Our long-range scanners just detected this comet entering our solar system. And it appears to be coming straight toward us.
Seven
Okay, Zoe said. Now I understand why you all wanted to get here.
After more than ninety days in transit, Saturn loomed before them in all its majesty. Although still more than four million kilometers away, the ringed planet dominated the view from the cockpit windows. All three astronauts, plus one stowaway, had gathered on the flight deck to take in the breathtaking sight. The mustard-colored planet was immeasurably vast, second only to Jupiter in size. Horizontal bands of yellow and gold marked the passage of cyclonic winds zipping past one another in opposite directions. Saturns winds were believed to be the most ferocious in the solar system, reaching speeds of more than eighteen thousand kilometers per hour, while its fabled rings, which could be subdivided into thousands of smaller ringlets, spread out in concentric circles from the planets equator, not unlike the tattoo at the back of Zoes neck. Shaun wondered if shed had it done for the voyage.
Almost there, Shaun said, proud of their accomplishment. They had passed through the asteroid belt unscathed, bypassed Jupiter and its deadly radiation field, and made it across the solar system to Saturn. They were farther from home than any explorer had ever ventured before any human explorer, that was. Well done, folks.
Yes, OHerlihy said hoarsely, choking up. So much hard work, all our sacrifices yet here we are. We made it.
Shaun patted him on his back. The doc was entitled to get emotional at a moment like this. Its a great feeling, isnt it?
You bet. Fontana high-fived Shaun, wedging her foot into a rail to keep the motion from sending her flying across the deck. Her face was alight with jubilation; she didnt even seem to mind that Zoe was sharing this moment with them. Just look at those rings. Earths got nothing like that.
Zoe tapped away at her smart tablet, recording the moment for posterity. Shaun had returned the device to her after making sure its wireless capacity had been disabled and that it held no terrorist-friendly apps. He suspected that the authorities would confiscate the tablet once she returned to Earth, but in the meantime, it gave her something to do, especially since she wasnt allowed to touch any of the ships computer terminals, not even for recreational purposes. Cabin fever could be dangerous in space, so it had seemed best to keep her occupied.
She looked up from the tablet and squinted at the windows. So, thats the famous hexagon, she said. Freaky.
As it happened, the planet was tilted toward them at about a twenty-six-degree angle, giving them a clear view of its north pole, where a distinctive honeycomb shape contained a colossal storm some forty thousand kilometers across. The hexagon had first been observed by Voyager 1 more than forty years ago, Shaun recalled. Scientists had been arguing about it ever since.
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One of the solar systems odder natural wonders, OHerlihy observed, somewhat less emotionally than before. His deep voice had regained its cool, professorial tone. Quite remarkable.
I dont know, Zoe said. That doesnt look natural at all to me. More like evidence of some arcane alien intelligence.
OHerlihy sighed; he had little patience for speculative pseudo-science. Really, Zoe, youre worse than my students. You need to rely less on the Internet and crackpot theories and more on actual scientific research. He nodded at the view. Although deceptively artificial in appearance, that vortex is nothing but an unusual storm formation created by rotational forces deep within the planets turbulent atmosphere.
Zoe wasnt convinced. But look at it. A perfect geometric figure with six sides of exactly equal length, unchanged for decades? Youre telling me that just happened by accident?
The universe is a big place, Shaun reminded her. Theres time and space enough for all sorts of unlikely occurrences. Anything that can happen probably has.
Like mysterious alien science projects? Zoe said. Who knows? Maybe theres some weird black monolith at the center of the hexagon.
Not on this space odyssey, Shaun said. I dont know about you, but Im not planning to evolve into a higher form of life anytime soon.
Zoe winked at him. Speak for yourself.
Jesus, Fontana said, exasperated. You really dont know when to give up, do you?
Would I be here if I did?
My point exactly.
Shaun intervened before Saturn witnessed its first zero-gravity catfight. In any event, I hope well learn a lot more about that storm, and the rest of Saturns weather patterns, while were in the neighborhood.
