‘Captain-Administrator Wilson, Rim Territories Survey. I’ve been fascinated by van Noon’s treatise on the uses of unorthodoxy. It so happens that out on the Rim we have a good example of one of these intractable problems. It involves a large asteroid called Negrav, which is part of a complex binary-planet system in orbit around the star Springer 218G.’
Van Noon stole a look at Colonel Belling, whose expression of smug innocence confirmed his worst suspicions. This problem had been hand-picked by a master.
‘Perhaps I should explain,’ continued Wilson, ‘that the companion planet in the binary, tentatively named Leda-four, is a body of considerable interest to us because of its mineral resources. To gain maximum effect from our exploitation of these minerals, however, we require a three-year detailed space survey of Leda. It’s impossible to tie up a ship for this length of time, but an ideal observation platform would be the associated asteroid.’
Fritz van Noon listened to this with a patient frown. So far nothing unusual had emerged. Therefore, whatever the problem was, it had to be a honey.
Wilson was deliberately avoiding looking at Belling. ‘I said the asteroid was called Negrav. The reason for this is that the centrifugal force of its rotation at the equator exceeds the gravitational attraction of its mass. Thus, except at the poles it has a negative gravity averaging about point seven Terrestrial. Unfortunately, because of its spin alignment, it’s a point on the equator we need for observation.’
‘If I understand you rightly,’ said van Noon, ‘yours is a simple problem of securing an observatory on to a surface which exhibits an effective negative gravity. This is slightly more difficult than free-fall work, but not much. Any good adhesive can get you started, and once you’ve obtained a reasonable foothold, you can surely anchor into the surface by any of a great number of standard methods?’
Wilson took the point sedately, but caught Colonel Belling’s eye and was hard-put to restrain the amusement which welled suddenly inside him.
‘It’s not quite as easy as that,’ he said, striving to retain his academic pose. ‘I said that Leda was one of a binary pair. Negrav’s only an asteroid, and not large enough to effect the gravitational balance substantially. Rather, it functions as a satellite to the other component of the binary—which is a rather small black hole.’
‘A what?’ said van Noon, sitting down weakly.
‘A black hole,’ said Wilson, happily, under the approving eyes of his triumphant mentor. ‘The second component of the binary is a small black hole of roughly terran mass, which has an event horizon of about one centimetre.’
‘And Negrav is in orbit about this?’
‘A very close orbit.’
‘How close?’ asked Fritz suspiciously.
‘It actually shaves the surface. Our problem on Negrav isn’t getting an observatory to adhere, it’s how to stop it being eaten by the black hole in grazing orbit—no pun intended. Orthodoxy doesn’t have any good answers. I’d be interested in hearing the unorthodox approach.’
* * * *
Colonel Belling was still laughing the next morning. When van Noon received a summons to report to his superior’s office at the Engineering Reserve he sensed it was only so that salt could be rubbed into an already smarting wound. It made a change, however, to find his commanding officer in a congenial mood so early in the morning. This was a situation van Noon had plans to rectify.
‘Ah, Fritz! Sit down! I’ve to congratulate you. Your reputation for unorthodoxy is unimpaired. Nobody ever gave such an unorthodox reply to a question at a Space Engineering Symposium. I was particularly intrigued by what you told him to do with his black hole.’
‘It was deliberate provocation,’ said van Noon. ‘A put-up job designed to discredit unorthodox engineering.’
‘Which it did beautifully,’ said Belling, happily. ‘I always said I’d show you crackpots up for what you are.’
‘Then you haven’t heard yet?’ said Fritz, carefully.
‘Heard what?’ Belling’s suspicion hardened like a forgotten ladle of molten steel passing through cooling-point.
‘General Nash was in the assembly representing Space Engineering Command.’
‘Of course. What of it?’
‘Well, the Unorthodox Engineers have pulled him out of several holes in the past. I think he saw the chance to return the favour.’
‘What chance?’
‘That building an observatory on Negrav wasn’t entirely a leg-pull. With respect, Colonel, you were so busy looking at the absurdity of it, that you overlooked the possibility there might be a genuine need. It so happens there is a need. The Negrav-Leda complex promises to provide easily-won mineral resources for a large sector of the Rim, avoiding the long hauls from Terra.’
‘Go on, Fritz,’ said Belling, grimly.
‘Well, General Nash got together with the Director of the Space Territories Administration and offered to build the Negrav observatory for him. The Director was delighted, and an inter-Service contract was drawn up on the spot.’
‘And?’ asked Belling. He had the look of a man who knew what the answer must be, but hoped against hope that the truth could not be as bad as he imagined.
‘The contract makes this Engineering Reserve responsible for building the observatory,’ said Fritz. ‘That means it’ll be your pidgin.’
‘I’ll never forgive you for this, Fritz.’
‘But I did nothing. It was you who had the matter raised.’
‘I still shan’t forgive you. It has all the hallmarks of your devious organisation.’
