Now it was less than a million miles away; it would be upon us in little more than an hour. The automatic cameras were recording every complete sweep of the radar scan, storing up evidence which was to keep us arguing for years. The magnetic disturbance riding ahead of the cloud had already reached us; indeed, there was hardly an instrument in the Observatory that was not reacting in some way to the onrushing apparition.

I switched to the short-range scanner, and the image of the cloud expanded so enormously that only its central portion was on the screen. At the same time I began to change frequency, turning across the spectrum to differentiate among~ the various levels. The shorter the wave length, the farther you can penetrate into a layer of ionized gas; by this technique I hope to get a kind of X-ray picture of the cloud’s interior.

It seemed to change before my eyes as I sliced down through the tenuous outer envelope with its trailing arms -and approached the denser core. “Denser,” of course, was a purely relative word; by terrestrial standards even its most closely packed regions were still a fairly good vacuum. I had almost reached the limit of my frequency band, and could shorten the wave length no farmer, when I noticed the curious, tight little echo not far from the center of the screen.

It was oval and much more sharp-edged than the knots of gas” we had watched adrift in the cloud’s fiery streams. Even in that first glimpse, I knew that here was something very strange and outside all previous records of solar phenomena. I watched it for a dozen scans of the radar beam, then called my assistant away from the radiospectrograph, with which he was analyzing the velocities of the swirling gas as it spun toward us.