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How do Gravimetric Engines work?
- Thread starter Kai
- Start date
Imagine space as a sort of grid mesh fabric in three dimensions of an infinite number of spokes along each axis so it's like an ultra-fine lattice in three dimensions.
Whenever a square is formed along any axis, a sort of bubble is made.
If you pull at the grid mesh, some bubbles will be forced to contract and others to expand within this shape and that vacuum pulls things in.
Bigger objects pull more in all directions but gravimetric drives pull along a vector - that is, a single axis juxtaposed to the direction the vessel's drive is pointed in at any given moment.
But they put the projection infront of them, not directly ontop of themselves by manipulating bosons and gravitational field potential, ergo the mesh we described earlier.
The wake then pulls the vessel toward the vacuum and the shape naturally returns as you travel through it.
You can sharpen your acceleration by pulling harder or providing a force that prohibits your motion in the given vector, like a sort of slingshot. When you let go, you'll go shooting off.
And you can think of subspace as a sort of lubricant that softens the rules of physics by spreading your quantum potentials across more than the current plains of space, thereby making a sort of manual frog-hop over the rules or relativity in terms of velocity - Like reducing your friction by putting some of you (or rather your potentials) in places with different rules.
A good analogy might be imagining space as a sort of cross-wind that slows you down as you go faster and faster. Subspace works by halving the wind by putting some of you out of it's reach in three dimensions so there is less drag and your maximum velocity isn't limited to C.
The physics themselves aren't quite the same and the analogies don't match the math too well but it comes very close in terms of human understanding so there's no sense in worrying.
I hope that helps.
Whenever a square is formed along any axis, a sort of bubble is made.
If you pull at the grid mesh, some bubbles will be forced to contract and others to expand within this shape and that vacuum pulls things in.
Bigger objects pull more in all directions but gravimetric drives pull along a vector - that is, a single axis juxtaposed to the direction the vessel's drive is pointed in at any given moment.
But they put the projection infront of them, not directly ontop of themselves by manipulating bosons and gravitational field potential, ergo the mesh we described earlier.
The wake then pulls the vessel toward the vacuum and the shape naturally returns as you travel through it.
You can sharpen your acceleration by pulling harder or providing a force that prohibits your motion in the given vector, like a sort of slingshot. When you let go, you'll go shooting off.
And you can think of subspace as a sort of lubricant that softens the rules of physics by spreading your quantum potentials across more than the current plains of space, thereby making a sort of manual frog-hop over the rules or relativity in terms of velocity - Like reducing your friction by putting some of you (or rather your potentials) in places with different rules.
A good analogy might be imagining space as a sort of cross-wind that slows you down as you go faster and faster. Subspace works by halving the wind by putting some of you out of it's reach in three dimensions so there is less drag and your maximum velocity isn't limited to C.
The physics themselves aren't quite the same and the analogies don't match the math too well but it comes very close in terms of human understanding so there's no sense in worrying.
I hope that helps.
Fred
Retired Staff
Basically, it's a much less powerful Continuum Distortion Drive - right?
That seems really ironic to me. These devices came up in the first place as auxiliary engines so to allow units stuck in FTL dead zones to remain mobile (Ke-M1 Lamias)... but they really aren't conventional engines in that sense.
This begs the question: if gravimetric engines don't propel a ship via impulse, then why do they have exhaust points in this RolePlay?
Another question could be: why have them at all, if CDD/CFS effectively fills the niche better?
That seems really ironic to me. These devices came up in the first place as auxiliary engines so to allow units stuck in FTL dead zones to remain mobile (Ke-M1 Lamias)... but they really aren't conventional engines in that sense.
This begs the question: if gravimetric engines don't propel a ship via impulse, then why do they have exhaust points in this RolePlay?
Another question could be: why have them at all, if CDD/CFS effectively fills the niche better?
Zack
Inactive Member
Oskan's explanation would be the equivalent of flying by lifting yourself up by your shoelaces and makes no sense. For Fred: No, but I'll explain that later.
A drive system based on gravity manipulates gravity to push the starship. By generating massive amounts of anti-gravity the ship will repel everything nearby just like how earth pulls everything towards it only in reverse. This will cause the ship to shoot off in a certain direction. Alternatively it will create a massive amount of gravity, increasing the rate at which it falls towards something.
