Brainstorming a “Kitchen Sink“ Sci-Fi campaign

[Zardnaar]

That was my point earlier. An actual dinosaur killer size asteroid needs a lot of energy to get enough delta-V to accelerate it out of the Asteroid belt or trojan orbits. Lugging something big enough to do that insystem, and then doing the burn isn't going to be subtle. Even a burn to get it into a minimal energy orbit to intersect with your target planet is going to be pretty hard to overlook.

The minimal estimated size for the Chixulub impactor is about 2x10**12 tons. A minimal Jupiter-Earth transfer is about 3.1km/sec worth of delta-V, and that's an orbit that would take years to make the rendezvous with Earth. Even with a 100% efficient reaction drive, that's about 1.5x10**22J of energy, or equivalent to the explosive yield of 3.5x10**6 megatons that you have to somehow conceal while you accelerate the asteroid. Bearing in mind that at a relative velocity of 3km/sec the kinetic energy of an object is roughly equivalent to the explosive yield of its weight in TNT; attempting to sink even 1% waste energy into the object itself is going to make it quite warm.

A city killer could be a lot smaller, but that's some real precision sharpshooting to hit a city-sized target from Jupiter.

Having said this, although I think we now have a sense of the scale of the effort involved in humping dinosaur killers around a star system, we are also in the business of trying to apply real-world physics to a fantastic setting ...

I wouldn't worry about physics touch but would put that up there in terms of sci fi power. Not ringworlds or dyson level power but probably beyond Star Wars and Trek.

Using small asteroids accelerated a'la Mass Effect better idea.

 

[Eyes of Nine]

Randomly, it would be interesting to have the gates at 90 degrees to the plane of the elliptic

 

[Umbran]

I know this - reaction drives and guidance. It's pretty obvious when you're doing this, as an asteroid big enough to be a dinosaur killer needs a large drive and a naughty word-load of reaction mass to move it in any reasonable length of time.

Dude, we are talking about a culture that can to FTL jumps. They are NOT using chemical reactions to power ships of any sort. So, no huge plume of brightly burning gas to be seen by a telescope. There's probably a nice quiet ion drive back there - little reaction mass used. Cheap. Low thrust, low emissions. Gravity does most of the work for you.

Unless you can accelerate it to velocities in the 1,000's of km/sec it will still take months or years to get to an inner planet from the outer system.

Um, dude. The thing that actually killed the dinosaurs had no reaction mass at all. It just fell from the outer solar system to the inner system. Yes, it takes time. You lack patience, grasshopper?

Okay, so the Earth itself is moving at about 30 km/sec. You can pop a rock out of hyperspace dead still right in its path, and have that much relative velocity. WHAMMO!

If you've ever done an orbital rendezvous in Kerbal Space Program, hitting the sphere of influence of a planet, let alone the planet itself is not a trivial undertaking from (say) Jool to Kerbin. The asteroid will still need terminal guidance or a very precise initial shove indeed to hit the target.

So, what you are saying is... you, here and now in 2020, have the computer power on your own laptop sufficient enough to do that job. So, thank you for proving that the computing power for guidance isn't a barrier....

This will not be prevented by anything as simple as "where do you get the velocity" or "math is hard!" as if our aggressors are frelling Barbie. Which is why I ask why it doesn't happen.

 

[aramis erak]

Here's the secret - when you are dealing with space opera RPGs... the distances are arbitrary. Because you aren't going to have them hex-crawl through the galaxy. For one thing, it is a 3d volume, not a flat map. For another, the number of sites they can reach goes up too fast.

Many RPGs ignore the 3D. Probably the best known of these is Traveller.

For combat, many more ignore local 3D, even while doing 3D for interstellar.

If you go with big enough hexes, you can treat it as a single hex thick. The thickness is about 1 kPc; the Shapley center is 2 kPc across (and tall). It's 120 kPc across the disk.
the LMC is ~50 kpc away, 14 kPc diameter across the disk, probably under half a kpc thick, distorted barred spiral
the SMC is ~ 62 kpc away, between 7 and 12 kpc across, barred spiral
Sag dSph is roughly 50 kpc away from the galactic center, in a polar orbit... and what little I can glean, is a 7x14 stretched sphere.

Note at a scale of 1 kpc per hex, only the center hex of the Milky Way is 2 hexes thick.
The LMC is a 14 hex disk only 50 kpc from earth...
The SMC is a 7x14 oval.

All very mappable.

