Which of these starship propulsion methods is best for an advanced society?

[Eldan]

How would one get useful energy out of a black hole? Feed matter into it and somehow use radiation it produces?

[Anonymouswizard]

How would one get useful energy out of a black hole? Feed matter into it and somehow use radiation it produces?

I believe that's the basic idea.

[Grey_Wolf_c]

How would one get useful energy out of a black hole?

I think the idea here is that the black hole distorts spacetime, and you place it such that you "roll downhill" the distortion towards your destination.

GW

[Iruka]

How would one get useful energy out of a black hole? Feed matter into it and somehow use radiation it produces?

You tie it to a pole and hold it out of the front window of your spaceship. That way you are constantly accelerated through the attraction to the black hole. To deccelerate, stick the pole with the hole through the rear window.

To steer in a comfortable manner, you would however need two black holes. Attach each to the ends of a cross beam at the end of your pole. Pivot the cross beam with strings you tie to its ends, leisurely from the front seat of your space ship.

Proof of concept by L.d. Lokomotivführer, J. Knopf.

[Peelee]

You tie it to a pole and hold it out of the front window of your spaceship. That way you are constantly accelerated through the attraction to the black hole. To deccelerate, stick the pole with the hole through the rear window.

To steer in a comfortable manner, you would however need two black holes. Attach each to the ends of a cross beam at the end of your pole. Pivot the cross beam with strings you tie to its ends, leisurely from the front seat of your space ship.

This is the most sensible idea in this thread. I told y'all that black hole starship was the best choice.

[Eldan]

You tie it to a pole and hold it out of the front window of your spaceship. That way you are constantly accelerated through the attraction to the black hole. To deccelerate, stick the pole with the hole through the rear window.

To steer in a comfortable manner, you would however need two black holes. Attach each to the ends of a cross beam at the end of your pole. Pivot the cross beam with strings you tie to its ends, leisurely from the front seat of your space ship.

Did you by any chance read Jim Knopf as a child?

[Iruka]

Did you by any chance read Jim Knopf as a child?

You are correct. I failed in giving my sources, as would be good scientific practice. I will edit my post.

Also worked kinda differently than I remembered.

[Excession]

You tie it to a pole and hold it out of the front window of your spaceship.

Wouldn't it just eat the pole, and the string you tied it on with for that matter? Ah, is this what the magnetic mono-poles are for? Maybe some cosmic string as well?

[Iruka]

Wouldn't it just eat the pole, and the string you tied it on with for that matter? Ah, is this what the magnetic mono-poles are for? Maybe some cosmic string as well?

This is where string theory comes into play.

[Peelee]

This is where string theory comes into play.

Plus the magnetic monopole. That thing threaded with string theory can hook any fish.

[Rockphed]

Plus the magnetic monopole. That thing threaded with string theory can hook any fish.

*Twitch. Twitch.*

The purposeful misunderstanding of physics is strong here.

[Peelee]

*Twitch. Twitch.*

The purposeful misunderstanding of physics is strong here.

Well, a lot of physics are pretty easy. I've got the astrology, crystals, and tea leaves down. It's the palm readings that throw me.

[Grey_Wolf_c]

Well, a lot of physics are pretty easy. I've got the astrology, crystals, and tea leaves down. It's the palm readings that throw me.

The important thing to remember is that you can extend the palm lines to increase life expectancy. Just like phrenology teaches that hitting people with a big hammer means you can subtly change their personality.



GW

[Iruka]

Well, a lot of physics are pretty easy. I've got the astrology, crystals, and tea leaves down. It's the palm readings that throw me.

It works pretty much like homeopathy. The less you read, the more powerful your reading becomes.

[Eldan]

Just remember to frown and say "Hm" a lot as you look at someone's hands.

[LordEntrails]

The only way I could conceive of a black hole starship would have to use a particular kind of black hole, called a Kugelblitz. Depending on how the physics turns out to work beyond that singularity, the "black hole made of light" could have the gravitational pull of say, Earth, without any inertial mass. You could magnetically push in front of your hull (for practically no energy) and then fall towards it to wherever you needed to go.

It would also absorb or deflect a bunch of the space dust and radiation that makes relativistic travel a deadly problem.

I always liked this idea, but have always wondered.... How do you choose not to move or not to continue accelerating in some direction? And what about docking to another ship without destroying it? And if to stop accelerating you need two black holes how does your ship not get torn apart? And how do you handle space-time distortions from one end of you ship to the other?

[Brother Oni]

Just like phrenology teaches that hitting people with a big hammer means you can subtly change their personality.

Well technically you can, like conscious to unconscious or alive to dead.

[Grey_Wolf_c]

Well technically you can, like conscious to unconscious or alive to dead.

Your definition of "subtle" doesn't quite match mine, I'm afraid.

GW

[Anonymouswizard]

I always liked this idea, but have always wondered.... How do you choose not to move or not to continue accelerating in some direction? And what about docking to another ship without destroying it? And if to stop accelerating you need two black holes how does your ship not get torn apart? And how do you handle space-time distortions from one end of you ship to the other?

