0:00:06 > 0:00:11This is the story of an incredible scientific adventure.
0:00:11 > 0:00:15Of an unlikely collection of scientists and engineers,
0:00:15 > 0:00:20dreamers and schemers, who attempted the impossible.
0:00:24 > 0:00:25To control gravity.
0:00:28 > 0:00:31Gravity is the fundamental force that holds us to the earth
0:00:31 > 0:00:36and binds the universe together, yet we still don't fully understand it.
0:00:36 > 0:00:41Gravity is the most mysterious of all the fundamental forces.
0:00:41 > 0:00:45The ultimate challenge I can think of as a scientist
0:00:45 > 0:00:46is to control gravity.
0:00:47 > 0:00:51The scientific quest triggered a race between rival corporations,
0:00:51 > 0:00:53governments, and military...
0:00:55 > 0:01:00It can destroy the missiles or remove them from their trajectory.
0:01:01 > 0:01:03..fuelled by the paranoid fear of missing
0:01:03 > 0:01:06the greatest technological advance in history.
0:01:08 > 0:01:14If just one that here works, if only partly, you won the jackpot!
0:01:14 > 0:01:19If this ever happened, it's going to change aerospace.
0:01:19 > 0:01:22The potential is so great, if I did not bring this to
0:01:22 > 0:01:26the attention of the Pentagon, oh, I would have been fired!
0:01:26 > 0:01:28The search for gravity control
0:01:28 > 0:01:32ranges from Washington to the streets of Eastern Europe,
0:01:32 > 0:01:37from the deserts of America to the furthest reaches of the cosmos.
0:01:37 > 0:01:39Dark energy has some sort of antigravity.
0:01:39 > 0:01:43We still don't know whether it's something that we can ever harness.
0:01:43 > 0:01:46Someone might wonder, why can't we build a machine with it?
0:01:46 > 0:01:49We just need to find the trick.
0:01:51 > 0:01:53Unlikely as it may seem,
0:01:53 > 0:01:57the story begins in a corner of Lancashire, near Blackpool,
0:01:57 > 0:02:01with a humble engineer who had a dream.
0:02:01 > 0:02:04It's only another force field, but wouldn't it be good
0:02:04 > 0:02:07if we could actually control it and do more?
0:02:07 > 0:02:10If the dream of gravity control ever came true, it would
0:02:10 > 0:02:14revolutionise the world and could send us to the stars.
0:02:16 > 0:02:18PEOPLE WHOOP AND SCREAM
0:02:48 > 0:02:51In the late 1980s, aerospace engineer Ron Evans
0:02:51 > 0:02:54was working in the defence industry in Lancashire.
0:02:57 > 0:03:00He'd been trying to find a way to detect stealth bombers
0:03:00 > 0:03:02using fluctuations in gravity...
0:03:04 > 0:03:07..and he wondered if he could take it even further.
0:03:09 > 0:03:12Could he use gravity to levitate a plane?
0:03:14 > 0:03:17Of course, it was impossible, but Ron did something
0:03:17 > 0:03:22a bit reckless - he asked his employer if they'd let him try.
0:03:24 > 0:03:26Ron's employer was the biggest defence
0:03:26 > 0:03:30and aerospace contractor in Europe - BAE Systems.
0:03:33 > 0:03:37And instead of telling him to have a cup of tea and a lie down,
0:03:37 > 0:03:39they listened.
0:03:39 > 0:03:43I had to go to the head of the technology board -
0:03:43 > 0:03:47it's a panel - and persuade them that it was worth doing.
0:03:47 > 0:03:50Now, clearly, it was very speculative.
0:03:50 > 0:03:53I had to go away and come up with some concepts
0:03:53 > 0:03:57and come up with some ideas that could actually feature
0:03:57 > 0:04:00an antigravity or a gravity-type propulsion system.
0:04:00 > 0:04:04Well, this was one of the designs that we came up with.
0:04:04 > 0:04:07For a start, it wouldn't be limited to just flying in the air.
0:04:07 > 0:04:12It could fly anywhere - into space, even into water.
0:04:12 > 0:04:14And of course, it was a vertical takeoff design
0:04:14 > 0:04:16because it had a gravity engine inside
0:04:16 > 0:04:20but it didn't look very exciting, and so...
0:04:20 > 0:04:24we asked the artist to put some green rays underneath.
0:04:24 > 0:04:26That made it look far more futuristic.
0:04:27 > 0:04:30Let's be clear that not everyone in the company
0:04:30 > 0:04:31thought we should be doing it.
0:04:31 > 0:04:35There were quite a few that felt, we make aircraft,
0:04:35 > 0:04:37we're good at it and that's what we should be doing.
0:04:37 > 0:04:41But there were a few - and some very senior people - that felt,
0:04:41 > 0:04:45OK, let's just have a little look at the future.
0:04:45 > 0:04:47And the concept became known as Greenglow.
0:04:53 > 0:04:57As head of Project Greenglow, Ron's job was to find
0:04:57 > 0:05:02and develop advanced propulsion systems to overcome gravity.
0:05:02 > 0:05:05The potential was enormous, if it happened.
0:05:05 > 0:05:08It would totally change aerospace.
0:05:08 > 0:05:11And Ron was not alone.
0:05:16 > 0:05:19At around the same time, in the US,
0:05:19 > 0:05:24NASA began a parallel project headed by aerospace engineer Marc Millis.
0:05:26 > 0:05:29It was around 1996 when I was asked to lead
0:05:29 > 0:05:32the Breakthrough Propulsion Physics Project -
0:05:32 > 0:05:36things like non-rocket space drives,
0:05:36 > 0:05:39interstellar propulsion and manipulating gravity,
0:05:39 > 0:05:41things like that.
0:05:41 > 0:05:44For that project, the idea was to think radical, think big.
0:05:46 > 0:05:48However, today,
0:05:48 > 0:05:51NASA says it has moved on and doesn't want to look back.
0:05:53 > 0:05:55We can't go in there to talk about it now
0:05:55 > 0:05:57because NASA's not doing that work right now.
0:06:05 > 0:06:08At BAE Systems, the same situation.
0:06:09 > 0:06:13The company no longer wants to discuss Project Greenglow.
0:06:13 > 0:06:15We asked whether we could go there
0:06:15 > 0:06:18and talk to them about it and they just said no.
0:06:21 > 0:06:25Gravity control is a dark and dangerous science.
0:06:25 > 0:06:30Like modern-day alchemy, it promises a glittering prize,
0:06:30 > 0:06:32but it can destroy your reputation.
0:06:42 > 0:06:45Years earlier, Ron had watched a gravity experiment
0:06:45 > 0:06:48bring down one of Britain's best-known scientists...
0:06:48 > 0:06:51'This time, I call for a volunteer.'
0:06:51 > 0:06:54..professor of engineering at Imperial College London,
0:06:54 > 0:06:56Eric Laithwaite.
0:06:56 > 0:06:59'And then we're going to spin up the biggest gyro of the day,
0:06:59 > 0:07:01'which is here.'
0:07:01 > 0:07:03Like millions of others, Ron had been spellbound
0:07:03 > 0:07:07by Laithwaite's Christmas lecture at the Royal Institution in 1974.
0:07:09 > 0:07:10I can make him raise it.
0:07:12 > 0:07:14Now...
0:07:14 > 0:07:17Laithwaite suggested that by spinning a heavy wheel,
0:07:17 > 0:07:19he could make it counteract gravity.
0:07:21 > 0:07:23Ron has returned to the Royal Institution
0:07:23 > 0:07:25to try and recreate the effect.
0:07:25 > 0:07:27- Does it feel light?- It does.
0:07:27 > 0:07:33- It feels very light.- With the help of fellow engineer Dr Adam Wojcik.
