Arrival: Chapter 13

  Hello, Sadhika.  If you’re listening to this, a lot has had to go right already, and we’re both very lucky.   I don’t really know what to say… I can’t imagine what questions you might have, either very few or… or far too many to count I would imagine.

  You are there for only one reason: because I can’t be.  Don’t believe the story about needing any of you for the first descent team; there were other ways.  I would have given anything to be there instead of you, but instead I gave everything I had in my life to make sure that you could be there, instead of me.   You are not me though, you can never be me, and I can never see what you see… and that makes me sad.  It makes me happier though to know that you’ll be there, seeing and experiencing things for me.

  I want to make it clear that you don’t owe me anything, and I’m not going to lay a bunch of burdens on you as your creator.  You were programmed to be as faithful a simulation of me as possible; I told your programmers things about myself that I never told another living soul, and they were the best simulators in the whole system.  You are not me, but you are nonetheless a version of me, a new version of me… a new iteration of us.  The way I see it you and I are now joint owners of a shared Sadhika identity.   

  Follow your instincts, for they are my instincts.  Follow your heart, for it is my heart.  Live for us, and experience this world and adventure for the both of us.   Be significant Sadhika, be extraordinary… outshine my star.

   

  The sun had gone down.  It was their first night on the strange alien world, which was in some ways strangely familiar.  The last vestiges of light had only recently evaporated and their new starscape was now in its full glory.  Sadhika Sengupta, or at least whatever was left of her, was lying on her back on the shuttle runway some distance from the shuttle and the First Descent Module.   She was processing, reflecting on the day that had been, a day so long in the making…  

  She pushed closed the scroll on which she’d been watching the message left to her by her originator.  Her eyes were teared up; she’d found the messaged deeply emotionally moving.  It was a message left for her by a long dead figure who was something much more profound and intimate to her than any parent could possibly be.  

  She felt a tinge of sadness for the woman; the original Sadhika couldn’t be here to enjoy all of the benefits of all of her own hard work.  She found herself likewise comforted though, that she could in a way experience and enjoy it for her.  That’s why she, her simulant, was really here in the first place.  Her role, she now understood, was to experience this great moment in human history on behalf of her human progenitor.  She was her witness.

  “Would you look at that…” Neil said in wonderment, nearly tripping over Sadhika as he approached her with an undeviating absorption with the sky above him.   “It’s so…”

  “Alien.” Sadhika offered.  Neil only nodded in agreement, and then got down to join her on the ground.  He put his head down right beside hers but in the inverted orientation, with his feet out in the opposite direction from her own.

  “I’ve spent my whole life looking up… I’ve practically memorized Earth’s night sky, now I have to start all over again… what a treat!”

  “What do you see?” Sadhika asked.

  “Oh a jumble… I usually orient based on constellations, but… for now it’s still just a jumble of stars.”

  “Well we’ll have to invent some then… there,” she pointed to the south east, about halfway between the horizon and zenith.  There’s four stars that seem to roughly form an upright ellipse, with a bright star ahead of it, and two fairly bright ones trailing it?  It’s the New Horizon…”

  “Alright, alright… and see there,” Neil pointed to the north, closer to the zenith, “there’s four stars that make kind of a box, and a few stars you could call its legs, and two bright stars forming a horn, it’s that big beast we saw in the jungle today!”

  Sadhika laughed.  This was fun.   “Hmm… and look there,” she pointed straight up, “just off the zenith, four particularly bright stars just hanging out together…”

  “What about em?” 

  “They’re us… they’re the simulants,” she answered, turning her head over to look at him.

  “I like it,” he answered without removing his gaze from the sky.

  For several minutes the two fell into silence, lost in their respective thoughts and the endlessly fascinating starscape.  On Earth light pollution always interfered with this kind of viewing of the night sky unless one got far enough away from the lights of civilization.  Here however, there were no artificial lights whatsoever, and no moon.  It was an amazingly deep dark which allowed an amazingly bright and detailed view of the celestial sphere.

  “Have you checked on the shuttle?” Sadhika finally broke the silence to ask.

  “Yup,” he answered, “On my way over.  The fuel tanks are almost at sixty percent already, so… we should be ready to leave by morning.”

  Sadhika chuckled and feigned a whine in her voice.  “Aww, but we just got here!”

  Neil smiled in the dark.  “Were you able to do some more detailed research on those samples we got?”

  “Yes,” she answered.  “We’ll need to analyze them with the ship’s equipment to be able to do it properly, but the FDMs equipment was able to code the DNA of all of the samples we obtained.”

  “And?”

  “Well first of all, it’s a phenomenal discovery in and of itself to find that they operate on something we recognize as DNA at all!  Let’s not let that get old!  Beyond that though, it only gets more interesting.  Like I said earlier today, they use two DNA base pairs of the four we use but also use two different ones that we don’t.  That means that we share no genes at all with life on this planet.”

