by Eric Flint
So, it wasn't the equipment.
Next up, test the mass of the ship.
There were several ways to do this. The easiest was to bang it with a hammer and measure the vibrations. Of course, you needed a very special hammer, and a very good ear, but the Bean had both of those. Additional tests could be performed by applying an incredibly precise thrust in a specific direction and measuring the shift in velocity. We could also shut down the centrifuge and rotate the ship on her gyros and measure how long that took. There were other tests as well, some as esoteric as comparing the ship's stress points by comparing her current holographic interference patterns with the patterns recorded on previous tests. All these separate measurements had been performed routinely before launch, and at least half-a-dozen times during the journey, including three times during flipover. Nine days later, the ship's mass had been sliced and diced 37 different ways. Allowing for the expenditure of fuel, allowing for the expected accretion of a half-gram of micro-dust, The Baked Bean massed essentially the same as it had ninety minutes prior to first boost.
So, if the ship hadn't gained mass, then either space had gotten thicker, or time ran slower out here. Or something else we hadn't imagined, and we just weren't thinking far enough outside the box. This is why a human being had to make the journey.
I don't know how long I sat there, staring out the window and picking my nose. I suppose I could look it up on the monitors. But it was a long time. First, I had to assume that the answer was knowable, that there was a physically measurable and testable phenomenon at work here. Starting from that assumption, what tests could I run?
There aren't a lot of ways to measure the speed of time without also measuring the speed of light. And the nasty thing about the speed of light is that it always measures the same, no matter where you are, or how fast you're going. You can only measure your location and your speed and your time-rate by comparing it with the location and speed and vector of another object. Out here, those measurements would take a long while. But in the meantime, I had to assume that the laws of physics did not metamorphose with distance from Sol. Why? Because the low-level perturbation was not a constant. 293 robot-vehicles had left the Sol system in the past century. 17 of them had ceased functioning by the time they crossed Neptune's orbit. 187 of them had experienced perturbation, most of them along the forward edge of Sol's movement in the galactic spin-cycle. Therefore, the phenomenon could be localized.
Gravity. Maybe we had miscalculated the gravitational pull of local objects. Maybe we had miscalculated the combined gravitational weight of multiple objects. Maybe the solar shelf was a gravitational ripple from Sol. But no. The gravitometers hadn't shown anything unexpected for 5 giga-klicks, and they weren't showing anything weird now. It wasn't that.
Solar winds? Maybe this far out, the effect of the solar wind dropped off precipitously? Nope. Nothing. No evidence of that. The solar winds were behaving exactly as they had behaved ever since we started measuring solar winds.
Solar wind. Wind. There was a thought. What if we'd run through a cosmic dust storm? Something with a lot of micro-particles—a zillion little high-speed collisions. Not a lot of mass, but a significant exchange of velocity. What if the low-level perturbation phenomenon was just a dense, fast-moving cloud of micro-particles that had impacted on the cow-catcher and transferred some of their momentum to the Bean?
But the sensors would have detected that, wouldn't they? Or would they?
I ran it through IRMA. Given the mass and velocity of the Bean, how much mass traveling at what velocity, would have to strike us head on to produce the drag we were experiencing?
The answer was simple. Enough to vaporize the Bean. Force equals mass times acceleration. No matter how you juggled the mass and momentum, the amount of force necessary to slow the Bean was more than enough to shred the cow-catcher and the ship. You could do it slowly or instantly, the result was the same.
What if—? No, that didn't make sense either. If we had overtaken a patch of dust heading in the same general direction, it wouldn't have slowed us—not this much.
Hm. What about the external bots? And all the other moving parts outside? The rotating panels? The remote arms? The sensors and antennae? Were they still fully operational? Several hours of tests later—yes, they were all still optimal. Maybe a smidge off, maybe not. If there were any measurable differences, they were so small as to be lost in the hash.
Everything was working just the way it was supposed to. I was almost disappointed.
What else? What was I missing?
