by "Lensman" (with thanks to Alex Aplin) created 11/28/07
updated 9/24/08 with information from Juggler of Worlds [Spoiler alert: "The Borderland of Sol"]

Ye Editor wishes to thank Edward M. Lerner, co-author of Fleet of Worlds and Juggler of Worlds, for his input on this article, which has been updated to address some of his comments.

Outline

1. Overview
2. The Nature of Hyperspace and Hyperdrive
3. Hyperspace Singularities
4. The Hyperdrive Shunt
5. The Mass Pointer
6. Encountering a Singularity
7. Higher Quantum Levels
8. Hyperwave
9. The Hyperspace "Blind-Spot" Phenomenon
10. Tracking in Hyperspace
    
11. Tunesmith and the Monsters of Hyperspace
12. Slaver Hyperdrive
13. Theorem Summary

A. Overview

In the Known Space series, hyperspace is a domain (or condition of existence) outside the normal (Einsteinian) universe through which starships using hyperdrive can travel at superluminal (faster-than-light, or FTL) speed, and through which instantaneous messages can be sent using a hyperwave communicator. Standard hyperdrive, also called Quantum I hyperdrive, propels a starship at a speed of one lightyear per three days Beowulf Shaeffer states a Quantum I hyperdrive ship makes the trip from Jinx (Sirius) to We Made It (Procyon) in 12 days, at a distance of four light-years ("At the Core", Neutron Star p. 53).. The Long Shot, the only known starship with a Quantum II hyperdrive, travels at one light-year per 1.25 minutes "Sirius to Procyon is a distance of four light-years. Our ship would make the trip in five minutes" ("At the Core", Neutron Star p. 53)..

To safely travel in hyperspace, a starship must avoid coming close to any star or other significant mass. It must enter and exit hyperspace in "flat space", outside any gravitational singularity. In Sol System, the sun's singularity extends well beyond the orbit of Neptune Sol's singularity extends to "almost five light-hours" from Earth, which is about eight light-minutes from Sol ("The Borderland of Sol", Tales of Known Space p. 170). This works out to about 35-36 AU (Astronomical Units), and Neptune orbits at an average distance of 30.07 AU.. Smaller masses at closer distances also prevent a ship from safely entering hyperspace; even the mass of a large starship is sufficient if it is close enough "There was a ship," said Margo. "A big one. I noticed... it was inside the mass limit. I couldn't go into hyperspace until it left" ("Grendel", Neutron Star p. 245). .

To navigate in hyperspace, one must be able to perceive it in order to safely steer around dangerous masses. To perceive hyperspace, Humans require a mass pointer, also called mass indicator or mass sensor. This is a big transparent sphere with a number of green (or blue) lines radiating from the center. It is a psionic device, requiring a living mind to operate "At the Core", Neutron Star pp. 57-8. Some few Kzinti can perceive hyperspace directly; they need no mass pointer "Human beings can't look into the Blind Spot. Most would go mad. Some can use a mass pointer to steer through hyperspace and keep their sanity too. Some Kzinti can perceive hyperspace directly; their female kin have mated into the family of the Patriarch for half a thousand years" (Ringworld's Children ch. 6, p. 76). On the same page, Tunesmith asks a Puppeteer, "Hindmost, can you perceive hyperspace directly?" Hindmost answers "Yes.".

Humans, Kzinti, Jotoki and probably other species find hyperspace travel disturbing. Human minds refuse to see hyperspace, as do most Kzinti minds Beowulf Shaeffer (using the alias "Mart"), a Kzin named Fly-By-Night, and a Jotok named Paradoxical were in a spacecraft which went into hyperpace: "Space around me winked like an eye. I caught it happening and looked at the floor. Fly-By-Night looked up, and blinked at the distortion. 'Mart, I don't think... Mart? I'm blind.' [paragraph] Paradoxical was in a knot, his arms covering all of his eyes. [paragraph] 'Lost! Confused! Blind! How do you survive this?' the Jotok demanded. [...] 'Fly-By-Night, lower your head. Look at the floor. See the floor? Hold that pose.'" ("Fly-By-Night", Man-Kzin Wars IX p. 349) . If, for example, a window is present on a starship in hyperspace, the mind of a person looking at it "edits it out" of view by stretching the surrounding objects to fill in the space. This phenomenon is known as the "hyperspace blind-spot". But the psychological effect is not merely the normal "blind spot" of a Hman retina. It can drive some insane; they are said to have "blind-spot phobia" "At the Core", Neutron Star p. 57, and "Flatlander", Neutron Star pp. 131, 153, 165-7.

Hyperspace can also be used to send messages instantly, in a manner similar to a two-way radio. A hyperspace communicator is called a "hyperphone" "At the Core", Neutron Star p. 60 , "hyperwave radio" "Grendel", Neutron Star p. 245, or just a "hyperwave" "The Borderland of Sol", Tales of Known Space p. 170.

So much is established in the canon of Known Space. In the remainder of this article, Ye Editor will speculate on the nature of hyperspace, and the implications of how hyperdrive and hyperwave work. While we have attempted to adhere as closely as possible to the information given in the canon, it should be noted that some of our speculation ventures into the category of "fan theory" (or more accurately, one fan's hypothesis).