0:07:33 > 0:07:35'What I think was at the back of Laithwaite's mind'
0:07:35 > 0:07:39was that there was a force in one direction more than in the other,
0:07:39 > 0:07:42and so the gyro will start to rise up.
0:07:43 > 0:07:48And that gives you the illusion as though it's losing weight. It isn't.
0:07:48 > 0:07:50It's just an illusion.
0:07:50 > 0:07:51But is it lighter?
0:07:53 > 0:07:57When the gyroscope is rotated in the same direction it's spinning,
0:07:57 > 0:07:59it's given an upward lift.
0:08:01 > 0:08:05- And if I rotate in the opposite sense...- Oh! That does look heavy.
0:08:05 > 0:08:08- Ooh, careful!- Wow!- Careful, careful!
0:08:08 > 0:08:11When it's rotated in the opposite direction,
0:08:11 > 0:08:14the opposite happens, and it seems to get heavier.
0:08:15 > 0:08:20Still hoping to make gravity control a subject of serious research,
0:08:20 > 0:08:23Laithwaite acknowledged his mistake.
0:08:23 > 0:08:27Yet his reputation was irreparably damaged.
0:08:27 > 0:08:31He was snubbed by the academic establishment
0:08:31 > 0:08:35and felt obliged to leave his position at the Royal Institution.
0:08:36 > 0:08:39Professor Laithwaite got into a lot of trouble with this,
0:08:39 > 0:08:45really, because of the claim that it got lighter, which is antigravity.
0:08:45 > 0:08:48And the academics jump on any antigravity device
0:08:48 > 0:08:51as being impossible.
0:08:51 > 0:08:52Well, it's not impossible.
0:08:52 > 0:08:56It's just we don't know how to do it. But we should look.
0:08:56 > 0:08:59It's like flight in the last century.
0:08:59 > 0:09:02In those days, anybody that said they could fly
0:09:02 > 0:09:03was looked upon as a lunatic!
0:09:10 > 0:09:13The difference is that, before humans could fly,
0:09:13 > 0:09:17we knew birds could. We could study aerodynamics.
0:09:19 > 0:09:21But there was nothing we knew of
0:09:21 > 0:09:23that could actually overcome gravity.
0:09:35 > 0:09:37The dream of lifting effortlessly from the earth
0:09:37 > 0:09:39is not confined to engineers.
0:09:41 > 0:09:42Despite being so contentious,
0:09:42 > 0:09:45many academics are rather seduced by the idea.
0:09:47 > 0:09:49Dr Tamara Davis is among them.
0:09:51 > 0:09:54From a little kid, I always wanted to go and visit other planets
0:09:54 > 0:09:56and go up into space.
0:09:56 > 0:09:58And to be able to have a form of propulsion
0:09:58 > 0:10:01that could get me there easily would be fantastic.
0:10:01 > 0:10:03But we don't yet know
0:10:03 > 0:10:07whether we can manipulate gravity or have any control over it.
0:10:08 > 0:10:12There is one fundamental force we know we CAN control,
0:10:12 > 0:10:17which we've used to build our modern world - electromagnetism.
0:10:19 > 0:10:23It gives us a tantalising illusion of gravity control...
0:10:24 > 0:10:25..when we levitate a magnet.
0:10:27 > 0:10:28Ta-da!
0:10:30 > 0:10:35Electromagnetic repulsion balances the weight of the magnet
0:10:35 > 0:10:39by using the same magnetic polarity in the base.
0:10:39 > 0:10:42We know that like charges repel.
0:10:42 > 0:10:46So here, we just have a magnetic field that's levitating a magnet.
0:10:46 > 0:10:50So this is nothing mysterious. This is just electromagnetism.
0:10:50 > 0:10:52Let's see if I can get this across.
0:10:54 > 0:10:55Come on!
0:10:58 > 0:11:01The power of control we get from electromagnetism lies in
0:11:01 > 0:11:04the fact that we can change its polarity
0:11:04 > 0:11:07and make it either repel or attract.
0:11:09 > 0:11:10So in electromagnetism,
0:11:10 > 0:11:13we have positive charges and negative charges.
0:11:13 > 0:11:15And they tend to attract each other.
0:11:19 > 0:11:21If you have a positive charge and a positive charge,
0:11:21 > 0:11:24it will repel from each other, but...
0:11:24 > 0:11:25wouldn't it be great
0:11:25 > 0:11:30if we could get gravity to work in reverse and be able to
0:11:30 > 0:11:32levitate things using gravity?
0:11:32 > 0:11:36Only problem is, there isn't any negative gravity,
0:11:36 > 0:11:39there isn't any antigravity that pushes.
0:11:39 > 0:11:41Gravity always pulls, as far as we know.
0:11:45 > 0:11:49The reason seems to be that, unlike electromagnetism,
0:11:49 > 0:11:53gravity has only one kind of polarity - positive.
0:11:55 > 0:11:57One mass is simply attracted to another.
0:12:00 > 0:12:05Gravity and electromagnetism are completely different forces.
0:12:05 > 0:12:09There's a very special property of gravity - that is that it adds up.
0:12:12 > 0:12:16Inside an atom, there's a positive nucleus surrounded by
0:12:16 > 0:12:22negative electrons, so the electromagnetic value cancels out,
0:12:22 > 0:12:26whereas there's nothing to cancel out its mass.
0:12:28 > 0:12:32So the force on one atom adds to the force on another atom,
0:12:32 > 0:12:36and so they generate an attractive gravitational force.
0:12:36 > 0:12:40So if you get enough of those atoms together, like in a planet
0:12:40 > 0:12:44or in a star, then the gravitational force is very strong.
0:12:47 > 0:12:49So gravity is different.
0:12:49 > 0:12:51It adds up as you increase the amount of matter
0:12:51 > 0:12:53in a way the other forces don't.
0:12:55 > 0:12:59For physicists like John Ellis, the dream of making a one-way force
0:12:59 > 0:13:03behave like a two-way force remains just that - a dream.
0:13:04 > 0:13:07The idea that you might be able to make antigravity
0:13:07 > 0:13:10is, of course, incredibly seductive.
0:13:10 > 0:13:14We particle theorists are also seduced by that, on occasion.
0:13:15 > 0:13:20But don't think it's going to be possible within my lifetime,
0:13:20 > 0:13:22your lifetime, anybody's lifetime.
0:13:33 > 0:13:35Yet back in 1996,
0:13:35 > 0:13:39a Russian scientist working in Finland claimed to have done
0:13:39 > 0:13:45the very thing the sceptics said was impossible - control gravity.
0:13:49 > 0:13:52Dr Eugene Podkletnov had been using a machine called a cryostat
0:13:52 > 0:13:54to cool electrical superconductors
0:13:54 > 0:13:57when something very strange happened.
0:13:59 > 0:14:02One evening, we were working with our cryostat,
0:14:02 > 0:14:07and one of my colleagues, who was leaving at that time,
0:14:07 > 0:14:09just came to the laboratory and said,
0:14:09 > 0:14:12"Guys, what are you doing here?"
0:14:12 > 0:14:15And we said, "Just working." And he was smoking his pipe.
0:14:15 > 0:14:17A very interesting person.
0:14:17 > 0:14:22It is, by the way, not allowed to smoke a pipe in the laboratory,
0:14:22 > 0:14:24but it was late in the evening.
0:14:25 > 0:14:28And he blew his pipe over the cryostat,
0:14:28 > 0:14:32and the smoke went close to the cryostat,
0:14:32 > 0:14:37hit some unseen barrier and, very fast, went up.
0:14:39 > 0:14:41And it was pretty amazing.
0:14:41 > 0:14:45He repeated this several times and said,
0:14:45 > 0:14:47"You are working with magic things!"
0:14:47 > 0:14:50And he left. So that was the beginning.