Back in school, my graduate thesis required several thousand hours of coding. I intended to prove that software ecologies would inevitably stop evolving when they hit their Skotak radius, the limits of the hardware. The underlying algorithms would generate new ecological entities at random, then evolve them until their inevitable collapse. While long-term stability was achievable, permanent stability was impossible in an evolutionary environment. The stats on the project were impressive. Over thirty thousand mutable objects, agents, and bots, four hundred billion generations of parallel evolution per run. Sixteen hundred hours of high-impact debugging and deconstruction. Three weeks before the submission deadline, I thought I was done. Except—there was something gnawing at the woodwork of my brain. Something didn't feel right. I spent the better part of a week, studying columns of numbers until I found the one column that didn't balance. A point and a half of something—one of the minor elements of the ecology—was simply evaporating. It wasn't a rounding error, that was a beginner's mistake. It was something else.
Logically, I knew that no one would ever notice this discrepancy—but I would know it was there. I spent most of a week tracing the hundred different processes that accessed element AXO-1011. I could have taken the element out of the ecology, but it had become an obsession. I was going to be right about this. Eventually, I did find the source of the discrepancy—I'd made an assumption about a relationship instead of testing it. That tiny uncorrected assertion was why the system was unstable and always collapsed. When I corrected it—I had to change the conclusion of my thesis. Software can evolve to a state of permanent stability, given a fixed evolutionary range.
Of course, I had to report this in my oral examination. Professor Whitlaw gave me the fabled Whitlaw frown and asked, "So what did you learn?"
"I learned that . . . if God is in the details, so is the devil."
Whitlaw nodded. "Close enough."
Fifteen years and 5 giga-klicks later, I was looking for the devil again. The difference of 33.7 kilometers was statistically insignificant. But where were those kilometers going? And why? What fundamental conclusions about the nature of space-time were being challenged here? I wasn't thinking about awards or prizes or scientific immortality, I just wanted to solve the damn mystery.
I hauled down the hardcopy of the Mission Book and began paging through it idly. There were over three hundred pages of theories and ideas and suggestions for experiments. I wasn't sure what I was looking for, but maybe something would leap off the page at me.
But the only thing that leapt off the page was a little bit of dust. Several of the pages came up together, they had a cobweb on the edge—that annoyed me. I hate dirt. That's one of the reasons I go to space. I wondered if the authoring-spider had done its work before the book was loaded or if it had done its work enroute and starved to death for the lack of flies. Perhaps its curled-up corpse was nestled behind a panel somewhere, impossible to find.
As hard as human beings had worked to avoid bringing non-human volunteers into space, more than a few had found ship-life to their liking. Tales of star-faring mice, ants, flies, gnats, cockroaches, cats, snakes, and snails were not uncommon. Assorted spore and mold and fungal passengers had also found their way aboard spaceships. Some had escaped from their transport capsules; others had simply demonstrated that old truism that life will find a way.
Hm.
What if we were dealing with some kind of
. . . no, not life, but something that had some of the characteristics of life? Invisible glass spiders. Hundreds and thousands of tiny little mites, not alive, but crawling all over the outside of the ship as if they were? It was as likely as any other crackpot idea. Spinning webs to catch interstellar butterflies—
No, wait. There was something in the book. I flipped through the pages, almost frantically, until I found it again. Suggested by some late-night comedian. He thought he was being funny. Cosmic spiderwebs. The universe is so old, it should have cobwebs hanging from the rafters. Where are the cobwebs? Mission Control had thoughtfully tucked that into the book along with all the other crackpot ideas.
But . . . what the hell? It almost made sense. What if The Baked Bean had flown through some kind of a . . . something? And it was just enough to slow the ship down. Just a smidge.
Right. Giant space-spiders. When they do that episode, you know they've jumped the snark.
But . . . I leaned back in my couch and thought about it anyway.
