'We need help with Svetlanas viruses, if thats what they are.

'There are thousands of them, Svetlana said without looking up from her screen.

Gibson pushed his spectacles back to the bridge of his nose. 'There are also thousands of terrestrial viruses. I was wondering if you might like to try to match them up. There are pictures of them on websites.

'Its a big job, Svetlana said. 'For instance, there are things called pico-rna-viridae, and theyre divided into five genera entero-, rhino-, aphto-, cardio- and una.s.signedo-viruses. If you take the rhinovirus its divided into human and bovine, and if you take the human it has a hundred serotypes. And these are just the small RNA viruses; there are thousands more.

Hanning looked blank. 'RNA viruses?

'Forget them, Shtyrkov called over. 'They change by the year. Any signal representing them would refer to viruses which have evolved beyond recognition. In fact, this is a big problem, people. Any picture beamed to us from far away and long ago should refer to microorganisms which no longer exist. E. coli reproduces so fast it can mutate as much in a day as humanity does in a thousand years.

Svetlana sighed. 'Theres another problem. Were all desperately ignorant about this and were running out of time.

Charlie said, 'So work harder. I want us to learn as much as we possibly can about this signal before we go public with it.

'Ive told you about going public without authorisation, Charlie.

'I know. Gibsons cheek twitched nervously. 'Youre just being asked to match pictures. Any idiot could do it.

Hanning said, 'Have you ever thought about a career in the Diplomatic Service?

'Im sorry, I- Hanning laughed. 'Of course Ill help. Lets see if these things are earthly.

Gibson sighed with relief, and promptly exited from his unctuous mode. 'Svetlana, you still havent told me if that thing is human. He turned to Shtyrkov, who was lying back on another sofa, staring at the ceiling. 'Vashislav, are you a waste of s.p.a.ce or what?

The Russian waved a dismissive arm in the air. 'Im meditating.

'What the h.e.l.l use is that? And what about you two? Gibson wanted to know. Freya and Petrie were heading for the door. 'Dont tell me you people are meditating too?

'Ill be in the theological library, Petrie said.

'Good, good. More decoding, Tom?

'No, Ill be looking for a Bible. I expect the theological library has one.

Gibsons face showed bafflement. 'What in G.o.ds name has the Bible got to do with anything?

18.

Visions of G.o.d Petrie heard the footsteps hurrying behind him in the broad corridor. Freya. She caught him by the arm and sat him firmly down on the velvet sofa. 'Dont be so secretive, Tom. What are you up to?

He shook his head. 'Its too embarra.s.sing to say.

'Tell me anyway.

'Look, its too silly, Freya. Lets just say Im off on some eccentric tangent and leave it at that.

She nipped his thigh viciously. Petrie, taken by surprise, yelped.

'Tom!

Petrie hesitated, then: 'Okay, okay. Look at the position. Theres no way for others to confirm this signal its a one-off. Hannings right, credibility is an issue. And if we make a wrong identification well lose it.

Freya nodded impatiently. 'But were all agreed on that.

'Charlies fixated on the F star. The timings right, like he says.

'But Tom, it lies outside the two-sigma error circle. Theres only one chance in twenty that hes right.

'You know that and I know that, Freya, but Charlies an idiot and hes going to blow it.

'So, what is this silly idea?

Petrie hesitated again. Freya looked threatening, and he said, 'I might be able to disprove his timing argument. Suppose theyve been probing us for centuries. Say theyve been firing at us routinely, maybe even for thousands of years, to see if weve reached a level where we can understand and reply with our sticks and stones, like radio or lasers.

Freya nodded.

'In that case there might be evidence in historical records.

Another encouraging nod.

In a burst of bravado he added, 'Maybe even pre-history or mythology. Lights in the sky, things like that.

Freya pursed her lips. 'That is embarra.s.sing. Its unprofessional, like looking for flying saucers or something.

Petrie flushed.

She grinned. 'But brilliant. History should have a record of glowing patterns in water, maybe even in heavy clouds. Ill join you.

In the theological library, Freya made straight for the computer terminal and fired it up. Petrie started with an illuminated Bible on a lectern, its pages laboriously written in calligraphic script in some past century. Its preface began with an enormous letter, made up of little fantasy animals with a swastika-like cross in the middle. He could just recognise it as an uncial D, and barely make out the ornate lettering: Dominus Deus noster Jesus Christus ...

He blew out his cheeks. This was going to take years. More prowling the shelves revealed more Bibles, all in Latin. His hopes rose with an ill.u.s.trated book on Mirabili. Perusal showed that the book described miracles indeed, if two-headed babies, statues weeping blood and winged basilisks could be believed.

He clattered up the spiral staircase. After some minutes, tucked in a corner, he found a shelf of modest-sized Bibles, in a.s.sorted vulgar tongues including English. He guessed this was the modern collection, grudgingly acknowledging the existence of the last three centuries or so. He pulled out a St James edition; its leather binding, he thought, was less than a century old, but the font and the feel of the pages told of something printed maybe three hundred years ago. It had a musty smell and he playfully wondered if the plague bacillus could survive for three hundred years.

Apart from the one at Heathrow chapel, Petrie hadnt looked at a Bible since his school days and had no more than the vaguest memory of the contents. He was dismayed to find that there were a thousand pages. He clattered down the staircase, sat himself at a table, and started on them systematically, speed-reading.

Two hours later, bleary-eyed and head spinning, he was practically through the Bible, and was beginning to think his memory had played tricks, when he came across the first nugget.

I was in the spirit on the Lords day, and heard behind me a great voice, as of a trumpet.