The plan was to settle into a polar orbit threading the planets rings and study Saturn and its moons for fourteen days before turning around and heading home. NASA expected them to accumulate enough data to keep scientists back on Earth occupied for years. With any luck, some of the data might actually explain the enigmatic hexagon once and for all.
Indeed, OHerlihy said. Im looking forward to checking out the magnetometer readings on that storm, not to mention getting a close-up look at that comet.
The comet was only a misty smudge in the distance at this point. In theory, it would be joining them any day now.
This is where your work really starts, Shaun said. OHerlihy was the chief scientist on this mission; he would be taking center stage now. Im just glad we got you here in one piece.
I appreciate the smooth ride, Colonel, OHerlihy said. My thanks to you and your esteemed copilot.
Youre welcome, Shaun said. Recommend us to your friends.
Hey, Ive got an idea. Zoe waved her hand in the air to get their attention. How about I take a snapshot of the three of you at this historic moment? Years from now, you can even pretend I wasnt here.
Oh, Im already doing that, Fontana said. Trust me.
Not a bad idea, though, Shaun said. NASA had issued them a couple of digital cameras so they could capture candid moments of life aboard the ship. The public-relations folks intended to get plenty of mileage out of the photos later; there was even talk of a coffee-table book and a calendar. Lets do it.
He retrieved a camera from a supply locker and flew it over to Zoe. There was no need to lob it to her in an arc; momentum carried it across the cabin in a straight line. She snatched it out of the air and backed up to get the three astronauts in her sights.
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Okay, then, she said. All together now, in front of the big pretty planet.
The crew posed in front of the cockpit windows, their feet not touching the floor. They were literally walking on air. Fontana took the center spot, flanked by the two men.
Squeeze together closer, Zoe urged them. Cmon, Skipper, put your arm around Fontana. Dont be shy.
Zoe gave Shaun a puckish smirk. He resisted the urge to glare back at her. That probably wouldnt look good in the photos.
Smiling, he hugged Fontana and felt her own arm slip around his waist. She gave his hand a furtive squeeze and beamed at the camera. OHerlihy leaned in from the other side of her.
Perfect! Zoe decreed. Everybody say hexagon.
Hexagon! they shouted in unison. A flash lit up the flight deck.
As Shaun recalled, they still had one bottle of champagne left.
LIDAR still tracking the comet, OHerlihy reported. Its right on schedule.
Today was Comet Day. The Lewis & Clark had been in a polar orbit around Saturn, perpendicular to the rings, for more than seventy-two hours. That was more than a week by Saturn time, since the planet rotated completely every ten hours or so, giving them numerous chances to observe both its eastern and western hemispheres. They were orbiting the planet at a distance of twenty thousand kilometers, which conveniently allowed them to pass through the Cassini Division without colliding with the rings. The ships hull was tough enough to withstand a few minor impacts, but nobody felt like tempting fate by plowing through the rings themselves.
Today, Saturn was just a backdrop, however. Their agenda was to observe the comet close-up and guide an unmanned probe to take samples of both its icy crust and its inner core. The probe, which had been christened Sacagawea, was already waiting outside the ship to intercept the comet. The goal was to land it on the comets surface so that it could transmit its findings back to the Lewis & Clark. Christopher and Fontana had spent most of yesterday launching it from the ships cargo bay.
Zoe drifted about the flight deck, staying more or less out of the way. The comets not going to hit the rings, is it?
Not a chance, Shaun said from the helm. Its going to swing past Saturn at a distance of about two hundred twenty-five thousand kilometers, well clear of the rings.
Too bad. That would have been quite a show. Zoe floated over to one of the auxiliary consoles, where OHerlihy was directing Sacagawea by remote control. She tapped the scientist on the shoulder. So, Ive been meaning to ask you. Now that were here, whats the story with the rings, anyway? Are they more or less wobbly than you expected?
He looked up from his terminal with a slightly sheepish expression. To be honest, my preliminary observations indicate that the rings do seem to be rather more unstable than originally anticipated.
