take the example of an ion engine, it typically has 100 milli newtons for one kilowatt. We’re talking probably 3-5 times less at the moment, but you have to see that we haven’t had 20 years of development. It’s early days, and we can certainly improve the technology.

Fraser: And then as I understand now, the European Space Agency has picked up the technology and is doing some in-house testing. And how’s that gone for them?

Dr. Charles: Okay, they had a few projects. The first thing is that we had a grant in Australia from a funding agency, and that was during 2004-2005. And we designed and manufactured the first HDLT prototype, which we brought to ESA last April, and which we tested for a month. We had limited funding so we couldn’t test it for more than a month. And this showed that all aspects of the thruster worked perfectly. But we tested all the powers that we could, and we had different gas pressures, etc. We didn’t have the diagnostics we needed to measure the thrust, so we didn’t know what the actual thrust was. The thrust that we have is what we can measure from the ion beam in Australia – it still has to be done. And it’s based on this very new concept of the double layer, which we had to convince people about. And ESA thought it was really interesting, so they had decided to have an independent study to validate the double layer effect. It’s the basic concept behind the thruster; the acceleration mechanism. So now we really have to see what this is about.

What is a double layer? You can just imagine, it’s like a river and suddenly the bed of the river falls down so that a waterfall is created. Then you have these ions which fall down this waterfall, and get accelerated and then get connected to the rocket with a large exhaust velocity. So the double layer is a potential drop in the plasma. What’s very interesting is that in the HDLT, we don’t have any electrodes; the plasma just decides to do this, by using a certain magnetic field, which is a magnetic bottle or nozzle. And that’s all. So it’s like having the waterfall without pumping the water through. So this is the basic concept.

So ESA had this independent study to validate the concept of the double layer. Have you seen the latest press release?

Fraser: Yes, I have.

Dr. Charles: So there was this latest study by Australia. We have the first prototype, and we have demonstrated some aspects; although, the thrust hasn’t been measured in a space simulation chamber yet. And ESA has also validated the concept behind the thruster, which is this double layer concept. So that’s where we’re at at the moment.

Fraser: So what kinds of missions do you think the HDLT thruster would be better for?

Dr. Charles: It has to be for really long term missions where you’re forced to go slowly, but for a long time. And it’s also has this nice safety aspect. It has the potential to be used for manned spaceflight. So it’s really for deep space missions, or going to Mars… things like that.

Fraser: I see. I guess one of its main advantages here is that it has less moving parts – parts that could break down.

Dr. Charles: And it can be scaled up in power, which is also important. NASA has made a simulation of what type of power you would need to send humans to Mars, and it’s in the megawatt range. So you will have to have the power. You’ll need to be able to scale up your thrusters as well. They need to be able to operate under large power to do the job. What NASA did is show that if you could have a proper plasma thruster, or plasma rocket, you could cut down the time to go to Mars because if you use plasma technology, you can use geodesic trajectories. If you use chemical propulsion, you’ll have more like a ballistic trajectory. So you can cut down on the time travel to Mars for example.

Fraser: So what are the next steps for your research?

Dr. Charles: Well, we’re doing various things in parallel. We’re still working very strongly on the double layer itself because this is a very nice kind of physics that has all kinds of other applications to the aurora, or solar wind acceleration, etc. We also have a new space simulation chamber here at the Australian National University. And we have mounted the prototype, which is back from ESA, into that space simulation chamber. And we’re going to start trying to measure the thrust balance and other ways, probably from January 2006. And there might be other news happening, I don’t know. We’ll see how it goes. We’ll definitely be putting a lot of effort into this subject. It’s very fascinating because many people are interested in the outcome.

HDLT Thruster Information from ANU

Artist illustration of Venus Express. Image credit: ESA. Click to enlarge.
Listen to the interview: Larry Esposito and Venus Express (5.5 MB)

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Fraser: First, congratulations on today’s launch.

Larry Esposito: The launch went very well. Venus Express spacecraft is now on its way to Venus.

Fraser: And how is the spacecraft?

Esposito: Everything appears to be perfectly healthy. Everything is as expected at the moment.

Fraser: That’s good. It almost seems unusual. A lot of the time there are glitches, so it’s great to hear that everything’s going so well.

