The Infinite Monkey Cage - Speed

Episode Date: August 3, 2015

The Need for SpeedThe Monkey Cage returns from its tour of the USA, as Brian Cox and Robin Ince take to the stage of the BBC Radio Theatre to look at the science of speed. They are joined by comedian and former motoring correspondent for the Daily Telegraph, Alexei Sayle, Land Speed Record Holder Andy Green and Professor Danielle George from the University of Manchester. They'll be looking at the engineering challenges of creating the fastest vehicle on the planet, and whether the limits to human speed are engineering or the laws of physics themselves.

This is the first radio ad you can smell. The new Cinnabon Pull Apart only at Wendy's. It's ooey, gooey, and just five bucks for the small coffee all day long. Taxes extra at participating Wendy's until May 5th. Terms and conditions apply. In our new podcast, Nature Answers, rural stories from a changing planet, we are traveling with you to Uganda and Ghana

to meet the people on the front lines of climate change. We will share stories of how they are thriving using lessons learned from nature. And good news, it is working. Learn more by listening to Nature Answers wherever you get your podcasts. answers wherever you get your podcast. Hello, I'm Robin Ince. And I'm Brian Cox. And welcome to the podcast version of the Infinite Monkey Cage,

which contains extra material that wasn't considered good enough for the radio. Enjoy it. Hello, I'm Robin Ince. And I'm Brian Cox. And this is our first show back from America. Yeah, LA didn't suit you, did it? LA didn't suit me, actually. I arrived wearing a duffel coat in 25-degree centigrade heat and managed to get a part in Hollywood as a bear.

Actually, America was great because a lot of the scientists, there was a lovely moment where they kept coming up to me going, oh, it's really great, you must be so happy to live in England because everyone in England is so fascinated by science and philosophy and ideas. And I thought, should I tell them? No. Let them dream of this utopia they've imagined.

Today we're discussing speed. Or rather, in fact, we should do this properly. You should do this, which is... Tonight we are talking about speed. Things that go really fast, like cars, reindeer, rockets, but not Mexicans because They've already given it to Chris Evans I thought I would really be in with a chance of presenting Top Gear even though I can't drive

But I do own a bicycle that has a small bell It's very tiring talking like this isn't it that's what I found the where's my hot meat we've never done such stick on the radio the thing that I like about it is what you meant to do is pretend but you didn didn't. You hit me very hard on the ear and it's created some form of tinnitus. So. OK. Today we're talking about land speed records, air speed records

and the engineering and physics of speed. How fast can humans aspire to travel? Are we restricted by engineering or are the laws of physics the only limit? As usual, we have a panel of experts, and they are... I'm Andy Green, fighter pilot in the Royal Air Force, and the fastest thing I've ever seen is a very small flock of birds on 15th October 1997,

when we were breaking the world land speed record, just before we went supersonic, this very small cluster of black objects passed just over my head doing 700 miles an hour with these huge eyes. Now technically I then saw the measured mile go past slightly faster but in subjective terms they were very fast. Hi I'm Danielle George, I'm a radio frequency engineer, professor of radio frequency engineering I should say sorry, at the University of Manchester and the fastest thing I've ever seen is a movie being beamed from one laptop to another

using light bulbs. Hi, I'm Alexis Sale. I'm a comedian, author and motoring correspondent. And the fastest thing I've ever seen is Robin out of the bar when the bill comes. And this is our panel. Andy, we'll start with you because you currently hold the land speed record, world land speed record, and this is what I'm kind of intrigued by,

which is why are we still trying to get faster on land? Because surely there's a point where all it does is just get you quicker to the seaside. There's, you know, going faster into space, into the air, I can understand, but what are the, what's the motivation between, you know, trying to get up to a thousand miles an hour? Well, there's a bit of simply because we can, it's a part of human endeavour and doing stuff like climbing Everest, going to the moon, etc. But there's also another bit, there's about bringing science and technology to life in a real sort of wow, incredible way

for the next generation of young scientists and actually teaching them and inspiring them about the magic of science and technology. Is it too early to involve the audience at this stage? Can we go there now? No. Right. Radio 4 audience, this is going to take 60 seconds. I've got four questions. You'll answer them all. And no pressure, Alexei, but if they can't, I'm going to send it to you. So first question then. Jet-powered car.

Okay, it's a military jet engine, supersonic military jet engine in a car. What's the physical mechanism that makes that car move? Air. No, thrust. Okay, go with the thrust. What is thrust? How does an engine generate thrust? Yeah, okay, so it generates pressure. What does the pressure do? Yeah, it expands, pushes out, you know, somebody said fast, high-speed gas coming out the back. Why does that generate thrust? Action and reaction, exactly. If you're pushing hard on the air, then it's pushing equally hard on the engine, engine bolt of the car, car moves. Right, it's a seven-ton car, and we've got 12 miles to get up to 1,000 miles an hour and back to stationary again. So you need to accelerate quickly.