But at that scale, 1 week per hex means hitting the LMC in under a year, and crossing the MW is 2 years and 2 months, plus another two weeks to avoid the Shapley Center and the Sag A* within.

 

[Nobby-W]

Dude, we are talking about a culture that can to FTL jumps. They are NOT using chemical reactions to power ships of any sort. So, no huge plume of brightly burning gas to be seen by a telescope. There's probably a nice quiet ion drive back there - little reaction mass used. Cheap. Low thrust, low emissions. Gravity does most of the work for you.

This is a straw man argument. At no point did I state the use of chemical rockets. It doesn't matter how you generate the thrust, the energy used is still the same (give or take any waste energy coming off as heat) and the delta-V is still the same.

You're changing goalposts and assumptions. You're making an implict assumption that your technology of choice is stealthy on a scale of shifting a multi-billion ton asteroid. At no point have you stated this assumption or said anything to back up this argument.

Um, dude. The thing that actually killed the dinosaurs had no reaction mass at all. It just fell from the outer solar system to the inner system. Yes, it takes time. You lack patience, grasshopper?

This is a red herring fallacy - introducing irrelevancies. Of course the actual Chixulub impactor had no reaction mass - it wasn't being aimed artifically, but just happened to be on the right orbit to hit earth, so it didn't need it. The discussion is specifically about somebody artifically shifting the orbit of a dinosaur killer.

Okay, so the Earth itself is moving at about 30 km/sec. You can pop a rock out of hyperspace dead still right in its path, and have that much relative velocity. WHAMMO!

You're shifting goalposts again. Now implying that it's trivial to move a dinosaur-killer through hyperspace, a new set of arguments that wasn't brought up before. Nothing offered to substantiate it.

So, what you are saying is... you, here and now in 2020, have the computer power on your own laptop sufficient enough to do that job. So, thank you for proving that the computing power for guidance isn't a barrier....

This is another straw man argument. I never stated that computer power was an issue.

This will not be prevented by anything as simple as "where do you get the velocity" or "math is hard!" as if our aggressors are frelling Barbie. Which is why I ask why it doesn't happen.

This is a hasty generalisation, Just saying it's possible in principle and that some trivial things don't say it can't, therefore it will happen. You haven't engaged further to explain your arguement.

This is also a straw man argument. I never said it was impossible, just hard to do without being noticed and much easier to undo than to do in the first place.

I'm calling you out on this. There's almost nothing in your post that wasn't disingenuous in some way. Please don't do this sort of thing. There's no point in engaging stuff like this if you're not going to argue in good faith. You've avoided the original suggestion, which is that the large energy expenditure needed for the delta-V to shift a dinosaur killer makes it difficult to do without being noticed. Instead you've decided to poo-poo a strawman interpretation of the post with a series of rhetorical devices and introduce your own new set of assumptions without bothering to state them. You're clearly not discussing this in good faith but pulling out rhetorical tricks to win an argument. If you don't want to be dismissed as a troll I suggest you don't engage in this behaviour.

You've previously posed a question about why it wasn't going to happen and I stated a scenario, specifically that the very large energy expenditure makes it hard to do without being noticed. I may not have been clear about defence, but I'll clarify it now. If you catch it early enough, you only need a small amount of delta-v (most efficiently applied prograde or retrograde), to deflect its trajectory so it misses. That's orbital mechanics. Ergo, it's much easier to defend against such an attack than to make it, by several orders of magnitude. That's a conceit that you can put into your game without needing handwavium over and above the assumption that such an attack could be made in the first place. The same technology used to make the attack can be used to defend against it, but only needing to be deployed on a much smaller scale.

That's before one asks the question of whether the scale of this endeavour makes it cost effective anyway - given the fantastically large amount of energy involved, is it cheaper to do it some other way - perhaps just rock up with a fleet of warships and attack the planet in person?

 

[Nobby-W]

I wouldn't worry about physics touch but would put that up there in terms of sci fi power. Not ringworlds or dyson level power but probably beyond Star Wars and Trek.

Using small asteroids accelerated a'la Mass Effect better idea.

The other question is whether this is really cost-effective in the first place. Kinetic weapons are great, but do you need to do it on that scale? Even if you've got the resources to accelerate an asteroid to relativistic speeds, would it just be cheaper to turn up with a fleet of warships and attack the planet in person?

 

[Zardnaar]

The other question is whether this is really cost-effective in the first place. Kinetic weapons are great, but do you need to do it on that scale? Even if you've got the resources to accelerate an asteroid to relativistic speeds, would it just be cheaper to turn up with a fleet of warships and attack the planet in person?