Esposito: The spacecraft did take a two-week delay while they looked for possible contamination, but it had not been contaminated so everything is looking very good at the moment.

Fraser: Okay, so let’s fast forward a few months into April when Venus Express does arrive at Venus. What’s going to happen?

Esposito: The spacecraft arrives at Venus on the 11th of April, 2006, and then goes into orbit around Venus by firing some retro-rockets. After that, there’s a period of commissioning the spacecraft, where the instruments and all the systems aboard are checked out. And then Venus Express begins observing the atmosphere, the clouds, and the surface of Venus.

Fraser: What scientific instruments does Venus Express bring to Venus that haven’t been there before?

Esposito: Venus Express is carrying telescopes and cameras that are similar to those that have previously been in orbit around Venus. But it benefits from better technology and also from a capability to look through the atmosphere at a very specific wavelength where the atmosphere is more transparent and it’s possible to actually see the surface of Venus.

Fraser: What kinds of mysteries are you hoping to reveal with this mission?

Esposito: Venus is considered by many to be a twin of Earth. It’s almost the same size, it was formed at the same time around the Sun, it receives about the same amount of light from the Sun as the Earth. And the question that we have, probably the most basic question, is giving that they’re nearly twin planets, what went wrong on Venus? Venus, if anything, is an evil twin of the Earth. Its surface temperature is as hot as the inside of a self-cleaning oven. It has pressure of 100 times that of the atmospheric pressure of the surface of the Earth. The atmosphere is filled with sulphurous gasses and completely shrouded by clouds. So Venus, in some way has gone terribly wrong compared to the Earth. The mystery may be how global warming on Venus got out of control and put it into the state it’s currently in. And on the Earth, where we’re experimenting with our own atmosphere by releasing greenhouse gasses, though the burning of oil and coal, the question is: could the Earth go along the same path? So one of the basic mysteries is, how did Venus go wrong, and how can we avoid that on the Earth? I’d like to say it’s much better to do a theoretical study and experiments on Venus instead of doing the experiments on Earth through global warming, where the result may be very poo for the future of life on the Earth. So the biggest mystery has to do with the history of Venus and the potential for the Earth to follow that path.

Fraser: What kind of evidence would you be looking for to tell you what might have sent Venus down that path?

Esposito: Measurements that Venus Express will be taking are measurements of the composition of Venus’ atmosphere, the motions of the atmosphere, and measurements of how sunlight absorbs into the atmosphere of Venus. In addition to that, the spacecraft will be looking through the atmosphere and measuring the temperature of the surface. So it could well be that the history of Venus’ climate is very much related to geological activity, volcanic activity, on the surface. So we’ll be looking for signs of active volcanoes, we’ll be looking for volcanic gasses in the atmosphere, we’ll be looking for absorbing compounds that could capture some of the Sun’s radiation, that warm Venus’ atmosphere. And in addition to that, that spacecraft has an objective to look for the possibility of any connection the environment has to the possibility of past or present life on Venus.

Fraser: And what kinds of additional challenges went in to build the spacecraft to let it be able to survive the environment there. Isn’t it very much related to the Mars Express spacecraft?

Esposito: Right, and luckily for the Europeans, who have built and launched and are operating the spacecraft, it doesn’t have to enter the Venus environment. It simply goes into orbit around Venus the way the Mars Express mission is in orbit around Mars. And it’s essentially a copy of that mission. So the spacecraft remotely senses through cameras and telescopes and spectrometers the Venus environment but it doesn’t actually enter into it. That would be a much more difficult, much more expensive, technical task and that’s not the mission of Venus Express.

Fraser: I know it’s been done briefly in the past by the Russians. Are there any plans in the near or far future to try and get back down onto the surface?

Esposito: The US National Research Council has issued a report about new frontiers in exploring the Solar System, and one of their top four missions is a mission that would land on the surface of Venus and investigate that surface. And in response to that recommendation by the National Research Council, I led a team that developed a proposal for a mission that would land on the surface of Venus and drill into sample the surface and atmosphere. But unfortunately NASA has declined to fly that mission at the present time. It’s possible that we’ll propose something like that in the future. But right now, the techincal and financial challenges were too large for NASA to take on at the moment.

