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How do Honorverse ships generate their energy?

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Re: How do Honorverse ships generate their energy?
Post by ThinksMarkedly   » Thu Jan 20, 2022 12:04 am

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tlb wrote:The central problem with using a black hole is trying to handle it, while staying outside of it.


Not with a black hole created from energy, not mass.

Where you're going to get that energy is another story. It probably needs to be beamed from the star.
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Re: How do Honorverse ships generate their energy?
Post by tlb   » Thu Jan 20, 2022 12:28 am

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tlb wrote:The central problem with using a black hole is trying to handle it, while staying outside of it.

ThinksMarkedly wrote:Not with a black hole created from energy, not mass.

Where you're going to get that energy is another story. It probably needs to be beamed from the star.

The article that you pointed out said the following:
this would be a black hole whose original mass–energy had been in the form of radiant energy rather than matter. In simpler terms, a kugelblitz is a black hole formed from radiation as opposed to matter. Such a black hole would nonetheless have properties identical to one of equivalent mass and angular momentum began more conventionally
Which means that you can be sucked into it, doesn't it?
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Re: How do Honorverse ships generate their energy?
Post by ThinksMarkedly   » Thu Jan 20, 2022 12:50 am

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tlb wrote:Which means that you can be sucked into it, doesn't it?


Sure, but black holes aren't vacuum cleaners. So long as you're outside of the event horizon, you're being pulled towards it but exactly the same way as another body if the same mass would.

Using Viktor Toth's Black Hole Calculator, let's see if we can figure this out. A BH massing one millionth of Earth's mass would have a Schwarzschild radius of 8.86 nm. Since the force of gravity falls with the square of the distance, you need to be at one thousandth Earth's radius from that BH to feel an acceleration of 1 gravity: 6 km. That's plenty of room to spare.

We could reduce the BH's mass by another million and we'd still need to be only 6 m from it to feel 1 G of acceleration. Meanwhile, the Schwarzschild radius is proportional to the mass, so it would be one millionth what it was, at 8.86 fm. On the other hand, such a blackhole is producing 10 MW of power in the form of Hawking radiation, so I wouldn't want to be just 6 m from it, not unless that's an energy collector.
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Re: How do Honorverse ships generate their energy?
Post by Brigade XO   » Thu Jan 20, 2022 8:41 am

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So....what is the smallest a Black Hole can be? Or, to ask it differently, how large does a mass have to be to initiate the effect of gravity caused by said mass to collapse the matter involved into a Black Hole and what would be the diameter of said hole?

Given that SIFI has been depicting Black Holes for a long time, we mostly seem to represent them as either a whirlpool in space- think the movie "The Black Hole" - or a circular image representing what the presently visible around the circumference of the "hole" edge of the event horizon since we can't see into (or anything like light) coming out of the hole in our direction. So Hollywood has given us a ring of sparkles theoretically showing matter tearing itself apart just before entering the black hole.

Does the formation of a Black Hole create a giant sucking effect in every direction like turning on a star sized vaccume cleaner?

And why, pray tell, have various story universes use "singularities" as their power sources? I thought that was another term for Black Hole (at least in popular usage) and how would it power anything since what it does is pull EVERYTHING into itself- how do you get "power" out of it unless you have an equivalent of a turbine being spun by the movement of matter/light/whatever from the outside to the event horizon.
Not accepting "artistic license" as an explination. Big Smile
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Re: How do Honorverse ships generate their energy?
Post by Jonathan_S   » Thu Jan 20, 2022 10:06 am

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ThinksMarkedly wrote:Sure, but black holes aren't vacuum cleaners. So long as you're outside of the event horizon, you're being pulled towards it but exactly the same way as another body if the same mass would.

Using Viktor Toth's Black Hole Calculator, let's see if we can figure this out. A BH massing one millionth of Earth's mass would have a Schwarzschild radius of 8.86 nm. Since the force of gravity falls with the square of the distance, you need to be at one thousandth Earth's radius from that BH to feel an acceleration of 1 gravity: 6 km. That's plenty of room to spare.

We could reduce the BH's mass by another million and we'd still need to be only 6 m from it to feel 1 G of acceleration. Meanwhile, the Schwarzschild radius is proportional to the mass, so it would be one millionth what it was, at 8.86 fm. On the other hand, such a blackhole is producing 10 MW of power in the form of Hawking radiation, so I wouldn't want to be just 6 m from it, not unless that's an energy collector.

Though unless your technology also includes something like Honorverse grav plates - an artificially gravity field that can be adjusted almost foot by foot throughout a ship I'd think that being that close to a small black hole would be a bit disorienting. You'd have a gravity gradient down the length of the ship - the bow at 6m from the hole is experiencing 1g but the stern isn't (though it's being pulled towards the bow at that acceleration because the ship's structure would be strong enough to handle that stress).