It is fairly safe to assume that the drive systems ‘shoot’ their gravity in one direction to move the ship in the other direction but the same sort of thing still applies, gravity is moving the ship. So if you were to shoot anti-gravity out the rear of your ship, your ship would move forward as much as it repels everything behind it. The further you get away from things to repel against the more energy it is going to cost you to move at the same acceleration.
This means a few things, namely because gravity weakens the further two objects are apart, the engine’s thrust will drop off quickly the further it is from some object to repel against.
Also because E=MC^2, and gravity is related to mass, it is going to cost a metric shit-ton of energy to go anywhere at any kind of speed. My estimate is that the same amount of energy it takes to move a ship at 1g worth of acceleration would cause it to fly forward at 10 or more g if it were shot out the back of the ship using a flashlight or 1000+ more times faster if you used a railgun type system.
So why have a gravity engine at all? The first thing that comes to mind is that it doesn’t use reaction mass, but neither does a light based drive system. However most starships already have at least one or two of these things on them, namely as part of the FTL system or as part of the artificial gravity system. Sense you probably already have them on your ship it makes sense to use them.
Edit: didn't get a chance to add this before lunch but a gravity drive is also not a CDD/CFS, merely one part of a CDD/CFS. IF it were the same thing a ship wouldn't be able to use one in an interdiction field, it would also cost even more energy to use because the CDD/CFS would require even more crazy space bending antics to work.
Basically because it doesn't get nulled by interdiction, it can't be the same thing.
A drive system based on gravity manipulates gravity to push the starship. By generating massive amounts of anti-gravity the ship will repel everything nearby just like how earth pulls everything towards it only in reverse. This will cause the ship to shoot off in a certain direction. Alternatively it will create a massive amount of gravity, increasing the rate at which it falls towards something.
It is fairly safe to assume that the drive systems ‘shoot’ their gravity in one direction to move the ship in the other direction but the same sort of thing still applies, gravity is moving the ship. So if you were to shoot anti-gravity out the rear of your ship, your ship would move forward as much as it repels everything behind it. The further you get away from things to repel against the more energy it is going to cost you to move at the same acceleration.
This means a few things, namely because gravity weakens the further two objects are apart, the engine’s thrust will drop off quickly the further it is from some object to repel against.
Also because E=MC^2, and gravity is related to mass, it is going to cost a metric shit-ton of energy to go anywhere at any kind of speed. My estimate is that the same amount of energy it takes to move a ship at 1g worth of acceleration would cause it to fly forward at 10 or more g if it were shot out the back of the ship using a flashlight or 1000+ more times faster if you used a railgun type system.
So why have a gravity engine at all? The first thing that comes to mind is that it doesn’t use reaction mass, but neither does a light based drive system. However most starships already have at least one or two of these things on them, namely as part of the FTL system or as part of the artificial gravity system. Sense you probably already have them on your ship it makes sense to use them.
Edit: didn't get a chance to add this before lunch but a gravity drive is also not a CDD/CFS, merely one part of a CDD/CFS. IF it were the same thing a ship wouldn't be able to use one in an interdiction field, it would also cost even more energy to use because the CDD/CFS would require even more crazy space bending antics to work.
Basically because it doesn't get nulled by interdiction, it can't be the same thing.
I once had a Gravimetric engine described to me as placing virtual mass in the direction you wanted to travel and having your ship 'fall' at it, varying speed by varying this virtual mass's size and distance in comparison to your ship.
Obviously these explanations are all different, we need to figure out which one is correct, and/or best for the setting.
Obviously these explanations are all different, we need to figure out which one is correct, and/or best for the setting.
Zack
Inactive Member
This explanation is wrong.
Doing this is the exact same thing as trying to lift yourself up by your shoelaces, IE it is impossible. The series of events will go something like this:
* Placing a 'virtual mass' in front of your ship is going to move your ship backwards because of action/reaction.
* Gravity will then pull the two objects towards each other.
* Dissipating or impacting the virtual mass will stop both objects due to action/reaction.