Fraser: And one of the questions I always want to ask the people working on these missions is that a lot of the time there are pretty big surprises; some of them are expected, and some you have a hope that you’re going to find something. What would be one of the big surprises that you think might be waiting for us at Venus?

Esposito: Of course you’re right, there are always many surprises ahead, even after all the missions that have flown to Venus. And I’d particularly like to see some confirmation of volcanic activity. Another possible surprise is the identification of ultraviolet absorbers and the possibility that they might be connected with life forms in the Venus atmosphere. As the other surprises, it’s hard to predict. Maybe we’ll just be surprised because this Venus mission is more capable than any that have been sent into orbit Venus, and just maybe be able to find out things that we have no expectation. Anything that was related to volcanic eruptions and life would be very interesting on Venus.

Fraser: I’d read that recently that something is blocking ultraviolet light in the high atmosphere and that could actually create an ecosystem that life could survive in?

Esposito: We know definitely that there are ultraviolet absorbers in the clouds, but we haven’t been able to identify them, yet. The fact that they absorb sunlight could be the start of some biological ecosystem in the Venus clouds. That’s pretty speculative at the moment, but very interesting to think of those possibilities. And Venus express will be observing in ways that could shed more light on that question, on Venus life at the present time.

Fraser: I know Mars Express has equipment that can detect methane in the Martian atmosphere. Would there be something similar…

Esposito: The same experiment is flying on Venus express – the Planetary Fourier Spectrometer – on Venus Express, and it could also detect methane and other chemicals in Venus’ atmosphere. But methane is very unlikely at Venus because of the high temperatures and the strong sunlight there.

Fraser: So the sunlight would be destroying the methane quickly on Venus as it would be on Mars. If there was methane, it would be…

Esposito: Yes, sunlight and heat are very disruptive to methane.

Fraser: So the spacecraft is equipped to detect it, but it would be quite surprising if it was there.

Esposito: That’s right.

Horsehead Nebula by Tom Davis.
Listen to the interview: Astrophotography with Tom Davis (6.1 MB)

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Fraser Cain: This is going to be one of those podcasts where I think people are going to want to sit in front of their computer at some point and take a look at your photographs, so just to let everyone know, I’m going to have them point their browser at http://www.tvdavisastropics.com. And so I recommend you get this up in your browser before you listen to the rest of the show because talking about astrophotos is kind of like dancing about architecture (to steal a phrase). Now Tom Davis, you’ve got some amazing pictures, and you’re an amateur photographer out of Idaho. Can you explain the setup you’ve got?

Tom Davis: I have a dome; it’s a clamshell dome in my front yard, and I live on the side of a mountain at about 5,700 feet above sea level. And in that dome – it’s a 7-foot dome – I have a pier, and on the pier is an Astrophysics 1200 GTO mount, which is an outstanding mount. And on the mount, I have a couple different variety of setups. Currently I have an Astrophysics 155 EDF refractor, and on top of that, riding piggyback is an Astrophysics 105 EDF f6 traveller refractor. And I use the traveller as a guide scope. The two cameras I use predominantly are both made by the Santa Barbara Imaging Group (SBIG). One is the STL 11000M; that’s the monochrome version. And then the other is the ST 10 XME. They’re both very sensitive cameras; they both do different things. Certainly the STL 11000 has a much wider field of view, and it’s an anti-blooming gate camera, which means the stars won’t get those funny spikes that you often see. It’s not quite as sensitive in the red spectrum, particularly hydrogen alpha, but it does a marvelous job, nonetheless. And certainly the ST10 is one of SBIG’s most sensitive and flagship cameras. So that’s what I have.

I have a computer in the dome. It sits on a little shelf, and it’s the computer that I have on a wireless system, and I actually sit in my kitchen when I image. I have a laptop in there that I’m actually looking at right now. Through the wireless network using real VNC, I can run the telescope and everything just from inside my house, so it’s awfully nice in the Winter.

Fraser: I was about to say that. It must get pretty cold there at that altitude.

Davis: It gets very cold at this altitude, but everything runs fine. People who live in really cold climates wonder if their camera’s going to run, or if their mount is going to run, or is it going to hurt the telescope, and the answer to that is absolutely not. With some very simple precautions, everything runs great. I’ve been imaging down even to -20 degrees.

Fraser: What kind of investment have you put in to get yourself to the level of equipment that you’ve got today?

