Through his mushroom helmet's kingsize view window, still polarized at half max to guard his eyes from solar glare, Lieutenant Don Merriam USSF watched the last curved sliver of solid sun, already blurred by Earth's atmosphere, edge behind the solid bulk of the mother planet.

The last twinges of orange light reproduced with frightening exactitude the winter sun setting through the black tangle of leafless trees a quarter mile west of the Minnesota farmhouse where Don Merriam had spent his childhood.

Twisting his head toward the righthand mini-console, he tongued a key to cut polarization. ("The airless planets will be pioneered by men with long, active tongues," Commander Gompert had summed it up. "Frogmen?" Dufresne had suggested.)

The stars sprang out in their multitudes  -  a desert night squared, a night with sequins. The pearly shock of Sol's corona blended with the Milky Way.

Earth was ringed by a ruddy glow  -  sunlight bent by the planet's thick atmosphere  -  and would remain so throughout the eclipse. The ring was brightest near the planet's crust, fading out a quarter diameter away, and brightest of all along the lefthand rim behind which the sun had just vanished.

Don noted without surprise that the central bulk of Earth was the blackest he had ever seen it. Because of the eclipse, it was no longer brushed with the ghostly glow of moonlight.

He had been half crouched in his suit, leaning back and supporting himself on one arm to get an easy view of Earth, which was halfway to his zenith. Now with a wrist-flick nicely gauged to the moon's dreamy gravitation, he came fully to his feet and looked around him.

Starlight and ring-glow tinged with bronze the dark gray plain of dust, mouse-soft, a mixture of powdered pumice and magnetic iron oxide.

Back when Cromwell's New Model Army ruled England, Hevelius had named this crater the Great Black Lake. But even in bright sunlight Don could not have seen the walls of Plato. That near-mile-high, circular rampart, thirty miles away from him moon-east, north, south, and west, was hidden by the curve of the moon's surface, sharper than the earth's.

The same close horizon cut off the bottom half of the Hut, only three hundred yards away. It was good to see those five little glowing portholes at the margin between the dark plain and the starfield  -  and near them, silhouetted by starlight, the truncated cones of the base's three rocket ships, each standing high on its three landing legs.

"How's the dark dark?" Johannsen's voice softly asked in his ear. "Roger and over."

"Warm and spicy. Suzie sends love," Don responded. "Roger to you."

"Outside temperature?"

Don glanced down at the magnified fluorescent dials beneath the view window. "Dropping past 200 Kelvin," he replied, giving the absolute equivalent of a temperature of almost exactly 100 degrees below zero on the Fahrenheit scale still widely used in Earth's English-speaking areas.

"Your SOS working?" Johannsen continued.

Don tongued a key and a faint musical ululation filled his helmet. "Loud and clear, my captain," he said with a flourish.

"I can hear it," Johannsen assured him sourly. Don tongued it off.

"Have you harvested our cans?" Johannsen next asked, referring to the tiny, rod-supported cannisters regularly put out and collected to check on the movements of moon dust and other materials, including radioactively tagged atoms planted at various distances from the Hut.

"I haven't sharpened my scythe yet," Don told him.

"Take your time," Johannsen advised with a knowing snort as he signed off. He and Don were well aware that planting and harvesting the cans was mostly an excuse to get a man suited up and out of the Hut as a safety measure during times of greatest danger from moonquakes  -  when Earth and Sun were dragging at the moon from the same side, as now, or from opposite sides, as would happen in two weeks. Gravitational traction has been thought to trigger earthquakes, and so, possibly, moonquakes. Moonbase had not yet experienced anything beyond the mildest temblor  -  the pen of the seismograph keyed to the solid rock below the dust cushioning the Hut had hardly quivered; just the same, Gompert made a point of having a man outside for several hours each fortnight  -  at "new earth" and "full earth" (or full moon and new moon, if you stayed with the groundster lingo, or simply the spring tides). Thus if the unexpected did occur and the Hut sustained serious damage, Gompert would have one egg outside his basket.

It was just another of the many fine-drawn precautions Moonbase took for its safety. Besides, it provided a tough regular check on the efficiency of spacesuits and of personnel working solo.

Don looked up again at the Earth. The ring was glowing less lopsidedly now. He couldn't make out a single feature of the inky circle inside, though he knew the eastern Pacific and the Americas were to the left and the Atlantic and the western tips of Africa and Europe to the right. He thought of dear, slightly hysterical Margo and good old neurotic Paul, and truly even they seemed to him rather trivial at the moment  -  nice little beetles scuttling under the bark of Earth's atmosphere.

