Semi-OT: A General Tech Question Thread for me :)

[El_Phil]

Wolfman77 said:
Wouldn't a rotating ship require alot more thrust to accelerate. Manuverability would also be greatly reduced, I believe, as it would be harder to change directions. Another problem turning when spinning is that the thrusters to move you into a turn would be rotating and would create a couple of problems, depending on how much you wanted to explain.

They would need to be pulsed on ond off in a serial order to keep thrust on just one side of the ship.

If you wanted to go farther into it, then that wouldn't work either as each thruster would still fire in an arc, not just at one point. It would be massively unstable.

I can't think of any way to explain around this, and there may be other problems I haven't thought ofas well.

How to solve that? Computer controled constant correction. Modern aircraft (F-22, Eurofighter) are 'dynamically unstable' airframes. You kill the computers and the plane goes out of control. Similar thing with this. Or just pre compensated burns, you allow for the fact the thruster is moving when you calculate the burns. You know all the factors that will affect the stability so it's calcuable, with fast enough computers.

Weapons however are tricky, it would depend on how fast the outer edge of the ship is spinning, which would depend on how much gravity you want in the ship and how big the ship is.

OR the ship rotates round its axis of movement. The main engines are mounted on the 'hub' of the ship as are your forward firing main weapons. Simplifies some of the problems certainly, if not solving all of them.

[Wolfman77]

Yup, computers could do the trick there. And with some sort of Thrust vectoring you could control it's tendancy to pitch throughout each burn. It would still have poor manuverability though.

Nice ship, btw. I guess these problems won't matter for you ship much but they are still fun to discuss. Grav plating sound ok to me, but then I'm ok with just about anything in sci-fi. At least there are not any commonly accepted theories that prohibit it from functioning (well none that I'm aware of anyway).

[kerensky]

As far as shooting while spinning, I don't knw if this came from a book or video game, but the ships spun to keep gravity but when they went into combat or needed to do some tricky maneuvering, they killed the spin and everyone strapped in or floated.

[El_Phil]

That would work as well, the problem would be the inertia. Just because you stopped powering the spin doesn't mean it will suddenly stop, there's no resistance (or practically none) in space so you have to apply power to stop the spin. Not a big problem granted, you got it spinning in the first place after all.

Gravity plating. Wonderfull and how do you propose for this to work? Last I checked you needed mass for gravity.

Lets see how you would get this. OK use Newtonian gravitational theory, its fine for practical stuff involving small fields. And its a hell of alot simpler.

So to get earth strength gravity you need about 6E24 kilograms, or the mass of the earth, at a distance of ~ 6400 km. This isn't really practical to lug around, but your plating is on the floor! Say under a few cm of carpet (or funky futuristic space floorboards) lets say its 1 cm down. So you only need 9E15 kgs of mass to create that much gravity. Tricky. Oh and it's unidirectional so your crew on the deck below are being attracted to the ceiling.

Frankly I can't see how you can ever get that into plating and then directional. But I'd like to hear this theory that would be fine.

[Wolfman77]

I never said I could explain it. Only that "there are not any commonly accepted theories that prohibit it from functioning (well none that I'm aware of anyway)."

Currently, it is generally accepted that gravity is mediated by a particle called a graviton. I admit, there is no solid proof of its existence, but then science has relatively few proofs when compared to theories. If we assume the graviton does exist, then it is not that much of a stretch to think that with 2000 years more science, that someone might figure out how to control it without needing all that mass.

If you have proof that the graviton does not exist, then please share this information with the rest of the scientific community so they can spend their time on other theories.

If you do not believe that science will ever explain anything not already known, or pose new questions never thought of, then you will always nit-pick science fiction, and never gain anything from it.

Just as a note: Newtonian gravity works OK on large scale, but breaks down at smaller scales. It does work for your example, however, because with newtonian gravity that is considered large scale. Small scale is considered less than the width of an atom. But then, I'm just being nit-picky.