0:14:51 > 0:14:53After months of investigation,
0:14:53 > 0:14:59Podkletnov concluded that what he'd created was an antigravity field.
0:14:59 > 0:15:04So we have a vacuum chamber with a disc which can be rotated
0:15:04 > 0:15:07over 10,000 rotations per minute.
0:15:07 > 0:15:12And this is a weight sample, which can move freely over the disc.
0:15:14 > 0:15:17And when the disc reaches a certain speed of rotation,
0:15:17 > 0:15:23it exerts a repulsive force on the weight sample and pushes it up.
0:15:24 > 0:15:29In fact, this is a direct demonstration of the gravity fields.
0:15:29 > 0:15:33This gravity field is, in our case, repulsive,
0:15:33 > 0:15:37and, as you can see, the repulsive force is pretty big.
0:15:41 > 0:15:45Podkletnov published a paper in a popular science journal
0:15:45 > 0:15:48which caught the attention of Ron Evans at Greenglow.
0:15:52 > 0:15:56By now, the scale of Podkletnov's claim had sent red flags
0:15:56 > 0:16:01waving everywhere - including the Ministry of Defence.
0:16:01 > 0:16:07Out of the blue, from the MoD, I got a letter...
0:16:10 > 0:16:14..asking me what I made of the Podkletnov withdrawn paper.
0:16:14 > 0:16:19Well, at the time, I didn't know what to make of it - not a lot!
0:16:19 > 0:16:24Why should a spinning superconductor change gravity?
0:16:24 > 0:16:26It was just so odd
0:16:26 > 0:16:31that it never occurred to anybody before that it even should.
0:16:31 > 0:16:34And, of course, many of the academics said, "Impossible!"
0:16:34 > 0:16:39But what Podkletnov did was, having seen it, he explored it further.
0:16:39 > 0:16:43If you spot an anomaly, then you go and investigate it to see why.
0:16:44 > 0:16:49So we invited Podkletnov to come to BAE Systems at Walton,
0:16:49 > 0:16:53but we had to get special permission from the Ministry of Defence
0:16:53 > 0:16:55to allow him to come on site.
0:16:55 > 0:16:59And I think he was quite taken that a Russian was actually...
0:16:59 > 0:17:01The very first, and probably the only,
0:17:01 > 0:17:04Russian that's ever been allowed at our Walton site.
0:17:08 > 0:17:10Ron organised a team
0:17:10 > 0:17:13to try and recreate Podkletnov's breakthrough. But they didn't
0:17:13 > 0:17:18have the budget to work with the highly specialised superconductor.
0:17:18 > 0:17:22We couldn't replicate what he'd done, so we couldn't say yes,
0:17:22 > 0:17:24he had found an effect, or no, he hadn't.
0:17:30 > 0:17:33By now, Marc Millis at NASA also wanted to know
0:17:33 > 0:17:36if there was something in Podkletnov's claim.
0:17:36 > 0:17:39And he had a much bigger budget.
0:17:39 > 0:17:43We found people who replicated the experiment with Podkletnov's help,
0:17:43 > 0:17:47and they even had 50 times the detection sensitivity
0:17:47 > 0:17:51that Podkletnov had had, and did not find any effect.
0:17:54 > 0:17:57Despite exhaustive tests, no-one seemed able to reproduce
0:17:57 > 0:18:00Podkletnov's so-called gravity field.
0:18:01 > 0:18:04I think Podkletnov had jumped to a conclusion,
0:18:04 > 0:18:09had seen some things and did not take the...rigour to go through
0:18:09 > 0:18:12and make sure that he wasn't misleading himself.
0:18:13 > 0:18:16Meanwhile, news of Podkletnov's breakthrough
0:18:16 > 0:18:20had been leaked to the press, and the resulting media storm
0:18:20 > 0:18:24obliged him to leave his university post.
0:18:27 > 0:18:31So Podkletnov went back to Moscow to work in secret.
0:18:31 > 0:18:36And by late 2001, he claimed he had a new way to manipulate gravity.
0:18:39 > 0:18:42Wary of the Western media, he contacted the one man
0:18:42 > 0:18:46he trusted to give him a fair hearing - Ron Evans at Greenglow.
0:18:48 > 0:18:50He offered to meet with Ron,
0:18:50 > 0:18:55but it would have to be in secret at a hotel in London, specified by him.
0:18:56 > 0:19:00It was a secret meeting because I did not want to attract
0:19:00 > 0:19:03the attention of military people in Russia.
0:19:07 > 0:19:09By now, Ron was getting concerned
0:19:09 > 0:19:13his project was being dragged into a world of fantasy and subterfuge.
0:19:15 > 0:19:17It really was like a John le Carre story.
0:19:17 > 0:19:21And he said he could afford us just a little bit of time, if we wanted
0:19:21 > 0:19:25to learn a little bit more about what he'd been doing in Moscow.
0:19:27 > 0:19:29Because of his security concerns,
0:19:29 > 0:19:34Podkletnov was only prepared to tell Ron the basic concept.
0:19:34 > 0:19:40I presented to him my latest works with impulse gravity generator,
0:19:40 > 0:19:44which gives a very short impulse of gravity waves.
0:19:45 > 0:19:48It's really a giant spark plug, really.
0:19:48 > 0:19:50But according to Dr Podkletnov,
0:19:50 > 0:19:56someone way away, a kilometre away, on the balcony of some flats
0:19:56 > 0:20:01in line with the beam, was still able to detect a slight effect.
0:20:03 > 0:20:04That was incredible.
0:20:05 > 0:20:09It can be used for propulsion in space,
0:20:09 > 0:20:12but at the same time, it is a very powerful weapon
0:20:12 > 0:20:19and it can destroy the missiles or remove them from their trajectory,
0:20:19 > 0:20:24so the interest from military people will be definitely big.
0:20:24 > 0:20:26What did I think? It was very...
0:20:29 > 0:20:32Dr Podkletnov is a scientist, and, you know...
0:20:33 > 0:20:35I don't know, is the answer.
0:20:35 > 0:20:37It's very hard to say, yes, I believed it.
0:20:37 > 0:20:41On the other hand, I wanted to know more, because it might be true.
0:20:42 > 0:20:44Did you really think that was feasible?
0:20:47 > 0:20:49We don't know, with gravity.
0:20:49 > 0:20:52Gravity is a subject we don't know about.
0:20:52 > 0:20:54That's why we're exploring it.
0:20:57 > 0:21:01For years, the gravity pulse concept remained shrouded in secrecy,
0:21:01 > 0:21:03and stayed unproven.
0:21:06 > 0:21:09But by the early 2000s, a new generation of scientists
0:21:09 > 0:21:12had picked up the baton from Project Greenglow...
0:21:15 > 0:21:17..including Dr Martin Tajmar,
0:21:17 > 0:21:20professor of space systems at Dresden University.
0:21:22 > 0:21:26If you look for a challenge, always look for a big challenge.
0:21:27 > 0:21:31The ultimate challenge I can think of as a scientist
0:21:31 > 0:21:32is to control gravity.
0:21:32 > 0:21:37That's maybe the most difficult thing there is, right?
0:21:37 > 0:21:40Martin is about to comprehensively test Podkletnov's concept
0:21:40 > 0:21:42once and for all.
0:21:42 > 0:21:46His claims are that it can drill holes into brick walls
0:21:46 > 0:21:49and this kind of stuff, which is an extraordinary claim.
0:21:49 > 0:21:51And if you have an extraordinary claim,
0:21:51 > 0:21:54you must have extraordinary proof.
0:21:54 > 0:21:58Antigravity is a kind of synonym for impossible.
0:21:58 > 0:22:00But always be ready for the surprise.
0:22:01 > 0:22:06This, in effect, is Podkletnov's gravity pulse generator,
0:22:06 > 0:22:08recreated by Martin and his team.