Why do we need a really powerful engine to accelerate quickly? To overcome inertia. Keep going with that line. It's a seven-tonne car. If you only pushed it very gently, it would accelerate very slowly. If you push it hard, it accelerates quickly. Correct. So you need a big engine. Third thing, then. If there was no way of slowing this car, if there was no air brakes, no parachutes,

it's a very slippery vehicle. It's designed to be minimum drag. As close to zero drag as we can get. If we had no aerodynamic stopping aids, what would happen? When we shut it off, the car would just... ..carry on in a straight line at the same speed. OK. Last question. What ties those first three questions together? What do they all have in common? Correct. That's Newton's third law, second law and first law in order.

I'd rather more deeply know it as theorem. You always have to spoil it, don't you? Someone there goes, oh, I got it right, and you go, well, it wasn't quite right. It's three minutes into the programme and I've lost. Links symmetries of space and time to conservation laws. Everyone knows that, obviously. I love the idea...

To answer your question, it brings science and technology. Everybody's going to remember that. Newton's laws about the big engine, the thrust and the needing parachutes or airbrakes. That's a way of getting a 12-year-old excited and then going out to build their own little rocket car and put it in the playground, and we're now running... No, seriously. There must be some health and safety laws.

We are now running a global rocket car challenge. Brazil's taking part, South Africa's taking part. Have a guess what the... And there's four categories. They're all Guinness World Records. The unlimited category is currently held by a British school up near Derby. Have a guess what that record is. Anybody want to have a guess? Alexei, you're looking interested. Have a guess. This was set by a bunch of school kids

with a rocket-powered car. 100 miles an hour? Rocket-powered car, school kids. 500 miles an hour. 500 miles an hour. See, he's much cleverer than you are. Yeah, 530 miles an hour. Are you saying that some school kids... A child got in that? No, it's a model car. Oh, it's a model...

Just, you know... Think about speed programmes. You've got to keep up with all the words. Model rocket car. Sorry, I couldn't read this back. I suddenly feel like David Attenborough. And as we see the two alpha males, he usurps his Newton's law

I started it Danielle, a beautiful description there of how these challenges can excite people about engineering so is that what you really see the point of the land speed

records really is or is it genuinely this pushing the boundaries of technology? I would say probably it's a mixture of both, but I think first and foremost, getting the next generation really excited about engineering should be first and foremost in so many people's minds. So many people go to school and do the sciences, but don't really think that what they're doing is engineering.

And having something like this, that's got so many different bits of engineering in it and having it it's such a great thing for kids to get involved in make something actually yeah I can be an engineer and I can change the world so I'm really good at maths I'm really good at physics I'm actually going to do engineering when I go to university or when I get a job. Alexei, you actually were, and I find it unusual that an alternative Marxist comedian would become the Daily Telegraph motoring correspondent. I'm reforming the system from the inside. How did you end up being a motoring correspondent? Well, because my parents being communists, they didn't like cars.

Communists always thought the only good car was one that was painted green and was armoured. And had a big red star on the front and was preferably putting down a worker's uprising. So they, my dad worked on the railway, so we got free

travel. So cars just seemed like these magical, rare kind of things to me, and so I never thought that I'd ever be able to drive, so I just became fascinated with them as kind of rare objects, and so I also think that people talk to each other with cars, I think like the car that you drive, people choose them because it says volumes about them, and so I became fascinated with that really, the kind of iconography of cars, and all this before I could drive. And then, finally, I did...

I mean, I didn't learn to drive until I was 30, and so I think I just have this kind of odd, kind of outsider view of automobiles, which, you know, I think means that I can write quite interestingly about them, really, and that's what the Telegraph saw in me, was that ability. And then they didn't and they sacked me. They stopped seeing that.

But before then, I don't, you know, because I used to... I actually used to present Top Gear in the... When it was, like, really at its worst. When it was, like, all about the boot lining and carpeting in a Ford Orion. And did you... So you got into cars at sort of a late age, started driving. Yes.

Was it the engineering? Did you, do you like the fast cars, the Ferraris, the big engines? Do you like what was, what was your kind of car? It was sort of about, no, it was more the kind of like clothes again, the kind of, it was about the styling and the way that

people, you know, that if you, I mean, then it was, it's more complex now, but it's the about the style and the way that people... I mean, then it's more complex now, but it's the kind of, you know, you drove a Cortana, you were a Connor, you know, all that kind of thing. It was about the kind of philosophical ideas that were contained within cars, I think. I mean, Roland Barthes, the French philosopher and writer, said that cars are the modern equivalent of the medieval cathedral,

in that they embody both the technological but also the social and kind of philosophical pinnacle of our age. And I think that that's actually true. And that's what, you know, Richard Hammond is striving at constantly to express. At that point, he's striving for the philosophical. And Andy, so you began life as a fighter pilot. So were you always interested in land speed as well, in cars, or did you come to that from the aircraft just for the speed, really? That was very much a progression.

I actually started life as a mathematician, so that's very much my training. I then was lucky enough to get what I still think is the best day job in the world as a fighter pilot so that's very much by training. I then was lucky enough to get what I still think is the best day job in the world as a fighter pilot in the Royal Air Force, and very lately then bring those skills, both as a mathematician and as a fighter pilot, to the world of the land speed record, which I agree completely with everything Alexis said about cars and medieval cathedrals. I hadn't heard that before. That's fascinating. The land speed record is somewhat different. It is a pure, the purest form of motorsport.