I mean, with a bit of work slowing down isn't a problem, just add the ability to swing the ship around the poles. Stopping is more difficult.

[Excession]

The only way I could conceive of a black hole starship would have to use a particular kind of black hole, called a Kugelblitz. Depending on how the physics turns out to work beyond that singularity, the "black hole made of light" could have the gravitational pull of say, Earth, without any inertial mass. You could magnetically push in front of your hull (for practically no energy) and then fall towards it to wherever you needed to go.

It would also absorb or deflect a bunch of the space dust and radiation that makes relativistic travel a deadly problem.

To be serious for a minute, I pretty sure this is not how mass works. No rest mass doesn't mean no inertial mass. Energy has mass, so photons have mass, and inertial mass and gravitational mass are the same thing. I think the idea of a "black hole drive" is to use the black hole as a matter to energy converter. You fire mass into a small black hole at exactly the same rate as it outputs energy via Hawking radiation. In theory it is a very efficient way to generate power. In practice you're trying to hold onto a nuclear bomb that is constantly exploding, and somehow moving it around as well.

A Kugelblitz might be a way to initially generate the block hole. You just need an absurd amount of lasers all pointing to one place, pulse them all at once, and then catch the resulting black hole.

[Bucky]

The theoretical best possible drive you can get that uses fuel that it carries is a lightweight antimatter-powered photon recoil drive (i.e. a giant laser). But that assumes you also have a container for your antimatter that weighs less than the antimatter. If you don't, you're better off with an antimatter rocket that uses the antimatter jars as reaction mass - that way they're an asset rather than dead weight.

Other types of fuel can't be more efficient than antimatter unless they let you use a much lighter fuel tank; the limit for alternate fuels is E=MC^2, but antimatter lets you cheat by reacting the fuel with part of its tank to increase M.

Fuel efficiency is based on how fast you can eject your exhaust, and it's impossible to beat the speed of light.

Ramjets and solar sails cheat by not carrying all their fuel on board. They're basically the same thing in different gears; a solar sail catches fuel that's moving faster than the spaceship in the direction it wants to go, while a ramjet catches fuel moving in the opposite direction. As a result, a ramjet requires spending stored energy while a solar sail doesn't and can even generate a little on its own. Which one's better depends on which way the fuel's moving.

[LordEntrails]

Fuel efficiency is based on how fast you can eject your exhaust, and it's impossible to beat the speed of light.

Maybe.

Yes given current theories. But then again at one time "current" theories and supporting mathematical equations showed that matter could not travel faster than sound.

We don't truly understand everything. And some day we are bound to learn that things we believe today are simply wrong. What those theories that are proven wrong,we just don't know.

[Bucky]

If you do find a way to make matter travel faster than light, and can fit a machine to do it on your spaceship then forget about rockets and just use one of those.

Re: Kugelblitz

A Kugelblitz is unlikely to be construable even by a super-advanced alien civilization. But if you somehow did make one, it wouldn't be different from an ordinary black hole in any way that matters for rocket science.

[Peelee]

Maybe.

Yes given current theories. But then again at one time "current" theories and supporting mathematical equations showed that matter could not travel faster than sound.

Let's see if I remember how to do this!

Prandtl-Gleurt Singularity?

[Grey_Wolf_c]

at one time "current" theories and supporting mathematical equations showed that matter could not travel faster than sound

[citation needed]

GW

[Peelee]

[citation needed]

GW

https://en.m.wikipedia.org/wiki/Pran...rt_singularity

I did not remember the spellin, btw.

[Anymage]

Maybe.

Yes given current theories. But then again at one time "current" theories and supporting mathematical equations showed that matter could not travel faster than sound.

We don't truly understand everything. And some day we are bound to learn that things we believe today are simply wrong. What those theories that are proven wrong,we just don't know.

The closest thing we have to a warp drive idea that works is not based on reaction drives. If we discover some other form of breaking C, there's basically a guaranteed chance that it will work through some other mechanisms and look absolutely nothing like the reaction drives on normal rockets. So when we're talking the theoretical limits of existing technology, we're far more likely to break those limits through a completely different technology than through some magical new refinement of the current stuff.

Granted, "can't break C" isn't really a reason why a rocket ship could never go faster. One with magically everfull fuel tanks could continue a constant acceleration forever, but still never hit that point. The real limit is intrinsic to the nature of spacetime itself, which goes back to the point that no amount of better rockets will ever push you past that.

[Eldan]

[citation needed]

GW

Basically, the idea was that as you approached the speed of sound, more and more pressure would build up in front of you. Which it does. However, it was predicted that the pressure would go up to infinity as one approached the speed of sound, which it doesn't. So, by those theories, you could get infinitely close to the speed of sound, but not over it.

[LordEntrails]

https://en.m.wikipedia.org/wiki/Pran...rt_singularity

I did not remember the spellin, btw.

Thank you. That is a more direct reference.

I was going to point the question towards the theory of incompressible aerodynamics that date back to Isaac Newton's theory of air resistance as well as Bernoulli's Principle. Both of which provide equations that "prove" a physical object can not travel faster than sound.

EDIT: They were early lectures when I earned my degree in Aerospace Engineering.