Incandescence

«Are you a child of DNA?»

Rakesh was affronted; if he'd considered this to be information that any stranger wandering by had a right to know, it would have been included in his précis. After a moment's reflection, though, his indignation gave way to curiosity. The stranger was either being deliberately offensive, or had a very good reason for asking. Either way, this was the most interesting thing that had happened to him all day.

«Why do you wish to know?» he replied. The stranger's own précis contained extensive details of its ancestry and sensory modalities, but Rakesh wasn't in the mood to acquire the necessary skills to apprehend it on its own terms. By default, he was already perceiving it as human-shaped, and hearing it speak in his own native tongue. Now, in place of its declared chemosensory label, he assigned it a simple phonetic name chosen at random: Lahl.

Before Lahl could reply, Viya had risen to her feet beside Rakesh and gestured toward an empty spot on the annular bench that surrounded their table. «Please join us,» she said.

Lahl nodded graciously. «Thank you.» Lahl's actual gender didn't map on to Rakesh's language neatly, but the arbitrary name he'd given her was grammatically female. She sat between the other two members of the group, Parantham and Csi, facing Rakesh squarely. Behind her in the distance, water cascaded down a jagged rocky slope, sending a mist of fine droplets raining down on to the forest below.

«I couldn't help overhearing your complaint,» Lahl said. «'Everything has been done. Everything has been discovered.'» To Rakesh, they were seated in the open air, near the edge of a mesa that rose above the treetops of a vast jungle. The murmur of multilingual conversation from the tables around them might have been the sound of insects, if it had not been for the occasional translated phrase that Rakesh allowed himself to hear at random, in case anything piqued his interest. Perhaps to Lahl his words had come across as a distinctive aroma, standing out from a jumble of background odors.

Csi spread his hands in a gesture of apology to this stranger unfamiliar with their customs. «That's just Rakesh's way of talking,» he confided. «You should pay him no attention. We get the same speech every day.»

«Which makes it no less true,» Rakesh protested. «Our ancestors have sucked the Milky Way dry. We were born too late; there's nothing left for us.»

«Only several billion other galaxies,» Parantham observed mildly. She smiled; her position on this subject had barely shifted since Rakesh had met her, but for her it was still a worthwhile debate, not the empty ritual it had become for Csi.

«Containing what?» Rakesh countered. «Probably more or less the same kinds of worlds and civilizations as our own. Probably nothing that would not be a hideous anticlimax, after traveling such a distance.» A few thousand intrepid fools had, in fact, set out for Andromeda, with no guarantee that the spore packages they'd sent in advance would survive the two-million-light-year journey and construct receivers for them.

Rakesh turned to Lahl. «I'm sorry, we keep interrupting you. But what exactly does my molecular ancestry have to do with this?»

«I could be mistaken,» Lahl said, «but it might have some bearing on whether or not I can offer you a cure for your malaise.»

Rakesh hesitated, then took the bait. «I do come from DNA,» he said. «But I warn you, I think that's a strange way to pigeonhole people.» His human ancestors had fashioned descendants in their own image — who in turn were largely content to do the same — but membership of the broader DNA panspermia implied no particular cultural traits. Entirely different replicators had given rise to creatures more similar to humans, in temperament and values, than any of their molecular cousins.

Lahl said, «I don't mean to judge you by your ancestry, but in my experience even molecular kinship can sometimes lead to a sense of affinity that would otherwise be lacking. The DNA panspermia has been extensively studied; every world it reached was thought to have been identified long ago. Adding the first new entry to that catalog in almost a million years might well hold more interest for you than it does for me.»

Rakesh smiled uncertainly. This was not exactly the kind of momentous discovery that people had made in the Age of Exploration, but in his blackest hours he had often imagined contributing far less to the sum of knowledge than this modest footnote.

It was a pity he'd been beaten to it. «If you've found such a world,» he said, «then you're the one who has extended the list.»

Lahl shook her head. «Strictly speaking, the crucial evidence was obtained by a third party, but that's not the point. We can quibble all day about the formal attributions, but at present only a fragment of the story is known. Almost everything about this world remains to be discovered, and until someone is willing to pursue the matter vigorously, the few scraps of information I'm carrying will mean very little.»

Viya said, «So you're here to trade what you do know?»

«Trade?» Lahl appeared startled. «No. I'm merely hoping to find someone who can do justice to this, since I don't have the time or inclination myself.»

Rakesh was beginning to feel as if he was being prodded awake from a stupefying dream that had gone on so long he'd stopped believing that it could ever end. He'd come to this node, this crossroads, in the hope of encountering exactly this kind of traveler, but in ninety-six years he'd learned nothing from the people passing through that he could not have heard on his home world. He'd made friends among the other node-dawdlers, and they passed the time together pleasantly enough, but his old, naive fantasy of colliding with a stranger bearing a surfeit of mysteries — a weary explorer announcing, «I've seen enough for one lifetime, but here, take this crumb from my pocket» — had been buried long ago.

Now that it was being resurrected before his eyes, he felt more wary than excited. He addressed Lahl respectfully, but chose his words with care. «I can't promise you anything, but if you have the time to tell us what you've learned, I'd be honored.»