1898, I'm sorry to tell you ladies and gentlemen, it was a Frenchman that started this. 39.24 miles an hour in 1898. For those French, is anybody French in the audience? Yeah, enjoy this moment. This is your last mention. Because

this is a very unusual sport. This is your last mention. Because this is a very unusual sport. This is a sport that Britain is better at than everybody else in the world put together. We've held it for pretty much most of the period since 1898. And it combines the very best of engineering disciplines that we have in the UK. We've got the world's best motorsport engineers here. My background, fighter pilot.

You know, we make things like the Eurofighter Typhoon, one of the world's best jet fighters. The Rolls-Royce EJ200, world's best military jet engine. British expertise through and through. If we are going to have the next generation of excellence in engineering and technology and everything that makes our world work, from high-end technology from aerospace and motorsport

all the way through to transport and infrastructure and other places in the world where you need enough food and water to drink. If we are going to contribute to that, we are going to need that next generation of engineers. And that using the land speed record to create a car which is part Formula One race car and it's part supersonic jet fighter

and it's part next generation space rocket and package it all in something to do a thousand miles an hour and then put it in front of a ten year old and go how cool is that? And then start having science lessons about what makes it go without them even seeing it coming. It's like hiding the peas in the mashed potato.

It's a very cunning way, get them to do good things without really seeing it coming. That's how I actually see the land speed record. And how difficult is it? Because essentially, you described it, it's a typhoon jet engine, the EJ200, with four wheels on it. And you sit on it and press go. And you go...

And? But how difficult actually is it? It's obviously slightly more difficult than that. Well, there are a couple of challenges in this, because, of course, no jet fighter in history has actually done 1,000 miles an hour at ground level. So we're not only going to set the world's land speed record, but for the first time in over 100 years,

we're going back to the natural order of things where cars are faster than aeroplanes at ground level. Just a jet engine won't get there, because we're actually going faster than the jet engine was designed to go. So we are combining it with this next generation hybrid rocket technology, which is being developed for European Space Agency. All of you in the audience, your kids will be using satellite phones one day.

You won't have a mobile master, you'll be talking to a satellite. Those satellites will be launched with the sort of technology we're going to use in the car. The tricky bit is to start off, we've got an engine intake sitting behind my head, which is optimized for about Mach 1.2, about 850 miles an hour. So we can't put full power on, but I've got to get as much power on as possible. So we have got to go to what's called the distortion limit, the maximum amount of air we can stuff through that tiny hole without it breaking down and choking the engine. So I've got to drive a very precise

thrust profile with the engine screaming away behind me as I'm winding it up very, very precisely on the pedal underneath my right foot. I've got a jet engine underneath my right foot. When we get to, and it's going to be about 100, 150 miles an hour, we'll establish exactly what speed. Once we get to full power, kick it through the D10, full reheat lights one second later, the car is then accelerating at 1G, so 20 miles an hour per second. It's the equivalent of 0 to 60 in 1.5 seconds. So it's pretty ferocious. I've then got about six seconds

before I start the wind-up process for the rocket, because it's a hybrid rocket, I need to hit it at exactly the right time, 20 seconds before we get to the measured mile, because it burns for just over 20 seconds, need it to burn out in the measured mile. So I've got to hit that at exactly the right point. And while I'm doing all of that, I've also got to monitor the loads front and rear

to check that the aerodynamic balance of the car is exactly the same as we had the run before and the run before. And at slow speed, slow speed for this car is anything below about 200 miles an hour. The wheels are basically, they're sort of V-shaped metal wheels. They are using their form, just the actual grip and the V-shape in the dry mud surface in South Africa, to actually keep the car straight. They're not V-shaped wheels?

V-shaped, yes. You can't put tyres on it. They're not round? Because... I've got a tip for you. I'm going to have to speak more slowly. The round wheels have a V-shaped profile on the tread. Oh, OK. We're going to cut through them.

The shoulders of that, at slow speed, give me a little bit of grip. Medium speed, 300, 400, 500 miles an hour, the wheel is now starting to plane like a speedboat hull, so it's starting to skim across the surface. We are now down to possibly two or three millimetres of wheel sticking into the surface. So there is almost no lateral grip. I'm literally, you know, plus or minus 90 degrees of steering is what we estimate I may have to use to keep the car straight at this stage,

while firing the rocket and now bumping the acceleration up to 2G, 40 miles an hour per second. You know, the car is now cracking on at a fair rate, and it's like driving on ice. The aerodynamic stability has yet to kick in because at 300 miles an hour the aerodynamic force is only about a tenth of what it is at a thousand because it's you know comes up with a square law now jump forward until we're fully supersonic doing eight nine hundred thousand miles an hour the wheels are still skimming so they're still doing very very little but now the aerodynamics are absolutely doing a huge amount the front wheels stick down into supersonic airflow, doing Mach 1.3, 1.5 between the front wheels,

so now a tiny change in the steering wheel will produce a huge response in the steering input. So the car goes from being reasonably predictable at 200 miles an hour to 300 or 400 miles an hour, it's all over the place, to 1,000 miles an hour, tiny changes making it dart all over the place. While I'm controlling the jet engine and the rocket and monitoring the downloads and looking for the measured mile so that we can actually get the car up to speed.

