Castaway Planet, Chapter 5

They had set their sights on a distant star...

 

 

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Chapter 5

 

        

The unnamed star glowed before them, a visible disk, as LS-5 came out of the Trapdoor Drive. Now the next cycle of worry begins, Whips messaged to Sakura, who gave a tense, wry grin. Finding a good star was excellent luck… but we cannot live on a star.

Yeah. But let's take one problem at a time. He saw her shove the worries out of her mind and concentrate on trying to figure out their location. We're already moving some with respect to the star, so if I can get any parallax at all that will give me a good idea of distance. I can sorta guess based on the likely diameter of the star, probably about one and a quarter hundred million kilometers, but it could be significantly more or less than that.

Finally she shook her head and sat back. "I've got a rough guess as to our distance, but it'll take a while to refine that and get a velocity vector. At a guess, we're maybe two AU from the star."

"I thought the star looked a lot more than Europa-sized," Whips said. "I mean, the size the Sun looks from Europa."

"Yeah, that was really all I had to go on, given the uncertainty in the Trapdoor transit distance. If it's a yellow supergiant I'd be totally wrong… but I don't see all the gas and stuff it should be shedding if it was a supergiant, and if that's what it was we'd be pretty much out of luck anyway, so it has to be a regular G-class."

Caroline nodded. "Besides, if it was a yellow supergiant it would have been incredibly bright at a quarter light year distance. Trust me, it's a regular G3."

"Why do we have to wait to get parallax?" Laura asked reasonably. "Just do a quick jump with the Trapdoor Drive."

"We could do that," Whips said, since he saw Sakura looking uncertain. "But the Drive doesn't come up and go down fast; what happened to separate us from Outward Initiative is almost certainly partly due to something trying to do a fast adjustment on the field. You're deforming spacetime itself, after all, and that's something you need to do very, very carefully. So… in practice you don't want to do jumps shorter than, oh, thirty seconds or so, which since that's going to be a full continuous jump instead of one that's interspersed with recharging moments, that's a minimum jump of… well over seven hundred million kilometers."

"Oh." Laura's brow wrinkled as she accessed the data. "Ah. That means that even the shortest practical jump covers a distance almost as far as Jupiter from the Sun."

"Roughly, yes," Whips agreed. "There are special drive designs that can do shorter, faster jumps, or ways to tune these for that, but…" he gave the rippling gesture of arms and color that was his equivalent of the human's shrugs, "I'm an apprentice. I know the theory but no way am I going to try doing that in practice."

"We wouldn't want you to!" Sakura agreed emphatically. "So that means we need to just let our own speed give us the parallax, and then we can deploy the Nebula Drive to get us to our target."

Whips actually looked forward to that. The "Nebula Drive", or more technically the "dusty-plasma sail" had been originally invented by Bemmius secordii sapiens—not his direct ancestors, but the ones who'd seeded his ancestors on Europa. Human scientists such as Dr. Robert Sheldon had theorized it was possible, but it wasn't until an ancient Bemmius relic had been uncovered and repaired that the Nebula Drive was simultaneously reborn and renamed, a method for using ionized plasma to inflate a magnetic field to immense sizes, confining dust and gas within the field and providing the most ethereally beautiful, and low-cost, way to move around a solar system.

"Can we get closer to the star?" her dad asked. "I don't want to worry anyone, but I know the only other long-distance capability we have comes from the Nebula Drive, and that's sort of like a solar sail, right? So I can see how it can push us away from the star, but…"

"Remember that we're not just sitting still with respect to the star," Whips said. "So the real key is which direction you are orbiting the star, and at what distance."

"Right," said Sakura, picking up the conversation, "To oversimplify, you just point your sail so you go against your orbiting direction, and that'll make you go closer. You can tack with a dusty-plasma sail just like a regular sail. If we can find a good-sized gas giant somewhere, we can also use the gravity assist to send us in the right direction."

Hitomi spoke up. "And we need to find a planet to land on. So we should be looking for planets now!"

Whips was impressed with his friend's self-control, as Sakura managed to keep a smile on her face at Hitomi's innocent assertion. Whips didn't need to read the datastream from Sakura to know what thoughts were going through her head. There might not be a planet to land on. Probably won't be. Only one of ten stars like this have good planets in the habitable zone—which is a whole ocean of a lot more than they used to think there would be…

Aloud, Laura Kimei said, "Hitomi's completely right. Caroline?"