Davis: Well, this hobby, obviously can require a lot of money – 10s of thousands of dollars. Certainly that’s where I am at with this investment. However, for people who want to just start imaging with CCD, the cameras nowadays are so affordable, and far better than the cameras that I first started out with. Literally they can get very good images for a couple of thousand dollars. Even simple telescopes, such as a simple refractor. Even if it’s not one of the high-end ones, and a simple camera, can give you very good images that a lot of people would be absolutely delighted to take. So yes, it’s one of those high-end hobbies, unfortunately, it does require a lot of money once you really get into it. But I highly encourage anyone, any amateur, any visual astronomer out there – if they’re interested at all – now is the time to get into imaging; the software is much better to get into, the mounts, the telescopes, and even the cameras are just phenomenal now.

Fraser: Yeah, that’s been my impression in seeing the quality of the astrophotos that amateurs are taking. I just seemed like in the last couple of years, the photos sent in have just blown me away. And so, what kinds of advancements have been made in the last little while that’s made this so possible?

Davis: Well I think the biggest thing is the understanding that to get really high quality images, you need to put a lot of time into your image. The film astroimager would take 50 minutes to an hour open shutter images, and then take two or three of those and then combine them. Well, in CCD imaging, you don’t do that. Essentially we take subframes. Typically 5-10 minutes, maybe 20-25 minutes at the most on specific narrow band filters like a hydrogen alpha. And you take a whole series of those or 6 or 7 or 10, and then digitally you stack them. In the past we were just so thrilled with the images that we were getting, we were only shooting total imaging times of maybe an hour to 1.5 hours, and those were great images. The one thing interesting about CCD imaging is that the more time that you spend taking – in other words, more data, more photos you’re actually registering – the better the quality the image, and the less noise that comes from the sky. One of the main things that you’ve been seeing over these last couple of years is that most of us now don’t image for the average object, let’s say an average nebula, we really don’t image for anything less than 3 to 3.5 hours now. And so it’s a lot of time, sometimes over multiple nights, but when you stack all that data, the noise really reduces quite dramatically, and you start seeing these really beautiful and beautifully detailed images. I think the other thing that has really advanced, at least amateur astroimaging with CCD cameras, are large diameter telescopes. Now the largest I have right now is a 10″, I have a Takahashi BRC 250, which is a Ritchie Chretien type telescope. I haven’t really imaged with it much because I’ve been doing things mainly with the Astrophysics, but this Winter I’ll start using the Takahashi. A lot of guys have Ritchie Chretiens that are now 12.5″ or 14″ or 16″, and even one guy that has a 32″. These are amateurs and that aperture of telescope used to only be in the realm of professionals, well now some guys have those sizes of telescopes. Unfortunately, that style of telescope, the optical design is extraordinarily expensive and so it really limits for just everybody to buy that. But those two things are the main things. And then finally the camera technology; really the cameras and many of the chips are similar to what we’ve had in the past, but now we have much larger chips – similar sensitivity but they’re much larger, like this STL. It’s really opened up some beautiful vistas we can take.

Fraser: And do you find that your telescope and imaging setup can contribute to science as well?

Davis: Oh absolutely. The average amateur with a 6″ telescope and a CCD chip can do phenomenal science. I freely admit that I’m not a scientist, and I don’t think that my images are scientific quality. They like a certain type of data, but yes. If you were taking images of galaxies, you can discover new supernovae; we recently saw that in the Whirlpool Galaxy, an amateur discovering that. I’ve recently taken a picture this summer of M31 and was able to compare it to some of the pictures taken from the Palomar surveys of past, and I can actually pick out the Cephied variables of M31, and globular clusters around M31 just off of my image, my 6″ refractor. And if I wanted to do Cephied variables from M31, I could actually do that, so without question. There’s even been a couple of amateurs who have discovered new extra solar system planets with small telescopes, using the right software and having that right savvy to watch the data, so absolutely. The amateur now is able to contribute to science and many of the professional astronomers are going into collaboration with amateurs, and so it’s very exciting, not just pretty pictures, but you can actually get scientifically worth data.

Fraser: It sounds like a great time to be taking these photos.

