Genarr said, ‘Can astronomers tell when it's going to happen?’

‘Not so far. It's one of the many chaotic aspects of nature. We have not yet worked out the rules underlying stellar turbulence and there are some among us who think the rules can never be worked out entirely. They are simply too complex.’

‘Interesting,’ said Genarr.

‘It's not that we're not grateful to the flares. Three per cent of the energy reaching Erythro from Nemesis is the result of those flares.’

‘That doesn't sound like much.’

‘It is, though. Without the flares, Erythro would be an icy world and much less easy to live on. The flares do make problems for Rotor, which has to adjust its use of sunlight quickly whenever there's a flare, and strengthen its particle-absorption field.’

Marlene was looking from one to the other as they spoke, and she finally broke in with a small note of exasperation, ‘How long are you two going to keep this up? It's just to keep me sitting here. I can tell that very easily.’

Insigna said hastily, ‘Where will you go when you're out there?’

‘Just around. To the little river, or creek, or whatever it is.’

‘Why?’

‘Because it's interesting. Just flowing water in the open, and you can't see the ends, and you know it's not being pumped back to the beginning.’

‘But it is,’ said Insigna, ‘by the heat of Nemesis.’

‘That doesn't count. I mean human beings aren't doing it. Besides, I just want to stand there and watch it.’

‘Don't drink from it,’ said Insigna severely. ‘I don't intend to. I can last an hour without drinking. If I get hungry, or thirsty - or anything else - I'll come back. You're making such a fuss over nothing.’

Genarr smiled. ‘I suppose you want to recycle everything right here in the Dome.’

‘Yes, of course. Wouldn't anyone?’

Genarr's smile broadened. He said, ‘You know, Eugenia, I'm quite certain that living in Settlements has changed humanity permanently. The necessity of cycling is now ingrained in us. On Earth, you just threw things away, assuming it would recycle naturally, and, of course, sometimes it didn't.’

‘Genarr,’ said Insigna, ‘you're a dreamer. It may be posssible for human beings to learn good habits under pressure, but relieve the pressure and the bad habits are back at once. Downhill is easier than uphill. It's called the second law of thermodynamics, and if we ever do colonize Erythro, I predict that we will litter it from end to end in no time at all.’

‘No, we won't,’ said Marlene.

Genarr said in a tone of polite inquiry, ‘Why not, dear?’

And Marlene said with impatient force, ‘Because we won't. Now can I go out?’

Genarr looked at Insigna and said, ‘We might as well let her go, Eugenia. We can't hold her back for ever. Besides, for what it's worth, Ranay D'Aubisson, who just got back from Rotor, went over all the records from the start and told me yesterday that Marlene's brain scan seems so stable that she is convinced that Marlene will come to no harm on Erythro.’

Marlene, who had turned toward the door, as though ready to walk to the airlock, now turned back. ‘Wait, Uncle Siever, I almost forgot. You must be careful of Dr D'Aubisson.’

‘Why? She's an excellent neurophysicist.’

‘That's not what I mean. She was pleased when you were in trouble after your trip outside and pretty disappointed when you got better.’

Insigna looked surprised and said automatically, ‘What makes you say that?’

‘Because I know .’

‘But I don't understand that. Siever, don't you get along with D'Aubisson?’

‘Certainly, I do. We get along very well. Never a cross word. But if Marlene says-’

‘Mightn't Marlene be wrong?’

Marlene said at once, ‘But I'm not.’

Genarr said, ‘I'm sure you're right, Marlene.’ Then, to Insigna, ‘D'Aubisson is an ambitious woman. If anything happens to me, she's the logical choice as my successor. She's had a great deal of experience down here and she's surely the best person to deal with the Plague if it lifts its head again. What's more, she's older than I am and may not feel there's much time to waste. I couldn't blame her if she was anxious to succeed me, and if her heart lifted a bit when I was ill. The chances are she's not even consciously aware of these feelings.’

‘Yes, she is,’ said Marlene ominously. ‘She knows all about it. You watch out, Uncle Siever.’

‘Well, I will. Are you ready now?’

‘Of course I'm ready.’

‘Then let me walk you to the airlock. You come with us, Eugenia, and try not to look so tragic.’

And so it was that Marlene stepped out on to the surface of Erythro, alone and unprotected, for the first time. It was, by Earth Standard time, 9.20 p.m., 15 January 2237. By Erythro time, it was midmorning.