This was news to Shaun. He had been focused for the last few days on getting the probe launched in time to intercept the comet. He had left the pure scientific research to OHerlihy, on the assumption that it was way too early to draw any definitive conclusions from the data they had just started accumulating. Chances were, scientists would be chewing over the data for years to come.
How unstable, Doc? he asked.
Hard to say, OHerlihy answered. You have to remember, the rings have always been a dynamic system, full of troughs and waves and clumps. Some of the ringlets are even braided together, particularly out by the F Ring. The whole system is constantly in motion. Indeed, theres reason to believe that the rings are a relatively new and temporary phenomenon, that they did not even exist a few hundred million years ago, when the early dinosaurs were first roaming the Earth, and that they may be gone for good millions of years from now.
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And yet? Shaun prompted him.
Well, Im hesitant to jump to any rash conclusions without further evidence
Shaun grew impatient. Enough with the obligatory disclaimers, Doc. I dont want to wait for the peer-reviewed version. Cut to the chase.
All right, the scientist said reluctantly, but bear in mind that this is just off the cuff. I still need to collect more evidence and conduct a more detailed analysis.
Understood. But?
The rings appear to be collapsing inward at a steadily increasing rate. Debris from the outer rings is spiraling into the inner ones, whose orbits are gradually shrinking as well. The divisions between the rings are also narrowing, causing discrete rings to blur together much more than usual.
Shaun wondered what this meant for their mission. Is there any danger to the ship?
I shouldnt think so. The ring matter is falling inward, toward the planet, not aiming at us, although Im at a loss regarding what might be causing this or why it is happening now. Frankly, its quite unexpected and more than a little baffling.
Told you. Zoe gloated. I knew there was more to that rings angle than you wanted to admit earlier. She did a celebratory somersault in midair. So, who is the crackpot conspiracy theorist now?
Watch your mouth, brat, Fontana snarled from the copilots seat. Thats a future Nobel Prize winner youre talking to.
Its all right, Alice, OHerlihy said. Our guest has reason to feel vindicated to a degree. These findings are a humbling reminder that we are in unknown territory out here and that the universe can still surprise us.
Ordinarily, the scientist would have chided Zoe for letting her imagination run wild, but his response struck Shaun as uncharacteristically muted. He found that vaguely worrisome. When somebody like Marcus gave ground to Zoe, things were seriously out of whack.
Still, OHerlihy continued, Im sure its just a temporary aberration, caused by the approach of the comet or some other factor. Its bound to correct itself in time.
Oh, yeah. Zoe challenged him. Thats what they used to say about global warming. Tell that to the ice caps or whats left of them.
Shaun scowled. Despite the scientists provisos, this sounded like something he needed to stay on top of. I want daily reports on those rings from now on. Let me know if you think theres even a chance that we might need to adjust our orbit to put more distance between ourselves and the rings.
Their mission had been plotted and predicated on the fact that Saturn would act like Saturn, and so would its rings. He recalled OHerlihys earlier description, months ago, of the rings as roiling rivers, complete with dangerous currents, eddies, and other hazards. Granted, the rings were only about half a kilometer thick on average, and the Lewis & Clark had been built to withstand random micrometeoroid strikes, but Shaun was in no hurry to ride the rapids.
Will do, OHerlihy assured him. But Im sure its nothing to worry about.
I like hearing you say that, Doc. Shaun turned his attention back to the days agenda. Lets just hope our cometary friend doesnt surprise us, too.
Shh! Zoe held a finger to her lips. Dont jinx us.
Says the jinx herself, Fontana muttered. She kept her eye on the view out the cockpit windows. And they used to say comets were bad luck
The comet, designated C/2018-G2, had been visible for days as a faint white smudge in the distance, but it was growing clearer as it approached them. This far out from the sun, the comet had not melted enough to give it a truly impressive tail, yet it was already recognizable as a comet. A cloud of dusty vapor, known as the coma, formed an atmosphere around the comets nucleus, while a misty white stream trailed behind it, pointing away from the sun, whose solar winds created the tail by blowing the ionized comet material away from it. C/2018 was extremely small by cometary standards, its nucleus barely more than a hundred meters across, yet its tail already stretched for thousands of kilometers. The comets path was not expected to bring it anywhere near Earth, so this was their best chance to get a good look at it.
