"But what could be wrong?" Grantline demanded.
It was Drac who guessed it. "That radiance from the enemy's bow?"
It was that, we felt certain. Even at this thirty thousand mile distance, the bow-beacon seemed streaming upon us. We could not see that it illumined the Cometara, nor could our instruments measure any added illumination. Our flight-orbit, if held, would carry us with a swing some ten thousand miles above the South Pole of the Moon. It would cross diagonally in front of the trajectory that the enemy vessel was maintaining. But we were off our predetermined course, with a side-drift toward the enemy. That bow-beacon radiance was exerting a force upon us, a strange gravitational pull.
Grantline gasped when Drac said it. "If it's that now, what will it be when we get closer?"
The minutes were passing. The thirty thousand miles between us and the enemy was cut to ten thousand; to five. The ship was soon visible to the naked eye. Its visual movement, for all this time measurable only as a drift upon the amplified images of our instruments, now was obvious. We could see it plunging forward, could see that probably we would cross its bow. Within fifty miles? We hoped and guessed that would be the result, so that with this first passing we could use our weapons. Fifty miles of distance at combined speeds of some fifty thousand miles an hour: that would be something like three seconds from a collision. The danger of a collision, which both ships would do anything to avert, was negligible; in the immensity of space two objects so small could not strike each other, even with intention, once in a million times.
We could not calculate the passing so closely, but suddenly it seemed that perhaps the enemy could. The bow-beacon radiance, so obviously a miniature of the weird light-beams streaming from Earth, Mars and Venus, now swung away from us and was extinguished. Whatever alteration of our course the enemy had made, they seemed to be satisfied. The passing would be to their liking. Would it be to ours?
Grantline had left the turret. He was down on the deck, ready with his men. The weapons were ready.
We had long since advanced beyond the possibility of mathematical calculations keeping pace with our changing position in relation to the enemy, but it seemed that the passing would be within fifty miles. Grantline's weapons would carry their bolt that far.
It was barely two thousand miles away now. Two minutes of time before the passing. I stared at it, a long, low ship of dark metal, red where the moonlight struck upon it. I estimated its size to be about that of the Cometara, but it was much more nearly globular. Upon its top, seeming to project from the terraced dome, was an up-pointing funnel, like the smokestack of an old-fashioned surface steam vessel; or like a great black muzzle of an old-fashioned gun. And in a row along the bulging middle of the hull there was a series of little discs.
The vessel was still a tiny blob, but every instant it was enlarging, doubling its visual size. Drac said tensely, "Fifteen hundred miles! We'll pass in a minute and a half."