'How high are we?' he whispered.

'Two thousand kay. But now look upwards.'

This time, it was not such a shock: he had expected what he would see. The tower dwindled away until it became a glittering thread against the blackness of space, and he did not doubt that it continued all the way to the geostationary orbit, thirty-six thousand kilometres above the Equator. Such fantasies had been well known in Poole's day: he had never dreamed he would see the reality – and be living in it.

He pointed towards the distant thread reaching up from the eastern horizon.

'That must be another one.'

'Yes – the Asian Tower. We must look exactly the same to them.'

'How many are there?'

'Just four, equally spaced around the Equator. Africa, Asia, America, Pacifica. The last one's almost empty – only a few hundred levels completed. Nothing to see except water...'

Poole was still absorbing this stupendous concept when a disturbing thought occurred to him.

'There were already thousands of satellites, at all sorts of altitudes, in my time. How do you avoid collisions?'

Indra looked slightly embarrassed.

'You know – I never thought about that – it's not my field.' She paused for a moment, clearly searching her memory. Then her face brightened.

'I believe there was a big clean-up operation, centuries ago. There just aren't any satellites, below the stationary orbit.'

That made sense, Poole told himself. They wouldn't be needed – the four gigantic towers could provide all the facilities once provided by thousands of satellites and space-stations.

'And there have never been any accidents – any collisions with spaceships leaving earth, or re-entering the atmosphere?'

Indra looked at him with surprise.

'But they don't, any more,' She pointed to the ceiling. 'All the spaceports are where they should be – up there, on the outer ring. I believe it's four hundred years since the last rocket lifted off from the surface of the Earth.'

Poole was still digesting this when a trivial anomaly caught his attention. His training as an astronaut had made him alert to anything out of the ordinary: in space, that might be a matter of life or death.

The Sun was out of view, high overhead, but its rays streaming down through the great window painted a brilliant band of light on the floor underfoot. Cutting across that band at an angle was another, much fainter one, so that the frame of the window threw a double shadow.

Poole had to go almost down on his knees so that he could peer up at the sky. He had thought himself beyond surprise, but the spectacle of two suns left him momentarily speechless.

'What's that?' he gasped, when he had recovered his breath.

'Oh – haven't you been told? That's Lucifer.'

'Earth has another sun?'

'Well, it doesn't give us much heat, but it's put the Moon out of business... Before the Second Mission went there to look for you, that was the planet Jupiter.'

I knew I would have much to learn in this new world, Poole told himself. But just how much, I never dreamed.

Poole was both astonished and delighted when the television set was wheeled into the room and positioned at the end of his bed. Delighted because he was suffering from mild information starvation – and astonished because it was a model which had been obsolete even in his own time.

'We've had to promise the Museum we'll give it back,' Matron informed him. 'And I expect you know how to use this,'

As he fondled the remote-control, Poole felt a wave of acute nostalgia sweep over him. As few other artefacts could, it brought back memories of his childhood, and the days when most television sets were too stupid to understand spoken commands.

'Thank you, Matron. What's the best news channel?'

She seemed puzzled by his question, then brightened.

'Oh – I see what you mean. But Professor Anderson thinks you're not quite ready yet. So Archives has put together a collection that will make you feel at home.'

Poole wondered briefly what the storage medium was in this day and age. He could still remember compact disks, and his eccentric old Uncle George had been the proud possessor of a collection of vintage videotapes. But surely that technological contest must have finished centuries ago – in the usual Darwinian way, with the survival of the fittest.

He had to admit that the selection was well done, by someone (Indra?) familiar with the early twenty-first century. There was nothing disturbing – no wars or violence, and very little contemporary business or politics, all of which would now be utterly irrelevant. There were some light comedies, sporting events (how did they know that he had been a keen tennis fan?), classical and pop music, and wildlife documentaries.

And whoever had put this collection together had a sense of humour, or they would not have included episodes from each Star Trek series. As a very small boy, Poole had met both Patrick Stewart and Leonard Nimoy: he wondered what they would have thought if they could have known the destiny of the child who had shyly asked for their autographs.

A depressing thought occurred to him, soon after he had started exploring – much of the time in fast-forward – these relics of the past. He had read somewhere that by the turn of the century – his century! – there were approximately fifty thousand television stations broadcasting simultaneously. If that figure had been maintained and it might well have increased – by now millions of millions of hours of TV programming must have gone on the air. So even the most hardened cynic would admit that there were probably at least a billion hours of worthwhile viewing... and millions that would pass the highest standards of excellence. How to find these few – well, few million – needles in so gigantic a haystack?

The thought was so overwhelming – indeed, so demoralizing – that after a week of increasingly aimless channel-surfing Poole asked for the set to be removed.

Perhaps fortunately, he had less and less time to himself during his waking hours, which were steadily growing longer as his strength came back.

There was no risk of boredom, thanks to the continual parade not only of serious researchers but also inquisitive – and presumably influential – citizens who had managed to filter past the palace guard established by Matron and Professor Anderson. Nevertheless, he was glad when, one day, the television set reappeared, he was beginning to suffer from withdrawal symptoms – and this time, he resolved to be more selective in his viewing.

The venerable antique was accompanied by Indra Wallace, smiling broadly.

'We've found something you must see, Frank. We think it will help you to adjust – anyway, we're sure you'll enjoy it.'

Poole had always found that remark a recipe for guaranteed boredom, and prepared for the worst. But the opening had him instantly hooked, taking him back to his old life as few other things could have done. At once he recognized one of the most famous voices of his age, and remembered that he had seen this very programme before. Could it have been at its first transmission? No, he was only five then: must have been a repeat...

'Atlanta, 2000 December 31.'

'This is CNN International, five minutes from the dawn of the New Millennium, with all its unknown perils and promise...'

'But before we try to explore the future, let's look back a thousand years, and ask ourselves: could any persons living in Ad. 1000 even remotely imagine our world, or understand it, if they were magically transported across the centuries?'

'Almost the whole of the technology we take for granted was invented near the very end of our Millennium – the steam engine, electricity, telephones, radio, television, cinema, aviation, electronics. And, during a single lifetime, nuclear energy and space travel – what would the greatest minds of the past have made of these? How long could an Archimedes or a Leonardo have retained his sanity, if suddenly dumped into our world?'