0:22:09 > 0:22:14As Ron Evans guessed, it's based on a kind of giant spark plug -
0:22:14 > 0:22:17essentially two electrodes in a box.
0:22:17 > 0:22:22Basically, you have two electrodes - one here and one here - and you are
0:22:22 > 0:22:27running a very, very high electric current, a discharge through that.
0:22:30 > 0:22:33The discharge goes through a superconductor.
0:22:34 > 0:22:39According to Podkletnov, this somehow creates a pulse of gravity,
0:22:39 > 0:22:44which is picked up by a sensor, acting like an electronic pendulum.
0:22:46 > 0:22:49And let's say, if you have here a pendulum, here,
0:22:49 > 0:22:53that when this gravitational impulse hits the pendulum,
0:22:53 > 0:22:56you will actually get a deflection off the pendulum.
0:22:56 > 0:23:00And so, the claim is that this is actually also creating
0:23:00 > 0:23:05not only an electric discharge but a kind of gravitational impulse -
0:23:05 > 0:23:07a push to something at a distance.
0:23:17 > 0:23:20The superconductor is cooled with liquid nitrogen
0:23:20 > 0:23:22to remove its electrical resistance.
0:23:25 > 0:23:29Podkletnov claimed the resulting mass of electrical discharge
0:23:29 > 0:23:31creates the gravitational pulse.
0:23:35 > 0:23:37They switch on the power to charge up the system...
0:23:40 > 0:23:41..and wait for the discharge.
0:23:45 > 0:23:46Counting down.
0:23:55 > 0:23:57BANG
0:23:57 > 0:23:58There is a reading.
0:24:02 > 0:24:03So here's the data.
0:24:03 > 0:24:06Gravity goes with the speed of light,
0:24:06 > 0:24:08so you should see an instantaneous peak.
0:24:08 > 0:24:11And then, the sound from this bang, this takes some time
0:24:11 > 0:24:14until it arrives. So we should see two distinct peaks
0:24:14 > 0:24:16because we have such a high resolution.
0:24:16 > 0:24:20So that's the acoustic impulse, and exactly here,
0:24:20 > 0:24:23that's where the gravitation impulse should be, but we don't see it.
0:24:25 > 0:24:27The sensor felt the sound wave from the spark...
0:24:27 > 0:24:29BANG
0:24:29 > 0:24:31..but no gravity pulse.
0:24:31 > 0:24:35That's the most sensitive sensor there is in the world
0:24:35 > 0:24:38and we don't even see something out of the noise,
0:24:38 > 0:24:41so how can you make a claim to say that you move things metres away
0:24:41 > 0:24:44or that you actually push pendulums away?
0:24:44 > 0:24:46So that's a really outrageous claim.
0:24:46 > 0:24:52We haven't seen something, not even remotely like that, unfortunately.
0:24:52 > 0:24:55But, yeah... So far, no luck.
0:24:57 > 0:25:00So this guy had the idea that by,
0:25:00 > 0:25:03you know, messing around with superconductors,
0:25:03 > 0:25:07he could change the strength of the gravitational field.
0:25:07 > 0:25:09Crap!
0:25:10 > 0:25:14None of Podkletnov's methods seemed able to alter gravity in the lab.
0:25:15 > 0:25:19Could the reason be a simple problem of scale?
0:25:34 > 0:25:37For physicist Clifford Johnson,
0:25:37 > 0:25:42scale is the big Achilles heel in any idea of gravity control,
0:25:42 > 0:25:46because at human scales, there's almost nothing there TO control.
0:25:48 > 0:25:51Most people think that gravity's an extremely strong force.
0:25:51 > 0:25:55And indeed, it does seem to be - it binds us here to the earth.
0:25:55 > 0:25:59But actually, of all the forces we know in nature, it's the weakest.
0:26:03 > 0:26:05I'm actually going to show you something.
0:26:05 > 0:26:08We can see exactly how weak gravity is in this way.
0:26:08 > 0:26:12I have this fridge magnet - just an ordinary fridge magnet.
0:26:12 > 0:26:16And look - it sticks. It doesn't fall. What does that mean?
0:26:16 > 0:26:19It means that this electromagnetic force
0:26:19 > 0:26:21between this magnet and the car
0:26:21 > 0:26:26is beating the force of gravity due to the entire earth.
0:26:29 > 0:26:30Let me give you a number.
0:26:30 > 0:26:36It's 10 to the 40 times weaker than electromagnetism.
0:26:36 > 0:26:41That's not 10 or 10 x 40. It's 10 to the power 40.
0:26:41 > 0:26:45So that's a one with 40 zeros after it.
0:26:45 > 0:26:48So that's going to be part of the difficulty
0:26:48 > 0:26:51in any experiment that we might do that tries to modify gravity.
0:26:51 > 0:26:55It's trying to tinker with something that, on that scale, is so tiny.
0:26:55 > 0:26:59The real effects of gravity take place when you have
0:26:59 > 0:27:03huge amounts of mass, like the mass of the earth or something like that.
0:27:03 > 0:27:07That's the scale on which gravity is changing
0:27:07 > 0:27:08in a significant, measurable way.
0:27:12 > 0:27:15There is one industry that has to deal with gravity
0:27:15 > 0:27:16on a planetary scale.
0:27:18 > 0:27:20That has always clamoured for some form
0:27:20 > 0:27:22of gravity-beating propulsion.
0:27:26 > 0:27:27The space industry.
0:27:35 > 0:27:39Marc Millis ran NASA's Breakthrough Propulsion Project.
0:27:39 > 0:27:43One of its long-term goals was to move away from using rockets.
0:27:46 > 0:27:50The problem with rockets is not that they can't beat gravity -
0:27:50 > 0:27:53it's the amount of thrust they need to do it.
0:27:53 > 0:27:55If you think about the Apollo spacecraft
0:27:55 > 0:27:59and you imagine here's the Saturn V,
0:27:59 > 0:28:02the very tip of that and then a little bit below that
0:28:02 > 0:28:04was the actual spacecraft itself
0:28:04 > 0:28:08and all the rest of this was the propellant, the rocket fuel,
0:28:08 > 0:28:10and that's just to the moon.
0:28:14 > 0:28:17NASA aims to get humans to Mars and back
0:28:17 > 0:28:19within the next decade and a half...
0:28:20 > 0:28:23..maybe, one day, beyond the solar system itself...
0:28:25 > 0:28:26..but just the Martian step
0:28:26 > 0:28:29seems impractical with conventional rockets
0:28:29 > 0:28:33because leaving the earth's gravity takes so much fuel.
0:28:33 > 0:28:35The farther or faster that you want to go
0:28:35 > 0:28:37or more that you want to carry,
0:28:37 > 0:28:39you need this extra propellant to do that
0:28:39 > 0:28:42and then you need extra propellant for the extra propellant
0:28:42 > 0:28:44and it adds up exponentially.
0:28:46 > 0:28:48You wanted to go to our nearest neighbouring star,
0:28:48 > 0:28:50which is over four light-years away,
0:28:50 > 0:28:52and you wanted to do it with the kind of rockets
0:28:52 > 0:28:54that are on the space shuttle,
0:28:54 > 0:28:56and say you want to do it in 50 years,
0:28:56 > 0:28:58you're having to go a tenth of the speed of light.
0:28:58 > 0:29:01Well, the amount propellant you need for that journey
0:29:01 > 0:29:03is about the mass of our entire sun.
0:29:06 > 0:29:08For Mark and NASA,
0:29:08 > 0:29:11the focus was less on controlling gravity itself
0:29:11 > 0:29:14than finding ways to get to the stars.
0:29:15 > 0:29:17They didn't care how
0:29:17 > 0:29:19as long as it didn't need rocket fuel.