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Like most comets, it was probably just a large, dirty snowball from the outer reaches of the solar system, but who knew where exactly C/2018 had been and what secrets it might hold? Past comets had been found to contain complex organic compounds, including amino acids. Nobody had discovered life on a comet yet, but the possibility was there. If nothing else, Sacagawea might provide clues to determine whether C/2018 was from the Kuiper Belt, the Oort Cloud, or someplace farther out in space. It might even prove to be that rare comet that was just passing through the solar system on its way out to interstellar space. If it was on a truly hyperbolic orbit, it might never pass this way again.
All the more reason to check it out when we can, Shaun thought. You set, Doc?
Sacagawea is in position, OHerlihy reported. No orbital adjustments appear to be needed at this time. It should intercept C/2018 in approximately eighty-five minutes. We can initiate landing procedures then, assuming that what the devil?
Before their eyes, the comet suddenly veered to the left.
Crap! Fontana exclaimed. Is it supposed to be able to do that?
No! OHerlihy frantically worked the LIDAR controls, trying to keep it locked on the detouring comet. It was following a standard elliptical orbit, more or less. This should not be happening!
Zoe flew toward the windows for a better look. She typed more notes into her tablet, then held it up to take a picture. Holy cow. This trip is getting better and better.
Shaun was glad somebody felt that way. For himself, he was getting tired of the impossible biting them in the butt. Talk to me, Doc. What the hell is that thing doing?
Its changing course, away from Sacagawea, and slowing down. The shocked scientist stared at his monitors. Its heading in toward the planet, avoiding the rings. He shook his head, looking even more flabbergasted than when he had detected the stowaway aboard. Awe reduced his voice to a whisper. Its not behaving like a proper comet at all, more like
A UFO? Zoe winked at Shaun. What do you think, Skipper? Friends of your dad?
Fontana look askance at Shaun. You told her about that? She knew what Zoe was referring to, of course. Shaun had shared that colorful bit of family history with Fontana back when they were dating. Dont be ridiculous, the copilot snapped at Zoe. There must be a sensible explanation for this.
Like what? Zoe asked.
Fontana groped for a response. Maybe the same thing thats affecting the rings?
Whatever that is, Shaun thought, scowling. He wanted answers, not more mysteries. Where is it heading, Doc?
It seems to be heading for the north pole of the planet.
You mean the hexagon, Zoe said.
Possibly, OHerlihy admitted, with a distinctly pained expression. At least, that general vicinity.
Zoe let go of her tablet, which remained floating within reach, and rubbed her hands together gleefully. The plot thickens.
Tell me about it, Shaun said. Their carefully planned operation, meticulously worked out by NASA and its international partners, had just gone out the proverbial window. Sacagawea, waiting in orbit for its celestial rendezvous, had been stood up. C/2018 had ditched them, almost as though it was on a mission of its own. Careful, he warned himself, youre starting to think like Zoe.
But maybe that wasnt entirely a bad idea. Their mission had just gotten a whole lot stranger and more exciting. Perhaps it was time to start thinking outside the box.
Set a course for the north pole, he instructed. Were going after that comet.
Fontana stared at him as if he had lost his mind. But thats not part of the mission plan.
He couldnt blame her for being startled. NASA flights were not improvised. Every task and maneuver had been plotted out months, if not years, in advance, especially where dangerous new objectives were concerned. Hell, there had been ten trial runs before Apollo 11 had finally touched down on the moon. Space was no place to fly by the seat of your pants except when something truly unpredictable happened.
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Screw the mission plan. He switched off the automatic pilot. Were not robots, following a programmed script. Whats the point of sending actual flesh-and-blood humans into space if we cant react to unexpected circumstances and take advantage of amazing new opportunities?
Woo-hoo! Zoe cheered him on. You tell em, Skipper.