And of course if you try and keep the virtual mass in front of your ship, you will go no where because you will have to push against the virtual mass with the exact same amount of energy it is pulling you with in order to keep it in front of you. Again the closest equivalent is thinking that you can fly because your arms are exerting an upward force on your shoelaces.
So to get any real movement out of your gravimetric engine you're going to have to push off against something. The more stuff you push against and the closer it is to your drive the faster you will go which in turn means spreading your gravity out in a cone is best as it will cover more objects to pull against among other things.
Fred
Retired Staff
I think the 'choose in which direction you are falling' description was the one most prevalent in SARP so far.
Uso is arguing that it is a wrong interpretation (arguing you can't choose in which direction to fall... which puts the whole interpretation of gravity control for nekovalkyrja out of whack, but let's not go there), though, and from my understanding of his argument, he's saying that if you toss graviton particles behind you, you'll move forward like any other conventional engine.
At least, that's what I am understanding.
Uso is arguing that it is a wrong interpretation (arguing you can't choose in which direction to fall... which puts the whole interpretation of gravity control for nekovalkyrja out of whack, but let's not go there), though, and from my understanding of his argument, he's saying that if you toss graviton particles behind you, you'll move forward like any other conventional engine.
At least, that's what I am understanding.
Zack
Inactive Member
Basically, yes.
Like I said in a previous post it is safe to assume we have directed gravity technology (as it is used widely in this setting) so you can choose which objects you are repelling/attracting. Or if you want to phrase it in terms of falling you can choose which way you fall.
Gravitons also have no real 'weight' the way they are being used here, meaning that your engine also has to include a physical object to push against. Just like how a rocket engine requires something to be tossed out the back so to does a gravimetric engine. Because of how gravity works your gravimetric engine will work very well if it is pushing against something very close by, and it will work very poorly if it is just pushing against the random particles in space or some object at a great distance. In terms of effectiveness you can think of it like a beam weapon that is slowly dissipating over distance.
So in a nutshell you use the gravitons to push something away from your ship in order to move your ship forward. You can't have a working gravimetric engine without the 'pushing some object' away bit any more than you can have a rocket without reaction mass (Or fuel in layman's terms). For example if you shot gravitons out the back of your ship and there was absolutely nothing behind you, your ship would go nowhere.
Saying 'choose which way you are falling' is inaccurate at best and wrong at worst. It might be better to say you are pushing off of something or pulling yourself towards something.
Zack
Inactive Member
Anything with mass or resembling mass will work.
Or in order of effectiveness: Starlight, space dust, lasers, particle beams, dirt clumps, asteroids, other star ships, rocket exhaust, moons, planets, stars, and black holes. Of course the list isn't limited to this and includes anything that will move away with the same force that your ship is being moved forward with. Light waves will be bent slightly generating a little thrust. Dirt and small particles will be flung away from your ship at high speed while things like planets and stars will barely move at all unless you really floor it.
Anything attached to the engine (and by extension the ship) won't work.
You can't push against something physically attached to your ship like in Osakan's and Kai's explanations (which in each case would be the ship pushing against the ship). For example if you hold an object behind your ship to push off of you must exert the same force on it and by extension yourself that the engine is putting on the object in order for it to remain the same distance behind the engine. The forces balance out and you get 0 acceleration.
Or in order of effectiveness: Starlight, space dust, lasers, particle beams, dirt clumps, asteroids, other star ships, rocket exhaust, moons, planets, stars, and black holes. Of course the list isn't limited to this and includes anything that will move away with the same force that your ship is being moved forward with. Light waves will be bent slightly generating a little thrust. Dirt and small particles will be flung away from your ship at high speed while things like planets and stars will barely move at all unless you really floor it.
Anything attached to the engine (and by extension the ship) won't work.
You can't push against something physically attached to your ship like in Osakan's and Kai's explanations (which in each case would be the ship pushing against the ship). For example if you hold an object behind your ship to push off of you must exert the same force on it and by extension yourself that the engine is putting on the object in order for it to remain the same distance behind the engine. The forces balance out and you get 0 acceleration.