What if there were some kind of—I dunno—some kind of fuzzy stuff that floated through interstellar space in vast immeasurable clouds? It would have to be very light. It would have to be—
I sat up straight.
Aerogel.
The lightest material ever made. Light and strong. There were fifty or sixty different formulations, each one lighter and stronger than the last. Half a kilo would fill a football stadium. Something like that.
Some kind of nano-stuff, maybe. Interstellar cotton candy. You could move around inside it and never know you were caught. But if you moved through enough of it, and if you were caught in a large enough net—say, a thousand or a hundred thousand klicks across—it would have enough mass to function as a drag chute.
Hm.
It would have to be self-assembling.
Very slow growth.
But that's okay, there's nothing between the stars but time and dust. If it's possible, it's inevitable.
Hm.
Worth thinking about for a minute or two.
Okay, assume the possibility. Why hasn't anyone discovered this stuff yet?
Because no one has come out far enough? Only some bot-controlled probes.
Maybe the webs were strictly an interstellar phenomenon. Maybe they couldn't assemble themselves within a star system. Maybe too much light and heat worked against the process. Maybe the webs were so light the solar wind just pushed them out into the darkness. Maybe all the various rocks and meteors and asteroids and bits of dust that churned around the solar disk ripped the webs to pieces as fast as they formed.
But out in the Oort Cloud, in the Hills Cloud, there would be enough material for a web to assemble itself, but not so much as to shred it. Hmm. Maybe the deepest darkest spaces between the stars were filled with clouds of cosmic aerogel?
What a strange silly idea.
Too silly.
Much too silly.
Besides, how would you test it?
How do you grab a handful of nothing? Almost nothing.
I had a thought. I had IRMA list all 293 vehicles that had left the solar system and their relative speeds. 89 spacecraft had not experienced any detectable slowdown. Of those 89, 77 were long-life probes, accelerating toward distant stars. Gotcha. They were going too fast. They ripped right through, like a bullet through custard. But the others were slower-moving planetary probes, like the V'gers, which had finally drifted far enough out—or probes that were aimed specifically at the Oort and the Hills. Going slow enough to get caught. Aha. Okay. Maybe. There's a piece of useful evidence.
But unless I could grab some of the stuff and bring it back, it was all just theory. The Cosmic Cobwebs—right. Do that episode instead of the space spiders and you're still jumping the snark.
If this stuff was as light and as far-flung as I suspected, it was probably as undetectable as the rest of the space dust that hammered at the cow-catcher. We would only know if it had been there by the effects it left behind—did it score or scratch the shield? But there weren't any instruments designed for detecting threads so light they couldn't be measured. And if they were impossible to detect, then it would be even more impossible to gather up a shiftload. I'd need a net as big as . . . as big as the webs I was trying to catch. And probably twice as strong.
My brain hurt. I checked the monitors one more time, then climbed down into the centrifuge for a sleep shift—
—came awake laughing. I'd been dreaming of fly fishing on the river. And then I'd dreamt about a taffy-pulling machine. And then I knew how to catch a starweb.
It took a couple weeks for the bots to cobble it together, a couple of giant paddlewheels, one on each side of the Bean—slowly, slowly rotating, winding up invisible threads like a fisherman pulling in his nets.
The paddlewheels dwarfed the ship. They were each a third of a klick in diameter, and their paddles extended almost half a click out. They were spidery Tinker Toy constructions of carbon-fiber beams so thin, they were almost invisible; but they didn't need to be heavy, they only needed to be sturdy—and they were plenty of that. There were only six paddles to a wheel. Each carbon-fiber rod had a couple dozen meter-long teeth spaced out along its length to help snag any threads we encountered. I didn't know how big a starweb might be or how far it might extend. Its total mass might be so great that instead of the Bean reeling in a slice, we'd be reeling the Bean into the thickest part of it. We could end up getting caught in a mass so huge, there was no possible escape. But on the bright side, that would be evidence too.