Hush! Fontana said. The grown-ups are talking. She gave him a worried look. I dont know, Shaun. Maybe we should run this by Mission Control first.
Theres no time for that, Shaun said. Radio waves traveled at the speed of light through the vacuum of space, but there was still more than an hours time lag when it came to communicating with Earth, and that wasnt even figuring in the bureaucracy factor. That comet or whatever it is is going somewhere. I dont want it to get away while theyre holding conferences back home. He looked her in the eyes, struck as always by their brilliant green depths. I dont know about you, Alice, but I want to know what that so-called comet is.
You think I dont? She searched his face. You really think this might be a UFO, Shaun?
To be honest, I dont know what to think. He toyed with the dog tags around his neck. Like the doc said, were in unknown territory here.
Well, thats the job description, isnt it? Fontana sighed and settled back into her seat. He recognized the determined set of her jaw. All right. Lets go find out whats driving that puppy.
Shaun turned toward OHerlihy. This decision could have an enormous, and possibly catastrophic, effect on their careers. They could even be risking their lives. He needed to make sure his whole crew was okay with it. Marcus?
Youre in charge of this mission, Colonel. Its your call. The scientists gaze remained glued to his monitors. But personally, I would never forgive myself if we didnt at least try to solve this mystery.
Shaun felt the same way. Okay, its decided, then. He had never been more proud of his crew. Keep the LIDAR locked on that comet. Track its every move.
I wouldnt dream of doing anything else.
Zoe waved her hand in the air. Hey, dont I get a vote?
No, Fontana said in no uncertain terms.
Fair enough, Zoe said with a shrug. Although, just for the record, I think you folks are acting like real starship heroes.
Fontana rolled her eyes. Why dont I find that reassuring?
It took several minutes to calculate an intercept course based on the comets current trajectory. They would have to leave Sacagawea behind. The probes thrusters had been intended for only minor course corrections; they lacked the power for this sort of chase. Shaun would have to be careful not to expend too much of the Lewis & Clark s own engine power on this unplanned expedition. Mission Control would have a cow when they found out about it.
It will be worth it, Shaun thought, if we can make contact with a genuine UFO.
Everybody strap yourself in, he advised the crew and the stowaway. Zoe took a seat at the computer station next to OHerlihy. She tapped out a few last notes on her tablet before stowing it away for safekeeping. Were hitting the gas.
Tally-ho, Fontana said drily.
Shaun fired up the thrusters and initiated a controlled burn to accelerate the ship in the direction of the probe. The nose of the command module tilted as he altered the angle of their orbit to bring them into the same plane as their quarry. The Lewis & Clark climbed toward Saturns north pole. The planets axial tilt worked in their favor, as did the fact that Saturn was somewhat squashed in shape, being wider around the middle than from top to bottom, but because of the sheer size of the gas giant, it still took two-plus hours before they finally found themselves gazing down at the top of the planet.
Whoa! Zoe exclaimed. What happened to the hexagon?
Shaun was wondering the same thing. The celebrated six-sided vortex, which had been unchanged for decades, was visibly diminished. Its borders had contracted, so that it appeared to have shrunk in size by at least a third, and its color had faded, too, making it somewhat harder to make out against the planets turbulent yellow atmosphere. It almost looked as though the vortex was gradually shrinking away.
But was that even possible?
Marcus?
I see it, OHerlihy replied tersely. And no, our eyes are not deceiving us. The vortex has noticeably decreased in both size and intensity, almost thirty-two percent since the last time we analyzed it.
Why didnt we notice this before? Shaun asked.
OHerlihy shrugged. We werent looking for it, and theres been a lot of Saturn, including its various rings and moons. Plus, it appears that the rate of the shrinkage has increased exponentially with the approach of the comet.
Shaun didnt like this. The hexagon, the rings, the comet nothing was acting as it was supposed to. He supposed it could be seen as a lucky break that the Lewis & Clark had arrived in time to witness these astounding developments, but it didnt feel that way. He was starting to wish they had gone to Mars instead.
What about the comet? Fontana asked. Where is it now?