B. The Nature of Hyperspace and Hyperdrive

What is hyperspace? Unfortunately, the short answer is: We don't know. It appears that in Human Space, hyperdrive is used empirically; that is, without understanding its true nature. This is perhaps analogous to how electricity was used, empirically, to light the great cities of the world beginning in the 1880s; yet the electron was not discovered until 1897. Sigmund Ausfaller said "We do not understand hyperspace, even yet [in 2651]. Remember that we did not invent the hyperdrive; we bought it from an alien race" "The Borderland of Sol", Tales of Known Space p. 172.

Hyperspace holds unknown dangers even for Puppeteers, who clearly understand hyperspace better than Humans do, as they developed the Quantum II hyperdrive. Nessus said:

"Ships disappear in the Blind Spot. No puppeteer would go too near a singularity in hyperdrive; yet still they disappeared, in the days when our ships carried pilots. I trust the engineers who built the Liar. ... But even the engineers fear the Blind Spot." Ringworld ch. 8, p. 103

Although hyperspace is never defined, there is some discussion of the mathematics. Tunesmith, a Ringworld protector, said:

"The universe accessed through the Outsider drive corresponds to our own Einstein universe, point-to-point, but there are fixed velocities, quantized.
"You're aware that you can map any part of a mathematical domain onto the whole domain? For every point in one domain, you can place a unique point in the other." Ringworld's Children ch. 6, p. 73M

One thing seems certain: hyperdrive causes a starship to travel at a fixed speed, an unvarying "quantum" speed. When a starship enters hyperspace, it immediately attains the velocity of one light-year per three days; it can neither slow down nor speed up. This is made quite explicit in the labels "quantum I" and "quantum II" hyperdrive, and supported by such statements as "...the quantum II hyperdrive shunt... would move a ship a light year in one-and-a-quarter minutes, where conventional craft would cross that distance in three days" Ringworld ch. 2, p. 21.

This appears analogous to the movement of a photon in normal (Einsteinian) space: In a vacuum, it always moves at the fixed speed of 186,282 miles per second. Once a photon begins moving, no further energy is needed to keep it moving at that speed. The latter seems also true of hyperdrive, as we shall detail below.

Note also that a ship in hyperdrive can be steered, yet it continues at the same fixed velocity no matter which direction it moves "A star came toward me, and I dodged around it. I thought that another line [in the mass pointer] that didn't point quite straight ahead was long enough to show a dangerous mass, so I dodged. That put a blue dwarf right in front of me. I shifted fast..." ("At the Core", Neutron Star p. 58) . Thus, the fixed speed cannot be attributed to mere inertia.

This leads us to:

Theorem 1: A ship in hyperspace acts as a supermassive quantum particle, moving at an unvarying speed entirely determined by the quantum level of its hyperdrive motor. This speed is unaffected by other factors such as the ship's mass or shape, the amount of power supplied to its motor, or changes in direction of flight.

C. Hyperspace Singularities

"There are singularities in the mathematics of hyperspace. One such singularity surrounds every sufficiently large mass in the Einsteinian universe. Outside of these singularities, ships can travel faster than light. Inside, they disappear if they try it" Ringworld ch. 5, p. 58. This seems straightforward enough, although it should be noted a Ringworld protector, Tunesmith, offered a radically different theory. But to simplify things, we'll deal with that later in this article.

The singularity surrounding Sol (Earth's sun) extends to a radius of almost five light-hours "...almost five light-hours inward from the edge of the singularity inward to Earth" ("The Borderland of Sol", Tales of Known Space p. 170). Earth is only eight light-minutes from Sol. This is about 35-36 AU (Astronomical Units); in comparison, Neptune's average distance from Sol is 30.07 AU. In sharp contrast, Beowulf Shaeffer in the Skydiver was able to exit hyperspace only a million miles from the neutron star BVS-1 "The Skydiver dropped out of hyperspace an even million miles above the neutron star" ("Neutron Star", Neutron Star p. 9)., although that masses 1.3 times Sol's mass. Apparently the radius of the singularity is highly dependent on the density of the astronomical body in question, suggesting this rule of thumb: "For astronomical bodies of a given mass, the denser the body, the smaller the singularity."

What is the smallest mass which will make a ship in hyperspace disappear? Carlos Wu theorized "Planet size, Mars and up. Beyond that it depends on how close you get and how dense it is. If it's dense enough it can be less massive and still flip you out of the universe" "The Borderland of Sol", Tales of Known Space p. 166.

In "The Borderland of Sol", the starship Hobo Kelly was in hyperspace when it had a close encounter with a quantum black hole (a microscopic primordial black hole), which wrenched away its hyperdrive shunt and caused the ship to drop back into Einsteinian space. It isn't clear how close the ship came to the quantum black hole (QBH), but apparently it was within visual distance of some "space tugs" which were towing the tiny singularity, and therefore presumably was within a few dozen miles or less.

D. The Hyperdrive Shunt

Although a hyperdrive "shunt", or motor, is mentioned in several stories, and the appearance of one is described in The Ringworld Engineers, little if anything is said about how the device works. Why is a hyperdrive motor called a "shunt", and does this suggest anything? Merriam-Webster's Collegiate Dictionary defines "shunt" as "a means or mechanism for turning or thrusting aside". We infer this is an indication the hyperdrive motor thrusts, or "shunts", the starship into hyperspace. This function appears compatible with Theorem 1; the hyperdrive motor needs only "shunt" a ship into hyperspace, after which it will move at hyperdrive speed with no further energy expended.

