Part 13 (1/2)
”As a driving device it might be set to pull the entire s.h.i.+p along, and still not have any acceleration detectable to the occupants.
”I think we'll use that on our big s.h.i.+p,” he finished, his eyes far away on some future idea.
”Natural gravity of natural matter is, luckily, not selective. It goes in all directions. But this artificial gravity is controlled so that it does not spread, and the result is that the ma.s.s-attraction of a ma.s.s of matter does not fall off as the inverse square of the distance, but like the ray from the parallel beam spotlight, continues undiminished.
”Actually, they create an exceedingly intense, exceedingly small gravitational field, and direct it in a straight line. The building up of this field is what takes time.”
Zezdon Afthen, who had a question which was troubling him, looked anxiously at his friends. Finally he broke into their thoughts which had been too cryptically abbreviated for him to follow, like the work of a professor solving some problem, his steps taken so swiftly and so abbreviated that their following was impossible to his students.
”But how is it that the machine is not moved when exerting such force on some other body?” he asked at last.
”Oh, the ray concentrates the gravitational force, and projects it. The actual strain is in s.p.a.ce. It is s.p.a.ce that takes the strain, but in normal cases, unless the ma.s.ses are very large, no considerable acceleration is produced over any great distance. That law operates in the case of the pulled body; it pulls the gravitational field as a normal field, the inverse-square law applying.
”But on the other hand, the gravity-beam pulls with a constant force.
”It might be likened to the light-pressure effects of a spotlight and a star. The spotlight would push the sun with a force that was constant; no matter what the distance, while the light pressure of the sun would vary as the inverse square of the distance.
”But remember, it is not a body that pulls another body, but a gravitational field that pulls another. The field is in s.p.a.ce. A normal field is necessarily attached to the matter that it represents, or that represents it as you prefer, but this artificial field has no connection in the form of matter. It is a product of a machine, and exists only as a strain in s.p.a.ce. To move it you must move all s.p.a.ce, since it, like artificial matter, exists only where it is created in s.p.a.ce.
”Do you see now why the law of action and reaction is apparently flouted? Actually the reaction is taken up by s.p.a.ce.”
Arcot rose, and stretched. Morey and Wade had been looking at him, and now they asked when he intended leaving for the intergalactic s.p.a.ces.
”Now, I think. We have a lot of work to do. At present we have the mathematics of the artificial matter to carry on, and the math of the artificial gravity to develop. We gave the Sirians all we had on artificial matter and on moleculars.
”They gave us all they had--which wasn't much beyond the artificial gravity, and a lot of work. At any rate, let's go!”
Chapter XIII
ATTACKED
The _Ancient Mariner_ stirred, and rose lightly from its place beside the city. Visible over the horizon now, and coming at terrific speed, was a fleet of seven Thessian s.h.i.+ps.
They must do their best to protect that city. Arcot turned the s.h.i.+p and called his decision to Morey. As he did so, one of the Thessian s.h.i.+ps suddenly swerved violently, and plunged downward. The attractive ray was in action. It struck the rocks of Neptune, and plunged in. Half buried, it stopped. Stopped--and backed out! The tremendously strong relux and lux had withstood the blow, and these strange, inhumanly powerful men had not been injured!
Two of the s.h.i.+ps darted toward him simultaneously, flas.h.i.+ng out molecular rays. The rays glanced off of Arcot's screen already in place, but the tubes were showing almost at once that this could not be sustained. It was evident that the swiftly approaching s.h.i.+ps would soon break down the s.h.i.+elds. Arcot turned the s.h.i.+p and drove to one side. His eyes went dead.
He cut into artificial s.p.a.ce, waited ten seconds, then cut back. The scene before him changed. It seemed a different world. The light was very dim, so dim he could scarcely see the images on the view plate.
They were so deep a red that they were very near to black. Even Sirius, the flaming blue-white star was red. The darting Thessian s.h.i.+ps were moving quite slowly now, moving at a speed that was easy to follow.
Their rays, before ionizing the air brilliantly red, were now dark. The instruments showed that the screen was no longer encountering serious loading, and, further, the load was coming in at a frequency harmlessly far down the radio spectrum!
Arcot stared in wide-eyed amazement. What could the Thessians have done that caused this change? He reached up and increased the amplification on the eyes to a point that made even the dim illumination sufficient.
Wade was staring in amazement, too.
”Lord! What an idea!” suddenly exclaimed Arcot.
Wade was staring at Arcot in equally great amazement. ”What's the secret?” he asked.