Twenty-odd years before, when the then Dauntless and her crew were thrown

out of a hyper-spatial tube and into that highly enigmatic Nth space, La Verne

Thorndyke had been Chief Technician. Mentor of Arisia found them, and put into the

mind of Sir Austin Cardynge, mathematician extraordinary, the knowledge of how to find

the way back to normal space. Thorndyke, working under nerve-shattering difficulties,

had been in charge of building the machines which were to enable the vessel to return

to her home space. He built them. She returned.

     He was now again in charge, and every man of his present crew had been a

member of his former one. He did not command the space-ship or her regular crew, of

course, but they did not count. Not one of those kids would be allowed to set foot on the

fantastically dangerous planet to which the inertialess Space Laboratory Twelve was

anchored.

     Older, leaner, grayer, he was now, even more than then, Civilization's Past

Master of Mechanism. If anything could be built, "Thorny" Thorndyke could build it. If it

couldn't be built, he could build something just as good.

     He lined his crew up for inspection; men who, although many of them had as

much rank and had had as many years of as much authority as their present boss, had

been working for days to forget as completely as possible their executive positions and

responsibilities. Each man wore not one, but three, personal neutralizers; one inside

and two outside of his space-suit. Thorndyke, walking down the line, applied his test-kit

to each individual neutralize!-. He then tested his own. QX—all were at max.

     "Fellows," he said then, "you all remember what it was like last time. This is going

to be the same, except more so and for a longer time. How we did it before without any

casualties I'll never know. If we can do it again it'll be a major miracle, no less. Before,

all we had to do was to build a couple of small generators and some controls out of stuff

native to the planet, and we didn't find that any too easy a job. This time, for a starter,

we've got to build a Bergenholm big enough to free the whole planet; after which we

install the Bergs, tube-generators, atomic blasts, and other stuff we brought along.

     "But that native Berg is going to be a Class A Prime headache, and until we get it

running it's going to be hell on wheels. The only way we can get away with it is to check

and re-check every thing and every step. Check, check, double-check; then go back

and double-check again.

     "Remember that the fundamental characteristics of this Nth space are such that

inert matter can travel faster than light; and remember, every second of the time, that

our intrinsic velocity is something like fifteen lights relative to anything solid in this

space. I want every one of you to picture himself going inert accidentally. You might

take a tangent course or higher—but you might not, too. And it wouldn't only kill the one

who did it. It wouldn't only spoil our record. It could very easily kill us all and make a

crater full of boiling metal out of our whole installation. So BE CAREFUL! Also bear in

mind that one piece, however small, of this planet's material, accidentally brought

aboard, might wreck the Dauntless. Any questions?"

     "If the fundamental characteristics—constants—of this space are so different,

how do you know that the stuff will work here?"

     "Well, the stuff we built here before worked. The Arisians told Kit Kinnison that

two of the fundamentals, mass and length, are about normal. Time is a lot different, so

that we can't compute power-to-mass ratios and so on, but we'll have enough power,

anyway, to get any speed we can use." "I see. We miss the really fancy stuff?" "Yes.

Well, the quicker we get started the quicker we'll get done. Let's go."

     The planet was airless, waterless, desolate; a chaotic jumble of huge and jagged

fragments of various metals in a non-metallic continuous phase. It was as though some

playful child-giant of space had poured dipperfuis of silver, of iron, of copper, and of

other granulated pure metals into a tank of something else—and then, tired of play, had

thrown the whole mess away!

     Neither the metals nor the non-metallic substances were either hot or cold. They

had no apparent temperature, to thermometers or to the "feelers" of the suits. The

machines which these men had built so long before had not changed in any particular.

They still functioned perfectly: no spot of rust or corrosion or erosion marred any part.

This, at least, was good news.

     Inertialess machines, extravagantly equipped with devices to keep them

inertialess, were taken "ashore"; nor were any of these ever to be returned to the ship.

Kinnison had ordered and reiterated that no unnecessary chances were to be taken of

getting any particle of Nth-space stuff aboard Space Laboratory Twelve, and none were

taken.

     Since men cannot work indefinitely in space-suits, each man had periodically to

be relieved; but each such relief amounted almost to an operation. Before he left the

planet his suit was scrubbed, rinsed, and dried. In the vessel's airlock it was air-blasted

again before the outer port was closed. He unshelled in the lock and left his suit

there—everything which had come into contact with Nth-space matter either would be

left on the planet's surface or would be jettisoned before the vessel was again inerted.

Unnecessary precautions? Perhaps—but Thorndyke and his crew returned unharmed

to normal space in undamaged ships.

     Finally the Bergenholm was done;.by dint of what improvisation, substitutions

and artifice only "Thorny" Thorndyke ever knew; at what strain and cost was evidenced

by the gaunt bodies and haggard faces of his overworked and under-slept crew. To

those experts and particularly to Thorndyke, the thing was not a good job. It was not

quiet, nor smooth. It was not in balance, statically, dynamically, or electrically. The Chief

Technician, to whom a meter-jump of one and a half thousandths had always been a

matter of grave concern, swore feelingly in all the planetary languages he knew when

he saw what those meters were doing.