Davis: Absolutely, it’s a great time for anyone who really wants to image, they can get in. You can get CCD cameras now – they are expensive, but you can get used cameras and take some very very nice pictures, and see more detail in a 60 second simple monochrome picture of, let’s say, M42 than you can in an eyepiece if you just have an ordinary aperture telescope. So it is a very exciting time.

The SuperNova/Acceleration Probe, SNAP. Image credit: Berkeley Lab Click to enlarge
Listen to the interview: The Fate of the Universe (6.2 MB)

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Fraser Cain: Can you lay out the two fates that may await our Universe?

Eric Linder: Well, our picture of what the fate of the Universe is has really changed dramatically in the last 5-10 years. We used to think it was fairly simple, it was just a matter of how much content there was in the Universe, how much matter there was. If there was enough matter, then the gravitational attraction would cause the Universe to slow down in its current expansion, and to basically re collapse and we’d have what some people call a Big Crunch to end our Universe. And if there was not enough matter, there would not be enough gravity to slow down the current expansion and it would just become more and more diffused – a colder and lonelier place to live in. In 1998, these two groups of scientists discovered a very bizarre occurrence that the expansion of the Universe was not slowing down either dramatically or even gradually, under the gravity of the matter in the Universe, but rather, it was speeding up. It was accelerating. Sort of like if you threw a baseball up in the air you know eventually it’s going to slow down, reach a peak, and usually come down back to Earth. If you throw it hard enough, it’ll go off into orbit. But here the Universe threw a baseball up in the air, and now that baseball is speeding away faster and faster. So this has completely puzzled scientists, and was completely contrary to what we were expecting. Under this new picture, the fate of the Universe appears to be that it is going to simply expand forever and ever, become colder, more diffuse, atoms will get more and more spread out, the distance between galaxies will increase. And we’ll have this fate of the Universe which is sometimes called the “Heat Death”, where everything just becomes very cold and motionless and isolated from each other.

But it depends on what’s causing this acceleration. That’s the great mystery. It’s possible that the physics giving us this acceleration could suddenly go away, in which case we’d be back to the earlier picture where the Universe might collapse. Or it could do something completely bizarre and we don’t know. So this is a big question that we want to find out. What is the fate of the Universe, but trying to figure out, what is the physics in this acceleration.

Fraser: Why has that question not been answered so far? Have we not gotten a good enough look at the supernovae?

Linder: Right, as I said, the acceleration of this expansion was only discovered in 1998. And people haven’t been sitting on their hands, they’ve been trying to answer this question very passionately. By getting more supernovae, we can use these exploding stars sort of like fireworks off in the Universe. If we know that the fireworks always go off with the same energy, with the same brightness, we can tell how far away they are by how bright they appear to us today. And so we need more of these supernovae, and we need more and more distant ones, so we can map the history of the Universe; the expansion of the Universe over a greater period of time. And people are gradually doing that. There are some very large projects underway with telescopes on the ground attempting to get what were just tens of supernovae, now we’re trying to get hundreds of supernovae. But eventually, to really answer these fundamental questions, we’re going to need thousands of supernovae at great distances. In order to get that, we’re going to need observations from space, so currently we have one space telescope – the Hubble Space Telescope – that is suitable for these sort of observations, and it’s doing a great job. It’s seeing the most distant supernovae that we’ve yet discovered; about 10 billion years out in the history of space, but it can only see them one by one. And so what scientists have proposed is that we build a new space observatory, a new telescope in space, called SNAP (Supernova Acceleration Probe), and this will be able to get thousands of supernovae very efficiently, very rapidly, seeing them extremely faint and extremely deep. And this has really caught the imagination of the science community. There have been a number of recommendations from the National Academy of Sciences, from various professional organizations, that some sort of space observatory like this will figure out: what is this mysterious physics causing this completely unusual acceleration that’s acting opposite to gravity? So there’s almost like a repulsive version of gravity that’s really going to rewrite all the physics textbooks. So a lot of people think that we really do need to go forward with these observations, more precise observations and many more observations, such as you spoke about. We just need to improve the data that we already have, and the technology is good enough that we can go out and do this. It just requires us to sit down and build the thing, and launch it and try to find out these answers.

Fraser: Now I’ve heard quite a few suggestions for what this dark energy might be. What kinds of things would you be looking for in your observations that could maybe map against some of those theories that have been put forward?