He looked down again, and he was standing on glittering whiteness. Not whiteness literally, yet the effect of a new-fallen Minnesota snow by starlight had been duplicated with devilish precision. Carbon dioxide gas, seeping steadily up through the pumice and oxide of Plato's floor, had suddenly crystallized throughout into dry-ice flakes forming directly on the dust floor or falling onto it almost instantly.

Don smiled, feeling less inhumanly distant from life. The moon had not become a Mother to him yet, not by a long shot, but she was getting to seem just a little like a chilly Older Sister.

Balmy air sluiced the convertible carrying Paul Hagbolt and Margo Gelhorn and the cat Miaow along the Pacific Coast Highway. At almost regular intervals a weathered yellow roadsign would grow until it plainly said slide area or falling rock zone, and then it would duck out of the headlight beam. The highway traveled a generally narrow strip between the beach and an almost vertical, hundred-foot cliff of geologically infantile material  -  packed silt, sand, gravel, and other sediments, though here and there larger rocks thrust through.

Margo, her hair streaming, sat half switched around with her knees on the seat between her and Paul, so she could watch the smokingly bronzed moon. She had her jacket spread on her lap. On it was Miaow, curled up in a gray doughnut and fast asleep, or giving a good imitation.

"We're getting near Vandenberg Two," Paul said. "We could look at the moon through one of the Project 'scopes."

"Will Morton Opperly be there?" Margo asked.

"No," Paul replied, smiling faintly. "He's over in the Valley these days, at Vandenberg Three, playing master sorceror to all the other theory boys."

Margo shrugged and looked sideways up. "Doesn't the moon ever black out?" she wondered. "It's still sooty copper."

Paul explained to her about the ring-glow.

"How long does the eclipse last, anyway?" she asked, and when he said, "Two hours," she objected: "I thought eclipses were over in seconds, with everybody getting excited and dropping their cameras."

"Those are the eclipses of the sun  -  the totality part."

Margo smiled and leaned back. "Now tell me about the star photographs," she said. "You can't possibly be overheard in a moving car. And I'm not so worked up about them now. I've stopped worrying about Don  -  the eclipse is just a bronze blanket for him."

Paul hesitated.

She smiled again. "I promise not to rev my mind at all. I'd just like to understand them."

Paul said: "I can't promise you any understanding. Even the astro big-wigs only made profound noises. Including Opperly."

"Well?"

Paul wove the tires around a tiny scatter of gravel. Then he began. "Well, ordinarily, star photos don't get seen around for years, if ever, but the astro boys on the Project have a standing request out with their pals at the observatories to be shown anything unusual. We've even had star pix the day after they were taken."

Margo laughed. "Late Sports Final of the Stellar Atlas?"

"Exactly! Well, the first photo came in a week ago. It showed a starfield with the planet Pluto in it. But something had happened during the exposure so that the stars around Pluto had blanked out or shifted position. I got to look at it myself  -  there were three very faint squiggles where the brightest stars near Pluto had shifted. Black-on-white squiggles  -  in real astronomy you just look at the negatives."

"Inside stuff," Margo said solemnly. Then, "Paul!" she cried. "There was a newspaper story this morning about a man who claimed to have seen some stars twirl! I remember the headline: STARS MOVED, SAYS WRONG-WAY DRIVER."

"I saw it too," Paul said a bit sourly. "He was driving an open-top car at the time, and had an accident  -  because he was so fascinated by the stars, he said. Turned out he'd been drinking."

"Yes, but the people with him in the car backed him up. And later there were phone calls to the planetarium, reporting the same thing."

"I know, we had some at the Moon Project," Paul said. "Just the usual business of mass suggestion. Look, Margo, the photo I was telling you about was taken a week ago, and it was of something only a powerful telescope could see. Let's not get it mixed up with flying saucer-type nonsense. I'm saying, we got a photo of Pluto showing three faint star-squiggles. But get this  -  Pluto hadn't shifted at all! Its image was a black dot"

"What's so astonishing about that?"

"Ordinarily you don't get startled at starlight or even star images wavering. Earth's atmosphere does it, same as it makes hills waver on a hot day  -  in fact, that's what makes the stars twinkle. But in this case, whatever was twisting the starlight had to be out beyond Pluto. This side of the stars, but beyond Pluto."

"How far away is Pluto?"

"Almost forty times as far as the sun."

"What would twist starlight way out in space?"