‘And it raises a good question. Colonel. Who’re you going to send to Negrav? An orthodox engineering team—or a bunch of unorthodox crackpots?’
* * * *
‘I still think it was a heck of a tough way of proving your point,’ said Sergeant Jacko Hine.
Van Noon scowled at his second in command. ‘Not even Colonel Belling believes me, but I had nothing to do with us being sent to Negrav. The construction orders came down from General Nash, and Belling had to recant on his orthodox approach because there wasn’t an orthodox way to do it.’
‘I suppose it never occurred to you that there might not be an unorthodox way to do it, either?’
‘The thought did strike me, but I dismissed it as unlikely. Just how the heck we’re going to do it, I don’t have a clue at the moment. But at least it puts us marginally up on Belling’s approach.’
‘How do you figure that?’
‘Belling’s certain it can’t be done. I’m certain that it can. So all we have to figure out is how. That simplifies the problem no end.’
‘Not for me it doesn’t,’ said Jacko Hine. ‘You’d better clue me up on black holes. If we’re to tangle with one, I’d like to know something of the enemy.’
‘The classical theory’s that of the collapse of a burned-out star. Once a star’s used up its nuclear fuel the radiation pressures holding it up fall right away. It begins to contract under its own gravity. The size of the star controls how far the collapse can go. But for a star upwards of twice the mass of our own sun, no known physical process can prevent it continuing indefinitely. The whole star’s swallowed by its own gravitational pull. It creates a small region with such an intense gravitational field that not even light can escape from it—this is what’s known as the event horizon.’
‘Hence the name black hole?’
‘Sure. Light—or anything else for that matter—can be drawn into a black hole by the intense gravity, but nothing, including light, can ever get out again. It’s a one-way hole in space.’
‘What happens to the things it swallows?’
‘Virtually crushed out of existence. Everything, including the original star, ends up as a point of infinite density, which is known as a singularity. It’s the ultimate state in the compaction of matter.’
‘So how big is it?’
‘We don’t know about the size of the singularity; but the size of the event horizon is determined
by the mass contained in the singularity. For a collapsed star of around two solar masses, this would be a couple of kilometres in diameter.’
‘But Wilson was speaking of one about a centimetre in size.’
‘There’s another possible way by which black holes could have been formed. This is in the big bang which began the universe. Theory has it that baby black holes of a mass around ten to the minus five grammes and ten to the minus thirty-three centimetres in diameter could have been formed then and would have been wandering space ever since, consuming whatever mass they chanced to find in their travels. It’s entirely possible for one of these mini black holes to be able to eat an entire planet and still not finish up much larger than a marble. At a rough guess that’s what’s happened to Negrav.’
‘It gives me a very curious feeling,’ said Jacko, ‘to think of a little black hole which could eat a planet. The more I hear of this expedition, the less I begin to like it. As I said just now, I think you’ve chosen a heck of a tough way to prove your point.’
The hyper-ship of the S.T.A. had carried them out to Chronos, on the Rim. From there a slower Navy vessel— though still one with hyper-light capacity—had taken them on to the S.T.A. base on New Australia. By work-vessel it was then only a three week luminal trip to the star Springer 218G, with its curious binary satellite and the asteroid Negrav. When they were within two days of the Negrav contact, van Noon called a conference of his five-man team.
‘Now you’ve all read the preliminary S.T.A. survey report on Negrav. When we get within telescope range, we’ll be able to supplement what we know with our own observations. I hope to be able to discover a few items which the S.T.A. observers haven’t mentioned because they weren’t looking specifically for them. It’s highly unlikely that Negrav is totally composed of nickel-iron alloy, or that its entire surface is as smooth and unbroken as the S.T.A. report suggests. Initially we’ll need to establish a foothold, and this’ll have to be well below the orbital path of the black hole, so what we want particularly is a deep fissure or crack which we can hook into and work safely below the black hole.’
‘Check!’ said Jim Fanning, the U.E. geologist. “But if the S.T.A. photographs are to be believed, you’d stand more chance of hatching ball-bearings than you do of finding fissures in the surface of Negrav.’
‘I’m aware of that,’ said Fritz. ‘The theory’s that Negrav was once a full-sized planet, and all we see now is a remnant of the core. The rest of it’s been eaten by that darned black hole. But I’m hoping at least for a blowhole or some form of depression. The frequency with which the black hole sweeps the surface gives us less than thirty-six hours between touching the surface and getting safely tucked down underground out of its way.’
‘If I judge you right,’ said Jacko, ‘you’re thinking of building the observatory beneath the surface?’
‘We obviously can’t build on the surface, because anything on the surface gets eaten by the black hole. Besides which, it makes sense in other ways. Below the surface you don’t have to bring in construction materials. You simply carve out the shape of the cavity you want. Also you can make use of the negative gravity, because the centrifugal force’ll drift you towards the roof of the cavity, thus producing a semblance of positive gravity. Once the observers get used to making their observations by peering down through windows below their feet, it should be a fairly effective working situation.’
