Xenobiology

Monday 7 September 2195, morning

❦

T

he plants were lying. Or the sensors were. I preferred plants. A sensor could fail because somebody had fitted the wrong membrane, pushed a firmware update at an inconvenient hour or allowed mineral deposits to accumulate somewhere a maintenance model had assured us they wouldn't. Plants were harder to fool. They responded to the environment they actually inhabited, not the environment we believed we'd provided.

I leaned towards the display until the green spectral trace filled most of my field of view.

"Run it again."

Beside me, Vael Tareth didn't ask which sequence I meant.

He touched two long fingers to the control surface and restarted the analysis.

Greenhouse Bay C occupied the far side of the transparent partition, where ranks of human food crops grew beside experimental Aruun photobiology cultures beneath a lighting array designed to offend everybody equally.

That was unfair.

The plants seemed reasonably happy with it.

Most days.

The humans complained that the compromise spectrum made breakfast look faintly anaemic. The Aruun found the blue-white components unpleasant at full intensity, which was why the bay used stepped illumination and local filtering around the workstations. The Ilyr thought the air was too dry. The Thesk considered our complaints about light and humidity evidence that the other three species had entirely too much spare time.

Ariadne had been operational for two years and still hadn't discovered a universal environmental setting that four intelligent species agreed was comfortable.

That struck me as more reassuring than alarming.

Compromise was supposed to feel like compromise.

The trace repopulated.

I folded my arms.

There it was again.

Barely.

Vael had seen it before I had.

That irritated me by approximately three per cent and impressed me by rather more.

"Same magnitude," he said.

His voice came through the Accord translator almost without delay. Technical vocabulary was where the system performed best. Give it plant physiology, atmospheric chemistry or a membrane specification and it could make four languages behave as if they'd been designed for cooperation.

Ask it to translate family humour and diplomatic staff sometimes became involved.

I magnified the final section of the curve.

"Confidence?"

"Above the threshold I use for instrument review. Below the threshold I use for biological interpretation."

I glanced at him.

"That's an irritatingly precise answer."

"I believed you preferred those."

"I do. They're still irritating."

A faint shift appeared in the copper-toned vascular patterns along his throat.

Six months ago, I would have wondered whether it meant amusement.

Now I knew better than to assign human emotion to Aruun colour changes without context.

I also knew he was amused.

Those were not contradictory statements.

Vael stood almost a head taller than I did, which put him at an awkward angle for collaborative screen work and a much more troublesome angle for several thoughts I'd been refusing to examine since spring.

His skin was so dark a violet-brown that the colour registered almost black where the greenhouse lighting didn't catch it. Copper vascular lines showed at his temples, throat and inner wrists. His eyes were darker still, adapted to conditions under which I would have been searching for a torch.

The workbench lighting around him had automatically shifted warmer when he'd authenticated at the station.

Ariadne did hundreds of small things like that.

It had to.

First Contact had taught humanity many dramatic lessons about our place in the universe. Six years later, most of the practical consequences involved air filters, software permissions and learning not to assume the person beside you metabolised the same trace compounds.

I looked back at the trace.

"Which plants?"

"Primarily the human legumes. Two of the Aruun test cultures show a weaker response."

"Bay D?"

"Nothing outside expected variation."

That removed one of the more ordinary explanations.

"Position within C?"

Vael changed the display.

A three-dimensional bay map appeared, the planting racks simplified into coloured blocks. He overlaid his measurements across them.

The affected samples weren't clustered near a single inlet.

I frowned.

"Not local airflow."

"That was also my conclusion."

"You've checked the spectrometer?"

"Twice."

"With?"

"The reference standard, then the independent optical unit from Lab Two."

Of course he had.

I hadn't been questioning his competence. With Vael, the distinction mattered enough to say aloud.

"I'm checking the chain, not checking you."

"I know."

His answer came too quickly for the translator to have softened anything.

I looked sideways again.

He was watching the display.

Not me.

Months of working together had given us an increasingly elaborate collection of things we did not acknowledge.

The fact that I knew which environmental presets made the skin at his wrists show copper more clearly.

The fact that he knew I stopped drinking coffee when a problem became interesting enough to interfere with basic maintenance of the human organism.

The fact that Rukh always positioned himself close enough to a machine to feel it through the deck plates when he thought nobody was watching.

The fact that Silen could tell when I was angry from changes in my speech rhythm before I had admitted it to myself.

None of those observations was romantic on its own.

Taken together, they were becoming difficult to ignore.

I expanded the time series.

"How far back?"