     He scowled morosely. There might have been poorer machines built sometime,

somewhere, he supposed—but damned if he had ever seen any!

     But the improvised Berg ran, and kept on running. The planet became inertialess

and remained that way. For hours, then, Thorndyke climbed over and around and

through the Brobdingnagian fabrication, testing and checking the operation of every

part. Finally he climbed down and reported to his waiting crew.

     "QX, fellows, a nice job. A hell of a good job, in fact, considering—even though

we all know that it isn't what any of us would call a good machine. Part of that meter-

jump, of course, is due to the fact that nothing about the heap is true or balanced, but

most of it must be due to this cockeyed ether. Anyway, none of it is due to the usual

causes—loose bars and faulty insulation. So my best guess is that she'll keep on doing

her stuff while we do ours. One sure thing, she isn't going to fall apart, even under that

ungodly knocking; and I don't think she'll shake herself off of the planet."

     After Thorndyke's somewhat less than enthusiastic approval of his brain-child,

the adventurers into that fantastic region attacked the second phase of their project. The

planetary Bergenholm was landed and set up. Its meters jumped, too, but the engineers

were no longer worried about that. That machine would run indefinitely. Pits were dug.

Atomic blasts and other engines were installed; as were many exceedingly complex

instruments and mechanisms. A few tons of foreign matter on the planet's surface would

now make no difference; but there was no relaxation of the extreme precautions against

the transfer of any matter whatever from the planet to the space-ship.

     When the job was done, but before the clean-up, Thorndyke called his crew into

conference.

     "Fellows, I know just what a God-awful shellacking you've been taking. We all

feel as though we'd been on a Delgonian clambake. Nevertheless, I've got to tell you

something. Kinnison said that if we could get this one fixed up without too much trouble,

it'd be a mighty good idea to have two of them. What do you say? Did we have too

much trouble?"

     He got exactly the reaction he had expected.

     "Lead us to it!"

     "Pick out the one you want!"

     "Trouble? Hell, no! If this scrap-heap we built held together this long, she'll run for

years. We can tow her on a tractor-pressor combo, match intrinsics with clamp-on

drivers, and mount her anywhere!"

     Another metal-studded, barren, lifeless world was therefore found and prepared;

and no real argument arose until Thorndyke broached the matter of selecting the two

men who were to stay with him and Henderson in the two lifeboats which were to

remain for a time near the two loose planets after Space Laboratory Twelve had

returned to normal space. Everybody wanted to stay. Each one was going to stay, too,

by all the gods of space, if he had to pull rank to do it!

     "Hold it!" Thorndyke commanded. "We'll do the same as we did before, then, by

drawing lots. Quartermaster Allerdyce . . ."

     "Not by a damn sight!" Uhlenhuth, formerly Atomic Technician 1/c, objected

vigorously, and was supported by several others. "He's too clever with his fingers—look

what he did to the original draw! We're not squawking about that one, you

understand—a little fixing was QX back there— but this one's got to be on the level."

     "Now that you mention it, I do remember hearing about the laws of chance being

jimmied a bit " Thorndyke grinned broadly. "So you hold the pot yourself, Uhly, and

Hank and I will each pull out one name."

     So it was. Henderson drew Uhlenhuth, to that burly admiral's loud delight, and

Thorndyke drew Nelson, the erstwhile chief communications officer. The two lifeboats

disembarked, each near one of the newly "loosened" planets. Two men would stay on

or near each of those planets, to be sure that all the machinery functioned perfectly.

They would stay there until the atomic blasts went into action and it became clear that

the Arisians would need no help in navigating those tremendous globes through Nth

space to the points at which two hyper-spatial tubes were soon to appear.

     Long before the advance scouts of Grand Fleet were within surveying distance of

Floor, Kit and his sisters had spread a completely detailed chart of its defenses in the

tactical tank. A white star represented Floor's sun; a white sphere the planet itself; white

Ryerson string-lights marked a portion of the planetary orbit. Points of white light,

practically all of which were connected to the white sphere by red string-lights, marked

the directions of neighboring stars and the existence of sunbeams, installed and ready.

Pink globes were loose planets; purple ones negaspheres; red points of light were, as

before, Boskonian task-force fleets. Blues were mobile fortresses; bands of canary

yellow and amber luminescence showed the locations and emplacements of sunbeam

grids and deflectors.

     Layer after layer of pinks, purples, and blues almost hid the brilliant white sphere

from sight. More layers of the same colors, not quite as dense, surrounded the entire

solar system. Yellow and amber bands were everywhere.

     Kinnison studied the thing briefly, whistling unmelodiously through his teeth. The

picture was familiar enough, since it duplicated in practically every respect the chart of

the neighborhood of the Patrol's own Ultra Prime, around Klovia. Those defenses simply

could not be cracked by any concentration possible of any mobile devices theretofore

employed in war.

     "Just about what we expected," Kinnison thought to the group at large. "Some

new stuff, but not much. What I want to know, Kit and the rest of you, is there anything

there that looks as though it was supposed to handle our new baby? Don't see anything,

myself."

