Moonseed - Stephen Baxter

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had brought: the plankton die-backs, the collapse of the food chain in some parts of the oceans, depletion of stocks of fish and mammals. In the south she could see windsurfers skimming over the waves, radiation-proof skinsuits gleaming, their elegance and speed a balance between forces, aerodynamic and gravitational. In the west, the sun was already dropping towards the horizon. To the north the Miracle Mile along Waikiki Beach was a thin, golden strip of sand walled off from the interior by slab-like high-rise hotels. Sun, sand, sea, tourists.

      And when she looked back she could see into the crater of a volcano two million years dead.

      They found a seat. Alfred dug under his poncho and pulled out a laptop; without preamble, he started showing her images of Venus.

      ‘Before and after,’ he said drily. He retrieved a classic Venus-from-space image, the featureless pool ball. ‘Venus was our neighbour,’ he said. ‘At its closest, only a hundred times as far away as the Moon. And it wasn’t so different from Earth in size. But that’s as good as it gets. Otherwise, it was a hell-hole. Fifty miles of carbon dioxide, laced with a little sulphuric acid. So hot the rocks glowed, dull orange.’

      He showed her surface images, craters and domes and valleys and mountains, constructed from a radar survey by the Magellan spacecraft. ‘Venus was covered by volcanism. There were flood lavas and volcanic cones and domes, and other features which don’t have any analogues on Earth. We didn’t see plate tectonics, like Earth; we think Venus was a one-plate planet dominated by hot-spot volcanism. My favourite hypothesis is that there was a catastrophic global resurfacing every half-billion years.’

      ‘A what?’

      ‘The crust melting, globally. There are problems with the heat flow from the interior otherwise … It would be like five hundred million years of geology crammed into a few centuries. Now,’ he said. ‘After. An image taken by the Hubble this morning.’

      There was no evidence of a spherical shape. She made out a crudely-defined, blurred oval, with extensive tails, like a comet’s.

      Alfred said, ‘You’re looking at a cloud of atmospheric gas, mostly frozen, and ground-up rock.’

      ‘The rock’s from the surface?’

      ‘Mostly the mantle, as far as we can tell. Most of the mass is still concentrated near the point where the centre of gravity of the planet used to be. We tried radar pulses from Arecibo, and … Well. Monica, we can’t find a solid object there any more. The substance of the planet is spreading out along the orbit. The ring probably won’t stay stable; the perturbation by Earth’s gravity will –’

      ‘Hold it. Alfred, I can’t follow you. You’re saying that Venus no longer exists.’

      ‘Not as a coherent solid, no.’

      ‘That’s impossible. How much energy would it take to destroy a planet?’

      He considered. ‘Well, roughly speaking, you would have to lift every piece of rock to escape velocity, out of Venus’s own gravity well. There’s a quantity called the gravitational binding energy … For Venus, which had eighty per cent of Earth’s mass, it works out as ten to power thirty-two joules – umm, something like a thousand billion times our nuclear arsenal.’

      ‘Just for the record, we aren’t talking about your global volcanic resurfacing here, are we?’

      He smiled. ‘Even that would be quite a spectacle, if it occurred in the lifetime of this astronomer. But no, it’s orders of magnitude beyond that.’ He rubbed his nose, smearing the gaudy sun block there. ‘Those are big numbers. But there’s another way of looking at it. If you consider the energy density required, averaged over the planet’s volume, it isn’t so high. Something like a tanker of gas per cubic yard or so, I guess.’

      ‘What are you telling me?’

      ‘We think we are looking at some funny physics over there, Monica. Which is why you and the rest of the particle physicists are going to have to work on this with us.’

      ‘Funny physics?’

      ‘Look at this.’ He pulled up results from a cosmic ray detector, tracks left in bubble chambers, accompanying analysis. ‘We’ve found some strange products from the Venus event. Some exotic beasties, escaping from that particular zoo. Have you seen this result?’

      A spider-web of tracks, of splits and decay events and spirals and tiny explosions.

      She whistled. ‘No. I’d remember.’

      ‘Well, the results haven’t made it onto the nets yet. The authors are still checking.’

      ‘I don’t blame them,’ she said. ‘If this is right –’

      ‘You’re looking at a particle with a charge a fraction of an electron’s. Which is something we’ve never seen before.’

      ‘And this mass –’ She looked at him. ‘Alfred, this is the signature of an elementary particle with a fractional charge, and the mass of a bacterium. Now, what processes do we know of which could produce such a thing?’

      ‘We don’t know of anything since the Big Bang.’ He studied her. ‘We’re measuring the symptoms here. Guessing at a cause isn’t so easy.’

      ‘A cause?’

      ‘A purpose, then. Something has taken Venus apart. It seems to have transformed the planet’s own mass-energy to use against it.’ He grinned, uneasily. ‘We’re speculating. Maybe there is something out there that doesn’t like planets, deep gravity wells. Something that prefers thin matter clouds. Like the primordial cloud from which the Solar System formed in the first place.’

      ‘Something? You make it sound as if this was somehow deliberate.’

      He didn’t reply to that.

      ‘Listen,’ he said. ‘We’re on Hawaii. We should have ice cream. You want some ice cream?’

      She shrugged, indifferent, and he went anyway.

      After the Venus event Alfred had come here to the islands to work at the observatory on the summit of Mauna Kea, fourteen thousand feet above sea level. Up there, the air was so rarefied it was as clear a sky as anywhere on Earth, but human lungs only received forty per cent of their normal intake of oxygen. Nobody slept at the summit; the astronomers came down four thousand feet every dawn to sleep over at Hale Pohaku.

      Alfred had come down to meet her. Monica knew there was no way she would be able to tolerate the summit conditions.

      Thus, death was already closing in on her, already cutting the options available to her, the circles closing in. She would never see another mountain top.

      Bullshit, she thought.

      She tried to focus on Hawaii.

      This island, Oahu, was dying too, though a little more slowly than she was. It had bloomed out of the sea in a fiery birth, amid gouts of lava and steam. But every year erosion dragged it down towards the water, and there was nothing, no process, to restore it.

      It had happened before. There was a flaw in Earth’s mantle here, a great plume of magma which had welled up steadily for a hundred million years. It had generated Oahu; right now the Big Island was over the plume, and was being pushed towards the sky by that lithic fountain. But the relentless sliding of the tectonic plates beneath the Pacific would eventually, in a few million years, take the Big Island away from the plume. The volcano at its heart would die, and the island would be abandoned to the forces of erosion.

      Thus there was a chain of dying islands tailing off to the north-west, Oahu and Kauai and Niihau, and beyond that a trail of corpses, nameless undersea mountains, each of which had once been a paradise of forests and beaches, just like this one.

      Somehow it seemed an appropriate place to come to talk about the death of Venus.

      Alfred

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