"I found the first deviation in yesterday's early cycle."

"Found?"

"I was reviewing last week's gas-exchange data."

"At what time?"

"Fourteen minutes past six."

I stared at him.

"You're telling me you voluntarily reviewed a week's worth of plant data before seven in the morning."

"You voluntarily came here when I messaged you."

"That was different."

"Naturally."

The translator rendered the word in an impeccably neutral human tone.

The vascular pattern at his throat shifted again.

Bastard.

I turned to the glass.

Greenhouse C looked normal.

That was the problem.

Rows of climbing beans reached towards their supports. Compact wheat cultivars stood beneath tuned lights. Root trays fed through isolated nutrient lines designed to let us measure exactly what entered and left each section. Between them sat the Aruun cultures, darker-leaved organisms adapted to a home world's redder star and very different daily light regime.

Nothing drooped.

Nothing discoloured.

No visible leaf curl. No root alarms. No obvious gas imbalance.

I tapped the sensor panel beside the partition.

SEL-3 showed nominal.

Water recovery was inside expected range.

Carbon dioxide transfer was inside expected range.

Nitrogen processing was inside expected range.

Humidity stable.

No contamination flag.

No pressure fault.

No reason for Vael's plants to be changing their spectral behaviour.

"How much stress?"

"Very little."

"Enough to matter?"

"That is a different question."

I smiled despite myself.

"Yes, Vael. That's why I asked it."

He angled his head towards me.

Aruun faces were close enough to human ones that the similarities could mislead you if you allowed them. The bone structure was finer. The eyes were larger and almost entirely dark. Small vascular changes carried information humans tended to miss.

He'd once told me that humans moved our eyebrows with exhausting frequency.

I'd spent the following week noticing every eyebrow in the station.

"It may be ordinary variance," he said. "But it is variance I cannot presently explain."

That was sufficient.

My job existed because explainable systems had a habit of becoming less explainable when people combined them.

Before Contact, I'd spent years modelling microbial communities inside closed human habitats. Mars transfer systems. Orbital research platforms. Long-duration recycling loops where a small shift in community behaviour could become an engineering problem weeks before anybody noticed a clinical consequence.

Then the universe had produced three other biospheres.

Humanity's response had been delight, terror, legislation, bad journalism and an entirely reasonable expansion of the xenobiology budget.

I'd arrived at Ariadne on 14 January.

By February, I had stopped waking with the awareness that there were aliens three corridors from my quarters.

By March, I'd started arguing with them.

By April, I'd stopped thinking of that as remarkable.

By May, I had developed several problems that definitely weren't covered by my employment contract.

Vael was one of them.

Rukh and Silen were the others.

I pulled SEL-3's morning report into a second window.

Shared Environmental Loop 3 was not Ariadne's life support, despite the way certain Earth news feeds preferred to describe it. Nobody sensible had connected four newly acquainted biospheres into one indispensable waste-recovery system and hoped for the best.

SEL-3 was a pilot.

Secondary treated water. Carbon dioxide streams. Mineral nutrients. Greenhouse returns from shared zones.

Primary sewage and high-risk species waste remained segregated.

Every organism used in the pilot had passed single-species and pairwise compatibility testing before introduction. The system was monitored with enough redundancy to satisfy Ariadne engineering and Tala Venn's biosecurity office, which was an achievement in itself.

The point was to find out whether mixed-species environmental processing could work efficiently enough for future stations and expeditions.

So far, it had.

I moved yesterday's sensor values beside Vael's spectral measurements.

They disagreed without technically contradicting one another.

The worst sort of disagreement.

"How long between the spectral change and the logged gas data?"

"Depends which feature you consider the beginning."

"Show me your earliest defensible point."

He did.

I overlaid it against SEL-3.

Nothing.

"Again."

"Alice."

"Humour me."

"I have been doing that for several months."

My hand stopped over the display.

He continued looking at the data.

I had no idea whether the translator understood what he'd just done to the sentence.

I was fairly certain Vael did.

"Careful," I said.

His dark eyes moved to mine.

"Was that a professional warning?"

"Entirely."

"Then I will record it appropriately."

His vascular pattern deepened by a shade.

I turned back to the workstation before my own face became useful data.

"Show me yesterday against the last fourteen days."

The display redrew.

Vael shifted closer to reach the controls.

Aruun body temperature ran lower than ours. I could usually tell when he was near me because the air didn't change in the way it did around a human body.

That shouldn't have been noticeable.

It was.

His hand paused beside mine without touching.

