“Think I’ll try to nap,” Matt said, not in the mood for a zero-gee romp. Martha nodded and closed her eyes, but she was too agitated to sleep, which probably kept Jesus away.

19

It was obvious as they approached the continentin their suborbital arc that things were much different. The signal was not coming from the southeastern coastal city; there apparently had been some continent-wide disaster, and as far as the orbital eye could see, there was nothing but ash and slag, giving off a faint aura of gamma rays. Not a trace of plant life.

“The signal’s coming from northeast of here,” La said. “Toward the geometrical center of the continent.”

The ship slewed sideways. “Strap in for de-orbit.”

Coming down was easier, knowing what to expect. When the ship stopped shaking, rattling, and rolling, and started to glide through the lower atmosphere, they could easily see their destination: a two-mile-high obelisk like a silver dagger pointed to the sky. The ground was a plane of tarnished metal.

They rolled to a stop at the base, a couple of hundred yards square, and walked down the ramp. The air was hot and thick and smelled of ashes.

La touched the metal wall. “Platinum. Built to last.”

“Can you read it?” Martha said. The wall was covered up past eye level with incised curlicues that were obviously writing.

“Not yet. I’ve sent a probe around to record and analyze all the markings. The building’s covered with them.”

“Is there a door?” Matt said.

“I’m not sure we’d want to go in. But no, we haven’t found one yet.”

After a couple of minutes, La said, “I’m getting it now. There’s a mathematical Rosetta Stone on the other side.”

“I know about the Dead Sea Scrolls,” Martha said, “but what does the Rosetta Stone have to do with mathematics? ”

“It has to do with language, actually,” La said. “Mathematics is universal, so you can start with logical operators and addition and subtraction and build it into something like a natural language. You put it all on a high-technology artifact like this, and anyone who uses high technology to find it should eventually be able to decipher the language.”

“How long will that take?”

“Maybe thousands of years. More likely, minutes. You could go make a sandwich.”

“I’ll do that,” Matt said, partly out of self-defense since Martha’s idea of a sandwich was pretty basic, and he went up the ramp. But by the time he’d finished, and put the meat and cheese and condiments back into the fridge, La and Martha had followed him up.

“It’s from the future!” Martha said, excited.

“It may be. It isfrom a time traveler, but he or she or it doesn’t say from which direction, or even whether it came from Earth.”

“So what happened to Australia?”

“It doesn’t say. It notes that this planet used to be the only place humans lived, but there weren’t any here now. After what it called the Truth Wars and the Diaspora, the planet didn’t have any ‘natural’ humans.”

“So what’s an unnatural human?”

“It didn’t say. Maybe something like me. Maybe robots, vampires, werewolves.

“Anyhow, it said it was going out to 61 Cygni. That’s a lot farther than we can go, about eleven light-years. So it came from myfuture, at least.”

“But it still may have forward-only time travel.” La shrugged.

“Look at the moon,” Martha said.

It was just rising, almost full. But it was like a miniature Earth, blue and brown, white at the poles.

“Terraformed,” Matt said.

“Made like Earth?” Martha said. “Maybe that’s where the people are.”

“It’s not impossible,” La said, “though you’d think the person who made this obelisk would check there before going a million times farther away.”

“It could have been later than the obelisk, though. Matt looked at the artifact, and then the Moon, “Like people came back, but didn’t want to settle on the Earth.”

La nodded. “It’s too radioactive, if it’s all like here. Short-term exposure wouldn’t hurt, but if you settled here, you’d have reproductive problems. Sterility, or at least a high frequency of mutations.”

“So we should look at the Moon,” Martha said. “Can you go that far?”

“Easily. Anywhere in the solar system. But it would be smart to check the rest of the Earth first. Let’s go up into orbit and look around.”

They did one pass in low-Earth orbit, passing North America in a line from Baja California to Maine, all sterile ruins, then back down through Africa, a gray tundra. The radiation wasn’t as bad elsewhere, but there were no signs of human habitation anywhere.

Up in a higher orbit, where they could see the planet as an entire globe, there were still no cities or obvious ports or roads. The gamma radiation diminished to a negligible trace in Africa and most of Asia, but there was still no sign of human life.

“Might as well try the Moon,” La said. “We could get there in a couple of hours, accelerating halfway, then decelerating. But to save energy, I’d rather blast for a few minutes and drift weightless for a day or so. Can you handle that?”

“Yes!” Martha said, before Matt could express an opinion.

They accelerated for a few minutes, and then were falling free. “You might as well go rest,” La said. “Come out when you’re hungry.”

Martha was more efficient at swimming through zero gee. She was waiting for Matt in their room, semi-sitting in a chair.

“This is funny,” she said. “Furniture is kind of useless.”

He grabbed the bed and perched at an odd angle, and laughed. “I guess to sleep, you have to slip under the sheet and hope it holds you in place.”

“At least you can’t fall out.” She rummaged through the bag and came out with the porn box, and looked at it, frowning. “I guess this is as close as I’m going to come to an actual Passage. Could you watch it with me and explain things?”

It was not Matt’s idea of a first date, but it was certainly interesting. She knew about fertilization in a vague way, bees and flowers, but hadn’t been taught anything about the mechanics of it. The other girls had told her the man sort of peed into the woman, and that was all she knew.

“Is this what they mean by rape?”

“When the woman doesn’t want to do it, yes. Or if she’s not old enough. Under eighteen, where I come from,” he added optimistically.

“The sisters warned us about rape, but they couldn’t describe it. Of course, they were virgins. They’d never seen anything like . . . what we just saw. But it doesn’t look like it hurts.”

“It can . . . when it’s rape, it does. The point of rape is to hurt, to dominate. But that’s not what they’re doing here.”

They watched several performances, fast-forwarding through the repetitive parts, and he explained which could lead to pregnancy and which were more or less for fun.

Of course his formfitting superhero costume did nothing to hide his own sustained reaction to the show and its audience, and she couldn’t help noticing.

“May I see?” He let her roll down his trousers. “Oh . . . so if you were circumcised, this would be—” One touch was enough.

She had just seen several examples of ejaculation, but none in zero gravity. Out of instinct as much as observation, she grabbed it and pumped up and down a couple of times, and the result was a kind of sticky spiderweb expanding in three dimensions. Fortunately, there was a tissue dispenser on the table by the bed, and they chased down the mess, laughing together.

He was startled by how matter-of-fact she was about it, but realized she was carrying a different set of cultural baggage. Like most men, he’d been more or less obsessed with the processes of erection and ejaculation ever since the first times they had happened, but she’d never given them much thought before the past hour. It was a process, not a fixation.