And then there's the slowing down bit, which is like what I've described, but in reverse involving air brakes and parachutes and still keeping the car straight. But apart from that, yeah, it'll be quite easy. LAUGHTER APPLAUSE See, about halfway through that, all I saw you was dressed as Batman. And it kind of ruined it. I suddenly realised I'm very childish.

It was that when you went, my day job's a fighter pilot, which was, my day job's a fighter pilot, by night I'm a secret greengrocer. Daniel, in terms of engineering, as well as the practical side, would you be drawn to actually going on an adventure like that, the attempt to try and get to 1,000 miles an hour? Could you see yourself behind the steering wheel? The driving wheel? I don't drive. I don't know any of the technical terms.

I don't think I could see myself behind the wheel, but more behind the technology. So if Andy's in the car, I could see me being there going, right, the electronics is doing this, the mechanics is doing that, and we need that person doing this. And so being more on the sort of the engineering side,

and Andy can take all the glory. And well, no, that is actually, that's the story we're trying to tell. The glory is the, how do you get the engineering to come together and make all of that? You know, I'm part of the engineering team showing off exactly what you've just described you start you worked um with not on engines but on turbines but the same jets can you tell us a bit about that the

i suppose the engineering and the the design that goes into a modern jet engine oh it's just amazing i mean it's absolutely so i i was in Rolls-Royce in Derby, very privileged to sort of be near one of their Trent 1000 engines, and it's truly beautiful. You know, you're talking about art, Alexi, and how cars are like that. An engine is truly

beautiful, and, you know, they talk about STEM, and a lot of people are talking about STEAM now, so bringing the art, the A, into it. And it is. They're such beautiful things to look at as well. And the engineering behind it is truly amazing. You just stand there.

And they're huge, these things. You feel so small when you're standing in front of them. But the amount of engineering that goes in them is truly amazing. So they're the engines that are on things like 777s? That's right, yeah. One of the interesting things, I was watching a film about Rolls-Royce and Derby, and, you know, like at the BBC, everybody kind of... It's like everybody talks posh.

But, like, there's a variety of regional accents that I notice. They're even in the very senior positions. I don't know whether... I mean, you've obviously got, like, a Geordie accent. I don't know whether you think that that's... I don't know, it just seems something significant in a way. Something like the media seems to be dominated by... Because it's not a meritocracy.

Dominated by posh people. Whereas engineering, because it is a meritocracy, seems to be... You seem to get a lot of working-class accents. That's true. I never really thought of it, but yeah. Yeah, it just struck me watching that film. Just making a bit of a Marxist point there, you know. Really. I'm absolutely telling you, we've got to correspond to that.

Still wondering how he lost his job. And you work specifically on the electronics around those engines. Yeah, yeah, so we were looking at the RF, the radio frequency, and can you effectively try and get rid of some of the wiring that's in a lot of jets? So not when they're actually flying, but when they're either in the test beds or when they're on the aircrafts but on the runways

or they're parked in the airports. You want to communicate with them, and it would be really, really good to get rid of all of the wires. So can you do it wirelessly but there's a lot of huge infrastructure just in the engine and you imagine if you close the cowl doors on an engine it's like a Faraday cage

no signals can get in or out so trying to communicate outside of those cowl doors because they have to be there's sort of metal strips in them for lightning protection as well so there's a lot of metal to communicate outside of those cowl doors because they have to be... There's sort of metal strips in them for lightning protection as well, so there's a lot of metal in them. So trying to get wireless communication out,

or radio waves out of an engine, is really, really difficult. Are they the most complicated things that we mass-produce as a civilisation, aircraft engines? They probably are, aren't they? Yeah, they probably are, yeah. When you look at one, you sort of think... Yeah, because the amount that goes in is... And they cost as much

as the plane, don't they? Oh, yeah. The amazing thing is they monitor them, don't they? Rolls-Royce actually monitors every Rolls-Royce engine as it's flying. Yeah. Which is great. But it is amazing we think how many there are and what are the different challenges

Andy was going through a lot of the challenges in terms of land speed but when we're talking about going into space and obviously we have to find ways if we're going to manage to travel any distance into even our own solar system, human beings, we're going to have to find new technology, what are the challenges the engineering challenges of going into

space and building up speed? I think a lot of it is the sort of human side in terms of the sort of biomedical side. So there's a lot of biomedical engineering that needs to be done, or bioengineering that needs to be done. Making people

be able to breathe properly when you're out there. Sort of very basic functions. But also size. I mean, sort of very basic functions. But also size. I mean, sort of forget cost for now, but think about the size of things. If we as humans want to travel into space, we need to take a lot of stuff with us.