Lahl explained that she belonged to a synchronization clan. Its members roamed the galaxy, traveling alone, but had agreed to remain in contact by meeting regularly at prearranged locations, and doing their best to experience similar periods of subjective time between these reunions. She was on her way to the next such event, in a planetary system twelve hundred light years outward from this node. Given that the meetings took place just once every hundred millennia, travel plans could be made well in advance, and there was no excuse for tardiness.

However, for reasons she did not wish to detail, when the time had come to begin the journey Lahl had found herself on the wrong side of the galaxy, with no prospect of fulfilling her appointment by any conventional means. The communications network run by the Amalgam skirted the crowded sphere of stars that formed a bulge at the center of the galactic disk, adding several thousand lightyears to the journey compared to the straight-line distance. So she had weighed her options, and her sense of obligation, and placed her fate in the hands of the Aloof.

Viya gazed at her wonderingly. «You've been through their network?»

«Yes.»

«You would have been encrypted, though?»

«That's the usual practice,» Lahl said. «But I came at a bad time. There'd been an unexpected surge in traffic a few decades before, and there were no encryption keys available for my destination. Keys have to be distributed the long way around; shortages can take centuries to fill. So I had no choice. I traveled in plain sight.»

«Yet you emerged unscathed?»

«I believe I'm intact,» Lahl replied. She added mischievously, «Though I would think that, wouldn't I?»

Three hundred millennia ago, certain brash citizens of the Amalgam had studied the Aloof's data traffic, deciphered its basic protocols, and constructed links between the two networks. This unilateral act of bridge-building had apparently been tolerated by the Aloof, albeit with only a trickle of data passing through, since few people were willing to trust the short cut. The Amalgam had tried many times to extend its own physical infrastructure into the same territory, but the Aloof had calmly and methodically reversed the trajectory of every spore.

Csi said, «I think I would have arranged for a suitably located backup to wake, and attend the reunion on my behalf instead.»

«That would have been grossly discourteous,» Lahl explained. «And to have the slightest chance of pulling it off, I would have needed to start planning about sixty millennia ago. If I'd had that much foresight, I would never have ended up cutting things so fine in the first place.»

The table fell silent as the four of them contemplated the risk she'd taken. The Aloof had never been known to act maliciously — even the insentient engineering spores they'd swatted back out of the bulge had been left unharmed — but their stubborn refusal to communicate gave them an aura, if not of danger, at the very least of unaccountability. Worse, the part of their network accessible to the Amalgam did not carry quantum data, so the Amalgam's standard protocols — which rendered it physically impossible for an eavesdropper to decipher a transmission, or to alter it without detection — could not be employed. That problem had been addressed, in part, by distributing matched pairs of quantum keys around the edge of the bulge via the Amalgam's own network, creating stockpiles that could be used to encrypt the classical data of travelers taking the short cut. If demand for the keys outstripped supply, though, it could take a while for the stockpiles to be replenished.

Rakesh said, «The explorer you mentioned: did she take the same route? Is that how you met?»

«Explorer?»

«Didn't you say that a third party found this uncatalogued DNA world?»

«They found evidence for it,» Lahl said. «Not the world itself, as far as I know.»

Rakesh was perplexed. «As far as you know?»

«The Aloof embodied me,» Lahl explained, «deep inside their territory. I was shown a meteor, which appeared to be a fragment of a planetary crust ejected by an impact event. Inside, it was riddled with DNA.»

«So you've met them?» Viya asked, incredulous now. «You've met the Aloof?»

«Of course not,» Lahl replied. «They kept me at arm's length. They woke me in a small interstellar habitat, well suited to my customary embodiment, alone with this rock and the instruments needed to examine it. The short cut had bought me five thousand years' grace, so I had no qualms about spending a few days obliging my hosts, and satisfying my own curiosity. The cells inside the meteor were all dead, but there was enough intact genetic material to reveal that it hadn't been blasted straight off the surface of any of the known DNA worlds. It was from a mature divergent branch of the panspermia. It must have originated on a world of its own.»

«Do you know where they collected it?» Parantham asked. «They would have had to travel out of the bulge, surely?»

Lahl said, «There was a map showing where they'd found it: not far from the place where I was examining it. Particle tracks in the outer layers of the rock seemed to bear that out; it looked as if it had been exposed to ambient radiation levels for about fifty million years. And as best as I could date the impact event, that was about fifty million years ago, too.»

Viya frowned. «That makes no sense. For ejecta to get from a typical DNA world down into the bulge would take at least half a billion years.»

«Exactly,» Lahl said. «So it can't be from a typical DNA world. The planetary system itself must be deep in the Aloof's territory.»

Rakesh felt a thrill of astonishment, though he was far from convinced that Lahl's conclusion was the right one. All eleven panspermias were believed to have originated at middle radii in the galactic disk, between twenty and thirty thousand light years from the center. Certainly, the worlds on which the eleven replicators were known to have thrived were confined to that zone, where the galactic chemistry favored the formation of suitable planets, the radiation levels were reasonably low, and such biosphere-sterilizing calamities as supernovae were relatively rare. The process by which collision ejecta had spread the replicators between star systems was supposedly well understood, and though nothing ruled out the possibility of debris carrying DNA-based micro-organisms all the way down to the galactic bulge, no one would have expected them to gain a foothold there.