However, there are three indications this is not a complete explanation: (a) If a ship doesn't require energy to remain in hyperspace, how can a ship "drop out" of hyperspace? "The Skydiver dropped out of hyperspace an even million miles above the neutron star" ("Neutron Star", Neutron Star p. 9). Shouldn't the hyperdrive shunt have to thrust it back into normal space? (b) The Hobo Kelly's encounter with the QBH gives more clues. When the hyperdrive shunt was wrenched out of the ship, it immediately dropped into normal space. If the motor isn't needed to keep the ship in hyperspace, why did it drop out? (c) After the motor disappeared, Beowulf Shaeffer noted "The motor was drawing no power..." "The Borderland of Sol", Tales of Known Space p. 167. Why would the motor normally be drawing power while flying through hyperspace?

Another question relating to the hyperdrive shunt: How is a starship steered? It appears that hyperspace is frictionless; there's no air, water or other fluid medium for a ship's rudder to push against to change course. What method is used?

In answer to these questions, we propose:

Theorem 2: The function of the hyperdrive shunt is to thrust a starship into hyperspace; or more precisely, thrust a "bubble" of Einsteinian space containing the starship into hyperspace. Maintaining this bubble inside hyperspace requires continual thrust, and continual application of power, unless the ship enters a singularity. Corollary (speculative): Although it provides no propulsion, this thrust can be controlled in a manner which allows the ship to be steered.

We acknowledge there's no actual evidence for the corollary given, regarding how the ship is steered. However, since it's established that starships can be steered in hyperspace, this seems as good an explanation as any.

E. The Mass Pointer

Star pilot Beowulf Shaeffer stated "We wouldn't need pilots if the mass pointer could be hooked into an autopilot, but it can't. Dependable as it is, accurate as it is, the mass pointer is a psionic device. It needs a mind to work it" "At the Core", Neutron Star pp. 57-8. However, despite this and similar statements, autopilots are regularly used to fly starships Commercial starship pilot Beowulf Shaffer states "...the autopilot did everything for me except wear the uniform" ("At the Core", Neutron Star p. 53). , and there is one documented instance of a hyperdrive cargo ship "flown by computer" "Grendel", Neutron Star p. 250.

Perhaps the situation is better summed up as: "Ships fly themselves in hyperdrive. All a pilot need do is watch for green radial lines in the mass sensor. But he has to do that frequently, because the mass sensor is a psionic device; it must be watched by a mind, not another machine" "The Borderland of Sol", Tales of Known Space p. 166.

Therefore, it seems reasonable to conclude:

Theorem 3: For dynamic or responsive navigation in hyperspace, the pilot must be able to perceive masses in hyperspace. Humans require a psionic device, the mass pointer, to perceive anything. A small percentage of Kzinti, and at least some Puppeteers, can perceive hyperspace directly. However, on a regular route, where the course has been thoroughly surveyed and all gravity wells are accurately mapped, it is possible for an autopilot to fly the ship "blind" (using an inertial navigation system) on a pre-set course.

Presumably what is being perceived, either directly or in the mass pointer, is gravity wells. However, Tunesmith suggested otherwise; see below. Carlos Wu and Beowulf Shaeffer discussed the minimum mass necessary to cause a ship to disappear while traveling in hyperspace. Carlos said that even if a mass were much smaller and denser than normal for a planet or star (as with a neutronium "moon", or a QBH), "...you'd see it in the mass sensor." But Bey replied "Only for an instant..." ibid.

Evidence in varous accounts suggests any Human can use a mass pointer, although Human protectors cannot When Lous Wu was turned into a protector, he lost the ability to use a mass pointer (Ringworld's Children ch. 21, hc pp. 277-8). When he later was returned to breeder stage (a non-protector), he was again able to use the mass pointer (ch. 22, hc p. 284).. It is well established that some few Kzinti can perceive hyperspace directly "Some Kzinti can perceive hyperspace directly; their female kin have mated into the family of the Patriarch for half a thousand years" (Ringworld's Children ch. 6, hc p. 76). , which gives them status as other Kzinti are unable to navigate in hyperspace. However, the evidence regarding Puppeteers appears contradictory. Hindmost told Tunesmith he could percieve hyperspace directly When Tunesmith asked "Hindmost, can you perceive hyperspace directly?", the Puppeteer replied "Yes" (Ringworld's Children ch. 6, hc p. 76)., yet Nessus used a mass pointer on his own starship "From heads held far apart Nessus stared into the masss pointer, the transparent sphere that was the heart of Aegis' navigational console" (Juggler of Worlds ch. 29, hc p. 137). . We speculate that Nessus could perceive hyperspace directly, but chose not to because opaque spacecraft walls made him feel safer.

There is one aspect of using the mass pointer which doesn't seem to add up. Beowulf Shaeffer stated that when he was working as a commercial starship pilot, he typically checked the mass pointer "every six hours or so" "At the Core", Neutron Star p. 58. The speed of travel for Quantum I hyperdrive is one light-year per three days. Stars are not so closely spaced in the Known Space area of the galaxy. For example, it's 3.5 light-years from Sol to the nearest star; a 10.5 day journey. For most of the duration of a flight, wouldn't checking the mass pointer just once every few days be sufficient? Generally speaking, the actual reason for such frequent checking of the mass pointer is due to the psychology of the Blind-Spot phenomenon; see below.

F. Encountering a Singularity

What happens when a ship in hyperspace encounters a singularity? Carlos Wu theorized "...this is one well-established model of what happens when a motor hits a singularity... the motor would take the whole ship with it, then strew atoms of the ship along its path till there was nothing left but the hyperdrive field itself7quot; "The Borderland of Sol", Tales of Known Space p. 170. Note this is a strong indication that a ship in hyperspace acts as a super-massive quantum particle. If the hyperdrive field itself could continue on its way even after the ship was destroyed, then clearly it needs no power input to continue moving in hyperspace. This supports Theorem 1.