     "There is not," Kit stated, definitely. "We looked. There couldn't be, anyway. It

can't be handled. Looking backwards at it, they may be able to reconstruct how it was

done, but in advance? No. Even Mentor couldn't—he had to call in a fellow who has

studied ultra-high mathematics for Klono-only-knows-how-many-millions of years to

compute the resultant vectors."

     Kit's use of the word "they", which of course meant Ploorans to everyone except

his sisters, concealed his knowledge of the fact that the Eddorians had taken over the

defense of Floor. Eddorians were handling those screens. Eddorians were directing and

correlating those far-flung task forces, with a precision which Kinnison soon noticed.

     "Much smoother work than I ever saw them do before," he commented.

"Suppose they have developed a Z9M9Z?"

     "Could be. They copied everything else you invented, why not that?" Again the

highly ambiguous "they". "No sign of it around Arisia, though—but maybe they didn't

think they'd need it there."

     "Or, more likely, they didn't want to risk it so far from home. We can tell better

after the mopping-up starts—if the widget performs as per specs . . . but if your dope is

right, this is about close enough. You might tip the boys off, and I'll call Mentor."

Kinnison could not reach Nth space, but it was no secret that Kit could.

     The terminus of one of the Patrol's hyper-spatial tubes erupted into space close

to Ploor. That such phenomena were expected was evident—a Boskonian fleet moved

promptly and smoothly to englobe it. But this was an Arisian tube; computed, installed,

and handled by Arisians. It would be in existence only three seconds; and anything the

fleet could do, even if it got there in nothing flat, would make no difference.

     To the observers in the Z9M9Z those three seconds stretched endlessly. What

would happen when that utterly foreign planet, with its absolutely impossible intrinsic

velocity of over fifteen times that of light, erupted into normal space and went inert?

Nobody, not even the Arisian, knew.

     Everybody there had seen pictures of what happened when the insignificant

mass of a space-ship, traveling at only a hundredth of the velocity of light, collided with

a planetoid. That was bad enough. This projectile, however, had a mass of about eight

times ten to the twenty-first power—an eight followed by twenty-one zeroes—metric

tons; would tend to travel fifteen hundred times as fast; and kinetic energy equals mass

times velocity squared.

     There seemed to be a theoretical possibility, since the mass would

instantaneously become some higher order of infinity, that all the matter in normal

space would coalesce with it in zero time; but Mentor had assured Kit that operators

would come into effect to prevent such an occurrence, and that untoward events would

be limited to a radius of ten or fifteen parsecs. Mentor could solve the problem in detail;

but since the solution would require some two hundred Klovian years and the event was

due to occur in two weeks . . .

     "How about the big computer at Ultra Prime?" Kinnison had asked, innocently.

"You know how fast that works."

     "Roughly two thousand years—if it could take that kind of math, which it can't,"

Kit had replied, and the subject had been dropped.

     Finally it happened. What happened? Even after the fact none of the observers

knew; nor did any except the L3's ever find out. The fuses of all the recorder and

analyzer circuits blew at once. Needles jumped instantly to maximum and wrapped

themselves around their stops. Charts and ultra-photographic films showed only straight

or curved lines running from the origin to and through the limits in zero time. Floor and

everything around it disappeared in an utterly indescribable and completely

incomprehensible blast of pure, wild, raw, uncontrolled and uncontrollable energy. The

infinitesimal fraction of that energy which was visible, heterodyned upon the ultra as it

was and screened as it was, blazed so savagely upon the plates that it seared the eyes.

     And if the events caused by the planet aimed at Floor were indescribable, what

can be said of those initiated by the one directed against Floor's sun?

     When the heat generated in the interior of a sun becomes greater than its

effective surface is able to radiate, that surface expands. If the expansion is not fast

enough, a more or less insignificant amount of the sun's material explodes, thus

enlarging by force the radiant surface to whatever extent is necessary to restore

equilibrium. Thus come into being the ordinary novae; suns which may for a few days or

for a few weeks radiate energy at a rate a few hundreds of thousands of times greater

than normal. Since ordinary novae can be produced at will by the collision of a planet

with a sun, the scientists of the Patrol had long since completed their studies of all the

phenomena involved.

     The mechanisms of super-novae, however, remained obscure. No adequate

instrumentation had been developed to study conclusively the occasional super-nova

which occurred naturally. No super-nova had ever been produced artificially—with all its

resources of mass, atomic energy, cosmic energy, and sunbeams, Civilization could

neither assemble nor concentrate enough power.

     At the impact of the second loose planet, accompanied by the excess energy of

its impossible and unattainable intrinsic velocity, Floor's sun became a super-nova. How

deeply the intruding thing penetrated, how much of the sun's mass exploded, never was

and perhaps never will be determined. The violence of the explosion was such,

however, that Klovian astronomers reported—a few years later—that it was radiating

energy at the rate of some five hundred and fifty million suns.

     Thus no attempt will be made to describe what happened when the planet from