The Arrows of Time: Orthogonal Book Three (27 page)

‘Space is curved!’ Tarquinia exclaimed delightedly. She’d taken no prior position on Lila’s theory, but the sheer strangeness of the notion seemed to
please her now that it could finally be justified.

‘Very slightly,’ Azelio conceded. ‘It’s barely measurable.’

‘This might seem like a tiny, obscure effect now,’ Tarquinia replied, ‘but I guarantee that in a couple of generations, every astronomer will be making use of it
somehow.’

Ramiro squeezed Agata’s shoulder. ‘Congratulations.’

She said, ‘It was Lila’s prediction, not mine.’

‘And yet I don’t see Lila here making the measurements.’

‘When I told her I was going to be doing this,’ Agata recalled, ‘she said: “If the results aren’t what my equations dictate, all we can do is pity the poor cosmos
– because true or not, the theory will be the more beautiful of the two by far.“ ’

‘So you’ve proved that the cosmos is beautiful,’ Azelio concluded. ‘But you still can’t tell us its shape.’

‘The beauty is that it’s comprehensible,’ Agata declared. ‘Even if its shape is unknown.’

‘Unknown to you,’ Ramiro said provocatively.

‘Yes.’ Agata frowned. ‘But why the distinction? Have you been working with Lila’s equations yourself, on all those long watches?’

‘Ha! I wish I were that smart.’

‘Then who . . . ?’

‘If the messaging system’s been operating on the
Peerless
since a year or so after we left,’ Ramiro reasoned, ‘then Lila and her students will have had a year by
now to think over all the results we bring back. So who knows how far they might have taken things?’

‘That doesn’t bother me,’ Agata said firmly. ‘I’ve stolen an advantage over everyone on the
Peerless
, squeezing three years into each year that passed for
them. If they end up deriving some beautiful corollaries from my results by the time I return, that will give me the best of both worlds: I’ll get to see what other people make of my work
– and I won’t even have to wait around while they do it.’

It was a nice idea in principle; maybe she really could live up to it. But whether or not her competitors had already had the last word, she was hungry to return to her calculations,
reinvigorated by this proof that her efforts so far had not been wasted.

Tarquinia said, ‘Make sure everything’s secure in your cabins. I’ll need to run the engines hard for a while; we still have a lot of velocity to shed before we can go into
orbit around the planet.’

Agata said, ‘Right.’ The shape of the cosmos would have to wait; there was still the small matter of Esilio.

While Azelio and Tarquinia debated the merits of different landing sites, Ramiro clung to a rope beside the window and gazed down at the starlit world below. How could he
understand Esilio? Of all the sciences he’d studied as a child, geology had been the least developed – and at the time, he’d imagined, the least likely ever to be of use to him.
Of the little that he remembered, he remained unsure what he should trust. The ancestors had had no idea what a rock was actually made of, while their successors, with all their superior knowledge,
had never set eyes on a planet.

‘We need to be within walking distance of four or five different kinds of soil, or what will the crop tests be worth?’ Azelio said heatedly.

‘I appreciate that,’ Tarquinia replied. ‘But if we don’t come down on flat, stable ground, we could damage the
Surveyor
irreparably.’

Over the eons, Ramiro had been taught, every kind of rock exuded traces of gas, and for a body with sufficient gravity this gas would accumulate into an atmosphere. If the body also happened to
orbit a star, winds driven by the temperature difference between day and night eroded the rock, and once there was airborne dust and sand that accelerated the process. The routes of the dust-flows
carved out valleys and mountains, shaped as well by the differing durability of the underlying rock. But where had those various minerals come from? As far as he recalled, no one even knew for sure
whether they dated all the way back to the entropy minimum, had formed over cosmic time from the sedate decay of some primordial substance, or had been forged in the core of a giant ur-world where
liquid fires – contained for a while by its unimaginable gravity – thrashed and churned until the whole thing finally split apart and scattered.

Tarquinia brought an image of the next candidate onto her console, taken in full sunlight with the time-reversed camera. Ramiro struggled to interpret it, but the combination of near-smoothness
and suspiciously delicate ridges suggested a plain of wind-ruffled dust into which the
Surveyor
might sink and vanish.

‘Can’t we just settle for the safest-looking ground?’ he proposed. ‘If it turns out that there’s a problem with the soil, we can always ascend and come down
somewhere else.’

Azelio turned to stare at him angrily. ‘I’m not spending years hopping from site to site! That’s not what we agreed to!’

‘All right. Forget it.’ Ramiro regretted speaking so carelessly; Azelio had his niece and nephew to think of.

Tarquinia summoned another image. ‘Why do we only have two probes?’ she fretted. They could send one down in advance of the
Surveyor
, and the second if their first choice
proved unsuitable, but that was the limit: the probes weren’t sophisticated enough to explore more than one location each.

‘Perhaps we could extend the survey for a few more days,’ Ramiro suggested. The planet was turning beneath them as they circled from pole to pole; each successive orbit carried them
over a different meridian, and though they’d sampled a wide variety of terrain they were still far short of seeing everything. ‘There has to be a perfect site down there.’

‘Exactly!’ Azelio replied. He gestured at the console. ‘None of these are acceptable.’

‘We can keep looking,’ Tarquinia agreed. ‘A few more days is nothing.’

Azelio excused himself to check on the plants. Weightlessness wasn’t good for them, but it wasn’t worth setting up the tether again – not unless the selection process was going
to stretch out into stints, rather than days.

Tarquinia switched to the live feed from the time-reversed camera: dawn was breaking over a red plain criss-crossed by brown fissures.