Somewhat counter-intuitively that mean the occupants and equipment within the ship feels like it has full 1g gravity back at the stern because they're only being accelerated by the movement of the ship - but as you move forward that ship movement pushing them forward is being more and more offset by the gravity of the tiny black hole pulling them forward -- so by the time you're up at the bow you're effectively in freefall where the ship and occupants are being pulled at about the same acceleration towards the black hole. (Like on the up-facing parabola of the "vomit comet" -- doesn't mater that both plane and passenger are in the Earth's 1G field because they're both falling at the same rate and so the passengers experience effectively free fall)
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Re: How do Honorverse ships generate their energy?
Post by tlb   » Thu Jan 20, 2022 10:59 am

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Brigade XO wrote:So....what is the smallest a Black Hole can be? Or, to ask it differently, how large does a mass have to be to initiate the effect of gravity caused by said mass to collapse the matter involved into a Black Hole and what would be the diameter of said hole?

Given that SIFI has been depicting Black Holes for a long time, we mostly seem to represent them as either a whirlpool in space- think the movie "The Black Hole" - or a circular image representing what the presently visible around the circumference of the "hole" edge of the event horizon since we can't see into (or anything like light) coming out of the hole in our direction. So Hollywood has given us a ring of sparkles theoretically showing matter tearing itself apart just before entering the black hole.

Does the formation of a Black Hole create a giant sucking effect in every direction like turning on a star sized vaccume cleaner?

And why, pray tell, have various story universes use "singularities" as their power sources? I thought that was another term for Black Hole (at least in popular usage) and how would it power anything since what it does is pull EVERYTHING into itself- how do you get "power" out of it unless you have an equivalent of a turbine being spun by the movement of matter/light/whatever from the outside to the event horizon.
Not accepting "artistic license" as an explination. Big Smile

The Schwarzschild radius is the event horizon of a nonrotating black-hole. You can calculate a Schwarzschild radius for any mass (for example, that of the Sun is about 3 km). If the mass is contained within a sphere of that size then it is a black-hole, otherwise it is not. So you need unimaginable (for people like me) densities to create a small one; consider that a neutron star, for all its density, is not a black-hole. So it is very much easier for a large black-hole to form than a small one. All black-holes have some mass and so do exert gravitational force outside the event horizon; even those originally formed by compressing energy (because of E = M * C**2).

The suggestion that a black hole could be used as a drive primarily involves the fact that radiation can tunnel out; so that if you could put it at a focus of a parabolic mirror, then radiation pressure would push your ship in the other direction. This behaves the same as using a laser as a reaction drive, like the humans had at the beginning of the Man-Kzin Wars. The advantage is that the black-hole is using its own mass as the fuel and does not need to be supplied with energy. So small ones could eventually evaporate.

However you are using something non-physical to keep the black-hole in position. It can not be physical because anything that touches the event horizon can be consumed. So what do you use? If you have artificial gravity, then that might be ideal; otherwise you have to give it an electrical charge and use electrostatic forces to keep it in place (that can be very tricky, particularly as it will attract the opposite charge).

In a short story I read (perhaps by Larry Niven), someone on Earth created a minuscule black-hole in their lab and dropped it. So then it fell past the center of the Earth and continued to fall back and forth consuming a little bit of the planet with every move.
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Re: How do Honorverse ships generate their energy?
Post by ThinksMarkedly   » Thu Jan 20, 2022 11:33 am

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Brigade XO wrote:So....what is the smallest a Black Hole can be? Or, to ask it differently, how large does a mass have to be to initiate the effect of gravity caused by said mass to collapse the matter involved into a Black Hole and what would be the diameter of said hole?


As tlb answered, any mass can be a black hole, so long as all of it is contained within the Schwarzschild radius of that mass.

So your question is just how one can put that much mass inside that tiny radius. The discussion above was about using energy density and E=mc² to do that, but we currently don't have technology to create such a BH.

The other way is that those were created during a very early age of the Universe, when the density was almost uniformly sufficient. Because it was uniform, it didn't collapse everywhere into a BH. But tiny variations in density could have created tiny BHs that would survive until this day: primordial black holes. This theory is sound, but no such PBH has ever been observed. In fact, we've been able to rule out many mass ranges for them, because if they had been there, we'd have seen them.

Finally, there's the traditional way of creating a BH: just too much mass packed together. The minimum mass for that is wel-known (if not precise): the Tolman–Oppenheimer–Volkoff limit. The current best estimates are of right about 3.0 solar masses.

Does the formation of a Black Hole create a giant sucking effect in every direction like turning on a star sized vaccume cleaner?


No. If the Sun were replaced by a BH of the same mass (see above how creating such would be difficult), we'd all die, but only because we suddenly lost our best source of energy. But if we had a way to generate energy ourselves and still feed ourselves, we could live on. The orbit of all the planets and asteroids would be undisturbed.

