‘But not from you.’
He just smiled.
‘Umm. So, we’re related to these creatures. Just like on Per Ardua. The evidence the first explorers brought back indicated that the life forms there were also based on an Earthlike biochemistry.’
‘Yes, but that relationship is more remote. Penny, I am sure you understand this. We can’t say on which world our kind of life originated – on Earth, Mars, Per Ardua, somewhere else entirely. It was probably spontaneous. On a world like the primitive Earth, the flow of energy – lightning, sunlight – in a primordial atmosphere of methane, ammonia, water, would create complex hydrocarbon compounds like formaldehyde, sugars, polymers. The food of life. Then comes a process of self-organisation, of complexification and combination … A spontaneous emergence of life.
‘And all the while the young worlds are pounded by huge falls of rock and ice from space, the relics of the formation of the planets themselves. Chunks of the surface are blasted into space and wander between the worlds: natural spacecraft, that carry life between the planets of a solar system – and, though much more rarely, across the interstellar gulf. This is called panspermia. If life began on Earth, it may have seeded Mars many times over – but Per Ardua, say, perhaps only once.’
‘Which is why Arduan life was a more remote relation.’
‘That’s it. Or, of course, it could have been the other way round. It seems that we’re living in the middle of a panspermia bubble, a complex of stars bearing life forms that all branch back to some originating event.’
She looked down at the purplish water. ‘A nice idea. But on some worlds life flourished better than on others. On Earth, rather than Mars—’
‘Well, it depends what you mean by “flourished”, Penny. On Earth, the biosphere, the realm of life, extends from the top of the lower atmosphere down through land and oceans, and into the deep subsurface rocks, kilometres deep, until the temperature is too high for biochemical molecules to survive. But even on Earth it is thought that there is more biomass, more life as measured in sheer tonnes, in the deep rocks than on land and air and in the oceans. And on Mars, as this small world cooled too quickly, and much of the water was lost, and then the air—’
‘It was only underground that life could survive.’
‘Yes. Microbes, living on mineral seeps and a trickle of water and the flow of heat from the interior – even on radiation from natural sources. The dark energy biosphere, some called it. Time moves slowly in those deeps, and the energy sources are minimal compared to the flow of cheap power from the sun at the surface. The bugs themselves are small – their very genomes are small. Reproduction is a rare event; the microbes of Mars, and Earth’s deeps, specialise rather in self-repair. Individual microbes, Penny, that can survive for millions of years.’
‘Wow,’ Penny said drily. ‘If only they could talk, the bar tales they could tell.’
‘In fact, that’s why I’m here, Penny. They may indeed have stories to tell. Let me show you. Step back now.’
She moved a few paces away from the pond. Earthshine clapped his hands.
And the office space, the desk, the carpet – even the pond, even the sky of Mars – faded from view. Walls and a ceiling congealed around Penny, and she found herself suddenly enclosed in a kind of elevator car, with a display on the wall of descending lights.
‘Going down,’ Earthshine said smoothly.
‘I can’t feel the motion.’
‘I’d need to tap into your deeper brain functions to simulate that. I figured that you’d rather pass.’
‘You figured right …’
After only a few minutes the doors slid back.
Earthshine led her out into a kind of cave, maybe a hundred metres across, the rock walls roughly shaped, the light coming from fluorescents attached to the walls. It looked like a classic Brikanti project to Penny, the heavy engineering made possible by kernel energies, if you were unscrupulous enough to use them on a planet. But there were also storage boxes here, white but scuffed, and stamped with ISF logos and tracking markers. One complex cylinder she remembered as the storage unit that had housed Earthshine’s consciousness aboard the Tatania.
And she saw scientific instruments set out on the floor, and standing on tripods by the walls. All these were connected by a mesh of cables over which she and Earthshine stepped now, gingerly, a network that terminated in contacts with the walls, plugs and sockets and deeply embedded probes.
‘How deep are we?’
‘Kilometres down. Obviously the facility requires some physical manpower down here – the Brikanti have no robots, after all – but the workers can survive only hour-long shifts. It’s not just the heat and the airlessness, it’s the sheer claustrophobia.’
‘This is ISF gear,’ she said accusingly. ‘The science stuff. You cannibalised Tatania for all this.’
‘Well, why not? The remnant hulk was only scrap to the Brikanti, of no value to them.’
‘Maybe. But it wasn’t yours to exploit either. And that pillar – you are in there, aren’t you? The processor and memory units that support you. Now here it is, kilometres deep. You built yourself another bunker. Just like the one you had on Earth.’
He smiled. ‘Well, wouldn’t you, if you were me?’
‘And you’ve come down here to commune with a bunch of Martian microbes.’
‘You can mock if you like. But that is essentially correct. Penny, on Earth even solitary microbes show complex behaviour. They can respond to gravity, heat, light, the chemical signals that betray sources of food or the threat of toxins. They have selves, in a sense. They can communicate with each other, Penny, interact, through chemical exchanges, even through gene swaps. And through that communication they form communities. Like biofilms, or stromatolites: coalitions of many species, in shelters that control humidity, temperature, sunlight, and provide food storage, defence – even a kind of “farming” of plants and lichen. Did you know there are certain slime-mould bacteria that hunt in packs, like wolves?
‘And, working together on a larger scale, they can achieve monumental things. On Earth it was the microbes, the planet’s first inhabitants, that put oxygen in the air, and loaded the soil with minerals and nutrients – they created the foundation on which complex life forms like ourselves could be constructed.’
‘OK. And on Mars—’
‘On Mars, because the surface conditions were so hostile, the microbes have had nothing else to do but grow their own communities, ever deeper and wider, ever more complex. Penny, I am detecting collective entities down here, all embedded in the rock, spanning kilometres at least. For all I know such communities might span the whole planet; Mars is small and static enough for that to be possible.
‘They swap information using strings of DNA, or their version of it, and tangled-up proteins. Every so often phages – targeted viruses – will pass through these communities in waves, taking out diseased or malfunctioning members, or injecting fresh DNA, in a kind of global upgrade – an evolution through learning and cooperation rather than through competition. It’s almost like watching my own information stores synchronise … We, my brothers and I, were aware of such entities on Earth.’
‘You were?’
‘We, after all, were also minds vast and distributed, buried deep in the terrestrial rocks. But the thinkers are stronger here, more clearly defined, on a world without the gaudy clutter of surface life. There is a profound unity here, with a complex distributed structure that would take decades to map, or more.
‘But these entities do more than just survive. More than just repair and upgrade. The density of the information flow, as best I’ve been able to measure it, is far too high for that. They are conscious, Penny. Vast diffuse entities locked in the rock – and yet aware of the wider universe, surely, as light and radiation sears the planet’s surface, as the geology shifts and heaves. Everything is very slow – the energy density is so sparse you’d need a collector the size of your classroom to gather the power to light up a bulb. The dreaming communities can only be aware of the slowest events, the grandest. But they have plenty of time down here. Plenty of time to dream.’