When the Hobo Kelly encountered the QBH while traveling in hyperspace, its motor entirely disappeared, leaving not even an exit hole. On this occasion, Carlos Wu theorized "The motor hit that, wrapped space around itself and took off at some higher level of hyperdrive, one we can't reach. By now it could be well on its way to the edge of the universe" ibid. Why did the QBH's singularity "swallow" only the motor, whereas a star's singularity (apparently) swallows the entire ship? Compared to a star's singularity, the QBH's singularity was tiny and had a very steep gravity well. The more limited effect might be a consequence of the singularity's relatively tiny size. However, Carlos Wu's theorized: "Well, this business of a hyperdrive motor disappearing and leaving the ship behind— that's brand new. I'd think it would take a sharp gravity gradient, with a tidal effect as strong as that of a neutron star or a black hole" "The Borderland of Sol7quot;, Tales of Known Space p. 187 . This is apparently supported by the fact that the Hobo Kelly "lurched savagely" "The Borderland of Sol", Tales of Known Space p. 167 when its hyperdrive shunt disappeared, suggesting the motor was wrenched so strongly and suddenly that it was pulled free of the ship.

Now, why did Carlos Wu theorize the Hobo Kelly's hyperdrive motor might have taken off for "the edge of the universe" after being disconnected from power? And why is it that no starship entering a singularity has ever been heard from again? Couldn't the pilot just shut off the hyperdrive and drop back into Einsteinian space?

If Carlos is right, then the hyperdrive field itself, the "supermassive quantum particle", continues in a higher quantum level, but the objects from Einsteinian space within the field are destroyed. Why? As noted in Theorem 2, it takes power to maintain a "bubble" of Einsteinian space in hyperspace. We suggest the quantum jump between hyperdrive speeds is accompanied by a similar quantum jump in the energy required to maintain the "bubble". In simple terms, if the ship is pulled into a deeper quantum level of hyperspace, then the bubble bursts. In more technical terms: A physical object's structural strength, shape etc. are a property of inter-atomic and molecular bonds. The "physical laws" of hyperspace are such that those bonds break down. So when the field maintaining the integrity of the Einsteinian space "bubble" fails, the objects within disintegrate. This is why a hyperdrive field with a "burst bubble" would "strew atoms of the ship along its path till there was nothing left but the hyperdrive field itself".

Presumably the Quantum II hyperdrive shunt creates a stronger "bubble", a field effect strong enough to maintain the Einsteinian space within the Quantum II level of hyperspace. This will not save the Long Shot if it encounters a singularity, because it will be pulled into an even deeper quantum level.

Theorem 4: A starship in hyperspace encountering a gravity well's singularity will be pulled into a deeper quantum level of hyperspace. If a sharp gravitational gradient is encountered, such as that from a neutron star or black hole, the effect may be limited to just part of the ship, particularly the space containing the hyperdrive shunt. When a ship (or part of a ship) is pulled into a deeper quantum level, the integrity of the Einsteinian space "bubble" is destroyed, whereupon any physical object within the hyperdrive field (that is, any object remaining in hyperspace) disintegrates.

G. Higher Quantum Levels

From the speeds quoted for Quantum I and Quantum II hyperdrive, Alex Aplin (a member of the Larryniven-l Internet discussion list) derived the formula:

V = C x e ^{4.801284071 x (Q 1.431365466)}

where V = velocity; C = speed of light; e = base of natural logarithm, 2.718281828; and Q = hyperdrive quantum level

Using this formula, the speed of higher quantum levels was extrapolated:

Quantum level	Speed times C	Travel time to galactic core
0	1	28,000 years
1	122	229.5 years
2	420,480	24.32 days
3	1.117 x 1010	79.11 seconds
4	1.470 x 1015	0.601 milliseconds

(The distance to the galactic core is estimated above at 28,000 light-years.)

H. Hyperwave

In addition to travel via hyperdrive, hyperspace allows radio-like communication via "hyperwave".

Hyperwave communication is said to be instantaneous "Fortunately hyperwave is instantaneous..." ("The Borderland of Sol", Tales of Known Space p. 170) . Apparently this is true even at galactic distances. While flying to the galactic core, Beowulf Shaeffer (Bey) held real-time conversations via hyperwave with a Puppeteer at Jinx, apparently with no communication lag "At the Core", Neutron Star pp. 59-60, 62, 64, 67. As Alex Aplin notes, Quantum IV speed would be sufficiently fast to allow such communication.

Theorem 5: Hyperwave, which allows instantaneous radio-like communication through hyperspace at galaxy-spanning distances, propagates at a speed of hyperspace Quantum IV or higher.

As with hyperdrive, hyperwave communication does not work within a gravitational singularity. For inhabited worlds, communications relay stations are placed just outside a star's singularity, with messages relayed to the planet via message laser "...every civilized system keeps a hyperwave relay station just outside the singularity. Southward Station would send our message inward by laser..." ("The Borderland of Sol", Tales of Known Space p. 170) . Turning on a hyperwave communicator within a gravitational singularity would cause it to explode Sigmund Ausfaller said "If we are still within the singularity of some mass, the hyperwave will destroy itself." Then Beowulf Shaeffer noted "We turned on the hyperwave and nothing exploded." ("The Borderland of Sol", Tales of Known Space p. 170).