And so there has to be a lot of spacecraft that not only carry humans, a bit like we have now with planes. You know, there are commercial flights, but there is cargo as well. We need cargo as well. so a lot of nanotechnology, so trying to shrink everything down into as small as possible, the technology, so that you can put more in a spacecraft,

so you can get more out there at any one time. And they're doing it now. So for the International Space Station, they're trying to detect toxic or toxins in the air. They have these tiny little... They've used nanotechnology in their tiny little sort of stamp-size vents, and they're detecting toxins in the air on the International Space Station. But that has taken a huge amount of engineering to get it right down.

At one point, it would have been this size, where they've got it all the way down to the size of a postage stamp now. So it's sort of nanotechnology, a lot of sort of bioengineering. And then, of course, there's the obvious mechanical engineering, the huge amounts of electronics. I mean, there's huge amounts. I imagine in the cars now that, Andy, you're dealing with, there's huge amounts of electronics.

There is in the Formula One cars, much less mechanical engineering and much more electronic engineering. So we need to think about that as well. Cling on. They're going to be a problem. Actually, I know you were saying beforehand about when you were a motoring correspondent, every now and again you were, about once a month

you would have to do something which you found reasonably terrifying yeah i mean in terms of things like land speed records or you know journeys into space are these either of these things things that you could imagine doing or is that really beyond your uh you know your fear factor um i don't mind as long as i'm if i can drive it i don't you know what i hated was like we were talking about before about going up the hill at Goodwood, and I went up there with one of their Ferrari drivers in a 458, and it was just the most terrifying, because I wasn't in control. It was just the most terrifying experience.

And just towards the end, it started to rain, and the driver didn't turn on the windscreen wipers. And I thought, that's what you do when you're a racing driver, you don't use the windscreen wipers. And I said afterwards, you didn't turn on the windscreen wipers. He said, I didn't know where the switch was. We're doing 120 coming up to a Flintstone wall and he hasn't got the windscreen wipers on.

So I would have been even more frightened. For me, yeah, it's a question of control. I don't mind going fast as long as I'm driving, but if I'm being driven, I find that really terrifying. I know, but you were talking... Brian was talking before about you going up in a typhoon and stuff. You don't mind that seed in control, too? No, I tend to think these pilots know what they're doing.

In fact, if they said to me, if they said to me, why don't you land this typhoon, I'd say, no, you land it. You see, I'd say, yeah, I can do that. I want to follow up with Alexis. It's all about control. Would you really be happy to go into space if they just said, yeah, you're on your own, you can fly it? Yeah, because I think I could.

I'm a comic. I think I can do everything. I did it on the Xbox, so, you know, I mean... How hard can it be? Yeah, you're right. How hard can it be? Andy, is there a limit that you see to land speed records? That's always a very dangerous question to answer, because, of course, you know, Malcolm Campbell, very famously, he was the greatest of our land speed record break nine world land speed records he almost

made a business out of it and he was the first man to uh to get over 300 miles an hour 1935 bonneville salt flats he climbs out of his car 300 first ever 300 mile an hour run amazing achievement and he climbs out he says i don't believe man will ever drive faster than that which was probably a little bit on the ambitious side to say because of course a few years later people were doing exactly that and you can almost by a commercial production count certainly go 200 miles an hour exactly but of course it also depends on how much you understand the technology so it may have seemed like a perfectly reasonable thing to say in 1935 because if you jump forward let's say 10, 10 years to 1945, end of the Second World War, airplanes

were now getting fast enough that in a power dive they could actually start to generate shockwaves over the wings. And they got all the buffeting and airplane was thrown all over the place. And some of them actually physically broke up. And they coined a term, the sound barrier. Because it was deemed a physical barrier that you would never get through.

Because the shockwaves were piling up, you could never punch through that because the loads would just be so high it'd be ridiculous and you know if we were in an audience right now saying do you think anybody could ever break the sound barrier of course it's been done 1945 you would have said no that can't be done we've got all sorts of evidence you get close to that the airplane will break up well two years later of course they developed the technology and uh the likes of uh chuck yeager were actually getting supersonic as part of the demonstrating the ability to manage high-speed flight because ultimately what they were looking at is very high speed re-entry into the atmosphere because they

were building the technology would ultimately allow the americans to go to space and come back again now is there a limit to how fast people can travel? They went pretty fast going to the moon and back, you know, tens of thousands of miles an hour. Does, then, the physics of the speed of light come in? And is that actually a physical limit, or is it just that we don't understand, like the sound barrier, we don't understand what lives beyond it? We could ask Danielle to come in there. Well, I just wonder, though, but in terms of land speed,

isn't there going to be just a limitation in terms of the amount of land? You know, there's a bit where you go, it's just a little bit too fast and I keep going over the end of the cliff. You know, there's kind of... So, for instance, I know that in South Africa, the fact that the people who are helping prepare where you're going to drive, they're spending a lot of time picking up every stone, is that right? They have to basically clear...