[Hunpecked]

What strikes me most about this thread, with its frequent emphasis on what's "really" possible, is that once you assume "warp" space travel (i.e. as in the SE IV game), 21st Century science goes out the window. Perhaps it would be more productive* to speculate how the "warp" travel already built into the game can explain other game features. Example: For in-system travel, why not replace Newtonian acceleration/deceleration, with its inconvenient mass/energy/velocity/fuel limitations, by a continuous "micro-warp" drive with constant velocity (very convenient) and whatever limitations you like? BTW, this is somewhat similar to the "stutterwarp" in the Traveller role-playing game, which is based on, yes, REAL science, i.e. [begin handwaving] quantum tunneling [end handwaving].

Or take the "Alderson Drive" in the Niven/Pournelle novel "The Mote in God's Eye". The "warp points" in this fictional universe arise from an as-yet-undiscovered "fifth force". Presumably the discovery of this new force would lead to a whole new branch of physics and many practical applications, but to my knowledge the authors made no use of this technology beyond interstellar travel. If so, then I'd say they missed a good opportunity.

Back to SE IV. You want "shields"? No problem! Apply the same game technology used for interstellar travel to generate a "warp field" around your ship that "warps" incoming matter/energy harmlessly AROUND the vessel! Now for game/story purposes you may want limits on how much "incoming" can be deflected (leaky shields) or you may want "incoming" to "use up" shield/warp energy (consumable shields). Your weapons can be modified shield projectors that create a long thin warp field (as opposed to a short fat shield) along which you can fling projectiles, photons, anti-protons, etc. toward enemy vessels. Since warp fields defy "conventional" physics your "beams" don't scatter and efficiency is so amazingly high that minimal cooling is required.

Just as the first lasers led to multiple practical applications in telecom, weaponry, medicine, computers, chemistry, physics, etc. I would expect a fictional scientific breakthrough to affect many aspects of a scifi story.


*by the phrase "be more productive" I mean "waste time more efficiently"

[El_Phil]

Well hunpecked the thing is if 'warp points' are just wormholes then your still probably OK in modern science. As long as you dont go FTL locally during your trip through the warp point your OK it's 'just' a distorion in the local spacetime.

Still its a nifty theory.

Are Gravitons really generally accepted? There was me thinking it was just part of the attempt at transfering quantum mechanics to gravity. There are many other quantum theories of gravity that involve no gravitons. I'm not saying they don't exist, similar quantum theories work in many other fields. But existing quantum graviton theorys are nastily convuluted, contrvied and internally inconsistent at the moment. Of course they could straighten out, or the correct theory could be that convoluted.

Still with gravity being mass, momentum and energy, taking Einstein's theory of gravitation as right of course, it doesn't matter what particle does the work, you still need those three to get gravity. Just because you can put a name to something does mean you can create it easier.

Why is this? Gravitons are just messenger particles, they don't create the force they just pass it on. So to create the gravitons you have to create the force, so you have to create that much gravity which is no real net gain. Or that is my understanding anyway.

[Suicide Junkie]

Energy loss via gravitational waves can be seen in binary pulsars like PSR 1913+16

Gravitons are to gravity waves as Photons are to light waves.

[Hunpecked]

El_Phil writes: "Well hunpecked the thing is if 'warp points' are just wormholes then your still probably OK in modern science."

I lack even a layman's understanding of "wormholes". From the Wikipedia I gather that it's all theory so far and usable wormholes may or may not be possible. In other words it's still sci fi, though with a possible but not solid theoretical basis.

Personally I doubt that wormholes, if they even exist, are usable for FTL travel, for the simple reason that no ET species has to our knowledge taken over the entire universe. Yeah, yeah, we could be alone, we could be in an interstellar "wildlife preserve," etc. But I get the distinct impression that our universe is just not very friendly to many of our cherished sci fi concepts.

[Renegade 13]

Considering that some scientists belive we live in a "multiverse", perhaps going sideways in time would work. Travel into one of those infinitely "other" universes.