  “They, not we,” Neil corrected her.

  “Whatever,” she said irritatedly.

  “Sorry, go on.”

  “Humans, share more genetic material with other Earth organism the closer they’re related to them in an evolutionary sense, but there’s a basic amount of genes shared by all life on Earth.  They share something like seven percent DNA with bacteria, it’s the most basic and fundamental stuff like ‘how to make and use DNA in the first place’ and ‘how to make a cell,’ and it’s all based on the same four DNA base pair tools.  Since life here has a different set of building blocks, there’s not one iota of overlap between life on Earth and life here.  However, there is the same genetic overlap with the life I’ve analyzed here as there is with all life on Earth.  There’s something like twenty-six percent genetic overlap between the insect we caught and the tree squid thing, eighteen percent between the insect and the plant I plucked a leaf off of.”

  “Especially given that,” Neil commented, “I find it odd that they’re somewhat familiar looking animals at all…  I always figured that people who thought that alien life would resemble Earth life in any way whatsoever just suffered from a lack of imagination and after-the-fact explaining.  Why still four limbs instead of six or eight, aren’t more better?  Why still body plans and classes of life that we understand or recognize at all?”

  “Convergence… evolution is essentially an exercise in engineering.  Under radically different conditions of gravity or atmosphere I too would expect to see much more exotic life, but conditions here are so similar to those on Earth that I would expect to find a lot of similar solutions to similar problems.  I mean, even on Earth things like flight and eyes, evolved independently a remarkable number of times.  The problems were the same, the limitations and available solutions were the same, so the end product solutions were remarkably similar.  To see light on Earth, you need some sort of eye within a certain range of parameters.  Likewise to fly through Earth’s atmosphere you need wings, again within a certain restricted range of required mechanical parameters.

  “Same thing goes for limbs.  In a higher gravity environment, six legs might make sense for a slow moving animal that can just barely make it to its feet in any case, but in this kind of gravity environment four seems to simply be ideal if you’re not built to stand on two.   Animals on Earth don’t have four limbs just because that’s just the way life is on Earth, they tend to have four because evolution has determined that to be most efficient given the surface conditions that exist on Earth.   Nothing is wasted in evolution and nothing is superfluous.  Each limb we have represents tremendous resources to grow, and tremendous risk of getting damaged.  A deep wound, a broken bone, or a mangled joint on an animal’s limb usually means certain death.  The more limbs you have, the more opportunities there are for that sort of thing.   I guess what I’m saying is… there’s nothing for animal life to gain by having more than four limbs which would offset the inherent costs and risks of just having them in the first place.  I mean, you certainly couldn’t run any faster on six legs than you could on four, they’d just get in each other’s way.”

  “But that’s not necessarily accurate,” Neil retorted a little defensively.  “I mean, all the four limbed animals you describe, could easily just have only four because they originally evolved from a tetrapod in the first place, and it would have been too radical a change for evolution to allow the addition of extra limbs along the way.  Besides, there’s certainly life on Earth with more than four limbs, arachnids have eight legs for example… arthropods can have a whole whack of legs!” 

  “You’re right,” she answered, “but I think your point about the arthropods serves my argument more than yours.  If they could evolve any number of extra limbs, then why couldn’t tetrapods?”

  “Oh come on, arthropods can do it because they’re segmented, they can evolve by just adding new discrete segments to their bodies which have legs or don’t.   Tetrapods are more holistic though, they can’t just develop a whole new segment to their body when their environment calls for it.”

  “True, but I still think that if there had been any significant advantage to more than four limbs that outweighed the inherent risks and costs, a new superclass of hexapods could have come along and supplanted the tetrapods or co-existed on the planet with them.  If there was a significant advantage to extra limbs I’m sure… I’m sure life would have found a way.”

  “Hmm… well, I’m skeptical that new limbs could just evolve on the fly without any architectural antecedent.  It just doesn’t work that way.  There’d need to be a whole other class of animals developing from a simple form, like a… like a six finned fish or something…”

  “You’re right of course, but what I’m saying, is that if there was a significant advantage to six or more legs, that simple form would have established itself, developed, and soon supplanted the four leggers.   Evolution… has a sort of gravity; similar challenges engender similar solutions over and over and over again in evolutionary history.  Need to see?   You build an eye.  Need to fly?  You build wings.  Need to get around efficiently on land as an animal of significant size in one gee?   Use two or four legs depending on your size and mobility requirements…”

  “But even if you’re right that four legs is just the most efficient for running or whatever, why not… why not four legs and two arms then?”

  “What?   You mean like, like a centaur?”

  “Sure!   Why not!?”

