Elsewhere in the ship, everything was normal. The engine room was a place of stillness and peace, save for   the almost inaudible hum of the drive, running at half a million Gauss flux-density. The skipper did whatever skippers do when they are invisible to their subordinates. The weapons officer, Taine, thought appropriate thoughts. In the navigation room the second officer conscientiously glanced at each separate instrument at least once in each five minutes, and then carefully surveyed all the screens showing space outside the ship. The stewards disposed of the debris of the last meal, and began to get ready for the next. In the crew’s quarters, those off duty read or worked at scrimshaw, or simply and contentedly loafed.

Diane handed over the transparent radar graph, to be fitted into the three-dimensional map in the making.

“There’s a lump of stuff here,” she said interestedly. “It could be the comet that once followed this orbit, now so old it’s lost all its gases and isn’t a comet any longer.”

At this instant, which was 04 hours 25 minutes ship time, the alarm-bell rang. It clanged stridently over Baird’s head, repeater-gongs sounded all through the ship, and there was a scurrying and a closing of doors. The alarm gong could mean only one thing. It made one’s breath come faster or one’s hair stand on end, according to temperament.

The skipper’s face appeared on the direct-line screen from the navigation room.

“Plumies?” he demanded harshly. “Mr. Baird! Plumies?”

Baird’s hands were already flipping switches and plugging the radar room apparatus into a new setup.

“There’s a contact, sir,” he said curtly. “No. There was a contact. It’s broken now. Something detected us. We picked up a radar pulse. One.”

The word “one” meant much. A radar system that could get adequate information from a single pulse was not the work of amateurs. It was the product of a very highly developed technology. Setting all equipment to full-globular scanning, Baird felt a certain crawling sensation at the back of his neck. He’d been mapping within a narrow range above and below the line of this system’s ecliptic. A lot could have happened outside the area he’d had under long-distance scanning.

But seconds passed. They seemed like years. The all-globe scanning covered every direction out from the Niccola. Nothing appeared which had not been reported before. The gas-giant planet far behind, and the only inner one on this side of the sun, would return their pulses only after minutes. Meanwhile the radars reported very faintfully, but they only repeated previous reports.

“No new object within half a million miles,” said Baird, after a suitable interval. Presently he added: “Nothing new within three-quarter million miles.” Then: “Nothing new within a million miles …”

The skipper said bitingly: