Henry showed images from Edinburgh, exploding rocks around a volcanic plug called Arthur’s Seat, evidence from the lab where Apollo sample 86047 had exploded.

“The contaminated rocks achieve densities, towards the centre, at which fusion processes, at least, can occur. When the Moonseed destroys a chunk of rock, the outcome is dust, and a flood of high-energy radiation, and more Moonseed. It’s a way of propagating.”

“Mini nukes?” asked the Admiral.

“Yes.”

“What do you mean, at least fusion?”

This was Monica’s speciality. “He means the Moonseed constructs may reach greater levels of force unification than just fusion.”

“We’ve also observed this astronomically, now we’ve started looking,” Alfred said. “In the Earth-Moon system. The same radiation signature as on the ground. There seems to be a concentration of Moonseed at the Lagrange points.” He looked around the table for understanding. “Lagrange points are gravitationally stable collection points in the Earth-Moon system. We always wondered why we couldn’t see anything at the Lagrange points: no minor bodies, asteroids, trapped there. Now we know. The Moonseed is there, destroying whatever drifts in.”

“Just here? Where else?” Bromwich asked.

“Venus,” said Alfred Synge bluntly.

“Maybe space is their natural habitat,” Henry said. “Rather than planets. Our models show that they have difficulty reaching the surface of a planet, from space. They burn up in atmospheres, or are smashed by simple impact, on an airless body like the Moon.”

Alfred said, “But if they do get to a planet—”

“If they do,” Henry said, “then they transform it. Like Venus.”

Petit said drily, “Explain something else to me. You say the planets are shielded from the Moonseed, by atmosphere and gravity. We brought it here, from the Moon. But how did it get to Venus?”

“We’ve developed a theory about that too,” said Henry.

Petit said drily, “I thought you might.”

“We took it there,” Henry said.

“What?”

“You need a soft landing to deliver Moonseed to a planetary surface. The only objects which have soft-landed on the planets are our probes.”

“You’re saying we did this?”

Henry shrugged. “It’s a hypothesis. The probes collected the dust from the Lagrange clouds in near-Earth space. Specks in the paint work. And then delivered them to the planetary surfaces.”

Petit pulled Henry’s laptop towards him. “Give me a minute… Ah. The first probe to soft-land on Venus was Soviet. Venera 7. Landed in 1970.” He looked up.

“So,” Alfred said softly, “it takes a few decades to destroy a world the size of Venus.”

The Admiral snapped, “How big is Venus?”

“Similar to Earth,” Alfred said. “Eighty per cent of the mass.”

“Jesus H — So there’s our timescale.”