The first time he had talked her down had been sixteen years ago in the year 2220, that exciting year in which the possibilities of the Galaxy had opened up for them.

Janus Pitt's hair was a dark brown then, and he was not yet Commissioner of Rotor, though everyone spoke of him as the up-and-coming man. He did head the Department of Exploration and Commerce, however, and the Far Probe was his responsibility, and, to a large extent, the result of his actions.

It was the first attempt to push matter through space with a hyper-assisted drive.

As far as was known, only Rotor had developed hyper-assistance and Pitt had been the strongest proponent of secrecy.

He had said at a meeting of the Council, ‘The Solar System is crowded. There are more space Settlements than can easily be found room for. Even the asteroid belt is only an amelioration. It will be uncomfortably crowded soon enough. What's more, each Settlement has its own ecological balance and we are drifting apart in that respect. Commerce is being throttled for fear of picking up someone else's strains of parasites or pathogens.

‘The only solution, fellow Councillors, is to leave the Solar System - without fanfare, without warning. Let us leave and find a new home, where we can build a new world, with our own brand of humanity, our own society, our own way of life. This can't be done without hyper-assistance - which we have. Other Settlements will eventually learn the technique and will leave, too. The Solar System will be a dandelion gone to seed, its various components drifting in space.

‘But if we go first, we will find a world, perhaps, before others follow. We can establish ourselves firmly, so that when others do follow and, perhaps, come across us in our new world, we will be strong enough to send them elsewhere. The Galaxy is large and there are bound to be elsewheres.’

There had been objections, of course, and fierce ones. There were those who argued out of fear - fear of leaving the familiar. There were those who argued out of sentiment - sentiment for the planet of birth. There were those who argued out of idealism - the desire to spread knowledge so that others might go, too.

Pitt had scarcely thought he would win out. He had done so because Eugenia Insigna had supplied the winning argument. What an incredible stroke of luck it was that she had come to him first.

She was quite young then, only twenty-six, married but not yet pregnant. She was excited, flushed, and laden down with computer sheets.

Pitt had frowned, he recalled, at her intrusion. He was Secretary of the Department and she - well, she was nobody although, as it happened, this was the very last moment when she would be nobody.

At the time, he didn't realize this, of course, and he was annoyed that she had forced her way in. He cringed at the obvious excitement of the young woman. She was going to make him go through the infinite complexities of whatever it was she was holding in her hand, and do so with an enthusiasm that would quickly exhaust him.

She should give a brief summary to one of his assistants. He decided to say so. ‘I see you have data there, Dr Insigna, that you wish to bring to my attention. I'll be glad to look at it in due course. Why don't you leave it with one of my people?’ And he indicated the door, hoping ardently that she would about-face and move in that direction. (Sometimes, in idle moments in later years, he would wonder what would have happened if she had, and his blood would run cold at the thought.)

But she said, ‘No, no, Mr Secretary. I must see you and no-one else.’ Her voice trembled as she spoke, as though her inner excitement was unbearable. ‘It's the greatest discovery anyone has made since - since-’ She gave up. ‘It's the greatest .’

Pitt looked dubiously at the sheets she was holding. They were quivering, but he felt no answering excitement of his own. These specialists always thought some micro-advance in their micro-field was system-shattering.

He said, resigned, ‘Well, Doctor, can you explain it simply?’

‘Are we shielded, sir?’

‘Why do we have to be shielded?’

‘I don't want anyone else to hear till I'm sure - sure - I have to check again and recheck, till there's no doubt. But, really, I have no doubt. I'm not making sense, am I?’

‘No, you're not,’ said Pitt coldly, placing his hand on a contact. ‘We're shielded. Now tell me.’

‘It's all here. I'll show it to you.’

‘No . First tell me. In words. Briefly.’

She drew a deep breath. ‘Mr Secretary, I've discovered the nearest star.’ Her eyes were wide and she was breathing rapidly.

Pitt said, ‘The nearest star is Alpha Centauri and that's been known for four centuries.’

‘It's the nearest star we've known, but it isn't the nearest we can know. I have discovered one that is closer. The Sun has a distant companion. Can you believe it?’

Pitt considered her carefully. It was rather typical. If they were young enough, enthusiastic enough, inexperienced enough, they would explode prematurely every time.

He said, ‘Are you sure?’