Fred
Retired Staff
So, in absolutely complete void - such as a CFS pocket-universe - this sounds like it would be entirely ineffective. that in turn would make gravimetric engines incompatible with subspace-distorsion based shielding under your explanation, right?
All in all, the gravimetric drive sounds a whole lot less reliable than the initial idea over vectors would have lead to believe. Startlingly so. However, the concept of distortion speed seems to survive more or less intact, so, I'll broach something else.
CFS systems aren't completely nulled by interdiction field. If so, a Plumeria's shielding wouldn't function under an interdiction field. As past documentation has shown (at least in Wes' writing) interdiction typically only disminishes a CFS' function rather than completely shuts it down.
That said, it nullifies most of its FTL capabilities. Nothing says you cannot use the CFS to make sublight maneuvers.
So, if a CFS can travel under those conditions as sublight speed, why couldn't the gravimetric drives be based off the same concept, albeit weaker?
All in all, the gravimetric drive sounds a whole lot less reliable than the initial idea over vectors would have lead to believe. Startlingly so. However, the concept of distortion speed seems to survive more or less intact, so, I'll broach something else.
CFS systems aren't completely nulled by interdiction field. If so, a Plumeria's shielding wouldn't function under an interdiction field. As past documentation has shown (at least in Wes' writing) interdiction typically only disminishes a CFS' function rather than completely shuts it down.
That said, it nullifies most of its FTL capabilities. Nothing says you cannot use the CFS to make sublight maneuvers.
So, if a CFS can travel under those conditions as sublight speed, why couldn't the gravimetric drives be based off the same concept, albeit weaker?
Zack
Inactive Member
Yes, in a complete void the drive would not impart any acceleration to the ship at all.
As for combining them with gravimetric shielding it is generally accepted that your shields don’t block your emissions. A ship could pull some technical tricks to let its gravity beam pass through its shield or even open up a small hole for its gravity beam to shoot out of. The shield could also not be entirely effective which is the most likely case. As such it just takes even more energy to get the same amount of acceleration.
As for interdiction and Nulling, A CDD can be completely nulled by an interdiction field. There is so much interdiction in the area that it can’t create its space bubble at all meaning the ship can not use the CDD bubble at all. When completely disabled the CDD can not change the ship’s location even at sub light speeds. In minor interdiction the bubble is just harder to form meaning it requires more energy to create (See: Less speed.) so the ship can still move about using it. Because the bubble forming gear still works in interdiction, although it can’t form the actual bubble, the other features of the CFS would still work in interdiction.
Gravimetric drives aren’t affected by interdiction at all, and will work under any level of interdiction without adverse affects. As such they are not the same thing as a CDD.
Of course nothing is stopping you from making a gravimetric drive on the same concept as a CDD as gravity manipulation is going to be a part of just about any FTL system. However you’ve just turned your gravimetric drive into a CDD, so interdiction shuts you down and you still need the same ludicrously high power requirements that an FTL drive requires. You would also get the big drawback of your ship not actually being accelerated. You couldn’t use this drive to say land on a planet or dock with another ship as the moment you turned it off your ship would either slam into the planet or go flying off into space. FTL drives only re-arrange your location relative to other things and does not actually impart acceleration. The same goes for an FTL drive being used for sublight speeds.
Or rather, you can’t make a gravimetric drive like a CDD without making it a CDD.
Most importantly the FTL systems are more hand wave than straight up STL engines. They all use tricks of some sort to get around the light speed thing but all the ‘real’ methods I’ve seen to create warp drive that haven’t been discredited all involve action/reaction at some level. So no matter what you do I would assume you are still stuck with my description of how they work unless you want to flat out dismiss physics.
As for combining them with gravimetric shielding it is generally accepted that your shields don’t block your emissions. A ship could pull some technical tricks to let its gravity beam pass through its shield or even open up a small hole for its gravity beam to shoot out of. The shield could also not be entirely effective which is the most likely case. As such it just takes even more energy to get the same amount of acceleration.