It was all guesswork. There was no way to know how big a web could be. I didn't know how much of this one I'd ripped through, and how much of it I'd actually snagged. Assuming the Bean had simply snagged without ripping, then we were dragging enough mass to cost us a measurable percentage of delta-vee. Not quite a flying mountain, but considering our velocity when we hit the Hills Cloud, something at least as large as the Bean, and probably quite a bit larger. So the paddlewheels and their axes had to be sturdy enough to carry that weight and not break off.
But if we'd ripped a hole and were caught by a smaller piece of a much greater whole—something we'd find out the hard way—then the stress on the paddles would start rising, and keep rising until they snapped off.
Of course, if the paddles did break off, that would prove the existence of the starwebs. Most embarrassingly.
On the other hand, if they churned for a year and there was still nothing caught up and wound up on them, that would prove equally embarrassing.
But if I was right . . . well, this might even solve the dark matter mystery. Where's all the missing matter in the universe? It's right here, where it's always been, floating between the stars. Occam's Chainsaw. Sometimes the simplest answer is right in front of you.
But as long as there was a measurable drag on the ship's velocity, the Bean was in the right neighborhood, so it was just a matter of time and patience. I watched the big wheels turning until I got bored, then I watched a while longer, then I went to bed. I woke up, checked all the monitors, watched the big wheels turning for a while, checked the monitors again, saw that everything was optimal, yawned, ate something forgettable, read my mail, checked the big wheels, checked the monitors, went to the toilet, and then did it all again.
IRMA predicted that if the webs existed, it could take several months to reel in enough material to have anything visible to the naked eye. It depended on the tensile strength of the threads. Assuming they were strong enough to catch a spaceship, they were probably strong enough to wind around the paddles without breaking. Another assumption, but the only one that made sense. The difference in relative velocity—the Bean vs. the starweb—could be thousands, perhaps tens of thousands, of klicks per hour. If we were simply ripping through and shredding the webs, then it was the same problem as with micro-particles. The amount of mass times acceleration needed to slow down The Baked Bean would also be enough to shred the cow-catcher. It didn't matter how you weighted the factors
—the product was still deadly. No, we had to be catching something and dragging something. Something strong enough to wind. I'd know for sure in a month or six. I checked the monitors again, because I like looking at green lights, then printed up a sandwich.
The paddlewheels were a third of a klick in diameter. That meant, every three turns, they would roll up a kilometer of thread—if they were rolling up anything at all. The paddlewheels turned once every five minutes. If we caught thread, they'd wind up four kilometers of it per hour, 96 per day, 672 klicks per week, over 2700 kilometers of thread in a month. Assume a kilometer-long thread might weigh—oh, I dunno, let's say—a gram; then in 30 days, the Bean should have at least 3 kilos of cosmic starweb wound around its paddles. Depending on how many threads the paddles caught, how long they were, and how much they actually massed per klick.
I didn't have to wait even that long for evidence. After 21 days, the first glints of something were visible on the paddlewheels—like a hint of plastic-wrap stretched between the rods. I couldn't see it directly, but the IRMA-enhanced videos showed multiple instances of consecutive frames of what looked like lines stretching from one paddle-rod to the next. There was no maybe about it. I lit the wheels all up and down the entire spectrum, trying to catch a reading. There wasn't enough mass yet to get the reflected signal up above the hash, but every turn of the paddlewheel gave us more.
I began writing up my report.
Three months later, I had nearly 20 kilos of material; either it was heavier than I thought, or I'd gathered more than I'd expected. This stuff was going to be a bitch to analyze. But it was time to bring The Baked Bean home. That meant collapsing the paddles and storing the web-stuff in something. I couldn't risk having it be shredded by micro-dust on the way home, and I wasn't sure how sensitive it would be to the solar winds, let alone the heat and light of Sol. I suspected the web-threads weren't just made of some pretty tough stuff, but that they were also assembled in some ingenious ways. Just the same, I'd hate to come home with an empty framework and a terrific story about the fishing line that got away.