0:29:24 > 0:29:26And, in 2002,
0:29:26 > 0:29:28a new device appeared
0:29:28 > 0:29:30that seemed to offer a solution...
0:29:38 > 0:29:41..invented by a former defence research engineer,
0:29:41 > 0:29:42Roger Shawyer.
0:29:43 > 0:29:49The big advantage of EmDrive is that it's a device which creates a force
0:29:49 > 0:29:54but it doesn't have to shoot out a propellant out of the back.
0:29:55 > 0:29:58Instead of using rocket fuel to create thrust,
0:29:58 > 0:30:01the EmDrive uses microwave energy...
0:30:02 > 0:30:04..just like a domestic oven.
0:30:06 > 0:30:10Microwaves bounce around inside the box in waves, cooking your food.
0:30:12 > 0:30:14To stop that energy cooking you,
0:30:14 > 0:30:17there is a mesh on the door with holes in.
0:30:17 > 0:30:20The diameter of these holes are so small
0:30:20 > 0:30:22that, instead of going through it,
0:30:22 > 0:30:26microwave radiation is actually bouncing up and down vertically
0:30:26 > 0:30:28in the hole.
0:30:30 > 0:30:32The holes trap the waves,
0:30:32 > 0:30:34slowing them to a standstill.
0:30:36 > 0:30:37According to Roger,
0:30:37 > 0:30:40the narrow end of his EmDrive does exactly the same job.
0:30:41 > 0:30:45The waves are going faster at the large end
0:30:45 > 0:30:47than they are at the small end.
0:30:47 > 0:30:51This means that the force at the large end
0:30:51 > 0:30:53is greater than the force at the small end
0:30:53 > 0:30:58which will cause the cavity to move in the opposite direction.
0:31:01 > 0:31:04It would only produce a small amount of thrust,
0:31:04 > 0:31:06but, in space, that would matter.
0:31:06 > 0:31:10An EmDrive thruster with continuous electrical power
0:31:10 > 0:31:12gives you continuous acceleration
0:31:12 > 0:31:16and therefore you can achieve very large velocities
0:31:16 > 0:31:18and travel very large distances.
0:31:19 > 0:31:22Roger believes that, if he could make it big enough,
0:31:22 > 0:31:26it could potentially lift us from the Earth.
0:31:26 > 0:31:27You suddenly have a lift engine
0:31:27 > 0:31:31which simply hovers there or indeed accelerates upwards.
0:31:31 > 0:31:36So we can obviously envisage launching large payloads into space
0:31:36 > 0:31:39on an EmDrive-driven space plane.
0:31:40 > 0:31:43Essentially, we are no longer looking at ways
0:31:43 > 0:31:45that we can control gravity itself.
0:31:45 > 0:31:48We are beating gravity the smart way.
0:31:49 > 0:31:51If it works.
0:31:52 > 0:31:55Though he didn't claim to control gravity,
0:31:55 > 0:32:01Roger's EmDrive concept was rejected by a lot of theoretical scientists,
0:32:01 > 0:32:04who claim the basic physics just didn't add up.
0:32:07 > 0:32:09So imagine I'm a particle of light
0:32:09 > 0:32:12and I bounce off one side of a box.
0:32:12 > 0:32:16I push off and I push the box that way, go this way,
0:32:16 > 0:32:21but then I hit the other side of the box and I bounce off just as hard.
0:32:21 > 0:32:24So the box doesn't go anywhere.
0:32:24 > 0:32:27So, for it move, I would have to push off one side
0:32:27 > 0:32:31and then escape out the other end the way that a rocket does.
0:32:31 > 0:32:33So that's why we're not sure how the EmDrive works
0:32:33 > 0:32:38because bouncing off both sides of a box you wouldn't get any thrust.
0:32:38 > 0:32:42Newton told us that action and reaction are equal and opposite,
0:32:42 > 0:32:44but, the EmDrive, nothing comes out
0:32:44 > 0:32:48and so I don't see how you can generate momentum out of nothing.
0:32:50 > 0:32:52My view is - who cares?
0:32:52 > 0:32:53It's the experiment.
0:32:53 > 0:32:55If the experiment works,
0:32:55 > 0:33:00it's up to the theoretical people to put a theory round why it works.
0:33:00 > 0:33:04From what we understand so far, it shouldn't work,
0:33:04 > 0:33:07but if you have an open mind and say, "Well, what if...?"
0:33:07 > 0:33:10If it does work, it's a revolution,
0:33:10 > 0:33:11it's a new propulsion system.
0:33:15 > 0:33:18To settle the argument between the theorists and engineers,
0:33:18 > 0:33:22Martin Tajmar had the perfect test facility in Dresden...
0:33:26 > 0:33:28..a large vacuum chamber mounted on dampers
0:33:28 > 0:33:31to isolate it from the surrounding world...
0:33:33 > 0:33:35..a carefully designed rig to hold the drive...
0:33:38 > 0:33:41..with a finely tuned balance to record any thrust...
0:33:44 > 0:33:45..and, most importantly,
0:33:45 > 0:33:48a copy of Roger Shawyer's original EmDrive.
0:33:49 > 0:33:52Martin's version is small
0:33:52 > 0:33:54but, if the principal works,
0:33:54 > 0:33:56there should be measurable thrust.
0:34:00 > 0:34:02The vacuum chamber is sealed.
0:34:05 > 0:34:08The thrust recorder inside is so sensitive
0:34:08 > 0:34:11it can detect Martin sitting down outside.
0:34:14 > 0:34:18We're here in a laboratory on earth so there's some seismic movement,
0:34:18 > 0:34:21so the balance themselves will move just a little bit.
0:34:21 > 0:34:23That's the noise we are seeing here.
0:34:27 > 0:34:28The EmDrive is switched on.
0:34:32 > 0:34:34Nothing appears to move.
0:34:37 > 0:34:41But on Martin's screen there is a reading.
0:34:41 > 0:34:42When we turn on the thruster,
0:34:42 > 0:34:44the balance in it reacts
0:34:44 > 0:34:47and we measure something which looks actually like a thrust.
0:34:47 > 0:34:51What we measured here in this case is something like 25 micronewtons.
0:34:51 > 0:34:54That's very, very small.
0:34:54 > 0:34:59You can compare this, for example, to a tenth of the weight force
0:34:59 > 0:35:01of a grain of rice. Incredibly small.
0:35:01 > 0:35:03Still, however, useful.
0:35:03 > 0:35:06For example, in space, we have thrusters actually
0:35:06 > 0:35:08which have this tiny amount of force
0:35:08 > 0:35:12which is still useful to manoeuvre spacecraft, for instance.
0:35:14 > 0:35:16The first results seem positive.
0:35:18 > 0:35:21But, when Martin experimented further,
0:35:21 > 0:35:23he discovered a problem.
0:35:23 > 0:35:26So, with the thruster pointing in that direction,
0:35:26 > 0:35:28we measured thrust in that direction
0:35:28 > 0:35:30and, when we tilted it 90 degrees,
0:35:30 > 0:35:34we still measured thrust in this direction, which we shouldn't have.
0:35:35 > 0:35:38There can still be some major influence
0:35:38 > 0:35:42from, for example, the power feeding lines that we still need to solve
0:35:42 > 0:35:45to find out what's the real thrust produced by the EmDrive,
0:35:45 > 0:35:47if there is any thrust produced.
0:35:55 > 0:35:57The great hope of the EmDrive was
0:35:57 > 0:35:59that, as a kind of propellant-less rocket,
0:35:59 > 0:36:02it would at least power vehicles in space,
0:36:02 > 0:36:04NASA's dream.
0:36:07 > 0:36:10But NASA didn't pursue the idea any further,
0:36:10 > 0:36:14or any other gravity-defying concepts,
0:36:14 > 0:36:16because, in 2002,
0:36:16 > 0:36:19they closed down Marc Millis's project.