Depends on the sci fi universe. Mass Effect you won't need a very large asteroid.

I'm not sure how many universes can do it. Star Wars sorta can in old legends but it's super weapons/precursor type stuff.

Thinking massive asteroids kilometers across, small ones a few universes can pull that off.

It's more if the galactic standard can do it reliably (Federation, Empire, Covenant, Empire of Man, Gou'Ald etc).

 

[Nobby-W]

Depends on the sci fi universe. Mass Effect you won't need a very large asteroid.

I'm not sure how many universes can do it. Star Wars sorta can in old legends but it's super weapons/precursor type stuff.

Thinking massive asteroids kilometers across, small ones a few universes can pull that off.

It's more if the galactic standard can do it reliably (Federation, Empire, Covenant, Empire of Man, Gou'Ald etc).

The question I put was more along the lines of "Is it cheaper to do it some other way?" There's a lot of handwavium involved in the assumption that you can accelerate an asteroid to relativistic speeds in the first place. One could do the maths, but it will come up with a very large number for even a small fraction of c, potentially even bigger than the dinosaur killer scenario. Also, at relativistic speeds, the impactor itself becomes vulnerable. Just getting something to collide with it on the way in could be enough to destroy it or scatter it into pieces harmlessly.

What was asked was "Why can't somebody do this?" The argument against it could be something along the lines of "Yes, you can do it, but it's infeasibly expensive due to the amount of energy involved, and comparatively easy to defend against. It's several orders of magnitude cheaper to warp a battlefleet into the system and attack the planet with that."

This argument turns up in Traveller circles on a semi-regular basis due to some poorly thought out setting conceits. IMO your core setting conceits are broken if you can't think of a reasonable way why folks don't do this. You don't have to look past first-year physics to come up with some impressively large numbers and say "Gosh, that's several major industrialised economies worth of output just to supply the energy to do this. There's got to be a cheaper way."

 

[Zardnaar]

The question I put was more along the lines of "Is it cheaper to do it some other way?" There's a lot of handwavium involved in the assumption that you can accelerate an asteroid to relativistic speeds in the first place. One could do the maths, but it will come up with a very large number for even a small fraction of c, potentially even bigger than the dinosaur killer scenario. Also, at relativistic speeds, the impactor itself becomes vulnerable. Just getting something to collide with it on the way in could be enough to destroy it or scatter it into pieces harmlessly.

What was asked was "Why can't somebody do this?" The argument against it could be something along the lines of "Yes, you can do it, but it's infeasibly expensive due to the amount of energy involved, and comparatively easy to defend against. It's several orders of magnitude cheaper to warp a battlefleet into the system and attack the planet with that."

This argument turns up in Traveller circles on a semi-regular basis due to some poorly thought out setting conceits. IMO your core setting conceits are broken if you can't think of a reasonable way why folks don't do this. You don't have to look past first-year physics to come up with some impressively large numbers and say "Gosh, that's several major industrialised economies worth of manufacturing capacity just to build the hardware to do this. There's got to be a cheaper way."

There's no real answer to that. Depends on the power level of the weapons.

An asteroid bomb requires a lot of nuclear bombs or a sing weapon in Warhammer 40k or Dune. If you just want to wreck or glass a planet.

Star Wars requires a fleet or kamikaze super star destroyer.

 

[Nobby-W]

There's no real answer to that. Depends on the power level of the weapons.

An asteroid bomb requires a lot of nuclear bombs or a sing weapon in Warhammer 40k or Dune. If you just want to wreck or glass a planet.

I think that's the point. You're designing setting conceits. If you want to answer "Why don't folks use dinosaur killers on a regular basis?" then you just tweak the capabilities of the societies so they can't. I just used some basic physics to show a few lines of argument that could be used - 'too big', 'too noisy to hide', 'too easy to defend against', and 'cheaper to do it some other way.'

 

[Dannyalcatraz]

So, I am going to come around to a point backwards.

What do you want to be the basic economic limiters on the cultures in this setting. Because those, combined with your ftl technology, will tell you what war will be like. Because, to be brutally honest, war is a problem.

Anyone who can manage casually moving around in a solar system, and make jumps between stars in independent ships, can destroy society on a planet, almost trivially. Slap engines on a ship-sized nickel-iron asteroid. Jump it to the outskirts of your target solar system. Drive full throttle at your target - engines and the gravity assist of falling towards the system's sun make your rock into a dinosaur killer. This is cheap and unmanned. You make 'em by the truckload. Eventually one gets through.