‘I am. Really. Let me show you the data. It's the most exciting thing that has happened in astronomy since-’

‘If it's happened. And don't show me that data. I'll look at it later. Tell me. If there's a star much closer than Alpha Centauri, why hasn't it been discovered before now? Why was it left to you to do so, Dr Insigna?’ He knew he was sounding sarcastic, but she didn't seem to pay attention to his tone. She was far too excited.

‘There's a reason. It's behind a cloud, a dark cloud, a puff of dust that just happens to be between the companion star and ourselves. Without the absorption of the dust, it would be an eighth-magnitude star, and it would certainly have been noticed. The dust cuts down the light and makes it nineteenth-magnitude, lost among many millions of other faint stars. There was no reason to notice it. No-one looked at it. It's in Earth's far southern sky, so that most of the telescopes in pre-Settlement days couldn't even point in that direction.’

‘And if so, how is it you've noticed it?’

‘Because of the Far Probe. You see, this Neighbor Star and the Sun are changing positions relative to each other, of course. I assume it and the Sun are revolving about a mutual center of gravity very slowly in a period of millions of years. Some centuries ago, the positions may have been such that we could have seen the Neighbor Star to one side of the cloud in its full brightness, but we would still have needed a telescope to see it and telescopes are only six centuries old - less old than that in those places on Earth from which the Neighbor Star would be visible. Some centuries from now, it will be seen clearly again, shining from the other side of the dust cloud. But we don't have to wait for centuries. The Far Probe did it for us.’

Pitt could feel himself igniting, a distant core of warmth arising within him. He said, ‘Do you mean that the Far Probe took a picture of that section of the sky containing this Neighbor Star and that the Far Probe was far enough out in space to see around the cloud and detect the Neighbor Star at full brightness?’

‘Exactly. We had an eighth-magnitude star where no eighth-magnitude star ought to be, and the spectrum was that of a red dwarf. You can't see red dwarf stars far away, so it had to be pretty close.’

‘Yes, but why closer than Alpha Centauri?’

‘Naturally, I studied the same area of the sky as seen from Rotor and the eighth-magnitude star wasn't there. However, fairly near it was a nineteenth-magnitude star that wasn't present in the photograph taken by the Far Probe. I assumed that the nineteenth-magnitude star was the eighth-magnitude star, obscured, and the fact that they weren't exactly in the same place had to be the result of parallactic displacement.’

‘Yes, I understand about that. A nearby object appears to be in different places against the distant background as one views it from different spots.’

‘That's right, but the stars are so distant that even if the Far Probe went out a big fraction of a light-year that change in position wouldn't produce a noticeable shift in distant stars, but it would in nearby stars. And for this Neighbor Star, it produced a huge shift; I mean, comparatively. I checked the sky for different positions of the Far Probe on its journey outward. There were three photographs taken during those intervals when it was in normal space, and the Neighbor Star was progressively brighter as the Probe viewed it farther and farther toward the edge of the cloud. From the parallactic displacement, the Neighbor Star turns out to be at a distance of just over two light-years. It's at half the distance of Alpha Centauri.’

Pitt looked at her thoughtfully and, in the long silence that followed, she grew restless and uncertain.

‘Secretary Pitt,’ she said, ‘do you want to see the data now?’

‘No,’ he said. ‘I'm satisfied with what you've told me. Now I must ask you some questions. It seems to me, if I understand you correctly, that the chance that someone would concentrate on a nineteenth-magnitude star, and try to get its parallax and determine its distance, is negligible.’

‘Just about zero.’

‘Is there any other way of noticing that an obscure star must be very near to us?’

‘It may have a large proper motion - for a star. I mean that if you watch it steadily, its own motion would change its place in the sky in a more or less straight line.’

‘Would that be noticed in this case?’

‘It might be, but not all stars have a large proper motion, even if they are close to us. They are moving in three dimensions and we see the proper motion only in a two-dimensional projection. I can explain-’

‘No, I'm continuing to take your word for it. Has this star got a large proper motion?’

‘That would take some time to determine. I do have a few older pictures of that part of the sky and I could detect an appreciable proper motion, That would need more work.’

‘But do you think it has the kind of proper motion that would force itself on astronomers, if they just happened by accident to note the star?’

‘No, I don't.’

‘Then is it possible that we on Rotor are the only ones who know about this Neighbor Star, since we're the only ones who've sent out a Far Probe? This is your field, Dr Insigna. Do you agree that we're the only ones who've sent out a Far Probe?’

‘The Far Probe isn't entirely a secret project, Mr Secretary. We've accepted experiments from the other Settlements and discussed that part of it with everyone, even Earth, which isn't too interested in astronomy these days.’