0:36:20 > 0:36:25The project ended when the funding for all propulsion research was cut.
0:36:25 > 0:36:28It wasn't just breakthrough propulsion physics,
0:36:28 > 0:36:32it was a Congressional earmark to build a building in a certain state
0:36:32 > 0:36:34and that took all the funding. It happens.
0:36:36 > 0:36:40The main progress that we made is we took science-fiction notions
0:36:40 > 0:36:44and evolved them to at least the first step of the scientific method.
0:36:44 > 0:36:48That step by itself is a degree of progress
0:36:48 > 0:36:50that, if I don't accomplish any more,
0:36:50 > 0:36:52it's like, "Yeah, that was pretty good."
0:37:04 > 0:37:07Ron Evans kept going for another three years.
0:37:08 > 0:37:12But, when he retired in 2005,
0:37:12 > 0:37:15BAE closed down Project Greenglow.
0:37:17 > 0:37:19For more than a decade,
0:37:19 > 0:37:22Ron had tried to find a way to control gravity.
0:37:24 > 0:37:25He never managed it.
0:37:28 > 0:37:30Is it a shame?
0:37:30 > 0:37:33Yeah, I suppose so. I would like...
0:37:33 > 0:37:36I would like to have worked at a company
0:37:36 > 0:37:39that actually made this idea work.
0:37:40 > 0:37:41It was a lovely idea.
0:37:46 > 0:37:48When Greenglow ended,
0:37:48 > 0:37:51the hope of mastering gravity seemed to end with it.
0:37:58 > 0:38:00If that was ever going to change,
0:38:00 > 0:38:05we needed to go much deeper into how gravity actually worked.
0:38:15 > 0:38:17Our understanding of gravity
0:38:17 > 0:38:20has come down from Galileo, Newton and Einstein...
0:38:21 > 0:38:25..from observations rooted in the motions of the heavens.
0:38:31 > 0:38:35Now, those same heavens seem to be showing us something
0:38:35 > 0:38:40that looks remarkably like antigravity.
0:38:40 > 0:38:43There are phenomena out there associated with gravity
0:38:43 > 0:38:47that have led us to rethink a lot about our universe.
0:38:47 > 0:38:49If you look at distant galaxies,
0:38:49 > 0:38:51they're moving away from us as we expect
0:38:51 > 0:38:53because the universe began with this big bang
0:38:53 > 0:38:56and everything's being thrown outwards,
0:38:56 > 0:38:59but one would expect that the gravity of everything
0:38:59 > 0:39:03would eventually start slowing that down.
0:39:03 > 0:39:06Instead, what's actually been measured, it's a huge surprise,
0:39:06 > 0:39:09is that the expansion of the universe is accelerating.
0:39:11 > 0:39:14It's a puzzle that has stumped both theoretical physicists
0:39:14 > 0:39:17like Clifford Johnson
0:39:17 > 0:39:21and cosmologists like Tamara Davis,
0:39:21 > 0:39:23because gravity seems to be doing
0:39:23 > 0:39:25the one thing we always assumed it couldn't.
0:39:29 > 0:39:31Gravity appears to be pushing.
0:39:31 > 0:39:34Something's accelerating the galaxies away from each other.
0:39:34 > 0:39:37That's as strange as if I took this ball,
0:39:37 > 0:39:39just gently threw it in the air
0:39:39 > 0:39:41and watched it accelerate off into space.
0:39:44 > 0:39:50Scientists call the force that is doing this pushing dark energy,
0:39:50 > 0:39:54estimated to account for roughly 70% of the universe.
0:39:56 > 0:39:59So dark energy has some sort of antigravity
0:39:59 > 0:40:01and it pushes the galaxies apart.
0:40:03 > 0:40:08The idea that the universe has some inherent form of antigravity
0:40:08 > 0:40:10is tantalising.
0:40:10 > 0:40:12If only we could get our hands on it.
0:40:15 > 0:40:20The problem is no-one knows what this antigravity force actually is.
0:40:21 > 0:40:24Only that it seems to originate from space itself.
0:40:26 > 0:40:30Although we think of space as this emptiness, the absence of stuff,
0:40:30 > 0:40:31it actually isn't.
0:40:31 > 0:40:35There is something that's intrinsic to the nature of space that
0:40:35 > 0:40:37imparted an energy.
0:40:39 > 0:40:43And one of the big mysteries is where has that energy come from?
0:40:47 > 0:40:50A number of scientists think the answer to this big question
0:40:50 > 0:40:57could lie-in the very small, the very, very, very small world
0:40:57 > 0:41:01of subatomic particles. Quantum physics.
0:41:04 > 0:41:06According to current quantum theory,
0:41:06 > 0:41:09particles can spontaneously appear from nowhere.
0:41:10 > 0:41:14Apparently they just pop into existence in the vacuum of space.
0:41:17 > 0:41:21Matter and antimatter,
0:41:21 > 0:41:25which because they are opposites cancel each other out in an instant.
0:41:26 > 0:41:29The lifetime is 1,000th
0:41:29 > 0:41:32of one billionth of one billionth of a second.
0:41:34 > 0:41:40We are now in an ocean of particle-antiparticle pairs
0:41:40 > 0:41:44permanently appearing and disappearing.
0:41:44 > 0:41:48Dr Dragan Hajdukovic thinks something else happens to these
0:41:48 > 0:41:52particles to produce an antigravity effect.
0:41:58 > 0:42:00For the briefest moment of their existence,
0:42:00 > 0:42:05these particles can be polarised like iron filings.
0:42:05 > 0:42:09The trouble is to get it in a random orientation.
0:42:09 > 0:42:16If there is a magnetic field, the random orientation will change. Yes.
0:42:19 > 0:42:24According to Dragan, in the same way iron filings respond to a magnet...
0:42:27 > 0:42:30..pairs of quantum particles respond to mass...
0:42:32 > 0:42:35..with matter and antimatter pairs briefly orienting themselves
0:42:35 > 0:42:37in relation to that mass.
0:42:39 > 0:42:43Matter is attracted to the positive mass of a planet or a star
0:42:43 > 0:42:46while antimatter is repelled by it.
0:42:49 > 0:42:53Dragan believes this creates a halo of antigravity dark energy
0:42:53 > 0:42:55around every mass in the universe.
0:42:57 > 0:43:01All these haloes together has negative pressure,
0:43:01 > 0:43:04what is exactly what we need
0:43:04 > 0:43:09in cosmological equations to produce the accelerated
0:43:09 > 0:43:11expansion of the universe.
0:43:13 > 0:43:16It means that there are both positive
0:43:16 > 0:43:19and negative rotational charges.
0:43:19 > 0:43:23So far, we know that gravity is an attraction.
0:43:23 > 0:43:30It may be that gravity is also a repulsion but not between matter
0:43:30 > 0:43:33and matter but between matter and antimatter.
0:43:37 > 0:43:40Dragan's theory that the key to antigravity
0:43:40 > 0:43:44lies in antimatter is actually going to be tested...
0:43:47 > 0:43:52..here in the world's biggest physics lab at CERN in Switzerland.
0:43:55 > 0:43:59Not in the famous Large Hadron Collider,
0:43:59 > 0:44:02but in the improbably named Antimatter Factory...
0:44:04 > 0:44:06..at its Alpha experiment.
0:44:10 > 0:44:13A team led by Jeffrey Hangst is building a machine that,
0:44:13 > 0:44:16in a couple of years, will answer one of the biggest questions
0:44:16 > 0:44:17in gravity research.
0:44:19 > 0:44:22Does antimatter fall down or up?
0:44:25 > 0:44:31The first step is to make antimatter particles of hydrogen.