So, you need a reason why wars don't happen. The gate system may be your answer.

Those kinds of considerations were on my mind when I started thinking about the portals & ship jump drive issue, and why I used the Umbransignal.

Drawing from RW history, one of the reasons for the lack of wars on American soil is those two big oceans. So I wanted something analogous in the setting that makes wars rare as well. This meant it would have to be VERY difficult to launch a war fleet of any real into space controlled by another civilization.

Step 1: ship drives have limited range. They have enough range that each civilization can span several or- in some regions- hundreds of stars- but each civilization’s boundaries are defined by interstellar gaps too large to cross as a practical matter.

Step 2: the big portals are nestled inside of big asteroids. While their range is much greater than a ship’s jump drive, they still have limitations on how much they can pass quickly. This also makes it difficult to transport a hostile force into someone else’s territory. Combined, that makes the portals into a more defensible choke point.

Step 3: Jump drives aren’t merely very expensive to build. They (and portals) also require expensive Unobtanium to function. Each ship drive is inherently precious, borderline irreplaceable. Even the ones used for commerce- if any such exist- might still be in part under government control. So it would be a rare tactic to sacrifice a jump drive in order to make an interstellar kamikaze strike. Rare, but not inconceivable. Possibly even tried by rogue imperialists, terrorists or xenophobes who manage to steal a drive. It may have even been done successfully a couple of times, resulting in higher security- possibly including unified efforts- to prevent history repeating.

There’s also something in my mind from The Retrieval Artist novels by Kristine Kathryn Rusch: there’s a very sophisticated court system that handles most conflicts between members of different civilizations, including major ones. As in, incidents that could touch off genocidal wars. While it’s never stated as such, you get the feeling that the civilizations that use the system are DEEPLY invested in making it work, to the point that they would take extreme measures to make sure the verdicts are obeyed.

That made me think of the 1964 film, Failsafe. In it, the President of the USA orders an American bomber to nuke NYC in order to stave off war with the USSR after a mistakenly deployed US bomber nukes Moscow.

Fail Safe (1964 film) - Wikipedia

None of this makes war impossible. Just improbable. Economic siege warfare would be more likely than actual military strikes.

 

[Zardnaar]

I think that's the point. You're designing setting conceits. If you want to answer "Why don't folks use dinosaur killers on a regular basis?" then you just tweak the capabilities of the societies so they can't. I just used some basic physics to show a few lines of argument that could be used - 'too big', 'too noisy to hide', 'too easy to defend against', and 'cheaper to do it some other way.'

My assumption is any setting with sufficient ly large enough ships that can win space superiority can basically wreck a planet from space.

Even a few real world missile cruisers in space could orbital bombard with nukes. If they have anything better than nukes well yeah.

Assuming said planet doesn't have planetary shields or some sort of surface to orbital weapon.

 

[Zardnaar]

Those kinds of considerations were on my mind when I started thinking about the portals & ship jump drive issue, and why I used the Umbransignal.

Drawing from RW history, one of the reasons for the lack of wars on American soil is those two big oceans. So I wanted something analogous in the setting that makes wars rare as well. This meant it would have to be VERY difficult to launch a war fleet of any real into space controlled by another civilization.

Step 1: ship drives have limited range. They have enough range that each civilization can span several or- in some regions- hundreds of stars- but each civilization’s boundaries are defined by interstellar gaps too large to cross as a practical matter.

Step 2: the big portals are nestled inside of big asteroids. While their range is much greater than a ship’s jump drive, they still have limitations on how much they can pass quickly. This also makes it difficult to transport a hostile force into someone else’s territory. Combined, that makes the portals into a more defensible choke point.

Step 3: Jump drives aren’t merely very expensive to build. They (and portals) also require expensive Unobtanium to function. Each ship drive is inherently precious, borderline irreplaceable. Even the ones used for commerce- if any such exist- might still be in part under government control. So it would be a rare tactic to sacrifice a jump drive in order to make an interstellar kamikaze strike. Rare, but not inconceivable. Possibly even tried by rogue imperialists, terrorists or xenophobes who manage to steal a drive. It may have even been done successfully a couple of times, resulting in higher security- possibly including unified efforts- to prevent history repeating.