Hyperwave is usually broadcast in all directions, as with a radio transmission, but can be made directional "No signs of settled worlds, but hyperwave signals. [...] And the signals are directional, so that we don't normally receive them" (Juggler of Worlds ch. 42, hc p. 197)..

For the sake of completeness, it should be noted that in two separate instances, it is said (or implied) that the deep-radar device uses a hyperwave pulse for radar-like detection and ranging "A deep-radar on high setting was an easy way to find Slaver stasis boxes, since only stasis fields and neutron stars would reflect a hyperwave pulse" ("The Soft Weapon", Neutron Star p. 78). "As he passed through the system, the deep-radar showed him planets like pale ghosts, light gray circles on the white screen. The G3 sun was a wide gray disc, darkening almost to black at the center. The near- black was degenerate matter... Nothing but stars and stasis boxes were dense enough to show black in the reflection of a hyperwave pulse" ("There Is a Tide", Tales of Known Space pp. 202-3).. There are two problems with this concept: First, it is stated deep-radar is used to detect objects within a star's or planet's gravity well, contradicting the concept that hyperwave doesn't function within such gravity wells. Second, as pointed out by Edward M. Lerner (co-author of the Known Space novel Fleet of Worlds): A hyperwave pulse travels instantaneously, making it impossible to use it for radar-like ranging. Such a measurement of distance depends on the length of time between a radar pulse and its return echo, but as hyperwave is instantaneous, there would be no delay between pulse and echo. All things considered, it seems best to ignore references to deep-radar using hyperwave pulses, and also ignore the one indication that deep-radar works instantaneously "I'll scan with deep-radar," Anne-Marie said helpfully. ... A moment later there was a beep. " ("The Soft Weapon", Neutron Star p. 77). In the more recent Fleet of Worlds, deep-radar uses neutrino pulses, which travel at near lightspeed Fleet of Worlds chapter 18 (hardcover p. 156). This retcon seems much more plausible.

J. The Hyperspace "Blind-Spot" Phenomenon

The Blind-Spot phenomenon is not only psychologically disturbing, it's insidious. Beowulf Shaeffer (Bey) had this to say:

When the hyperdrive goes on, it's like your blind spot expanding to take in all the windows. It's not that you don't see anything; you forget there's anything to see. If there's a window between the kitchen control bank and your print of Dali's "Spain," your eye and mind will put the picture right next to the kitchen bank, obliterating the space between. It takes getting used to, in fact has driven people insane... "At the Core", Neutron Star p. 57. If you look long enough enough, the Blind Spot starts to spread; the walls and the things against the walls draw even closer to the missing space, until they are engulfed.
It's all in your mind, they tell me. So? "Flatlander", Neutron Star p. 166-7

Bey had an even worse time when forced to fly through hyperspace in a ship with a missing hull. When he periodically had to crawl out of the habitat to check the mass pointer, half or more of his vision was Blind-Spot:

On my third trip I had the bad sense to look up— and went more than blind. Looking up, there was nothing at all in my field of vision, nothing but the Blind Spot.
It was more than blindness. A blind man, whose eyes have lost their function, at least remembers what things looked like. A man whose optic brain-center has been damaged doesn't. I could remember what I'd come out here for— to find out if there were masses near enough to harm us— but I couldn't remember how to do it. "Flatlander", Neutron Star p. 167

The psychologically disturbing effect of hyperspace flight also explains why the mass pointer is checked quite frequently:

Kirsten Quinn-Kovacs, alone on the bridge, studiously ignored the covered view port. ...
The nothingness that was hyperspace whispered to Kirsten, daring her to acknowledge its presence. She fixed her eyes instead on her console. The heart of the instrumentation was a large transparent sphere: the mass pointer. ...
Logic said that a glance every shift or two was more than sufficient— even at hyperdrive speed, they took three days to cross a light-year— but logic seemed a flimsy thing indeed while the nothingness stalked her mind Fleet of Worlds chapter 1 (hardcover pp. 24-5).

While some few Kzinti can perceive hyperspace directly, it affects most of them as it does humans. In "Fly-By-Night", the eponymous Kzin goes blind when exposed to the Blind Spot. A Jotok was also present, and the effect on it/them was even worse; it/they became agitated and confused. Beowulf Shaeffer (using the alias "Mart"), a Kzin named Fly-By-Night, and a Jotok named Paradoxical were in a spacecraft which went into hyperpace: "Space around me winked like an eye. I caught it happening and looked at the floor. Fly-By-Night looked up, and blinked at the distortion. 'Mart, I don't think... Mart? I'm blind.' [paragraph] Paradoxical was in a knot, his arms covering all of his eyes. [paragraph] 'Lost! Confused! Blind! How do you survive this?' the Jotok demanded. [...] 'Fly-By-Night, lower your head. Look at the floor. See the floor? Hold that pose.'" ("Fly-By-Night", Man-Kzin Wars IX p. 349). Although some Humans are driven insane by exposure to the Blind Spot, a later passage in "Fly-By-Night" suggests the problem is even more common among Kzinti Fly-By-Night, disguised as "Envoy", talked to a dominant Kzin about Packer, another Kzin: "'Dominant One... Packer looked on hyperspace.' [paragraph] 'He knew better!' [paragraph] 'Envoy' recoiled, then visibly pulled himself together. 'Soon or late, Dominant One, every Hero looks. Wealth and a name and the infinite future, if he has sisters and daughters, if he can stay sane. Packer did not. He hides in the waterfall [bathroom] when I let him. Set him in a hunting park soon or he will die.'" ("Fly-By-Night", Man-Kzin Wars IX p. 361).