‘All of which sounds very nice,’ said Fanning. ‘But I foresee a couple of practical snags. Like how do we get in deep enough quick enough to avoid being eaten by the black hole? And having got into the surface, how do we carve an observatory-sized cavity in what promises to be a very strong nickel-iron alloy?’
‘I admit it may be tough,’ said van Noon.
‘Tough!’ Fanning was aghast. ‘Blasting won’t do much more than deform the surface, and oxy-acetylene cutting could take a lifetime—assuming you could get the supplies. So you’re largely back to processes like drilling and spark erosion plus the occasional handfile. At a rough guess, Colonel Belling was exactly right when he said it couldn’t be done.’
‘I’ve told you all before,’ said van Noon, sternly. ‘Physical limitations aren’t absolutes. They’re a state of mind. They said iron ships wouldn’t float. They reached that conclusion because they hadn’t taken all the facts into account. From this distance I can’t see the answer to the Negrav problem either. But I’m sure as hell there is one. All we have to do is find it.’
* * * *
When the S.T.A. work-vessel reached its keep-station around Negrav, subsequent observations did nothing to support van Noon’s optimism. Negrav was a ball of solid nickel-iron, and its surface was flawless and honed to a micro-finish which would have done credit to a precision ball-bearing. Because of its small size, the black hole was not visible even with the most powerful telescopes available. Its relentless orbit around Negrav—or rather the orbit of the asteroid around it, which came to the same thing relatively speaking—had for some millions of years ceased to take more than microns of further material from the surface.
Now the black hole’s path hovered millimetres above the surface of Negrav and pursued a progressive rotation which effectively swept the entire sphere over a period of thirty-six hours. The position of the black hole was known with mathematical certainty at any time, but liberation and other effects of the binary on the orbit of Negrav introduced an uncertainty factor. The black hole’s progress across the surface had to be described in terms of statistical paths rather than positional lines. In practice this meant that thirty-six hours was the longest period any point on the surface of Negrav could be guaranteed safe from the marauding black hole.
‘Which isn’t long enough,’ said Jacko Hine. ‘Working under space conditions and negative gravity, we wouldn’t have time to cut far enough into the surface to be any significant use. We’ve not only got to get into the hole, but around some considerable corner to prevent being drawn out by the black hole’s gravity.’
‘How far d’you estimate we could penetrate in thirty-six hours?’ asked van Noon.
‘If the spectroanalyses of the surface material are correct, we’d be hard put to remove more than a cubic metre with the tools available. And once we get deeper, the work would slow considerably because we could only keep one man at the face.’
‘That’s not good enough,’ said van Noon. ‘I’m going down to Negrav myself to study the problem from the surface.’
‘If it’s not a rude question, how do you intend to hold to the unbroken surface against negative gravity? Chewing gum?’
‘No, permanent magnets. Nickel-iron of that structure ought to be highly magnetic. If the negative gravity’s only point seven I should get all the attraction I need from a fairly small magnet pack.’
‘Here’s hoping the sunshine doesn’t take the surface over Curie point,’ said Jacko. ‘Else we’re going to have a right game fishing you out of orbit around the small black hole.’
If he was being strictly honest, even van Noon would have admitted his confidence had fled as the little lifecraft dropped him towards Negrav’s implacable surface. The nearer they approached, the more smooth and polished the asteroid’s surface appeared, until from twenty metres up he could see the perfect reflection of the lifecraft mirrored in the giant metal ball.
The first problem was to secure a contact with the surface. While the power manoeuvrings of the lifecraft could keep station over a particular point on the asteroid, the problem of trying to attach an assembled magnet package to the surface was akin to trying to throw it twenty metres vertically above his head. It was not until he had experienced the situation that he began to appreciate the reasonings behind Jacko’s assertion of impossibility. What he had failed to accept subconsciously was that any work in negative gravity was akin to working on the ceiling, and that any drilling would have to take place in a ‘hands down, feet out’ position, which was both unnerving and extremely tiring. Jacko’s estimate o
f a cubic metre of material removed in thirty-six hours began to look wildly optimistic.
After a series of hair-raising manoeuvres by the lifecraft, the pilot managed to bring van Noon within striking distance of the metal ‘ceiling’. After a few breathless moments, the magnet package stuck and the long cable trailed outwards with Fritz swinging uncertainly on the end of it. Thereafter he had to climb up the cable to reach his destination, which was no mean feat despite the lightweight flexibility of his spacesuit. This did not accord at all with his ideas on how a conquering hero, even an unorthodox one, should reach the planetary body of his choice.
Having secured himself in a nest on the cable, he began to probe the surface above him. A small drill bit cleanly but slowly into the metal surface, though he was afraid to exert too much pressure lest he should lever away the magnets which held him there. He dutifully collected samples of the swarf which came away, tapped the hole, and screwed in a prepared eyebolt to which he attached a second line. More secure now, he brought up a larger drill and drilled a hole sufficiently large for a second eyebolt to be inserted completely recessed below the surface.
New Writings in SF 25 - [Anthology] Page 8