“That's it! And now we may as well go over the whole story, and tell Dad and your father all that happened. Perhaps in the telling, we can straighten out our own ideas a bit.”

For the next hour the three men talked, each telling his story, and trying to explain the whys and wherefores of what he had seen. In the end all agreed on one point: if they were to fight this enemy, they must have ships that could travel though space with speed to match that of the invaders, ships with a self-contained source of power.

During a brief lull in the conversation, Morey commented rather sarcastically: “I wonder if Arcot will now kindly explain his famous invisible light, or the lost star?” He was a bit nettled by his own failure to remember that a star could go black. “I can't see what connection this has with their sudden attack. If they were there, they must have developed when the star was bright, and as a star requires millions of years to cool down, I can't see how they could suddenly appear in space.”

Before answering, Arcot reached into a drawer of his desk and pulled out an old blackened briar pipe. Methodically he filled it, a thoughtful frown on his face; then carefully lighting it, he leaned back, puffing out a thin column of gray smoke.

“Those creatures must have developed on their planets before the sun cooled.” He puffed slowly. “They are, then, a race millions of years old—or so I believe. I can't give any scientific reason for this feeling; it's merely a hunch. I just have a feeling that the invaders are old, older than our very planet! This little globe is just about two billion years old. I feel that that race is so very ancient they may well have counted the revolutions of our galaxy as, once every twenty or thirty million years, it swung about its center.

“When I looked at those great machines, and those comparatively little beings as they handled their projectors, they seemed out of place. Why?” He shrugged. “Again, just a hunch, an impression.” He paused again, and the slow smoke drifted upward.

“If I'm granted the premise that a black, dead star is approaching the Solar System, then my theorizing may seem more logical. You agree?” The listeners nodded and Arcot continued. “Well—I had an idea—and when I went downstairs for the handling machine, I called the Lunar Observatory.” He couldn't quite keep a note of triumph out of his voice. “Gentlemen—some of the planets have been misbehaving! The outermost planets, and even some of those closer to the sun have not been moving as they should. A celestial body of appreciable mass is approaching the System; though thus far nothing has been seen of the visitor!”

A hubbub of excited comment followed this startling revelation. Arcot quieted them with an upraised hand. “The only reason you and the world at large haven't heard about this as yet is the fact that the perturbation of the planets is so very slight that the astronomers figured they might have made an error in calculation. They're rechecking now for mistakes.

“To get back to my visualization—It must have been many millions of years ago that life developed on the planets of the black star, a warm sun then, for it was much younger. It was probably rather dim as suns go even its younger days. Remember, our own sun is well above average in brilliance and heat radiation.

“In those long-gone ages I can imagine a race much like ours developing, differing chemically, in their atmosphere of hydrogen; but the chemical body is not what makes the race, it's the thought process. They must have developed, and then as their science grew, their sun waned. Dimmer and dimmer it became, until their planets could not maintain life naturally. Then they had to heat them artificially. There is no question as to their source of power; they had to use the energy of matter—so called atomic energy—for no other source would be great enough to do what had to be done. It is probable that their science had developed this long before their great need arose.