As for interdiction and Nulling, A CDD can be completely nulled by an interdiction field. There is so much interdiction in the area that it can’t create its space bubble at all meaning the ship can not use the CDD bubble at all. When completely disabled the CDD can not change the ship’s location even at sub light speeds. In minor interdiction the bubble is just harder to form meaning it requires more energy to create (See: Less speed.) so the ship can still move about using it. Because the bubble forming gear still works in interdiction, although it can’t form the actual bubble, the other features of the CFS would still work in interdiction.
Gravimetric drives aren’t affected by interdiction at all, and will work under any level of interdiction without adverse affects. As such they are not the same thing as a CDD.
Of course nothing is stopping you from making a gravimetric drive on the same concept as a CDD as gravity manipulation is going to be a part of just about any FTL system. However you’ve just turned your gravimetric drive into a CDD, so interdiction shuts you down and you still need the same ludicrously high power requirements that an FTL drive requires. You would also get the big drawback of your ship not actually being accelerated. You couldn’t use this drive to say land on a planet or dock with another ship as the moment you turned it off your ship would either slam into the planet or go flying off into space. FTL drives only re-arrange your location relative to other things and does not actually impart acceleration. The same goes for an FTL drive being used for sublight speeds.
Or rather, you can’t make a gravimetric drive like a CDD without making it a CDD.
Most importantly the FTL systems are more hand wave than straight up STL engines. They all use tricks of some sort to get around the light speed thing but all the ‘real’ methods I’ve seen to create warp drive that haven’t been discredited all involve action/reaction at some level. So no matter what you do I would assume you are still stuck with my description of how they work unless you want to flat out dismiss physics.
I think a lot of designers were drawn in by the promise of an engine system that didn't require a fuel tank.
I think I'm just going to replace all the Star Army's gravimetric engines with something else.
I think I'm just going to replace all the Star Army's gravimetric engines with something else.
Zack
Inactive Member
Or we could put in a little effort and do things right.
The way I see it is that the only problem with gravimetric drives is that people think they are absurdly powerful. Nearly all ships are already going to have one in one form or another, and they are going to have the power to use them so there really is no reason to get rid of them.
Its just they are going to require magnitudes more power to use than any other engine. Outside of that the problems I see in roleplay are more people not understanding how acceleration works in space, not the engine itself.
The way I see it is that the only problem with gravimetric drives is that people think they are absurdly powerful. Nearly all ships are already going to have one in one form or another, and they are going to have the power to use them so there really is no reason to get rid of them.
Its just they are going to require magnitudes more power to use than any other engine. Outside of that the problems I see in roleplay are more people not understanding how acceleration works in space, not the engine itself.
Soresu
Well-Known Member
Or we could remember this is fiction, role play, and fun. Acceleration in space aside for the moment, I wish we could simply put aside all this physics buffery, and remember what fun is instead of making things into outright physics tests and reference material.
Not everyone is going to want long winded explanations on these things, some people would prefer a simple, "It's there, it works, it moves things." Others, a mildly explanatory, allbeit fictional explanation of it. Instead of, "Well Johnson, let me get my charts and graphs." That's the whole point of a role play. To leave the real world nonsense behind, and immerse one's self into the realm of fiction.
It's like trying to rationally, in physics explain the Improbability Drive from the Heart of Gold. And seeing if the people follow along, if and or are interested in the whole thing which, if you're not a physics buff likely you wouldn't be. These things are components of the larger machine that is role play to enhance, not yank away in a swirling mass of numbers and a long speech, yes, they deserve some respect in terms of descriptions but it is ment to be fun, mildly informative in terms of fictional aspects of the setting, but above all, fun not boorish.
Now, acceleration in space. Once again, I refer to the above. Fun, not realistic and boorish. Let people have their entertainment and be done with it man. I know you like to explain things in a seemingly realistic sense, but just try and remember, this is a work of fiction. The moment it slips into reality, and what not, I'd be more then happy to sit and listen to everything you have to say in regards to the subject matter. Otherwise, let's try and keep things simple, fun, and not take away from it all.
A simplistic explanation of a gravimetric drive, from a fictional standpoint would be to google it. Frankly, there are a few different ways to go about it, but all are mildly satisfying considering the mind numbing hard science behind the realistic version. http://web.archive.org/web/20060623...misctech/engines/gravimetric/gravimetric.html There is one example. It has both fiction, with undertones of real science thrown in. But, in my opinion, it is a matter of how we, ourselves interpret the drives that in the end should matter considering where we are. Sure, it should have some irl science behind it, but enough not to put one into a stupor, but to glean, and say, "Hey, maybe if I look at it this way with how we do things with that on here it works."