Neither of us moved for half a second.

Then he selected the overlay.

Months of restraint reduced to less than a centimetre of air.

Professional.

Sensible.

Entirely manageable.

The graph appeared.

I inhaled.

"That's not yesterday."

"No."

The change hadn't started as a single clean event. Once we stopped asking where the anomaly began and looked instead for where the older pattern stopped behaving like itself, there was a faint drift.

Subtle enough that an automated threshold wouldn't care.

Subtle enough that a human reviewing each day independently might dismiss it.

Vael hadn't.

"Three days?" I asked.

"Possibly four."

"And still no visible plant response."

"Correct."

I switched to raw SEL-3 values.

Nominal.

Nominal.

Nominal.

Every line sat where it was supposed to sit.

"Could the plant model be overfitted?"

"I considered that."

"And?"

"I dislike the explanation."

"That's not evidence."

"No. The independent measurements are."

I looked at him.

He accepted the correction with a small inclination of his head.

That was another reason working with him was dangerous.

Professionally.

Mostly professionally.

There were people who wanted agreement because disagreement felt personal. Vael wanted an argument that survived contact with data.

So did I.

"Let's not escalate yet."

"I agree."

"Repeat the spectral measurements across both bays. Same plants, same growth stage where possible. Pull environmental conditions from the local bay sensors as well as SEL-3. I want to know whether we're looking at physiology, instrumentation or something embarrassingly ordinary."

"A human would call that three possibilities."

"A systems xenobiologist calls it Monday."

That earned another copper flicker.

I opened a message channel.

Rukh's name sat near the top of my recent contacts. Below it was Silen's.

I considered including both of them.

Then stopped.

We didn't have enough.

Rukh would give me a beautifully blunt assessment of whether SEL-3's mechanical state justified dragging him away from whatever piece of equipment currently had his attention. Silen would ask what chemistry I wanted tested and then immediately ask what observation justified the test.

Both questions would be correct.

Neither needed asking yet.

If I involved every specialist whenever one plant produced a strange graph, I'd deserve the meeting invitations that followed.

I closed the channel without sending anything.

Vael noticed.

He noticed far too much.

"You are not informing them."

"Not yet."

"Because the evidence is weak?"

"Because their time matters."

He considered that.

"Both can be true."

"I know."

The greenhouse access door opened behind us.

A human technician entered carrying a sealed nutrient cartridge, nodded to us and crossed towards the service station. Through the glass beyond him, the Shared Research Spine was beginning its morning rush.

Humans in standard station blues moved beside Aruun researchers wearing light-filtering collars. A Thesk engineer crossed towards the environmental decks with the deliberate, grounded stride common among people whose species had evolved under gravity that made Earth feel indulgent. Two Ilyr staff passed in the opposite direction, their throat structures moving subtly as the humidity transition from their sector registered.

Six years.

That was all.

Six years since humanity had discovered that intelligence wasn't unique to Earth.

Three years since the Accord had been signed.

Two since Ariadne had opened.

Less than one since I'd arrived.

Some mornings the impossible became so administratively normal that I resented it for not having the decency to announce itself.

Alien civilisation existed.

I had a nine-thirty resource meeting.

The universe was ridiculous.

"You're staring," Vael said.

"At the corridor."

"Of course."

I looked at him.

"Was that sarcasm?"

"I have been studying your species."

"You should request a better dataset."

"I selected the one available."

This time I laughed.

Quietly, because the technician was still within hearing range and because laughing with Vael felt more intimate than it had any right to.

The technician glanced over.

I returned to the data.

Professional.

Always professional.

The alternative wasn't simply awkward.

No public precedent existed for what attraction between our species would mean. Medical staff had protocols for accidental exposure, environmental contact, shared work and emergency treatment. The Accord had pages of law concerning research access, quarantine rights and cultural autonomy.

There was no useful policy for what happened when a human xenobiologist wanted to know what an Aruun colleague's mouth felt like.

Even less for what happened when the same woman had spent months wanting three different colleagues in three distinctly troublesome ways.

My romantic history wasn't especially conventional by Earth standards. Wanting more than one person didn't frighten me.

Wanting people whose bodies were still represented in some medical databases by sample sizes small enough to fit around a dinner table did.

Wanting colleagues whose private choices could become a diplomatic curiosity frightened me more.

So we'd done nothing.

All four of us.

Very carefully.

I cleared my throat.

"Send me the repeat set when it's complete."

"I will."

"And don't modify the bay conditions yet."

Vael's expression sharpened.

"I had not intended to."