A BH of a given mass has the exact same gravitational attraction as any other body of the same mass, at the same distance. The difference is that a BH is so small that you can get far, far closer to it, than any other body. And close by it, things get really freaky, like frame dragging: a rotating BH can drag spacetime outside the event horizon.

And why, pray tell, have various story universes use "singularities" as their power sources? I thought that was another term for Black Hole (at least in popular usage) and how would it power anything since what it does is pull EVERYTHING into itself- how do you get "power" out of it unless you have an equivalent of a turbine being spun by the movement of matter/light/whatever from the outside to the event horizon.
Not accepting "artistic license" as an explination. Big Smile


A BH is expected to produce energy, called the Hawking Radiation. That is nowadays accepted as fact, even though we have yet to measure it in any known BH. The power it produces is inversely proportional to the square of its mass, so the larger the BH is, the less it produces of power. The smallest known BH, at 3.04 solar masses, would be producing power in the 10^(-29) W range. There's no way we could see any effect of that.

However, if you make them smaller, much smaller, then you can extract useful energy from them, within practical time periods. The sweet spot would be in the range of one billion tonnes: such a BH would produce 356 MW of power and would last for 1.4 trillion years before it evaporated completely. And you can keep it alive indefinitely if you feed it mass.

All of this is within our known bounds of Physics.

Sci-Fi usually takes this much further. Most singularity drives aren't simple power generators. Singularity drives (often Artificial Quantum Singularities, AQS) usually exhibit properties that our physics don't account for, including the ability to somehow go FTL, travel between universes or dimensions, etc.
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Re: How do Honorverse ships generate their energy?
Post by Daryl   » Fri Jan 21, 2022 3:09 am

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Poul Anderson"s Tau Zero was an intelligent look at this, that illustrated how a Bussard Ram Jet space craft could outlive the heat death of this universe.
A one pager I enjoyed also pointed out that as you got closer and closer to C your weight grew exponentially. Ultimately as you reached C you would be infinitely heavy, and the universe would crunch down around you, forming a new Big Bang. The moral is that you can travel at C, but only momentarily, and only one per universe.
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Re: How do Honorverse ships generate their energy?
Post by munroburton   » Fri Jan 21, 2022 7:43 am

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ThinksMarkedly wrote:A BH is expected to produce energy, called the Hawking Radiation. That is nowadays accepted as fact, even though we have yet to measure it in any known BH. The power it produces is inversely proportional to the square of its mass, so the larger the BH is, the less it produces of power. The smallest known BH, at 3.04 solar masses, would be producing power in the 10^(-29) W range. There's no way we could see any effect of that.


Hawking radiation hasn't been detected, as its theoretical output is effectively suppressed by the Cosmic Microwave Background radiation in any black hole mass equivalent to our moon. The present universe with a background temperature of about 2.7 degrees Kelvin is still hotter than most black holes. A solar mass BH is thought to be .00000006 Kelvin and supermassive BHs have even more zeroes after the decimal.

Our moon turned into a black hole would be approximately 2.7 K, unable to grow and unable to evaporate. The reason we haven't seen any PBHs or micro BHs is because they've mostly fallen off either sides of that threshold - becoming more substantial black holes or vanishing away into subatomic scales(possibly accounting for dark matter).

One theory for Planet X is that it's a primordial black hole of approximately five earth masses. This would be a ball ten centimeters across with a temperature of 0.004 K instead of a rocky super-earth or small gas giant.

That would be quite handy - if it exists and if we could find it. With any black hole there is a way to extract energy without waiting for Hawking radiation. You fire a laser past its event horizon, closely enough that its gravity bends the laser around and returns it to an appropriate receiver. If correctly aligned, the laser beam 'steals' energy from the black hole's spin.

It wouldn't be infinite. Once its spin is completely harvested, it's over. However, we could use the same laser beam technique to spin it up again, probably using solar energy collected by a dyson swarm around the Sun. That's one heck of a rechargeable battery.
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Re: How do Honorverse ships generate their energy?
Post by isaac_newton   » Fri Jan 21, 2022 5:14 pm

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tlb wrote: SNIP

In a short story I read (perhaps by Larry Niven), someone on Earth created a minuscule black-hole in their lab and dropped it. So then it fell past the center of the Earth and continued to fall back and forth consuming a little bit of the planet with every move.


[Spoiler alert]
I sort of remember a similar[ish] story but it was set on Mars. IIRC they[team from earth] had come across the remains of an old civilisation and were lookin at the left over tech. Somehow they discerened that part of kit was a contained mini black hole... This was then used as a murder tool to kill one big mouth, by releasing it from containment. Well it killed said big mouth, by passing thru him from head to toe, but someone else in team then realised that this black hole would fall back and forth inside Mars, gorging itself as it went, and becoming a non mini black hole very rapidly indeed. The question was wether the next ship out would arrive before the planet was gone [this was an ooold story]

[Edit - just found it - it was by Larry Niven] https://en.wikipedia.org/wiki/The_Hole_Man
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