Kinder des Schicksals 4 (Xeelee 9): Resplendent

probably delivered here by comet impacts
during Callisto’s formation. There is carbon and hydrogen and
nitrogen and oxygen. The biochemistry is a matter of carbon-carbon
chains and water - like Earth’s, but not precisely so. Nothing
exactly like our DNA structures…’
    ’Spell it out,’ Gemo said casually, prowling around the gadgetry.
’Remember, Reth, the education of these young is woefully
inadequate.’
    ’This is life,’ Hama said. ’Native to Callisto.’
    ’Life - yes,’ Reth said. ’The highest forms are about equivalent
to Earth’s bacteria. But - native? I believe the life forms here have
a common ancestor with Earth life, buried deep in time - and that
they are related to the more extravagant biota of Europa’s buried
ocean, and probably most of the living things found elsewhere in Sol
system. Do you know the notion of panspermia? Life, you see, may have
originated in one place, perhaps even outside the system, and then
was spread through the worlds by the spraying of meteorite-impact
debris. And everywhere it landed, life embarked on a different
evolutionary path.’
    ’But here,’ Hama said slowly, fumbling to grasp these unfamiliar
concepts, ’it was unable to rise higher than the level of a
bacterium?’
    ’There is no room,’ said Reth. ’There is liquid water here: just
traces of it, soaked into the pores between the grains of rock and
ice, kept from freezing by the radiogenic heat. But energy flows
thin, and replication is very slow - spanning thousands of years.’ He
shrugged. ’Nevertheless there is a complete ecosystem. Do you
understand? My Callisto bacteria are rather like the cryptoendoliths
found in some inhospitable parts of Earth. In Antarctica, for
instance, you can crack open a rock and see layers of green life,
leaching nutrients from the stone itself, sheltering from the wind
and the desolating cold: communities of algae, cyanobacteria, fungi,
yeasts - ’
    ’Not any more,’ Gemo murmured, running a finger over control
panels. ’Reth, the Extirpation was very thorough, an effective
extinction event; I doubt if any of your cryptoendoliths can still
survive.’
    ’Ah,’ said Reth. ’A shame.’
    Hama straightened up, frowning. He had come far from the cramped
caverns of the Conurbations; he was confronting life from another
world, half a billion kilometres from Earth. He ought to feel wonder.
But these pale shadows evoked only a kind of pity. Perhaps this thin,
cold, purposeless existence was a suitable object for the obsessive
study of a lonely, half-mad immortal.
    Reth’s eyes were on him, hard.
    Hama said carefully, ’We know that before the Occupation, Sol
system was extensively explored, by Michael Poole and those who
followed him. The records of those times are lost - or hidden,’ he
said with a glance at the impassive Gemo. ’But we do know that
everywhere humans went, they found life. Life is commonplace. And in
most places we reached, life has attained a much higher peak than
this. Why not just catalogue these scrapings and abandon the
station?’
    Reth threw up his arms theatrically. ’I am wasting my time. Gemo,
how can this mayfly mind possibly grasp the subtleties here?’
    She said dryly, ’I think it would serve you to try to explain,
brother.’ She was studying a gadget that looked like a handgun
mounted on a floating platform. ’This, for example.’
    When Hama approached this device, his weapon-laden drone whirred
warningly. ’What is it?’
    Reth stalked forward. ’It is an experimental mechanism based on
laser light, which… It is a device for exploring the energy levels
of an extended quantum structure.’ He began to talk rapidly, lacing
his language with phrases like ’spectral lines’ and ’electrostatic
potential wells’, none of which Hama understood.
    At length Gemo interpreted for Hama.
    ’Imagine a very simple physical system - a hydrogen atom, for
instance. I can raise its energy by bombarding it with laser light.
But the atom is a quantum system; it can only assume energy levels at
a series of specific steps. There are simple mathematical rules to
describe the steps. This is called a >potential well<.’
    As he endured this lecture, irritation slowly built in Hama; it
was clear there was much knowledge to be reclaimed from these
patronising, arrogant pharaohs.
    ’The potential well of a hydrogen atom is simple,’ said Reth
rapidly. ’The simplest quantum system of all. It follows an
inverse-square rule. But