Why is it the mind refuses to see hyperspace, and why is hyperspace flight so disturbing? We suggest it's because the nature of hyperspace is so alien, so psychologically and perhaps even psionically disturbing, that the Human mind doesn't merely refuse to acknowledge it; rather, the mind actively rejects its existence. This is of course an incomplete and unsatisfactory answer, but since all the canonical evidence is both subjective and psychological, it appears impossible to get a better understanding of this phenomenon.

Theorem 6: The hyperspace Blind-Spot phenomenon is entirely psychological in nature, and is a result of hyperspace being so alien, compared to normal experience, that a mind actively rejects its very existence.

K. Tracking in Hyperspace

[Spoiler alert: Juggler of Worlds]

"Radar," Carlos [Wu] said in wonder. "It could be hyperwave futzy radar."
[Sigmund Ausfaller replied,] "There's no such thing." But if there were, it would locate things instantaneously, wouldn't it? "Is there?"
"There could be." An eerie assurance settled over Carlos. "Well, not radar exactly. Hyperwave pulses travel instantaneously, as do their echoes. You can't calculate a distance from the round-trip delay time. But if you were to take bearings on a bunch of echoes... and if the receivers compared notes instantaneously..."
Then you have hyperwave radar.
Those hyperwave ripples! Those were the tracks of vessels stalking Hobo Kelly, chasing after it as it hyperspace-hopped around! Juggler of Worlds ch. 42, hc p. 198

Although it is never explained, presumably this is the same system the Puppeteers used on an earlier occasion to track the Puppet Master, the ship of the pirate calling himself "Captain Kidd,7quot; as related in "A Relic of the Empire". He later complained, "I still don't know how they tracked us. Maybe they've got something which can track a gravity warp moving faster than light. I wouldn't put it past them to build it just for us. Anyway, when we angled towards Jinx, we heard them telling the police of We Made It just where we were" "A Relic of the Empire", Neutron Star pp. 37-8.

L. Tunesmith and the Monsters of Hyperspace

[Spoiler alert: Ringworld's Children]

Tunesmith, a Ringworld protector, claimed the hyperspace theory used in Known Space was all wrong. He said "Louis, I don't think there's a mathematical singularity here at all" Ringworld's Children chapter 6 (hardcover p. 73). And he backed up his claim, by traveling in hyperspace within the gravity well of Ringworld's star!

Tunesmith also claimed that what minds perceive in a mass pointer is not the star's singularity, but the mass of dark matter which "huddles close around suns in this other domain you've been calling hyperspace" Ringworld's Children chapter 6 (hc p. 74). When flying through this dark matter region in hyperspace, it appears as "neon paint streaming through oil"ibid, a "boil of colors" Ringworld's Children chapter 21 (hc p. 274) , which in this article will be termed psychedelic hyperspace.

Tunesmith showed Louis pictures of "a deep violet comma-shaped shadow", prompting this exchange:

[Tunesmith said,] "We find life everywhere we look in this universe. Would it be surprising if an ecology has grown up within dark matter? And predators?"
Maybe Tunesmith was mad. Louis asked, "Are you suggesting that ships that use hyperdrive near a star are eaten?"
Tunesmith said, "Yes." ...
[Tunesmith continued,] "Certainly there are mathematics involved, but they may be more complex than just places where an equation gives infinities" Ringworld's Children chapter 6 (hc p. 75).

Can everything we thought we knew about hyperspace be wrong? At this point we should make it clear that what follows is our own fanfix hypothesis. It is not well supported by canon; in fact, it may be quite contrary to what Niven intended. However, we find it noteworthy that at no time are the supposed hyperspace monsters referred to by the third-person-omniscient narrator in the story. Is it mere coincidence that Niven seems to have left the monsters' existence open to question?

Evidence supporting Tunesmith's claims:

1. A few starships— but only ones which Tunesmith had made, altered, or at least entered— traveled in hyperspace within the Ringworld sun's gravity well; within what in previous stories was called the "singularity".

2. Most convincingly, later in the book Louis-monster (Louis Wu, changed into a protector) similarly used the Long Shot to travel in hyperspace within the gravity well of Ringworld's sun, launching right through the floor of the Ringworld (!) and observing psychedelic hyperspace Ringworld's Children chapter 21 (hc p. 274, 276).

3. When the Ringworld was traveling in hyperspace, from the Ringworld floor Wembleth and Roxanny saw the following: "A little black comma fell wiggling across the sky, starboard to port. It left a pockmark near the top of the rim wall, visible through mag specs" Ringworld's Children chapter 21 (hc p. 280)

Evidence contradicting Tunesmith's claims:

1. Psychedelic hyperspace appears very different from the Blind-Spot of "normal" hyperspace, yet was never previously mentioned in any Known Space story. It was unknown to Louis Wu, an experienced starship pilot. Is it reasonable to believe no Human starship pilot ever entered hyperspace prematurely— by a very few seconds— or exited it belatedly, and lived to tell about it? As described, the supposed hyperspace predators appear to move extremely fast in relation to a quantum I hyperdrive ship. But if normal hyperdrive ships could travel within the dark matter realm for very short periods, this ability should have been discovered during the period Humans were testing and developing hyperdrive technology.

2. Similarly, is it reasonable to believe that during the Man-Kzin Wars, no Human pilot "trapped" in a star's or planet's gravity well ever desperately tried to escape a Kzinti warship by entering hyperspace briefly?