They've actually got their first world record. These guys have done something which is an achievement of biblical proportions. They have hand cleared over the last five years 20 million square metres by hand. A team of 300 people. Now if you want to picture what

20 million square metres looks like, if you imagine a three lane road from outside here, Broadcasting House, if you followed that, turned left when you get to central London and all the way to the coast, to Dover, three-lane road, through the tunnel, keep going, turn left at Paris, that would take you to Moscow. And you are clearing that by hand.

They lifted 16,000 tonnes of stones. That's 55 tonnes per person. It's just staggering numbers. And they've left us with the world's best prepared and certainly by a long way the largest hand-cleared racing surface in history. However, that's, you know, it's 12 miles long, there is no more land available, that's end-to-end on the desert.

If you needed to go faster, you've either got to accelerate quicker, which is challenging, we're already using the world's best jet engine and the hybrid rocket technology, or you need a longer surface. Now, here's the good news. If you really had to go somewhere longer, there is a salt flat in Bolivia. It's 13,000 feet up. It's at the end of 100 kilometers of gravel track. It's 100 miles long. So there's plenty of space out there. I wouldn't recommend actually going to Bolivia. I know a couple of people have been there, and they have had to make quite sizeable contributions

to the local economy at gunpoint. So there's several reasons we're not going there. That's just one of them. You can't get away fast enough, surely. LAUGHTER When you get to the other end of the desert and his mates are waiting for you, you don't have any fuel to get back again.

There is a lot of space left. So is there a limit to the land speed record? I mean, we've run up against several limits. First of all, the aerodynamics of keeping the car on the ground has been the massive challenge. The world's leaders in this, Swansea University, who did the aerodynamics for the previous car that we built, and they have developed the science to build a lift-neutral shape from 200 to 1,000

miles an hour. That's never been done before. It's an amazing achievement. And we'll validate that over the next two years. Then there's the wheel problem. 1,000 miles an hour, the wheels are turning 10,000 times a minute. These are the round wheels, Alexei, with just the V-shaped profile on the edge. 10,000 times a minute, that's 170 times a second. So the wheel rims are experiencing 50,000 times the force of gravity outwards. Now, that's exactly the same sort of loads that jet engines are exposed to,

which is why we've got a company called Castle Precision up in Glasgow, who make the big spinny bits and Rolls-Royce engines to make our wheels to the same standards and with the same technology. But that, again, is right up at the limit of modern aerospace-grade alloys, even with all of the forging and heat-treating

and specialist design that Castle and the consortium can put in. So you're then going to have to look at ever more exotic materials. And to go, let's say, 20% faster, you're looking at almost 50 increase in that load so now you're up at 75 000 g well you're way outside what most materials will cope with pretty much anything so very rapidly small increases start to have massive implications in terms of the aerodynamics in terms of the wheels in terms of the power you need and then you run into the distance problem because at a thousand miles an hour,

you're using a mile of track every 3.5 seconds. So you've got a limited amount of time, even on a 100-mile track, before you run out of the surface of the Earth. All of which leads me to confidently state, I don't think anybody's going to do more than 1,000 miles an hour in the near future, but I'm not going to fall into the Malcolm Campbell trap of, we're definitely the fastest. If you want to know, by the way, where that stone-cleared land is, it's next to the tallest rockery in the world.

Daniela, we spoke there about the speed limit, which is surely the speed of light. So could you speak about that, the universal speed limit? Yeah, so the speed of light is finite. It's around 300 million metres a second, 186,000 miles per second. So put it in context, if you were a traveller moving at the speed of light

and you circumnavigated the equator, you could circumnavigate it seven and a half times in one second. Pretty fast. But it is finite. But it wasn't always thought to be finite. So people thought it was infinite for centuries and centuries. So Aristotle, the Greek philosopher

who is in many ways a sort of godfather of physics, he didn't actually ever do any measurements or experiments. He just took it to be instantaneous and therefore it was it was infinite so it wasn't really till sort of Galileo 16th 17th century that people started to think it's not infinite it is it is finite so Galileo had this experiment which he never actually did but he wrote about it saying he never did it because he was under house arrest. That's his excuse, anyway.

But he said he thinks the speed of light is finite, and to prove it, get two guys with lanterns and put them on a hill each, and then one guy opens his lantern, shines the light at the other guy on the other hill. When the other guy sees the light, he then opens his lantern and the light shines back. And by measuring that light,

you'd be able to measure the speed of light. So, but like I say, he never actually did it. So other people took up the gauntlet later on There's a small flaw in that, the second bloke with the lantern is going to have to be really quick It was like a 16th century version of a Jean-Michel Jarre concert So it wasn't

it was sort of Ole Roma in the 17th century he sort of made some measurements when he was looking at Jupiter. So he was trying to observe the planet Jupiter, and the planet Jupiter's got many moons, and he was trying to observe the moons going around Jupiter and going into eclipse,

so the sunlight is blocked when it goes into eclipse. And he noticed that the timings were out sometimes, so they would fluctuate when he was observing them. And he was quite a confident guy and thought, well, actually, it's not my measurements, it's not my clock. Something strange is going on here. And what he was actually measuring was the fact that Jupiter and its moons are very far away,

