The hours drifted by; the sun had settled down after the immense convulsions that had shot so many millions of tons of its substance into space, never to return. The aftermath of that eruption was now a slowly twisting and turning cloud a hundred times the size of Earth, and soon it would be close enough for the short-range radar to reveal its finer structure.

Despite all the years I have been in the business, it still gives me a thrill to watch that line of light paint its picture on the screen as its spins in synchronism with the narrow beam of radio waves from the transmitter. I sometimes think of myself as a blind man exploring the space around him with a stick that may be a hundred million miles in length. For man is truly blind to the things I study; these great clouds of ionized gas moving far out from the sun are completely invisible to the eye and even to the most sensitive of photographic plates. They are ghosts that briefly haunt the solar system during the few hours of their existence; if they did not reflect our radar waves or disturb our magnetometers, we should never know that they were there.

The picture on the screen looked not unlike a photograph of a spiral nebula, for as the cloud slowly rotated it trailed ragged arms of gas for ten thousand miles around it. Or it might have been a terrestrial hurricane that I was watching from above as it spun through the atmosphere of Earth. The internal structure was extremely complicated and was changing minute by minute beneath the action of forces which we have never fully understood. Rivers of fire were flowing in curious paths under what could only be the influence of electric fields; but why were they appearing from nowhere and disappearing again as if matter was being created and destroyed? And what were those gleaming nodules, larger than the moon, that were being swept along like boulders before a flood?