3. The disappearance of Hobo Kelly's hyperdrive shunt when encountering the QBH cannot be explained by Tunesmith's theory. The ship wasn't eaten; only the motor was taken. We could hypothesize a tiny hyperspace predator, too small to eat the entire ship, which ate just the motor. But the mirror-like spherical surface left on the sheared-off motor mounts are not at all suggestive of a predator's bite marks; rather, they are suggestive of a fundamental phenomenon of physics.

4. Tunesmith's theory fails to explain why hyperwave doesn't work within a dark matter region, or why a hyperwave radio would explode if an attempt was made to use it in such a region. If hyperdrive travel is possible in a dark matter region, without real resistance— only slowed somewhat, as Tunesmith claimed— why can't hyperwave similarly function there at a slower speed?

5. The Long Shot was inside the Ringworld Repair Center, yet Louis-monster put the ship directly into hyperdrive and took it right through the floor of the Ringworld. This appears impossible for normal hyperdrive; note Captain Margo Tellefsen's statement that it wasn't safe for her ship to enter hyperdrive when another large starship was close "Grendel", Neutron Star p. 245.

Our conclusion:

We suggest Tunesmith lied. No real surprise there; protectors don't hesitate to lie when they think it will benefit them. Specifically, we suggest that Tunesmith devised a more complex mathematical model for hyperspace, allowing an improvement on Outsider hyperdrive, and altered the hyperdrive shunts of a few starships to operate according to this model.

Note that Tunesmith had access to every ship in the story which traveled in hyperspace within a star's gravity well. Perhaps significantly, he brought Louis along when the Long Shot was hijacked, ostensibly for Louis to pilot the ship, but then sent Louis back to the Needle. This gave Tunesmith the opportunity to alter the hyperdrive shunt(s) in the Long Shot without anyone else on board to observe, or even wonder what he was doing.

It seems reasonable to believe Tunesmith's claim that dark matter within a star's gravity well causes hyperdrive ships to travel slower in that region. Dark matter explains both the slower speed and the different appearance of psychedelic hyperspace.

Theorem 7 (speculative): Tunesmith developed a new mathematical model for hyperspace theory, and an improvement to Outsider hyperdrive based on that theory. He altered hyperdrive shunts of certain starships to operate accordingly, but obscured this fact. Tunesmith's improved hyperdrive can operate inside a star's or planet's gravity well, but normal hyperdrive ships still disappear if they attempt to operate in such regions.

Are hyperspace monsters real? They seem like something out of a pulp-era "scientifiction" story. The heading "Tunesmith and the Monsters of Hyperspace" is intended to suggest a story from that era. The "dark comma" which Wembleth and Roxanny saw when the Ringworld was in hyperspace appears to match what Tunesmith described as a hyperspace "predator". If it weren't for this, we would suggest the "violet comma" seen by Louis and Acolyte was an illusion projected by Tunesmith. However, it's possible what they saw was merely a physical phenomenon, perhaps merely turbulence in the dark matter region, or perhaps a fluctuation or instability in the hyperdrive field; there's no objective evidence that whatever made the divot on the Ringworld wall was alive.

We submit that whether or not it was alive, or was a predator, is largely unimportant. It appears that the existence or non-existence of hyperspace monsters has nothing to do with why standard hyperdrive shunts (and their ships), and hyperwave messages, disappear inside a gravity well.

So why did Tunesmith invent the supposed hyperspace monsters— or at least exaggerate their importance? If our theory is correct, his improved hyperdrive shunt gave him a military advantage in the Ringworld's Fringe War. It seems very likely he'd want to preserve that advantage as long as possible, and also discourage anyone else from making the same discovery. It appears that by claiming hyperspace monsters ate all starships previously attempting hyperdrive travel within a star's singularity, he was able to avoid admitting to Louis that he had invented an improvement on the hyperdrive. The "monsters" also make it seem that such travel is so dangerous that others may be discouraged from attempting to duplicate his feat.

Theorem 8 (speculative): The importance of hyperspace "monsters" was vastly overstated by Tunesmith. Even if the phenomenon he described as a "predator" is capable of "eating" a starship, this cannot account for every disappearance of a starship into a gravity well, nor why the presence of another large starship would interfere with entry into hyperspace. Nor do "hyperspace monsters" explain why hyperwave doesn't function within such a gravity well. Corollary: It seems quite possible that Tunesmith's claim was disinformation intended to hide the fact he had developed an improved hyperdrive.

M. Slaver Hyperdrive

The hyperdrive used by the Slaver Empire appears to function in a manner completely unlike the Outsider hyperdrive used by various species in Known Space. As described, the characteristics are:

1. Rather than flying through hyperspace, a Slaver starship jumps interstellar distances instantaneously, traveling in "a moment so short it had never been successfully measured..." World of Ptavvs p. 5.

2. Before making a jump, the ship must accelerate to 93% of lightspeed, "the speed at which the average mass of the universe becomes great enough to permit entry into hyperspace..." ibid.

3. The point at which a ship emerges from a jump cannot be controlled with any precision. While a single jump may carry a starship to the general vicinity of the destination, one or more smaller jumps will almost certainly be necessary to arrive at the actual star system which is the goal. "...luck, more than skill, decided when a hyperspace ship would make port. The Principle of Uncertainty is the law of hyperspace" ibid.

