'You dismiss it, then?'
Bradfield continued, 'I have a problem, Mister Cartwright. Because my views belong to the mainstream of physics I'm too easily portrayed as a sort of Establishment spokesman. I feel like the Sheriff of Nottingham against Robin Hood here —' Bradfield glanced briefly at Aristotle '— but in fact the consensus of opinion in physics is against the idea that empty space holds any significant energy. Opinions to the contrary have been expressed by a small, noisy clique of outsiders. I expect that's what has triggered your enquiry. However, you ought to know that these people carry little influence with the scientific community.'
The waiter came out carrying an oil lamp, which he placed in the centre of the table and lit with a cigarette lighter. Aristotle pointedly ignored Bradfield, speaking to Findhorn. 'Fashions come and go in science as elsewhere. The only opinion which matters is that of Mother Nature.'
'We get a lot of crank science in our field,' Bradfield countered smoothly. Aristotle visibly tensed.
Findhorn tried to deflect the rapidly growing animosity. 'I read something about the Casimir effect and zero point energy. What are these things? And just how much energy are we talking about?'
Aristotle produced a biro, moved a plate of bread aside and started to scribble on the tablecover. 'The vacuum is filled with a light of unimaginable intensity if we could only see it. Let me first write down its intensity.' Then he wrote an equation in a large, extrovert scrawclass="underline" Iv — Kv3. Findhorn tilted his head to read the equation. 'Remember I'm a mere journalist. You'll have to explain.'
The Greek tried a joke. 'Even journalists can read. I is the intensity of this light at a particular frequency v. K is an extremely small number.'
'Which would therefore make the intensity of the light extremely small,' Findhorn pointed out. 'What is K anyway?'
Aristotle scribbled down 6.14 x 10-57. 'For the innumerate, this is 6.14 divided by the number one followed by fifty-seven zeros.'
'K is as near to zero as makes no difference,' Findhorn said.
Aristotle was patient. 'But look at the other term, young man, the v3. The equation also tells you something else, namely that the intensity of this light increases with the cube of its frequency. No matter how tiny K is, its smallness is always overwhelmed at a sufficiently high frequency.'
'Okay, so we're immersed in a radiation field of tremendous intensity.' Findhorn broke some bread, dipped it in his wine. He'd seen people do this in movies. 'Why doesn't it just fry us? I don't even see it. Space is black.'
Aristotle waved his arms to encompass the sky; a slightly fanatical tone was creeping into his voice. Or maybe, Findhorn thought, it was just Latin dramatics. 'Does a fish at the bottom of the ocean feel the weight of a ton of overlying water on every square centimetre of its surface? Do you feel the atmosphere bearing down on you, a kilogram compressing every square centimetre of your body? You do not. Because it pervades you. Only differences in pressure can be felt. You cannot feel the crushing atmospheric pressure, but you can feel a light breeze on your cheeks.'
'You're telling me that we don't see this vacuum light because we're pervaded by it.'
Aristotle nodded again. 'It is everywhere, in the retinae of your eyes, in your gut, in the spaces between your atoms.'
'So how do we know it even exists?'
'If you were in a submarine, with no pressure gauge, how could you tell if you were under the ocean?'
'Tell me.'
More dramatics. Aristotle was now squeezing an imaginary submarine between the palms of his hands. 'By the tiny shrinking of its steel hull. A shrinkage of a few millimetres would let you infer the existence of a huge ocean pressure outside. In the same way there are subtle manifestations of the vacuum radiation. Tiny shifts in the expected energy levels of atoms. Miniscule forces acting between flat plates in a vacuum. The merest hints of this shadow world. The rest is inference. But we have no plumb lines to explore the ultimate depths of this ocean of energy. It is terra incognita.'
'And how does this relate to zero point energy?'
'ZPE, my journalist friend, is the energy of the vacuum, that is to say, the energy of this radiation field. It is a remnant of the Creation, and it is vast beyond comprehension.'
'And the Casimir effect?'
'So intense is this radiation, at the highest frequencies, that wherever there is the slightest shadow, the difference in intensity creates a pressure. This is what happens with the Casimir effect. The plates shield each other, however slightly, from the surrounding vacuum radiation. The differential pressure of the light forces them together.'
Bradfield interrupted the dialogue. His voice was carrying an undertone of annoyance. 'Don't let my colleague's enthusiasm sweep you along, Mr Cartwright. The best experiments have produced less Casimir force than the weight of a paperclip.'
Aristotle said, 'Beh!' dismissively. He scribbled some more: F = Cd-4. 'This is the force pushing the plates together. You see the closer the plates are, the better they shield each other, the bigger the push. The force increases with the inverse fourth power of their separation d. It is true that experimental limitations have put a wide separation between the plates in the laboratory and the measured force is small. But put them ten times closer and they would feel ten thousand times the force. One hundred times closer and the force is multiplied by one hundred million times.'
'A thousand times closer and you'd crush that submarine,' Archie suggested. His sweaty, red face had a strange, almost feverish look. Findhorn thought it was something like greed.
'But how could we get at all this power?' Findhorn asked. 'What did Petrosian see?'
Bradfield again, the irritation becoming open. 'What power? It doesn't exist. There is no vacuum energy.'
Archie was looking puzzled. 'But Professor Bradfield, you've just told us that people have measured the force between the plates.'
'They have measured a force. But it's all interatomic. The atoms feel it when they are close to each other.'
'It has nothing to do with the vacuum?'
Bradfield was emphatic. 'Nothing. The vacuum is empty. Ideas about extracting energy from it belong with anti-gravity devices and astral projection.'
Findhorn asked, 'Can you prove that?'
Bradfield held out his hand at arm's length. 'I see my hand. No distortion, no bending of light, my hand is just there.'
Findhorn looked baffled. 'That's proof?'
Bradfield said, 'Correct, Mister Cartwright. Energy has mass. Mass exerts gravity. If the vacuum carried as much energy as Papa here claims, the Universe would be far more massive than the astronomers tell us. It would collapse in on itself under its own weight. The cosmos would be the size of a golfball.' He waved his hands around, in a parody of Aristotle. 'Some golfball!'
Archie was scribbling with Aristotle's pen. 'I get your point. Even with the tiny energy already measured in the lab: you couldn't see distant galaxies.' He leaned back, frowning at Aristotle. 'There's already a contradiction between the lab and the telescope.'
Bradfield managed to sip his wine while nodding agreement. 'A blatant one. And Aristotle knows it. Vacuum energy extraction belongs with perpetual motion machines and cold fusion. It's nonsense.'