Revelation 1:10 And immediately I was in the spirit: and behold, a throne was set in heaven, and one sat on the throne. And he that sat was to look upon like a jasper and a sardine stone: and there was a rainbow round about the throne, in sight like unto an emerald.

Revelation 4:23 So he carried me away in the spirit into the wilderness: and I saw a woman sit upon a scarlet coloured beast, full of names of blasphemy, having seven heads and ten horns.

Revelation 17:3 * * *

'What are you getting at, Tom?

'Dont you see? The prophet is describing celestial visions, weird things in the sky. Okay, its overlaid with imagery but he sees them "in the spirit". What does it mean, in the spirit? He repeats it all the way through the Book of Revelation. Was he in some sort of trance? An altered state of consciousness?

'High on Ecstasy? Freya suggested.

Petrie ignored the interruption. 'And look at what hes raving about. Bright things, shiny things, glittering things like emeralds. What does he mean, a rainbow round about the throne, in sight like unto an emerald? Petrie was still flicking through the pages. 'Heres another one. Listen to this: And he carried me away in the spirit to a great and high mountain, and shewed me that great city, the holy Jerusalem, descending out of heaven from G.o.d. Having the glory of G.o.d: and her light was like unto a stone most precious, even like a jasper stone, clear as crystal.

Revelation 21:1011 'More shiny precious stones, more "in the spirit". This guys describing Shtyrkovs syndrome. Temporal lobe damage. The signal makes you mad.

Freya made a sceptical face. 'That is a monstrous speculation. Her voice deepened by an octave at the word 'monstrous.

But Petries eyes were shining with enthusiasm. 'No, it fits perfectly. The writers an astral prophet. He has a cast of thousands, the Beast rising over the sea, the Dragon, the throne in the sky, the plague of celestial locusts, falling stars, centaurs, the abyss, the temple in the sky...

'Tom...

'The seventh seal marks the return of seven comets, trumpet-shaped. The four hors.e.m.e.n of the apocalypse are comets, streaming their manes across the sky. Dont you see? Hes describing the sky and things that have taken place in the sky. And if thats right, Freya, if theyre all celestial phenomena, then they include a glowing sky, complete with the temporal lobe stuff. You must see that!

'No, Tom, I dont see it, not even remotely. In fact, Im beginning to wonder if youve had a touch of the magnetic fields yourself.

Petrie blinked in frustration. 'Theyve been sending us signals at least since the time of pastoral societies. Theyve been probing us for at least two thousand years.

'Ruling out Charlies F star?

'Yes. But more than that, anyone watching the Earth would know there was no technological civilisation capable of understanding the message. Sending sub-nuclear particle messages to sheep-farming societies is not the behaviour of an intelligence.

'What, then? Freyas brow was furrowed.

'A probe. An automated probe. Something set up to run by itself. Something waiting for a response, maybe for thousands of years.

'You keep talking about probes, probing us.

'Charlie and you are both wrong. Its not the M51 galaxy and its not the F star. I think its empty s.p.a.ce. Only the s.p.a.ce isnt empty it has a machine, something orbiting the Sun. Something that fires off bursts at us from time to time. It has to be close because it knows our geography and our rotation and all the rest. But itll stay dormant until we send it a reply.

Freya frowned. 'Tom, if thats right, it neednt be thirty million light years away or even three light years away. Its distance could be anything. She stood up, and paced up and down in thought. Then: 'Theres another clue. Whichever of the two directions it came from, its well away from the ecliptic.

'Meaning?

'Its not orbiting in the plane of the planets, or the asteroids, or the Edgeworth-Kuiper belt. It could be out in the Oort cloud.

'The what?

'A cloud of comets...o...b..ting the Sun far beyond the planets, where the Suns gravity is very weak. The comets just barely hang on to the solar system. You could have something the size of the Moon out there and youd never detect it.

'Whats the travel time of a signal from the Oort cloud?

'A few months. A few weeks from the inner cloud.

'Do you see what that means, Freya?

Freya was tight-lipped. 'Of course. The galactic club isnt something for our distant descendants. We could be members by this summer.

'An automated probe. An automated probe. Petrie began to pace up and down, his head bowed.

Freya, struck by a sudden thought, cupped her hands over her mouth. 'Theres more.

Petrie stopped.

She paused to gather her thoughts. Then, 'Okay. If theres a probe targeting us then its somewhere in the solar system otherwise it would just zip by. But if its too close it wouldnt last. If you injected something into an orbit between the planets, the chances are it would be thrown around chaotically by the gravitational fields of Jupiter and Saturn and end up falling into the Sun or being thrown out of the solar system altogether.

'How long would that take?

'It depends on the orbit, but youd be okay for typically a few millennia to a few hundred millennia. There are stable zones inside the asteroid belt but theyre crowded and anything in them eventually gets. .h.i.t by something moving at kilometres per second. If the signallers have put a robot probe well clear of the ecliptic plane well away from the planets theyve been planning for longevity.

Petries mouth opened and shut with astonishment. 'But youre talking millions of years.

'It looks like it. Were so used to thinking in short time spans, I suppose because our civilisation is only a few thousand years old.

To Freya, Petries round spectacles were making him look like a surprised owl. 'Im beginning to understand this. In fact... his voice trailed off.

'Well?

'No, it cant be.

'Do you want another nip?

Petrie shook his head. 'Im sorry, Freya, you just wouldnt grasp it.

Freya gaped. 'You conceited...

'No, no. It just needs a lot more thought. I can hardly take it in myself.

'Tom, come down to earth. Ancient texts can be interpreted in a hundred ways. We need something more concrete.

An hour later, Freya looked up from the terminal screen. Petrie was still at the table, reading the Bible and scribbling rapidly. There was an excited sparkle in her eyes. 'I think Ive struck gold.

19.