4. Between jumps, it takes a fusor (fusion reactor) several hours to recharge a "battery" for the next jump ibid. Perhaps this means the jump requires a massive surge of energy, and that a fusor charges a capacitor which provides the energy for the jump.

This isn't much to go on in developing a theory of how Slaver hyperdrive works. Some fans have suggested that the "jump" is a movement at Quantum III hyperdrive speed; they handwave away the difference implied in the requirement to enter hyperspace at a minimum of 93% lightspeed.

We suggest this is trying to force a square peg into a round hole, and that Slaver hyperdrive works on a fundamentally different principle. The quantum, unvarying speed of Outsider hyperdrive appears completely contrary to the Principle of Uncertainty of Slaver hyperdrive.

Fortunately, the story "One Face" appears to provide additional details on how this drive, or a very similar drive, operates. Although that story does not properly belong to the Known Space universe, Niven notes that he used ideas in the story which were later incorporated into Known Space Convergent Series, p. 23. The following can be gleaned from "One Face":

1. "...a Jumper creates an overspace in which the speed of light becomes infinite in the neighborhood of the ship... The speed of light goes all the way to infinity. Our speed is kept finite by the braking spine, which projects out of the effective neighborhood. Otherwise we'd go simultaneous: We'd be everywhere at once along a great circle of the universe" Convergent Series, pp. 29-30. Since a Slaver ship has no such spine sticking out of the field, we suggest that for Slaver hyperdrive, the speed of light in the neighborhood of the ship is is increased to an enormously high multiple of the norm, but does not actually become infinite.

2. "...the math of Jumper travel postulates a figure for the mass of a very large neighborhood, a neighborhood that takes in most of the local group of galaxies. That figure is almost twice the actual rest mass in the neighborhood. So we have to accelerate until the external universe is heavy enough for us to use the Jumper" Convergent Series, p. 35.

This appears to fit quite well into how Slaver drive operates, and provides sufficient detail for:

Theorem 9: Slaver hyperdrive works on a principle fundamentally different from Outsider hyperdrive. It performs instantaneous jumps, is capable of sending a ship sizable interstellar distances in a single jump, and has a large degree of uncertainty regarding the emergence point. The mathematics require the ship to accelerate to a minimum of 93% lightspeed, relative to the galaxy, before a jump can be initiated.

N. Theorem Summary

Theorem 1: A ship in hyperspace acts as a supermassive quantum particle, moving at an unvarying speed entirely determined by the quantum level of its hyperdrive motor. This speed is unaffected by other factors such as the ship's mass or shape, the amount of power supplied to its motor, or changes in direction of flight.

Theorem 2: The function of the hyperdrive shunt is to thrust a starship into hyperspace; or more precisely, thrust a "bubble" of Einsteinian space containing the starship into hyperspace. Maintaining this bubble inside hyperspace requires continual thrust, and continual application of power, unless the ship enters a singularity. Corollary (speculative): Although it provides no propulsion, this thrust can be controlled in a manner which allows the ship to be steered.

Theorem 3: For dynamic or responsive navigation in hyperspace, the pilot must be able to perceive masses in hyperspace. Humans require a psionic device, the mass pointer, to perceive anything. A small percentage of Kzinti, and at least some Puppeteers, can perceive hyperspace directly. However, on a regular route, where the course has been thoroughly surveyed and all gravity wells are accurately mapped, it is possible for an autopilot to fly the ship "blind" (using an inertial navigation system) on a pre-set course.

Theorem 4: A starship in hyperspace encountering a gravity well's singularity will be pulled into a deeper quantum level of hyperspace. If a sharp gravitational gradient is encountered, such as that from a neutron star or black hole, the effect may be limited to just part of the ship, particularly the space containing the hyperdrive shunt. When a ship (or part of a ship) is pulled into a deeper quantum level, the integrity of the Einsteinian space "bubble" is destroyed, whereupon any physical object within the hyperdrive field (that is, any object remaining in hyperspace) disintegrates.

Theorem 5: Hyperwave, which allows instantaneous radio-like communication through hyperspace at galaxy-spanning distances, propagates at a speed of hyperspace Quantum IV or higher.

Theorem 6: The hyperspace Blind-Spot phenomenon is entirely psychological in nature, and is a result of hyperspace being so alien, compared to normal experience, that a mind actively rejects its very existence.

Theorem 7 (speculative): Tunesmith developed a new mathematical model for hyperspace theory, and an improvement to Outsider hyperdrive based on that theory. He altered hyperdrive shunts of certain starships to operate accordingly, but obscured this fact. Tunesmith's improved hyperdrive can operate inside a star's or planet's gravity well, but normal hyperdrive ships still disappear if they attempt to operate in such regions.

Theorem 8 (speculative): The importance of hyperspace "monsters" was vastly overstated by Tunesmith. Even if the phenomenon he described as a "predator" is capable of "eating" a starship, this cannot account for every disappearance of a starship into any gravity well, nor why the presence of another large starship would interfere with entry into hyperspace. Nor do "hyperspace monsters" explain why hyperwave doesn't function within such a gravity well. Corollary: It seems quite possible that Tunesmith's claim was disinformation intended to hide the fact he had developed an improved hyperdrive.

Theorem 9: Slaver hyperdrive works on a principle fundamentally different from Outsider hyperdrive. It performs instantaneous jumps, is capable of traveling sizable interstellar distances in a single jump, and has a large degree of uncertainty regarding the emergence point. The mathematics require the ship to accelerate to a minimum of 93% lightspeed, relative to the galaxy, before a jump can be initiated.