and it's taking quite a long time for that light to reach us. So, therefore, that light must be finite, and we must be able to measure it somehow. So what are the... I mean, there are... There was a while ago, was it about two years ago, there was the neutrino, rumours that neutrinos went faster... And there are some ideas of possible particles, aren't there, which may... Yeah, the idea of conjecture,

that there might be something that goes faster than the speed of light. Now, can you tell me a little bit about those? Yeah, yeah, it's hugely theoretical, very Alice in Wonderland-type world here. But there are things called tachyons, or metaparticles, they were called before tachyons were termed. And basically, they have no mass. So if they have no mass,

then you can effectively travel faster than the speed of light. So the reason that they have no mass is because in mathematics you have a real number and an imaginary number, so you have complex numbers. There's a real number and an imaginary number and it is deemed that tachyons have imaginary mass. So they don't have real mass, they have imaginary mass. We should say that's a square root of minus one.

Yes. So the mass is i times something. I'm now really sorry I started this line of conversation. Because ten minutes ago we were talking about 350 metres a second, supersonic driving really fast, and now Concorde's out of service. Anybody that's flown, I've driven faster than that. Now we're up at 300 million metres a second, supersonic driving really fast. Now Concorde's out of service. Anybody that's flown, I've driven faster than that. Now we're up at 300 million metres a second. I've been left way behind.

So, yeah, so the imaginary mass, and then so this is... But what are the repercussions? You know, the idea that there would be something that... Once you have something that can travel faster than the speed of light, how does that change our universe? So the theory is if you can travel faster than the speed of light, how does that change our universe? The theory is if you can travel faster than the speed of light, you can effectively time travel

in the future. You can go forward. They don't talk about going back in time, but in forward you can travel forward in time. That's a cop-out, isn't it? Because if they said you could travel back in time, you'd say, well, not because there aren't loads of scientists

coming back here and bringing their data. I don't know where I'm going with this. What I'm hoping is another Alexei Sayles about to walk on and go, see, Alexei, I told you! He said, yeah, you can travel forward in time, but you can't go back because it would prove you could travel back, because people would turn up from the future, wouldn't they? Well, in Einstein's theory of special relativity,

the speed of light, the finite speed of light, is the thing that protects us from time travel. So if you travel faster than the speed of light, in Einstein's special theory of relativity, you can wander around in time in the same way that you can wander around in space, essentially. So what the speed of light does in that theory is protect the past from the future.

So physicists call that causality. So the finite speed of light protects cause and effect as an idea. But now these people are saying it's been repealed. Tachyons, the trick with tachyons, is that they can go... If they existed, they'd always go faster than light and they wouldn't be able to ever travel slower than light. Yeah, you'd have to put energy in them to make them slow down. So it's complete opposite to what we have now.

So we need energy to speed up. So obviously for Andy's car, he needs a lot of power, a lot of energy into his car to speed up. These things, you have to put energy in them, theoretically, to slow down. So they could go... So the message I'm getting here is we need a tachyon-powered car. And a very big runway.

Yeah. So in terms of what have we sent into space, and I include things like radio waves, I mean, this is one of the things you will often see used in films and television shows, where they will give this sense of journeying into space where the idea that extraterrestrials will now be watching, for instance, I Love Lucy somewhere,

or Alexei sells stuff, whatever it might be, that there will be... Oh, good, the Love Lucy somewhere or Alexei Sales Stuff, whatever it might be, that there will be... Isn't the oldest thing you can think of? Oh, good, the Montreal winning Alexei Sales Stuff. You've always dissed my audience, haven't you? You've always presumed there'll be extraterrestrials. Farage will be furious. But it's...

But so, what would... When we are, for instance, radio waves, say, for instance, television signals, when they go... But is there a point where, during that travel, the speed of that travel, that no longer, say, extraterrestrials at certain distant planets around stars, that they will not be able to actually see the picture or hear the sound because there will be fragmentation? Yes, there'll be huge amounts of fragmentation.

So as the radio waves leave the Earth, they'll propagate out, they'll move out into space, and there'll be a lot of noise associated with that. Well, the first thing, actually, we've got to get out of our ionosphere. So short waves, so short-wave radio doesn't have a chance. It's FM radio and long-wave radio would be able to break through, or television signals as well,

would be able to break through our atmosphere and get out there. But once it's out there, the signal would degrade, and it's an inverse square law that it degrades. So if you think about, the signal would be as quarter

a great as it was once it's travelled twice the distance. So it's really deteriorating as it goes out and out and out. So how far can we get then, Brian? How far would this show get? Do you know you must be able to do the maths? Well, you should as well. I won't be able to.

I know a lot about Bleak House. So this is... What do you know about Bleak House? So how the... I'll tell you what, it's not a happy place. It is not a happy place. If you get Bleak House on Monopoly and someone lands on it... Anyway, so the... I want to know exactly what you know about Bleak House.

Look, when I'm on Loose Ends again, I'll tell you about Bleak House, but that's not our agenda. So, I mean, in terms of... I'll fast-forward. How far out could this show get? I was going to say to the point where it starts to fragment and makes no sense, but that's only about as far... About as far as Alderney, I think, possibly.

