artificial gravity
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Nik
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Um, depends how close to 'real' !! I guess you want, "Gravitize the floor-plates to Earth-Normal, Flight-Eng !" rather than boost from a nuclear rocket or 'inward acceleration' by spinning habitat...
Snag is the weirder aspects of gravity such as frame-dragging, magneto-gravitics etc only show in very subtle and oft-arcane conditions like spinning superconductors. Gravity is such a weak force that it takes very, very careful work to eliminate potential interferences. At that level of sensitivity, you must worry about Solar and Lunar tides, atmospheric density changes, 'trivial' electrostatic and magnetic perturbation etc...
There's always a possibility that some-one will stumble across a 'giant magneto-gravitic effect' and turn the field --And a heap of theory !!-- on its head.
Sure would help to have superconductors that worked at '40 below' rather than cryogenic...
Until then, gotta spin the habitat...
Snag is the weirder aspects of gravity such as frame-dragging, magneto-gravitics etc only show in very subtle and oft-arcane conditions like spinning superconductors. Gravity is such a weak force that it takes very, very careful work to eliminate potential interferences. At that level of sensitivity, you must worry about Solar and Lunar tides, atmospheric density changes, 'trivial' electrostatic and magnetic perturbation etc...
There's always a possibility that some-one will stumble across a 'giant magneto-gravitic effect' and turn the field --And a heap of theory !!-- on its head.
Sure would help to have superconductors that worked at '40 below' rather than cryogenic...
Until then, gotta spin the habitat...
Nik
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Russian researcher Eugene Podkletnov thought he'd found *something*, but the effect was small and several potential interferences were not accounted for. Other workers failed to reproduce his work. He may have got lucky, he was probably wrong, the others may have missed some 'apparently trivial' but --With 2020 (CE) hindsight-- essential detail...
Anti-gravity - Wikipedia, the free encyclopedia
Um, many proposed 'anti-gravity' systems are best decribed as 'Fringe Science', are unhappy kin to 'perpetual motion', 'over-unity' and/or 'zero-point energy' devices. IIRC, US patent office has a blanket rule for such that a working prototype *must* be delivered before any application can be considered.
You Have Been Warned...
Anti-gravity - Wikipedia, the free encyclopedia
Um, many proposed 'anti-gravity' systems are best decribed as 'Fringe Science', are unhappy kin to 'perpetual motion', 'over-unity' and/or 'zero-point energy' devices. IIRC, US patent office has a blanket rule for such that a working prototype *must* be delivered before any application can be considered.
You Have Been Warned...
Still. there is no theoretical reason why inverted gravity, focussed gravity or generated gravity are impossible; we don't have a sufficiently good working theory of gravity to exclude the possibility.
Still, I will make a reasonable sized bet that generating a field that will cause a mass to accelerate at (say) ten metres per second per second for ten seconds will involve at least as much energy as the added kinetic and potential energy of the object in question; which suggests it will not be a case of constant power= constant acceleration (as in most space opera) but constant power = constant force, ie small objects experience a greater gravity than large ones (unless it's gravity lenses, rather than generators),
Still, I will make a reasonable sized bet that generating a field that will cause a mass to accelerate at (say) ten metres per second per second for ten seconds will involve at least as much energy as the added kinetic and potential energy of the object in question; which suggests it will not be a case of constant power= constant acceleration (as in most space opera) but constant power = constant force, ie small objects experience a greater gravity than large ones (unless it's gravity lenses, rather than generators),
Nik
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Even if it takes the same energy, that comes from an efficient electrical generator rather than lighting off an inefficient rocket...
Which is why getting to Clarke orbit by riding a lift up a 'Skyhook' would only cost a few kilowatts of mains power per kilo, rather than tens of thousands of dollars of rocketry...
FWIW, now Alan Bond's HOTOL tech is getting serious Euro-funding, perhaps gravity researchers may be able to afford to play in orbit in 2020...
Which is why getting to Clarke orbit by riding a lift up a 'Skyhook' would only cost a few kilowatts of mains power per kilo, rather than tens of thousands of dollars of rocketry...
FWIW, now Alan Bond's HOTOL tech is getting serious Euro-funding, perhaps gravity researchers may be able to afford to play in orbit in 2020...
Serious Eurofunding at a million Euro's? A serious Eurocrat can absorb that in expenses in six months, without a centime getting to the researchers. Look how much they managed to spend on HDTV, and everyone knew in advance what the answers were.
Even for private industry, a million doesn't go far in aerospace.
But I was in no way suggesting that any form of gravity control would not be extremely useful, particularly because it would enable transfer of momentum at a distance, without requiring ninety-five percent of the craft to be reaction mass.
It's just that switching on your synthetic gravity is likely to require different power levels depending on what is being attracted. Not very intuitive.
Even for private industry, a million doesn't go far in aerospace.
But I was in no way suggesting that any form of gravity control would not be extremely useful, particularly because it would enable transfer of momentum at a distance, without requiring ninety-five percent of the craft to be reaction mass.