Caroline looked uncomfortable. Whips knew that she hated doing things halfway, or out of order, or, well, just not the right way—and there was nothing "right" about this situation at all.

But she sat up straighter and nodded. "The most puzzling thing to me is that this star is just not on the charts. I checked with what I had from Earth, and if we did just drop off where I think we did, there aren't any stars where this one sits. Nothing. If there was, the big wide-baseline telescopes in our home system would have mapped any planets in detail, especially habitable ones, even if no one actually went there. But there's nothing. This star shouldn't be here… but it is here, and I guess we should just be grateful it is.

"But that does mean we've got to do all the survey work ourselves, without a single clue as to exactly what we're looking for or where it is." Caroline sighed, pursed her lips, then nodded again. "We'll need to get all our omnis linked in to the different cameras and do running background comparisons. Stars don't seem to move appreciably at orbital speeds, so what we're looking for are dots that move with respect to the background of the stars." She sighed. "If LS-5 were meant for this kind of work, it could run the whole comparison by itself while we slept even without the AI, but it was just meant to follow beacons to orbits and landings and take sights only when it knew pretty well what it was looking for. And when we were looking for a nearby star, well, we were looking at the few very bright stars in the sky. Planets might be pretty dim stars, especially depending on what angle we're viewing them at."

"Can you program the omnis to do the comparison?" Whips asked.

Caroline hesitated, then nodded. "I have a comparison program from my studies, actually. It can be transferred. But…"

"But..?" Laura Kimei prompted.

"But… well, without any benchmarks it's going to be really hard to know what we're looking at. Oh, you can tell the characteristic banding on a gas giant pretty easy, but how do you know if you're seeing one that's closer in or farther away? We don't even know which direction we are going yet."

"Never mind that," Laura said firmly. "First let's find planets. By the time we find some, I'm sure Sakura will have gotten enough data to tell us how fast we're moving with respect to our star and we can really start nailing things down then, right?"

"Yes, mom," Caroline said after another hesitation.

They all acquired the running comparator program a few moments later. "I've picked out some bright stars as landmarks," Sakura said. "LS-5 will use those to keep our orientation the same, so each of us has our own camera to focus on and the view won't shift."

Maybe a silly question, Whips sent to Sakura, but what if you've picked a planet as one of your landmarks?

Oh, come on, Whips, don't you think I thought of that? The transmitted voice came with a grin-symbol, so he knew she wasn't really annoyed. I put full magnification on each one to make sure it didn't change size and got a partial spectrum off each using Melody's program; they're emitters, not reflecting the local sun, so yeah, they're all stars.

Good. He hesitated, then, You know the odds are… not good?

Yeah, she sent back after a few moments. One out of ten chance there's a decent candidate, and then there's the question of the biosphere. She looked at her father, who had subtle frown lines on his normally cheerful face.

He knows—better than anyone else—what those odds are.

They're great odds… if you're not worried that your life's being bet on them, Sakura sent back.

That much was true, he had to concede. Out of all of the extrasolar planets found to harbor significant life, one-half had a biosphere that was, astonishingly, compatible with Earthly (and Europan) lifeforms. Why this was true was a source of spirited, not to say flamingly acrimonious, debate between biologists and allied professions. Some held that it was simply a matter of chemistry. There were only so many easily assembled building blocks of self-replicating chemistry, and the ones that Earth and Europa were based on were some of the most easily synthesized, and so it was just likely that similar lifeforms would evolve. Others had championed the old idea of Arrhenius' "panspermia," that life had evolved somewhere else a long time ago and been spread through the universe by light pressure or similar phenomena. But so far no one had found an unambiguous example of such spaceborne spores.

No matter the actual source, it was true that half the lifebearing planets found had compatible biospheres—although "compatible" did not in any way guarantee it was safe, or even easily digestible. The other half… were not compatible and generally lethal. And vice versa, of course—an animal of those biospheres eating me would likely die in agony.

So… one chance in twenty, then. We beat odds like that all the time in those card games.

Sure, agreed Sakura, darkly. But if we lose this game we won't be starting another.

Little Hitomi grew bored of the comparator fairly quickly and drifted through the air to start climbing on Whips, playing with her stuffed flying wolf along the way. Whips sighed, but tolerated it. He was bigger than everyone else, so she’d bother him less than the others. Besides, there was more of him for her to climb on. He quickly found he could keep her amused by wiggling his rear anchors gently so she had to hold on—and sometimes came off to drift away, so Hitomi had to bounce her way back, giggling.