"That's what puzzles the big boys. Some special sort of electric or magnetic field, maybe, though it would have to be very strong."

"How about the other photos?" Margo prompted.

Paul paused while he pulled around a deep-growling truck. "The second, taken four nights ago by our astro satellite and TV'ed down, was the same story, except that the planet involved was Jupiter, and the area of the twist was larger."

"So that whatever made the twist must have been nearer?" Margo suggested.

"Perhaps. Incidentally, Jupiter's moons hadn't wavered either. The third photo, which I saw day before yesterday, showed a still larger area of twist with Venus in it Only this time Venus had made a squiggle too  -  a big one."

"As if the light had been twisted this side of Venus?"

"Yes, between Venus and Earth. Of course it could have been atmosphere-waver this time, but the boys didn't think so."

Then Paul grew silent.

"Well?" Margo prodded him. "You said there were four photos."

"I saw the fourth today," he told her guardedly. "Taken last night. Still larger areas of twist. This time the edge of the moon was in it. The moon's image hadn't wavered."

"Paul! That must have been what the man who was driving saw. The same night."

"I don't think so," he told her. "You can hardly see any stars near the moon with the naked eye. Besides, these reports by laymen just don't mean anything."

"Well," she countered, "it certainly does sound as if something were creeping up on the moon. First Pluto, then Jupiter, then Venus, getting closer each time."

The road curved south and the darkly bronzed moon came swinging out over the Pacific as it rode along with them.

"Now, wait a minute, Margo," Paul protested, lifting his left hand for a moment from the wheel. "I got the same idea myself, so I asked Van Bruster about it He says it's completely unlikely that one single field, traveling through space, was responsible for the four twists. He thinks there were four different twist fields involved, not connected in any way  -  so there can't be any question of something creeping up on the moon. What's more, he says he's not too surprised at the photos. He says astronomers have known the theoretical possibility of such fields for years, and that evidence for them is beginning to show up now, not by chance, but because of the electronically amplified 'scopes and superfast photographic emulsions that have just gone into use this year. The twists show up in star snapshots where they wouldn't in long exposures."

"What did Morton Opperly think of the photos?" Margo asked.

"He didn't...No, wait, he was the one who insisted on plotting the course of the twist fields from Pluto to the moon. Say, we just passed Monica Mountainway! That's the fancy new road across the mountains to Vandenberg Three where Opperly is right now."

"Was the Pluto-moon course a straight one?" Margo asked, refusing to be deflected.

"No, the darndest zig-zag imaginable."

"But did Opperly say anything?" Margo insisted.

Paul hesitated, then said, "Oh, he chuckled, and said something like, 'Well, if Earth or Moon is their target, they're getting closer with each shot.' "

"You see?" Margo said with satisfaction. "You see? Whatever it is, it's aiming at planets!"

Barbara Katz, self-styled Girl Adventurer and long-time science-fiction fan, faded back across the lawn, away from the street-globes and the Palm Beach policeman's flashlight, and slipped behind the thick jagged bole of a cabbage palmetto before the cold bright beam swung her way. She thanked Mentor, her science-fiction god, that the long-hoarded, thirty-inch nylon foot-gloves she was wearing below her black playsuit were black, too  -  one of the popular pastel shades would have shown up even without the flash. The bag dangling from her shoulder was a black one, of the Black Ball Jetline. She didn't worry about her face and arms, they were dark enough to melt with the night  -  and get her mistaken for colored by day. Barbara was willing to do her bit for integration, but just the same she sometimes resented it that she tanned so dark so fast.

Another burden for Jews to bear bravely, her father might have told her, though her father wouldn't have approved of stouthearted girls hunting millionaires in their home lair in Florida, which they shared with the alligators. Or of such girls carrying bikinis in their swiped shoulder bags, either.

The policeman's flash was prodding the shrubs across the street now, so she continued across the lawn springy as foam rubber. She decided that this was certainly the house from beside which she'd seen a lens flashing while she'd sneaked her swim at sunset.

It got very dark around her as she advanced. As she rounded another palmetto, she heard the whisper of a tiny electric motor, and she almost overran a white suit that was seated at the eyepiece of a big white telescope supported on a white-legged tripod and directed at the western sky.

The suit got up with a kind of lurch that showed it was helped by a cane, and a voice quavered from atop it "Who's that?"

"Good evening," Barbara Katz responded in her warmest, politest voice. "I believe you know me  -  I'm the girl who was changing into the black-and-yellow striped bikini. May I watch the eclipse with you?"