OHerlihy consulted the LIDAR. Oh, my God. Youre not going to believe this.
At this point, Shaun was ready to accept just about anything short of a flock of winged unicorns. Try me.
Its come to a dead stop nine hundred kilometers above the planets north pole. Zoe started to open her mouth, but OHerlihy beat her to the punch. Yes, directly above the hexagon.
I dont understand, Fontana said. How does a comet come to a stop?
You tell me, the scientist said, sounding somewhat overwhelmed by the unexplainable phenomena he had been confronted with recently. But the comet is definitely parked in a stationary position above the pole. Not an easy feat to pull off, by the way, even for a satellite.
Shaun knew what he meant. Geosynchronous orbits were easier to maintain above a planets equator, where the satellites orbit could be matched to the planets rotation. A satellite would have to be able to modify its orbit continuously to hover in place above the pole. Back on Earth, solar sails had been employed to attempt this, with mixed results. Shaun had no idea how a comet could do it unless it wasnt really a comet.
Im bringing us in closer, he said. I want to see that thing with my own eyes.
Operating the thrusters manually, he cruised a kilometer above the comet. Because the ship was in an inverted position, with its belly facing away from the planet, they were able to gaze up at the comet as it hovered hundreds of kilometers above the anemic hexagon.
C/2018 floated like a hot-air balloon beneath them. To Shauns surprise, it was glowing much more brightly than before. Its misty coma expanded as jets of vapor steamed off the comets frozen nucleus, which appeared to be dissolving before their eyes.
Huh? Zoe said. Is it supposed to be doing that?
No, OHerlihy said, sounding torn between dismay and wonder. Not this far out from the sun. Granted, Saturn also radiates its own heat but not enough to melt a comet like that!
Shaun stared at the comet, which was shrinking like an ice cube on a hot summer day. Its icy core seemed to be subliming directly from solid to gas, skipping the liquid state. Billowing clouds of vapor poured off the nucleus. Solar winds blew the gas back into the comets tail, which was wrapping around the planet below before dissipating into the vacuum. He had never seen anything like it.
Whats happening, Doc?
Give me a second! the harried scientist replied. He recalibrated their equipment, directing all of their sensory apparatus, including the trans-spectral imager, at the fuming comet. Im at my wits end here. None of this makes any sense!
Join the club, Shaun thought. Hed had more jolts on this voyage than in the rest of his NASA career combined, up to and including the disappearance of the DY-100. Hold it together, Marcus. Just think of all the history were making. Were discovering stuff that nobody ever dreamed of before.
Thats one way to look at it, Fontana said. She snuck her hand across the helm to squeeze his. Count on you to see the upside.
He smiled back at her. Astronauts have to be optimists. Who else would blast themselves into space?
As long as we keep one foot on the ground, she said. Figuratively speaking.
You do a pretty good job of that. Thats why we make such a good team.
Was that a hint of a blush on her cheeks? Nice of you to say so, she said, but if we get abducted by aliens, its all your fault.
She said it lightly, but Shaun knew she was right. If there was some extraterrestrial intelligence directing C/2018, there was no way of telling how it might react to their presence. There was no guarantee that first contacts had to be peaceful. Just ask H. G. Wells, he thought. Or Montezuma.
Steam continued to pour off the comet, which had already shed most of its mass, so that it was now smaller than the Lewis & Clark. A bright blue glow emanated from the nucleus, visible even through the thick clouds of vapor surrounding the core. The comets tail extended beyond the curve of Saturn, almost like another ring.
Curiouser and curiouser, Zoe murmured. She grinned like the Cheshire Cat.
Shaun watched as the comet dissolved into mist. What was causing it to sublime like that? Surely not the heat of the planet.
Marcus?
Its heating up from within, the scientist reported, as though theres some sort of internal heat source beneath the ice.
Zoe stared at him. You mean, its defrosting itself?
That would be one interpretation, OHerlihy conceded. Although I probably would have phrased it differently.
Thats why Im a journalist and youre an academic. She peered at what remained of the comet. What do you think is under all that ice and fog?