Maybe to Alderney and back. Well, I don't know. I mean, it depends on the power of the transmitter, doesn't it? Right, OK, then. So, do you know the power of the transmitter? Like, if we go for someone like Ali Pally, someone like that? Do you know what a typical transmitter what a typical radio transmitter is? Kilowatts? Yeah, you're in kilowatts.

Is this FM or longwave? I'll tell you what, because it's radio 4, let's go longwave. It's like that Python sketch, and then it gets vaulted out. Longwave, no point! So, longwave is... What, 198? 198 megahertz. Kiloherts, yeah.

Oh, there's the signal. You've only got five seconds left, so... How would you work it out? Could you work it out with... This is always my favourite bit, is when he just looks up at the stars. Only you can enjoy this, because he hasn't got another landmark show for a few months. So if you imagine that it's photons rather than waves,

imagine it's photons, then there's a finite number of photons going out from the transmitter because there's a finite amount of energy. And as everyone knows in the audience, I can do that with your Q&A, the energy of a photon is Planck's constant multiplied by the... LAUGHTER

..frequency. Frequency. E equals HC over lambda, HF. Frequency. So, given the frequency, and we know Planck's constant, you can work out the energy of a photon. So, the energy of the transmitter. So, if it's 200 kilowatts, that's 200,000 joules per second.

Anyway... Hang on. The alpha males are now battling over the... But the point is that you've got a finite number of photons going out. So as you said, there's an inverse square law, so they decrease. So you get to a point where there's only one photon per... Yeah. ..per, I don't know, per cubic light-year or something like that,

if you go that far. So then you would have no signal, would you, because you'd have a single photon. And even the amount of information in this show can't be fitted inside a single photon. Well, the person that got that photon would still have to pay their licence fee. So that's a viewer's question for next week.

So given that there's a 200-kilowatt transmitter, let's say it transmits just for one second, then at 198 kilohertz, then it should be relatively trivial to work out the point at which there's a, the signal degrades such as one photon per, let's say per

square meter on some sphere out from the Earth at some distance, and that distance is the answer to Robin's question. I venture. And if we do get, if we get for the final episode... I just made this up. I'm ad-libbing mathematics and physics on the radio.

That's what you're known for. You're the John Sessions of Euclidean geometry. But it is going to be very exciting. Basically, if anyone does write in in the final show and get that answer right, it's doubly exciting because we're actually recording the last show before this one goes out. So it will also mean that they've conquered time travel as well.

So, um... You may assume. No, it's not about me. Hence our otherwise. So we asked the audience what is the thing that is most likely to make them move the fastest, and so far we have... This is correct. F equals MA.

OK, that's very... F equals MA on this answer. Christopher Biggins. And it's not often that on any Radio 4 show you go straight from F equals MA to Christopher Biggins, but there is a link. Do write in. Seeing Brian Cox at the end of the road. Moving towards, obviously.

That's Natasha. Brian Cox running towards... You've got a choice. Brian Cox running towards you naked, that's Emma. Brian Cox with a bottle of Shiraz. Happy days. That's Linda. LAUGHTER Brian Cox dancing wildly. That's Barry.

LAUGHTER Brian Cox riding naked on a velociraptor. That's Kathleen. And, er, nothing. The universe revolves around me. LAUGHTER That's Brian. APPLAUSE the universe revolves around me. That's Brian.

So, thank you very much for listening. Thank you to our panel, Andy Green, Danielle George and Alexei Sale. Next week is the final show in the series, where we are going to be discussing death and forensics. So, just in case you've forgotten that your life is finite, we always like to end the series with existential angst and murder. And while we're on that subject of death, here is the subject that never dies. It is actually strawberries again. We haven't had a reply to this for a while. We've got a letter from Samuel Furse who wrote, I don't think the strawberry has ever lived. This interpretation is informed by my year eight science work on classification

lived. This interpretation is informed by my year eight science work on classification that said that any part of a living thing that never lived but was part of something that had lived. Other examples include a severed arm and hair. Not your hair though. However the strawberry contains seeds at least some of which may be alive so perhaps your question is rather like asking whether a colony of living beings is alive like an anthill or Manchester. And the other letter we received was,

if you hold a piece of red litmus paper against Jim Al-Khalili, does it turn blue? Thank you very much for listening and goodnight and goodbye. Bye. In the infinite monkey cage. In the infinite monkey cage. In the infinite

monkey cage. Turned out nice again. This is the first radio ad you can smell. The new Cinnabon Pull Apart apart only at Wendy's. It's ooey gooey and just five bucks with a small coffee all day long. Taxes extra at participating Wendy's until May 5th. Terms and conditions apply.

In our new podcast, Nature Answers, rural stories from a changing planet. We are traveling with you to Uganda and Ghana to meet the people on the front lines of climate change. We will share stories of how they are thriving using lessons learned from nature. And good news, it is working. Learn more by listening to Nature Answers wherever you get your podcasts.