‘Look at all that land!’ Ramiro marvelled. If every field of wheat in the
Peerless
were laid out here side by side, they would pass by in a flicker, lost in the vastness.
The sagas were full of journeys on foot that had crossed ancient empires and lasted for years, but nothing he’d read or imagined had prepared him for the scale of the world below. ‘How
could the first travellers ever give up so much freedom?’

‘I think the Hurtlers might have helped,’ Tarquinia suggested.

‘Yes, but I still wouldn’t have been able to do it. We never belonged cooped up in a mountain; it’s a wonder we didn’t all lose our minds generations ago.’

‘So you’re set on making this your home?’ Tarquinia asked. ‘Esilio’s won you over already?’

Ramiro buzzed softly. ‘Esilio’s one thing, but twelve more years of travelling will probably finish me off.’ He would have relished defying Greta and staying behind when the
Surveyor
departed – and it would not have undermined the purpose of the mission if the rest of the crew returned to the
Peerless
with the news that a colony had already been
established. But he couldn’t do it alone.

Tarquinia said, ‘And wide-open spaces are one thing, but you can’t eat dirt. Before you start picturing the flowers on your grave, let’s see if anything can take root here at
all.’

The probe parted from the
Surveyor
, separated by a burst of air before it fired its engines to start the descent from orbit. Ramiro peered over Tarquinia’s
shoulder to watch the instrumentation feed. Azelio looked on from Tarquinia’s right, and even Agata had left her calculations for a while to cling to the rope beside him.

As the probe slowed to let gravity bring it down, it didn’t take long to fall back behind the
Surveyor
’s horizon, cutting the link. ‘Do you want to sleep for the next
few chimes?’ Agata teased Ramiro. ‘I promise to wake you when all the results are in.’

‘No thanks.’ Ramiro asked Tarquinia to replay the recorded data; something unsettling had caught his eye. ‘Look at how hot it was, just before we lost contact!’

Azelio said, ‘We were expecting some frictional heating, weren’t we?’

‘Not so soon. Not at that altitude.’

Tarquinia frowned. ‘We’re not suffering any unexplained drag ourselves, so I don’t see how we could have the density profile that wrong.’

Ramiro didn’t want to argue about the cause; the fact remained that the heating was unexpected. ‘If this thing burns up out of sight, we’re never going to know what happened
– or what we need to change when we try again. If we make the wrong guess we could lose the second probe the same way.’

Tarquinia contemplated this gloomy scenario. ‘Then we’d better move quickly,’ she said.

Ramiro was already strapped to his couch, but Agata and Azelio had to clamber into place as the
Surveyor
tilted then ascended rapidly. The cabin window faced the stars, but on the
navigation console the land could be seen falling away as Tarquinia widened their horizon to reestablish a line of sight to the probe.

When the link was restored she cut the engines, letting them continue the upwards arc from momentum alone. Ramiro was dizzy after the unaccustomed weight, but when his head cleared he focused on
the data feed. The probe’s temperature was still high, but it was less than before.

‘It must have been a false reading,’ he decided.

The image feed was growing shaky, as if the probe was being buffeted by high winds. Greta had only provided the expedition with a single time-reversed camera, and the probe’s sunless view
of the landscape below was almost impossible to read. The temperature was dropping steadily now. Maybe there was something going on with the cooling air: a valve had jammed when the flow had been
needed to dispose of the engine’s heat, but now it had simply snapped open and was overcompensating.

As the juddering machine rushed towards the surface, Ramiro felt equal parts fear and exultation. In the history of the
Peerless
, no one had ever performed a manoeuvre that deserved to
be described as a landing. But if this small, robust scout couldn’t survive the process, what chance would there be for the
Surveyor
?

The image turned black. Tarquinia said, ‘Side camera might be more informative now.’ She sent an instruction from her corset, and the feed changed to a slanted view of an expanse of
sandy ground. In the middle distance a few small grey rocks broke the flatness.

‘It’s down! It’s safe!’ Azelio chirped ecstatically, then turned to the instrument feed. ‘And the temperature’s fine. It’s already close to
Tarquinia’s estimate for the surface.’

Agata said, ‘In Esilio’s terms, it’s been there for days. What other temperature should it be?’

Ramiro struggled to accept this. On one level he understood her reasoning perfectly: according to Esilio’s arrow of time, the probe was
about to ascend
, with any frictional
heating yet to come. And if this was the correct perspective, the high temperature they’d seen when it was still above the atmosphere was due to its earlier heating during its ascent.

‘How was it ever cool, up here?’ he asked. ‘Before we launched it? Or in Esilio’s terms: what cooled it after it emerged from the atmosphere?’

‘Any answer to that will sound strange from either perspective,’ Agata replied. ‘I suppose it must have happened through interactions with the cooling air – but then,
from Esilio’s point of view that air was rushing in from the void and striking the probe in just the right way needed to cool it, while on our terms the probe was releasing cooling air but
heating up in the process.’

Ramiro clutched his skull. ‘Why, though?’

‘What’s the alternative?’ Agata replied. ‘Retaining all the heat from this ascent for the next six years, while it was sitting in its bay in contact with the
Surveyor
?’

‘That would have been absurd,’ Ramiro conceded. ‘But the fact that it heated up at all before it hit the atmosphere is absurd, too.’

‘Less so,’ Agata insisted. ‘And “absurd” is the wrong description. If I handed you two identical-looking slabs of stone at room temperature – one of which had
been heated for a while in a fire the day before – would you expect to be able to tell me which was which?’

‘Of course not.’

‘Now look at the same situation in reverse. Your failure to guess the stones’ history becomes a failure to predict their future – but the one that would become unexpectedly hot
well before it was actually in the fire would not have been doing anything absurd.’

Ramiro couldn’t argue with that. ‘So I should be grateful on those rare occasions when things make perfect sense from a single perspective, whether it’s ours or Esilio’s.
But when that doesn’t work . . . what are we left with?’