“There are two points in our favor,” Colin continued. “No official funds are involved, so we can’t be criticized for using government money. And let’s have no false modesty-Earth will expect a Makenzie. It might even be regarded as an insult if one of us didn’t go. And as Duncan is the only possibility, that settles the matter.”

“You’re perfectly correct, of course. But not everyone will see it that way. All the families will want to send their younger sons and daughters.”

“There’s nothing to stop them,” Duncan interjected.

“How many could afford it? We couldn’t.”

“We could if we didn’t have some expensive extras in mind. So can the

Tanaka-Smiths, the Mohadeens, the Schwartzes, the Deweys…”

“But not, I believe, the Helmers.”

Colin spoke lightly, but without humor, and there was a long silence while all three Makenzies shared a single thought. Then Malcolm said slowly:

“Don’t underrate Karl. We have only power and brains. But he has genius, and that’s always unpredictable.”

“But he’s crazy,” protested Duncan. “The last time we met, he tried to convince me that there’s intelligent life on Saturn.”

“Did he succeed?”

C6,811most.99

“If he’s crazy-which I doubt, despite that famous breakdown-then he’s even more dangerous. Especially to you, Duncan.”

Duncan made no attempt to answer. His wiser and older twins understood his feelings, even if they could never fully share them.

“There is one other point,” said Malcolm thoughtfully, “and it may be the most important of all. We may have only ten years in which to

change the whole basis of our economy. If you can find an answer to this problem on your trip—even a hint of an answer!-you’ll be a hero when you come home. No one will criticize any of your other activities, public or private.”

“That’s a tall order. I’m not a magician.”

“Then perhaps you’d better start taking lessons. If the Asymptotic Drive isn’t pure magic, I don’t know what it is.”

“Just a minute!” said Colin. “Isn’t the first A-Drive ship going to be here in a few weeks?”

“The second. There was that freighter, Fomalhaut. I went aboard, but they wouldn’t let me see anything. Sirius is the first passenger liner-she enters parking orbit-oh-in about thirty days.”

“Could you be ready by then, Duncan?”

“I very much doubt it.”

“Of course you can.”

“I mean physiologically. Even on a crash program, it takes months to prepare for Earth gravity.”

“Um. But this is far too good an opportunity to miss—everything is falling into place beautifully. After all, you were born on Earth.”

“So were you. And how long did you take to get ready when you went back?”

Colin sighed.

“It seemed like ages, but by now they must have improved the techniques.

Don’t they have neuro programming while you sleep?”

“It’s supposed to give you horrible dreams, and I’ll need all the sleep I can get. Still, what’s good for Titan…”

He had no need to complete the quotation, which had been coined by some unknown cynic half a century ago. In thirty years, Duncan had never really doubted this old cliche-once intended to wound, now virtually adopted as a family motto.

What was good for the Makenzies was indeed good for Titan.

THE RED MOON

If the eighty-five known natural satellites, only Ganymede, lord of the Jovian system, exceeds Titan in size-and that by a narrow margin.

But in another respect Titan has no rivals; no other moon of any planet has more than a trace of atmosphere. Titan’s is so dense that if it were made of oxygen, it would be easy for a man to breathe.

When this fact was discovered, late in the twentieth century, it presented the astronomers with a first-class mystery. Why should a world not much larger than the Earth’s totally airless Moon be able to hold on to any atmosphere-particularly one rich in hydrogen, lightest of all gases? It should long ago have leaked away into space.

Nor was that the only enigma. Like the Moon, almost all other satellites are virtually colorless, covered with rock and dust shattered by ages of meteoric bombardment. But Titan is red-as red as Mars, whose baleful glare reminded men in ancient times of bloodshed and of war.

The first robot probes solved some of Titan’s mysteries, but, as is always the case, raised a host of new problems. The red color came from a layer of low, thick clouds, made from much the same bewildering mixture of organic compounds as the Great Red Spot of Jupiter. Beneath those clouds was a world more than a hundred degrees hotter than it had any right to be; indeed, there were regions of Titan where a man needed little more than an oxygen mask and a simple thermofoil suit to move around in the open. To everyone’s great surprise, Titan had turned out to be the most hospitable place in the Solar System, next to Earth

itself. Part of this unexpected warmth came from the greenhouse effect, as the hydrogenous atmosphere trapped the feeble rays of the distant sun. But a good deal more was due to internal sources; the equatorial region of Titan abounded in what, for want of a better phrase, might be called cold volcanoes. On rare occasions, indeed, some of them actually erupted liquid water.

This activity, triggered by radioactive heat generated deep in the core of

Titan, spewed megatons of hydrogen compounds into the atmosphere, and so continually made up for the leakage into space. One day, of course, the bruised reserves-like the lost oil fields of Earth-would all be gone, but the geologists had calculated that Titan could hold the vacuum of space at bay for at least two billion years. Man’s most vigorous atmospheric mining activities would have only a negligible influence on this figure.

Like the Earth, Titan has distinct seasons-though it is difficult to apply the word “summer” where the temperature at high noon seldom climbs to fifty below. And as Saturn takes almost thirty years to circle the sun, each of the Titanian seasons is more than seven Terran years in length.

The tiny sun, taking eight days to cross the sky, is seldom visible through the cloud cover, and there is very little temperature difference between day and night—or, for that matter, between Poles and Equator. Titan thus lacks climate; but it can, on occasion, produce its own quite spectacular brand of weather.

The most impressive meteorological phenomenon is the so-called Methane

Monsoon, which often though not invariably-occurs with the onset of spring in the northern hemisphere. During the long winter, some of the methane in the atmosphere condenses in local cold spots and forms shallow lakes, up to a thousand kilometers square but seldom more than a few meters deep, and often covered with fantastically shaped bergs and floes of ammonia ice.

However, it requires the exceedingly low temperature of minus a hundred and sixty to keep methane liquefied, and no part of Titan is ever that

cold for very long. A “warm” wind, or a break in the clouds-and the methane lakes will flash suddenly into vapor. It is as if, on Earth, one of the oceans were to evaporate, abruptly increasing its volume hundreds of times and so completely changing the state of the atmosphere. The result would be catastrophic, and on Titan it is sometimes scarcely less so. Wind speeds of up to five hundred kilometers an hour have been recorded -or to be accurate, estimated from their aftereflects. They last only for a few minutes; but that is quite long enough. Several of the early expeditions were annihilated by the monsoon, before it became possible to predict its onset.

Before the first landings on Titan, at the beginning of the twenty-first century, some optimistic exobiologists had hoped to find life around the relatively warm oases that were known to exist. This hope was slow to fade, and for a while it was revived by the discovery of the strange wax formations of the famous Crystal Caves. But by the end of the century, it was quite certain that no indigenous life forms had ever existed on Titan.