Linder: So the granddaddy of all concepts of dark energy was put forward by Albert Einstein all the way back in 1917, what he called the cosmological constant. And it didn’t agree with the observations at the time, and so it kind of went into retirement for a while. And every few decades, scientists brought it back out to say, well maybe that could explain some other observations we’ve made. And then it goes back into retirement because it doesn’t really fit. But now it seems this might be its time, to bring back this 90 year old concept from Einstein, because it can give this acceleration of the expansion of the Universe. It’s a very simple picture for how you could get this acceleration, but it doesn’t solve everything. There are some really very puzzling aspects of it. What you would think if you did some naive calculations is that it should accelerate the Universe, but should have started accelerating the Universe all the way back from the very first instant of time, and we would not have the Universe we see today if that happened. In fact, we would not have been able to get stars and galaxies and the structure that we see in the Universe. And so for some reason there has to be much much weaker than we would think as its natural value. So it’s possible that it’s the answer, but we don’t understand why it’s so weak, relative to what we think it should be. To get around that, people come up with these other ideas, this idea of quintessence, or a 5th substance to the Universe where it acts like the cosmological constant, but it varies in time, and so it can start off very weak and now today it can be dominating the expansion of the Universe. And so that’s an attractive idea, but nobody really has any first, basic idea of how to make it work exactly. Right now it’s a concept but the details haven’t been worked out on how it arises from the physics. So that’s another thing that we can be very interested in. Another possibility is the way we’ve been analyzing the data, saying, well, gravity is an attractive force, it’s given by Einstein’s Theory of General Relativity. Maybe something breaks down there. Maybe what we’re seeing is a breakdown in the theory of gravity as we understand it. People have come up with ideas that involve extra dimensions for example. Instead of just three dimensions in space, there might be an extra few dimensions in space, and that gravity is gradually sort of leaking out into this extra dimension in space and that’s making it weaker and that will act in opposition to gravity and give us acceleration. So we have all these incredibly exciting possibilities for how physics might change and we don’t know which they are. And so what we need are these very detailed observations of mapping the expansion of the Universe for example through the supernovae, these exploding stars – and there are other methods as well – to really try and decide, how are we going to rewrite the physics textbooks; which direction do we need to start erasing things in and writing new things in. So, it’s incredibly exciting for scientists who have puzzles facing them like this.

Fraser: When are these missions planned for launch? When should they be operational?

Linder: So NASA and the US Department of Energy have agreed to work together to put a mission into orbit. The general name for it is called the Joint Dark Energy Mission. And there are currently studies going on for how one would design such a space telescope. And we’re hoping that if enough public shows a strong interest, and the professional societies – like the National Academies of Sciences, which recommended such a mission. If they continue to support this, then we hope that we can go forward and launch it within about 6-7 years. So it’s very much possible that the students in school now will know the answers to things in 6-7 years that currently no professional scientist has the slightest clue for what the answer is. So it’s always very exciting to be able to tell students, and to be able to tell the public: you’re going to know things 6-7 years from now that we have no idea what the answer is right now. You’re going to be smarter in 6 or 7 years than we are right now. So it’s really an exciting endeavour to be in the middle of.

Fraser: And if you had your way, would it be fiery hot death, or cold freezing death?

Linder: I think the main thing I’d like is that it be far off. So we know the ends of the Universe are not going to be for at least 10s of billions of years – about the length of time that we’ve already had in the Universe – so it’s nothing we have to be concerned with overnight, but I don’t know what would be the best solution. You could argue that something like an overturning of Einstein’s Theory of Gravity and just a completely new framework of physics, and new territory to explore. That might be the most exciting outcome where you might have all sorts of different possibilities arising. But as you allude to, the fate of the Universe that really grabs our imagination, of everyone, from the scientists to school children.

My guest today is Simon Singh, author of many science-related books including Fermat’s Enigma, and The Code Book. His latest book, Big Bang, investigates the origins of the search for our place in an ever expanding Universe. Simon speaks to me from his home in London, England. I just want to apologize in advance for the murky audio quality – that’s what you get when you call London from Canada through Skype. I’ve got an audio transcript that you can refer to if you’re have trouble making out what Simon said.
Continue reading “Podcast: Interview with Simon Singh”