I've actually found with that in mind, things can be pleasing from multiple standpoints, and satisfying as well. Besides, we got the power sources, and we're certainly not shy about using them either.
Not everyone is going to want long winded explanations on these things, some people would prefer a simple, "It's there, it works, it moves things." Others, a mildly explanatory, allbeit fictional explanation of it. Instead of, "Well Johnson, let me get my charts and graphs." That's the whole point of a role play. To leave the real world nonsense behind, and immerse one's self into the realm of fiction.
It's like trying to rationally, in physics explain the Improbability Drive from the Heart of Gold. And seeing if the people follow along, if and or are interested in the whole thing which, if you're not a physics buff likely you wouldn't be. These things are components of the larger machine that is role play to enhance, not yank away in a swirling mass of numbers and a long speech, yes, they deserve some respect in terms of descriptions but it is ment to be fun, mildly informative in terms of fictional aspects of the setting, but above all, fun not boorish.
Now, acceleration in space. Once again, I refer to the above. Fun, not realistic and boorish. Let people have their entertainment and be done with it man. I know you like to explain things in a seemingly realistic sense, but just try and remember, this is a work of fiction. The moment it slips into reality, and what not, I'd be more then happy to sit and listen to everything you have to say in regards to the subject matter. Otherwise, let's try and keep things simple, fun, and not take away from it all.
A simplistic explanation of a gravimetric drive, from a fictional standpoint would be to google it. Frankly, there are a few different ways to go about it, but all are mildly satisfying considering the mind numbing hard science behind the realistic version. http://web.archive.org/web/20060623...misctech/engines/gravimetric/gravimetric.html There is one example. It has both fiction, with undertones of real science thrown in. But, in my opinion, it is a matter of how we, ourselves interpret the drives that in the end should matter considering where we are. Sure, it should have some irl science behind it, but enough not to put one into a stupor, but to glean, and say, "Hey, maybe if I look at it this way with how we do things with that on here it works."
I've actually found with that in mind, things can be pleasing from multiple standpoints, and satisfying as well. Besides, we got the power sources, and we're certainly not shy about using them either.
Firebrand
Inactive Member
Following Soresu, I invoke the Zeroth Law.
This is roleplay. We want to have fun. We shouldnt let pesky things like Physics get in the way of fun. I mean, by god, We have Lesbian Catgirls fighting Grubbly tentacle monsters, A nation of mostly men spying on everything with their secret police, A company who'se pc's include Captain Tinkerbell, a Yandere IPG spah, and a Cyborg Cook.
We have Goat people piloting Organic mechs.
And Loli Goo Girls.
This is roleplay. We want to have fun. We shouldnt let pesky things like Physics get in the way of fun. I mean, by god, We have Lesbian Catgirls fighting Grubbly tentacle monsters, A nation of mostly men spying on everything with their secret police, A company who'se pc's include Captain Tinkerbell, a Yandere IPG spah, and a Cyborg Cook.
We have Goat people piloting Organic mechs.
And Loli Goo Girls.
Zack
Inactive Member
No undertones of real science, just science words thrown in with no consideration to what they mean. It would have been far better for Babylon 5 to just not explain certain things rather than trying to cover up their short comings.
Have some respecting science: http://www.projectrho.com/rocket/rocket3al.html#fiction
Then put in a little effort into understanding how the things in the setting work. Consistency promotes good RP and everyone wanting special exceptions just for them does not promote good RP.
For that matter, I'd like to point out this is a question about how an engine type would work not a discussion on if we should ignore information we don't like.
Have some respecting science: http://www.projectrho.com/rocket/rocket3al.html#fiction
Then put in a little effort into understanding how the things in the setting work. Consistency promotes good RP and everyone wanting special exceptions just for them does not promote good RP.
For that matter, I'd like to point out this is a question about how an engine type would work not a discussion on if we should ignore information we don't like.
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