It's just that switching on your synthetic gravity is likely to require different power levels depending on what is being attracted. Not very intuitive.
It's easy to create gravity artificially: just built a ship that has a mass of 6.6 sextillion tonnes...
Nik
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Serious Euro-funding: Euro-zone is as strapped for cash as anyone else, yet this money *made it through* the committees...
Now that's serious !!
Um, did you check out the web-site links ? Looks like they've solved the implausibly-efficient heat exchanger, amongst other issues and, incidentally, reckon they can squeeze 3~~5% more from a rocket nozzle.
NASA spent billions, flew stuff strapped to an SR71, yet never got this close.
;-( Um, NASA also broke their sub-scale VTOL rocket after a couple of flawless test-flights, then wrote off the entire concept. And let's not mention foam insulation or O-rings... )
Where did Reaction Engines get their money ? IIRC, they've had a few small grants, and a lot of the early work was done as student projects. Then, a Euro consortium figured that any engine intended to fly to orbit would carry a Concorde#2 to the Antipodes in a couple of hours. They put in money for a cut-down, non-rocket design.
Besides, us Brits have a history of building wondrous stuff on a shoe-string. Snag comes when the project really, really needs a tranche of serious money to go 'live'. That's when our sponsors get cold feet. UK.Gov has a grim track-record of spending vast sums on blatant lemons while starving anything worth-while, then pulling the plug on winners at last moment. IIRC, Beagle2 was most recent example. The investigation cost more than getting it right...
Now that's serious !!
Um, did you check out the web-site links ? Looks like they've solved the implausibly-efficient heat exchanger, amongst other issues and, incidentally, reckon they can squeeze 3~~5% more from a rocket nozzle.
NASA spent billions, flew stuff strapped to an SR71, yet never got this close.
;-( Um, NASA also broke their sub-scale VTOL rocket after a couple of flawless test-flights, then wrote off the entire concept. And let's not mention foam insulation or O-rings... )
Where did Reaction Engines get their money ? IIRC, they've had a few small grants, and a lot of the early work was done as student projects. Then, a Euro consortium figured that any engine intended to fly to orbit would carry a Concorde#2 to the Antipodes in a couple of hours. They put in money for a cut-down, non-rocket design.
Besides, us Brits have a history of building wondrous stuff on a shoe-string. Snag comes when the project really, really needs a tranche of serious money to go 'live'. That's when our sponsors get cold feet. UK.Gov has a grim track-record of spending vast sums on blatant lemons while starving anything worth-while, then pulling the plug on winners at last moment. IIRC, Beagle2 was most recent example. The investigation cost more than getting it right...
ManTimeForgot
Temporally Challenged
Is it possible to create gravity artificially? Yes. Gravity is not a force "native" to this dimension of the universe. As such it stands to reason that once we figure out how to tap the dimension that gravity is native to, then gravity can be produced locally on some scale. The better question here is: How long will it take to figure out how to produce artificial gravity? And how long till it is commercially useful (just because someone figures out how to produce gravity artificially doesn't mean it will be immediately useful: we know how to produce anti-matter, but its cost is so prodigious we can't really do much with it)?
Anti-gravity is a different question though. We don't really know enough about what gravity actually is to state with certainty that an opposition force is even able to exist in this universe: kinda like a white-hole (mathematically feasible, but pretty sure nature balks at that sort of shenanigans; I rather think nature dislikes the idea of replaying the Big Bang just for kicks). Does gravity need an opposition force to satisfy any kind of interaction or effect in the greater multiverse? *Shrug* Even if it did could that force translate into our pocket of reality? *Shrug* What would happen if you did introduce it in an area under the effects of gravity (which is every where since it propagates like wave...)? I certainly hope nothing bad... *shudder* And shielding or create a portion of space opaque to gravity poses similar and interesting propositions...
I'll save speculation on anti-gravity for successive generations after we know quite a bit more about the universe. They will undoubtedly be in a better position to speculate on how tenable actual anti-gravity will be.
MTF
Anti-gravity is a different question though. We don't really know enough about what gravity actually is to state with certainty that an opposition force is even able to exist in this universe: kinda like a white-hole (mathematically feasible, but pretty sure nature balks at that sort of shenanigans; I rather think nature dislikes the idea of replaying the Big Bang just for kicks). Does gravity need an opposition force to satisfy any kind of interaction or effect in the greater multiverse? *Shrug* Even if it did could that force translate into our pocket of reality? *Shrug* What would happen if you did introduce it in an area under the effects of gravity (which is every where since it propagates like wave...)? I certainly hope nothing bad... *shudder* And shielding or create a portion of space opaque to gravity poses similar and interesting propositions...
I'll save speculation on anti-gravity for successive generations after we know quite a bit more about the universe. They will undoubtedly be in a better position to speculate on how tenable actual anti-gravity will be.
MTF
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