  Sadhika just started laughing.  “I don’t know Neil, why not indeed…  I was just suggesting that there are certain solutions that evolutionarily speaking are ‘fallen’ into once you’re in the neighborhood.  A rhinoceros can’t just grow wings and fly, its way out of range, but a rodent?  If you’re already pretty small and light?  Well maybe you can slowly develop some webbing between your arms and legs, and maybe the more you have, the further you can glide and the better your odds of survival and passing on that trait to your offspring and having them survive.  Enough generations later you might just get it over with and become a bat.   Once you’re in range of that evolutionary gravitational well, it’s pretty easy to fall into it.”

  “But I think that’s what I’m getting at.  The more developed a tetrapod’s four limbs, the harder it would be for it to develop a sixth out of nowhere.  To put it your way, they started out well outside of the hexapod gravitational well, and only moved further and further away from it.”

  “Fair enough.”

  The two resumed soaking up the sights of the night sky.  Then, Neil pointed to a small point of light which appeared to be slowly moving against the background, and somewhat low towards the southern horizon.   “Look,” he said as he pointed.   “See that one that’s slowly moving?   That’s the ship.  Our satellites wouldn’t reflect that much light.”

  Sadhika put on her PANEs and put in a call up to the ship.  “I should share what I’ve learned with Blair too.”  When the woman on the ship answered, her image was three dimensional since she was projected onto both interior screens of Sadhika’s PANEs.

  “Hello Sadhika, enjoying yourself?”

  “Oh you have no idea... did you get my initial report?”

  “Yes indeed, actually I’ve been pouring over it.  I was particularly interested in your discovery that one of the sets of base pairs are different from those on Earth.”

  “Yeah, I guess we just struck another blow against the anthropocentric perspective, didn’t we?”

  “How’s that?” Neil asked.  Sadhika had relayed Blair’s voice to the external speakers on the PANEs so that Neil could hear the conversation.

  “Well, astrobiologists have always wondered if there was some mechanism which allowed panspermia, the seeding of life from one planet to the next, and the next and the next.   We wondered if life maybe only had one common source and was then seeded from one planet to the next over the eons.   If this was the case though, the DNA should have had the same base pairs in use.  The fact that life here uses different base pairs suggests that life evolved here completely independently of life on Earth.”
 “I see,” Neil considered.  “And that means that life is relatively easy to get started without any outside help, which means… that it is likely to be much more common in the cosmos than it would be if either Haven or Earth had seeded the other.”

  “Or were both seeded by a third source,” Blair added.  “It also specifically suggests most importantly I think, that cellular life is easier to evolve from scratch than we though.  The idea of panspermia was so appealing because once you’ve got a few cells landing on a planet, the rest is relatively easy.  Getting a functioning cell out of random biochemistry is really by far the hard part, and now we can prove it happened twice independently in relatively close cosmic proximity.  That’s huge!  And since animal life is relatively easy once you have cellular life, and intelligent life can only happen once there’s animal life…”

  “We’re really filling in that Drake equation now, aren’t we…” Neil observed.

  “Well today alone we’ve certainly really narrowed the error bars, that’s for sure,” Sadhika agreed.

  “I really can’t wait to get your samples back to the ship and run full cellular analyses on them,” Blair enthusiastically remarked.  “I’m intensely curious about the similarities and differences in the cellular physiology.”

  “Oh me too, believe me!” Sadhika affirmed with equally growing excitement at all the work still to be done.

  “Speaking of which,” Blair said, “how does the biological environment down there look?   Does it seem safe for us to come down?”

  “Well, between the shuttle’s bio-filters and the air samples Wiremu took, nothing has been recognized as necessarily dangerous to humans.  But of course it can only recognize what it knows to look for, so there’s no way to eliminate the risk altogether.  We’ll only know for sure when the first human landing crew actually walks around down here and breathes the air and whatnot.”

  “Well I’ll be among the first crew down Sadhika.  I’m betting my life on my belief that the physiology of life down there is just too different for us to be infected or otherwise seriously harmed by anything down there.  At least by anything microscopic… I saw the video you sent us of that horned animal you came across in the jungle, talk about the stuff of nightmares…”

  “Looked like good eats to me,” Neil commented with a grin.  Blair responded on Sadhika’s screens with a look which was a mixture of confusion and revulsion. 

  “You must be really looking forward to coming down tomorrow,” Sadhika commented, trying to put herself in Blair’s position.  

  “What, are you kidding?  I’ve literally been preparing for it my entire life.”

  “Understood.”   Sadhika knew something of singular existential purpose.  “Try to get some rest then, I have a feeling you’ll need it.”

  “Goodnight, Sadhika.” Blair said warmly.  “You too Neil.”

  “Goodnight.”   She took off her PANEs and rested them on her chest.  Her mind was swimming with thoughts, her mind constantly switching focus between the day’s events and discoveries, questions and thoughts about the nature of her existence, her role in the whole mission, and the part she was meant to play.

  “Yup,” Neil said, lost in his own thoughts.  “Quite a day…”