My own eyes were fixed upon it, and slowly I nodded, but made no other answer as we flashed on toward the object of our attention, the black sphere ahead. And now as we swept on we saw that it was a sphere of truly titanic dimensions, larger by far than any of the Galaxy's countless worlds, and that as it hung there, at the nebula's heart, it was slowly revolving, spinning, as fast or faster than the nebula itself. Black and mighty it hung there, while all around it, millions of miles from it, there flamed the nebula's encircling fires. On and on we raced toward it, and for all those minutes of flashing flight none of us spoke, and there was no sound in the pilot room but the throbbing drone of the generators below. I think that we all felt instinctively that in the grim, colossal globe ahead lay the answer to what we had come to solve, and as we hurtled on toward it we watched it broadening before us in tense silence. Larger and larger it was becoming, larger until its great black circle filled half the heavens before us. By then I had decreased our speed to a fraction of its former figure, and as we swept in toward the giant world I lessened it still further. Slowly, ever more slowly we moved, and now were circling above the great black planet, were beginning to drop cautiously down toward it. Eagerly we watched as the mighty world's surface changed from convex to concave, and as we dropped on we saw the needle of our atmosphere-pressure dial moving steadily forward, to show that this strange world had air, at least. Then all else was forgotten as our eyes took in the scene below. I think that we had all half expected to see some evidence of life and civilization on this strange world, some building or group of buildings, at least. But there was none such. Beneath us lay only a smooth black plain, extending from horizon to horizon, devoid of hill or stream or valley, in so far as we could see, unnaturally smooth and level. And as we dropped nearer, ever nearer, the surprize we felt rapidly intensified, until when at last we hung motionless a hundred feet above the surface of this world exclamations of utter astonishment broke from us. For seen thus near, the surface of this mighty planet was as utterly smooth and level as it had seemed from high above, a black, gleaming plain without an inch-high elevation or depression, an inconceivably strange smooth expanse of black _metal_, that stretched evenly away in every direction to the horizon, smoothly covering this colossal world.