There’s also something in my mind from The Retrieval Artist novels by Kristine Kathryn Rusch: there’s a very sophisticated court system that handles most conflicts between members of different civilizations, including major ones. As in, incidents that could touch off genocidal wars. While it’s never stated as such, you get the feeling that the civilizations that use the system are DEEPLY invested in making it work, to the point that they would take extreme measures to make sure the verdicts are obeyed.

That made me think of the 1964 film, Failsafe. In it, the President of the USA orders an American bomber to nuke NYC in order to stave off war with the USSR after a mistakenly deployed US bomber nukes Moscow.

Fail Safe (1964 film) - Wikipedia

None of this makes war impossible. Just improbable. Economic siege warfare would be more likely than actual military strikes.

Unless you have moon sized ships planetary defenses could just exceed the ability to attack. Fusion reactors or geothermal powered shields.

Or just lots and lots of something like Stargate Atlantis defense towers.

You could fit a huge amount of Patriot equivalents on very little space.

 

[Nobby-W]

My assumption is any setting with sufficient ly large enough ships that can win space superiority can basically wreck a planet from space.

Even a few real world missile cruisers in space could orbital bombard with nukes. If they have anything better than nukes well yeah.

Assuming said planet doesn't have planetary shields or some sort of surface to orbital weapon.

That's reasonable and passes a basic smell test. In the Star Trek canon (TOS at least), a Constitution class cruiser like the Enterprise has enough firepower to trash everything on the surface of a planet. If you assume that you can make a battlefleet capable of attacking a planet, then all you need to say about other things like dinosaur killers is that it's just easier and cheaper to deploy a battle fleet. Ergo, small terrorist cells who can't afford a battle fleet also can't afford the hardware to make a dinosaur killer.

 

[Zardnaar]

That's reasonable and passes a basic smell test. In the Star Trek canon (TOS at least), a Constitution class cruiser like the Enterprise has enough firepower to trash everything on the surface of a planet. If you assume that you can make a battlefleet capable of attacking a planet, then all you need to say about other things like dinosaur killers is that it's just easier and cheaper to deploy a battle fleet. Ergo, small terrorist cells who can't afford a battle fleet also can't afford the hardware to make a dinosaur killer.

Depends what type of other things you have in universe.

If you have something like a space battleship or dreadnought with a tractor beam that can nudge a dinosaur killer that's one thing.

If you've got super weapons that can fire a dinosaur killer or drag one through hyperspace or equivalent and fire it across the galaxy that's even more up there.

Stuff like that tends to be precursor tech though. Terrorists might be able to find something like that but couldn't build it.

It's Danny's idea if they don't have reliable ftl that's more towards Battlestar, early trek or Mass Effect technology vs Star Wars let alone ringworlds and dyson spheres.

 

[Nobby-W]

If you have something like a space battleship or dreadnought with a tractor beam that can nudge a dinosaur killer that's one thing.

All it needs is a tug that can impart a few m/sec of delta-v to it early enough and it will miss its target. If the tech exists to accelerate it by multiple km/sec or more then the tech exists to nudge it by less than 1/1000 of the delta-V you needed in the first place.

If you've got super weapons that can fire a dinosaur killer or drag one through hyperspace or equivalent and fire it across the galaxy that's even more up there.

Although that's back to the question of "Is this really the best way to do it. Just because you can doesn't mean that it's the best way."

Stuff like that tends to be precursor tech though. Terrorists might be able to find something like that but couldn't build it.

That gives you an interesting one-off scenario about a bunch of fanatics that get hold of some old precursor tech. In that state it's a one-off, rather than an existential threat to society.

What are your conceits - In a lot of ways it might be better to start with a list of capabilities that do/do not exist in your 'verse and work backwards from there. I've done that quite a lot with my settings.

 

[Zardnaar]

All it needs is a tug that can impart a few m/sec of delta-v to it early enough and it will miss its target. If the tech exists to accelerate it by multiple km/sec or more then the tech exists to nudge it by less than 1/1000 of the delta-V you needed in the first place.

Although that's back to the question of "Is this really the best way to do it. Just because you can doesn't mean that it's the best way."

That gives you an interesting one-off scenario about a bunch of fanatics that get hold of some old precursor tech. In that state it's a one-off, rather than an existential threat to society.

What are your conceits - In a lot of ways it might be better to start with a list of capabilities that do/do not exist in your 'verse and work backwards from there. I've done that quite a lot with my settings.

Depends what the precursors tech does.

In the upper scale I look at megaengineering (dyson spheres, ringworlds) and giga engineering (building star, solar systems, black holes etc).