0:44:31 > 0:44:33We start here with this beamline.
0:44:33 > 0:44:38That provides the nucleus of the antihydrogen atom, the antiprotons.
0:44:38 > 0:44:40They come through here at a reasonably high energy
0:44:40 > 0:44:45and get stopped inside this magnet which is where the actual
0:44:45 > 0:44:47antihydrogen will be formed and trapped.
0:44:50 > 0:44:54The next step will be to test how antimatter reacts
0:44:54 > 0:44:55to the Earth's gravity.
0:44:57 > 0:45:00OK, so this machine can trap and release antihydrogen
0:45:00 > 0:45:02but it's not ideal for gravity.
0:45:02 > 0:45:05What we want to do now is take a machine like this
0:45:05 > 0:45:08and turn it on its head so we can actually see
0:45:08 > 0:45:12the freefall of the antimatter that is released.
0:45:12 > 0:45:17If Dragan is right then the antihydrogen will fall up
0:45:17 > 0:45:19and somebody wins a Nobel Prize,
0:45:19 > 0:45:22that's for sure, and we have to rewrite a lot of textbooks.
0:45:24 > 0:45:29Hi, Dragan. Welcome. Come on in. Let's take a look at this machine.
0:45:29 > 0:45:33Alpha is part of CERN's ongoing exploration into the nature
0:45:33 > 0:45:35of matter and gravity.
0:45:35 > 0:45:37Right now, what we are doing is we're routinely
0:45:37 > 0:45:39trapping antihydrogen.
0:45:39 > 0:45:42But for Dragan Hajdukovic, it will be made or break.
0:45:44 > 0:45:47If he is right, creating antigravity on Earth
0:45:47 > 0:45:50is at least a theoretical possibility.
0:46:00 > 0:46:04One of the big theoretical objections to gravity control was
0:46:04 > 0:46:07always that, unlike electromagnetism,
0:46:07 > 0:46:09gravity had no negative form.
0:46:11 > 0:46:16Yet evidence from the cosmos seems to suggest that negative gravity
0:46:16 > 0:46:17does exist.
0:46:19 > 0:46:21To bring it down to Earth, however,
0:46:21 > 0:46:24seems to require some form of negative entity.
0:46:27 > 0:46:30Dragan Hajdukovic thinks it could be antimatter.
0:46:38 > 0:46:42Whereas Dr Martin Tajmar believes the best option would be to use
0:46:42 > 0:46:44negative mass.
0:46:44 > 0:46:47So let's imagine something that we can all imagine.
0:46:47 > 0:46:49Let's say we have positive mass.
0:46:50 > 0:46:53Positive mass means if I'm pushing
0:46:53 > 0:46:56positive mass, it always accelerates in the same
0:46:56 > 0:46:57direction as I am pushing.
0:46:59 > 0:47:01Let's imagine something magical.
0:47:01 > 0:47:04Let's imagine we have positive
0:47:04 > 0:47:06and we have negative mass.
0:47:06 > 0:47:08They will attract each other.
0:47:08 > 0:47:11Now, the positive mass is attracted here
0:47:11 > 0:47:13and it accelerates in the very same direction.
0:47:13 > 0:47:16The negative is attracted over there,
0:47:16 > 0:47:19but because it is negative mass, it accelerates over there.
0:47:19 > 0:47:24So they both would start to accelerate in one direction,
0:47:24 > 0:47:26the direction of the negative mass.
0:47:30 > 0:47:35According to Martin, negative mass is the perfect way to create
0:47:35 > 0:47:39the ultimate gravity propulsion device -
0:47:39 > 0:47:41a warp drive.
0:47:42 > 0:47:44Imagine the positive and negative mass.
0:47:44 > 0:47:47That together creates a self accelerating structure.
0:47:47 > 0:47:51We can make a spacecraft with that, that can get any speed we want.
0:47:54 > 0:47:58Now, if this is all sounding a tiny bit speculative,
0:47:58 > 0:48:02Martin believes there is experimental evidence to back it up.
0:48:02 > 0:48:05The principle of self acceleration has actually already been
0:48:05 > 0:48:07demonstrated in the lab.
0:48:07 > 0:48:10Here you see that positive and negative light particles
0:48:10 > 0:48:11are coming together
0:48:11 > 0:48:14and when they come together, they always move,
0:48:14 > 0:48:17they self accelerate towards the negative position.
0:48:17 > 0:48:19That's an optical warp drive.
0:48:19 > 0:48:22It demonstrates that self acceleration is possible.
0:48:24 > 0:48:27Is it impossible to go to the next star? I don't think so.
0:48:27 > 0:48:30Impossible means it's not possible now.
0:48:30 > 0:48:32We just have to invent the magic trick.
0:48:37 > 0:48:41For Martin, the concept of negative mass is more than just
0:48:41 > 0:48:43a clever theory.
0:48:43 > 0:48:45It's the key to conquering gravity.
0:48:50 > 0:48:54But even if negative mass could be manufactured and harnessed to
0:48:54 > 0:48:58power a warp drive, many scientists think it would be
0:48:58 > 0:48:59impossible to use...
0:49:01 > 0:49:05..because of Einstein's theory of gravity.
0:49:08 > 0:49:12From Einstein's perspective, a mass actually distorts
0:49:12 > 0:49:17the fabric of space and time or space-time as it is called.
0:49:17 > 0:49:19That distortion is rather like a well.
0:49:23 > 0:49:26So here's another object that is moving nearby
0:49:26 > 0:49:29our mass that has bent space time
0:49:29 > 0:49:30and as it goes past,
0:49:30 > 0:49:34it bends towards the massive object.
0:49:35 > 0:49:37But a negative mass would be,
0:49:37 > 0:49:39in our analogy here, something like
0:49:39 > 0:49:41a mound instead of a depression
0:49:41 > 0:49:43and then you run into problems.
0:49:45 > 0:49:50The problem, according to Einstein, is that using a negative mass
0:49:50 > 0:49:53would mean inverting space-time,
0:49:53 > 0:49:58effectively turning the fabric of the universe inside out.
0:49:58 > 0:50:01And what you end up with is something that is called
0:50:01 > 0:50:02a runaway problem.
0:50:03 > 0:50:06You have physics that is just running out of control.
0:50:06 > 0:50:10It'll accelerate away arbitrarily with zero cost of energy
0:50:10 > 0:50:14and, if that were really happening anywhere in the universe,
0:50:14 > 0:50:17we'd see it spectacularly becoming an unstable situation.
0:50:21 > 0:50:23That's been proposed by other people
0:50:23 > 0:50:25as an actual solution to the problem.
0:50:28 > 0:50:30That's hilarious.
0:50:33 > 0:50:37If Clifford Johnson and other theoretical physicists are right,
0:50:37 > 0:50:40antigravity propulsion will remain an unworkable dream.
0:50:41 > 0:50:45It seems the laws of physics simply don't allow it.
0:50:48 > 0:50:51At least, not as we understand those laws today.
0:50:54 > 0:50:57Because, just as Galileo gave way to Newton
0:50:57 > 0:51:00and Newton gave way to Einstein,
0:51:00 > 0:51:03theories do change.
0:51:16 > 0:51:17And, in the meantime...
0:51:17 > 0:51:20well, the engineers get on with doing what engineers do -
0:51:20 > 0:51:21build new kinds of propulsion.
0:51:24 > 0:51:26Today, that includes NASA.
0:51:27 > 0:51:30At the Glenn Research Laboratory in Ohio,
0:51:30 > 0:51:33work is underway to produce new forms of space engine...
0:51:36 > 0:51:39..ones that really could take us where rockets can't -
0:51:39 > 0:51:41beyond our solar system.