It was still somewhat distracting, but he was able to focus on the comparator data. The running comparator would flick back and forth between images in the field of view of interest, and kept the original images as the start point while constantly updating the second image with new data. Any planets, then, would show an increasing oscillation as the images flicked between original and new images.

"One here!" crowed Akira suddenly. "Definitely moving back and forth!"

"Wonderful, Dad!" Caroline said. "Show me!" She studied it for a moment. "All right, Sakura, I'll need our full magnification on that location for a minute."

"Hold on… I'll rotate us. Okay, there, we're steady."

The built-in telescopic optics in the forward imaging system gave Caroline a high-quality image to look at. "Ohh, how pretty!" she said a moment later, and projected the picture onto the forward screen for everyone to see.

Whips had to admit it was quite pretty, even to his perceptions, which weren't quite the same as those of his human friends. It was a good thing they had displays which actually emit the intended wavelengths, instead of that old human red-green-blue system; or he’d only be able to make out shapes in those displays.

In the projected image floated a slightly flattened sphere, banded with rippled stripes of startlingly bright colors. Based on what he knew of human perceptions, they ranged from bright red through purple and even some definite green, though he'd use different names for the colors back home. "That seems even more spectacular than Jupiter. What is it with all those colors?"

Caroline shook her head absently. "So many possibilities. Though I looked at the spectrum of the star, and this planet, and I'm pretty sure this system's got more heavy elements in it than ours. So it might be a higher concentration of complex compounds in the atmosphere."

"Well, that's one gas giant," Laura said. "We need to find others, presumably closer to the star. Sakura, have we gotten enough parallax to estimate distance?"

"I think so." His friend stared vacantly into air for a moment, seeing her own display. "Um, yeah. Looks like we're just a hair over one point two AU from the primary, which refines all my other estimates!"

"Where's the Goldilocks Zone?" asked Hitomi, startling them.

"I'll tell you in a second," Caroline said, but Melody, who'd been mostly silent, interjected, "Centered at one hundred thirty-seven million kilometers."

Caroline looked at Melody. "How –"

"Well, I'd brought up the data on calculating it earlier, so I just caught Sakura's data and threw it in."

"So what's the Goldilocks Zone?" asked Hitomi.

"You remember the story of Goldilocks and the Three Bears?" Sakura asked. When Hitomi nodded, Sakura went on, "Well, then, the Goldilocks Zone is the region around the star that's 'just right'—not too close and hot, not too far and cold—for planets like Earth."

"Oh! That makes sense!"

"Sakura, my measurements agree with yours," said Caroline. "If that's the case, then Whips and Mom have the best views of that region, at least where we currently are. But some of the Zone is going to be out of sight or hard to differentiate behind the primary.”

         "Let's allow the system to accumulate more movement," Akira suggested, "and take a break. The bathroom's fortunately able to accommodate a Bemmie, as they made all the shuttles from the same design, so why don't you take a turn if you need it, Whips?"

He had been feeling that need, so he flickered gratitude at the black-haired Akira Kimei. "I will, thank you!"

The others took their turns once he came out, and in the meantime he took a long drink of water and added some salts. He didn't say anything, but he caught Mr. Kimei looking at him with grave concern. Since Laura had the girls helping her to put a dinner together, he drifted over to Akira. "Don't worry, sir."

"It's not terribly dry in here, is it?"

"Not too bad, Mr. Kimei."

Akira Kimei shook his head. "Laura is working out a treatment."

Whips had no doubt that Laura Kimei was trying—and probably would succeed. But… "Sir… Mr. Kimei… if we're out here very long, we're probably not going to live anyway. The fact that I'm drying out… well, I'll stop needing rations –"

"Stop that right now, Harratrer!" The use of his real name made him stiffen, just as he might if his mother were there. "We are all getting out of this, or none of us."

"Sometimes one must leave the Pod for it to survive," he said, quoting one of the oldest rules.

"In this case, if we can't find a world to live on, none of us will. So don't worry about it."

He had to admit that Mr. Kimei had a good point, so he rippled his arms in a "you win" gesture, and went over to see about dinner. He might as well stay as well as he could until they knew if there was hope… or none.