If terrorists get hold of some facility like that and they can reuse it.

 

[MarkB]

That's reasonable and passes a basic smell test. In the Star Trek canon (TOS at least), a Constitution class cruiser like the Enterprise has enough firepower to trash everything on the surface of a planet. If you assume that you can make a battlefleet capable of attacking a planet, then all you need to say about other things like dinosaur killers is that it's just easier and cheaper to deploy a battle fleet. Ergo, small terrorist cells who can't afford a battle fleet also can't afford the hardware to make a dinosaur killer.

When it happens in The Expanse, any initial signs of it go unnoticed because there's literally an entire massive industry in the solar system of mining and moving asteroids. There's just too much going on in the system for any one set of drive plumes to really stand out, especially if they're way out in the asteroid belt. And once the rocks have been placed on course, they proceed under zero thrust and with their surface coated in stolen state-of-the-art stealth materials to give them almost no radar signature.

And the terrorist group that does it is part of the Belter culture, who have grown up as a workforce under the heel of both Earth and Mars. They have no space navy of their own, and little way to acquire one. What they do have is huge quantities of dedicated industrial vessels specialised in hauling, mining and prospecting.

 

[Dannyalcatraz]

When it happens in The Expanse, any initial signs of it go unnoticed because there's literally an entire massive industry in the solar system of mining and moving asteroids. There's just too much going on in the system for any one set of drive plumes to really stand out, especially if they're way out in the asteroid belt. And once the rocks have been placed on course, they proceed under zero thrust and with their surface coated in stolen state-of-the-art stealth materials to give them almost no radar signature.

And the terrorist group that does it is part of the Belter culture, who have grown up as a workforce under the heel of both Earth and Mars. They have no space navy of their own, and little way to acquire one. What they do have is huge quantities of dedicated industrial vessels specialised in hauling, mining and prospecting.

You don’t need a 50 cal (dino killer) if you have a shotgun (lots of smaller asteroids). A concentrated, unified effort by aggrieved Belters could ruin a planet.

Of course, if they’re not entirely self-sufficient, that could be a pyrrhic victory...

 

[Eyes of Nine]

Many RPGs ignore the 3D. Probably the best known of these is Traveller.

For combat, many more ignore local 3D, even while doing 3D for interstellar.

If you go with big enough hexes, you can treat it as a single hex thick. The thickness is about 1 kPc; the Shapley center is 2 kPc across (and tall). It's 120 kPc across the disk.
the LMC is ~50 kpc away, 14 kPc diameter across the disk, probably under half a kpc thick, distorted barred spiral
the SMC is ~ 62 kpc away, between 7 and 12 kpc across, barred spiral
Sag dSph is roughly 50 kpc away from the galactic center, in a polar orbit... and what little I can glean, is a 7x14 stretched sphere.

Note at a scale of 1 kpc per hex, only the center hex of the Milky Way is 2 hexes thick.
The LMC is a 14 hex disk only 50 kpc from earth...
The SMC is a 7x14 oval.

All very mappable.

But at that scale, 1 week per hex means hitting the LMC in under a year, and crossing the MW is 2 years and 2 months, plus another two weeks to avoid the Shapley Center and the Sag A* within.

I remember thinking about a way to make Traveller sectors 3-d. Hexes are ok for lateral movement. But as you think about taking the 8x10 grid of the Traveller sub-Sector, and then adding another 8 or 10 (or for fun, 9) layers on top of it, then wow.

Looking at Solomani Rim Sector book I have (Supplement 10 Little Black Book), on average in that sector, looks like 20-30 worlds per subsector. Let's go with 25 on average.

And a sector is 16 sub sectors, or 4x4 sub-sectors. So we are looking at a rectangular prism (cuboid? parallelipiped?) that is 32x40x36 hexes large. And 25 worlds per 80 hexes. So: 32x40x36/80x25=14,400 worlds. In one single 3d sector. And from one corner to the other would be hmmm, maybe 94 jumps? Anyway, 3d space is large.

(as an aside, if I was a coder, I'd love to have a web page where you start at a point in space, and then you define how dense the space is in that neighborhood, and as you travel with your mouse or keyboard keys (L, R, U, D, Back, Forward) the app build worlds for you, (or not) based on the Classic Traveller algorithm. And you could, if you wanted to, travel in any direction infinitely. And as you travel, the density of the space randomly changes, so you get rifts and clusters and mains.)