0:51:44 > 0:51:48What we have here is a high-powered ion thruster
0:51:48 > 0:51:53and the way it produces thrust is ions are created inside this ring
0:51:53 > 0:51:56and then we establish electrostatic potential
0:51:56 > 0:51:59that accelerates these ions out
0:51:59 > 0:52:01and produces large velocities
0:52:01 > 0:52:05and what that does is it gives us very efficient production of thrust.
0:52:07 > 0:52:09This is an ion thruster under test
0:52:09 > 0:52:12putting out a constant stream of charged particles.
0:52:14 > 0:52:17It's less powerful than a rocket
0:52:17 > 0:52:19but capable of accelerating a spacecraft
0:52:19 > 0:52:21almost indefinitely.
0:52:23 > 0:52:26These systems are ideal for in space.
0:52:26 > 0:52:29You know, we operate them purely in space because it's very gentle.
0:52:29 > 0:52:32You know, the thrust level is low
0:52:32 > 0:52:35but, over time, you can develop much higher velocities
0:52:35 > 0:52:37than you can with chemical rockets.
0:52:40 > 0:52:44NASA's focus is on space propulsion
0:52:44 > 0:52:46beyond the Earth's gravitation.
0:52:48 > 0:52:50Yet there is a propulsion concept
0:52:50 > 0:52:54that aims to revolutionise all of aerospace,
0:52:54 > 0:52:57resurrected from the days of project Greenglow.
0:52:57 > 0:53:01It's Roger Shawyer's microwave thruster,
0:53:01 > 0:53:02the EmDrive.
0:53:04 > 0:53:05Ten years ago,
0:53:05 > 0:53:08it was unproven technology.
0:53:08 > 0:53:11This is a newer, bigger model under test.
0:53:13 > 0:53:14Balanced on a pivot,
0:53:14 > 0:53:16Roger claims it is moving
0:53:16 > 0:53:18under its own steam.
0:53:20 > 0:53:23The thrust is coming out in this direction
0:53:23 > 0:53:28and it is pushing the whole rig in a counterclockwise direction.
0:53:28 > 0:53:33It's moving 100kg of mass exactly as it would
0:53:33 > 0:53:36if it was a satellite in weightless conditions.
0:53:38 > 0:53:39According to Roger,
0:53:39 > 0:53:42this model generates 9g of thrust,
0:53:42 > 0:53:45equivalent to NASA's ion thruster,
0:53:45 > 0:53:48but he hopes to make an EmDrive capable of generating
0:53:48 > 0:53:50a thrust of nine tonnes.
0:53:51 > 0:53:57Nine tonnes will be used to lift and accelerate vertically
0:53:57 > 0:54:00any air vehicle we wish.
0:54:00 > 0:54:01A true revolution.
0:54:05 > 0:54:08EmDrive is still at the concept stage,
0:54:08 > 0:54:11but, if it turns out it really does work,
0:54:11 > 0:54:13no-one wants to miss out on its potential.
0:54:24 > 0:54:28In the United States, a number of corporations and government agencies
0:54:28 > 0:54:31have recently sat up and taken notice,
0:54:31 > 0:54:33led by this man.
0:54:35 > 0:54:39Colonel Coyote Smith is the former head of Dream Works.
0:54:40 > 0:54:41Not the movie company
0:54:41 > 0:54:44but something even more powerful -
0:54:44 > 0:54:46a future concepts department
0:54:46 > 0:54:49in the Pentagon's National Security Space Office.
0:54:50 > 0:54:52The potential is so great,
0:54:52 > 0:54:54if I did not bring this to the attention
0:54:54 > 0:54:56of the scientific community inside the US
0:54:56 > 0:54:58that works inside space programme,
0:54:58 > 0:55:00oh, I would have been fired.
0:55:00 > 0:55:03That's just absolutely the type of technology
0:55:03 > 0:55:04that we have to track down,
0:55:04 > 0:55:06these revolutionary breakthroughs.
0:55:06 > 0:55:10Now, all the physicists disclaimed it
0:55:10 > 0:55:13but the ironic thing is, when I took it to the engineering community,
0:55:13 > 0:55:16they didn't care why it worked, they were just interested that it worked.
0:55:20 > 0:55:23Ten years ago, Project Greenglow ended
0:55:23 > 0:55:27and Ron Evans thought official gravity research had ended with it.
0:55:29 > 0:55:31But today he's been invited to witness
0:55:31 > 0:55:34a unique gravitational breakthrough.
0:55:37 > 0:55:40When Ron first began his gravity research,
0:55:40 > 0:55:42it started with a question -
0:55:42 > 0:55:46could gravity be used to detect aircraft
0:55:46 > 0:55:48that were invisible to radar?
0:55:49 > 0:55:52In the 1980s, our complete inability to work with gravity
0:55:52 > 0:55:54made it impossible.
0:55:56 > 0:56:00But today Ron is meeting someone who says he's done it.
0:56:01 > 0:56:04This time, there are no covert meetings.
0:56:04 > 0:56:07He's going inside the Ministry of Defence research laboratory
0:56:07 > 0:56:09at Porton Down.
0:56:09 > 0:56:13Ron, good morning. Welcome to the Defence Science and Technology.
0:56:13 > 0:56:15Neil Stansfield heads a department here
0:56:15 > 0:56:19that looks at what they call disruptive technology.
0:56:22 > 0:56:27And they have taken a potential step on the road to gravity control
0:56:27 > 0:56:29using quantum engineering.
0:56:30 > 0:56:34So, what we have here is our quantum gravity gradiometer.
0:56:34 > 0:56:36It's a small system.
0:56:36 > 0:56:39At the heart of the device, we have a vacuum chamber.
0:56:39 > 0:56:43The sensor uses lasers to freeze a cloud of atoms.
0:56:44 > 0:56:49This cloud responds to disturbance in the Earth's gravitational field
0:56:49 > 0:56:52caused by moving mass.
0:56:52 > 0:56:55The atoms, they're sensitive enough to detect the mass of my body
0:56:55 > 0:56:57at a range of about one metre.
0:56:57 > 0:57:00- So your gravitational field is affecting this device.- Yes.
0:57:02 > 0:57:06This is the first time Ron has seen anyone actively using gravity.
0:57:08 > 0:57:10To me, this is amazing technology.
0:57:10 > 0:57:13Getting into the quantum, that's really allowing us to do things
0:57:13 > 0:57:16that were just unbelievable 30 years ago.
0:57:16 > 0:57:19Yes, some people use the phrase, "They break the laws of physics."
0:57:19 > 0:57:21I prefer to say they break the laws of physics
0:57:21 > 0:57:23as we understand them today.
0:57:23 > 0:57:26100 years ago, we didn't understand the quantum physics.
0:57:26 > 0:57:29The idea of being able to measure changes in gravity,
0:57:29 > 0:57:33- science fiction, could never happen. Today, we can.- Yes.
0:57:33 > 0:57:36And possibly even gravitational propulsion
0:57:36 > 0:57:38might be a possibility in the future.
0:57:38 > 0:57:40It may be. Yeah.
0:57:40 > 0:57:42I have ideas.
0:57:42 > 0:57:44It could be that we've got something.
0:57:44 > 0:57:47Certainly, I see this as a start.
0:57:47 > 0:57:50There's no doubt in my mind the UK is really at the forefront of this.
0:57:59 > 0:58:03Ron Evans's mission to control gravity began here,
0:58:03 > 0:58:06in a cold, wet corner of Lancashire
0:58:06 > 0:58:10where people go to live their dreams,
0:58:10 > 0:58:13where no-one ever worried about the word impossible.
0:58:17 > 0:58:19For Ron Evans,
0:58:19 > 0:58:23gravity control is just something we haven't learned to do...
0:58:23 > 0:58:25yet.
0:58:25 > 0:58:26I'm sure we will one day.
0:58:26 > 0:58:28It's just a matter of time.