Tractor Beams/Gravitic Weapons... and why not?

[LordVince]

Originally posted by daryen:
I am not a scientist (rocket or otherwise), but I doubt it would work like this. The anti-gravity might cancel you gravitational attraction to the planet, but, without a corresponding "push", there is no reason to believe you will "fly" away. Likewise, the earth moving at 25 m/s isn't too big of a deal, as the victim is also moving at 25 m/s. While they victim may start slowing down, they won't lose all of their momentum immediately.

Most likely the victim will be out of the field of effect long before sufficient relative speed and height have been gained. [/QB]

Well, while I don't remember the NUMBERS involved, I do remember the Physical Laws that are involved.

A planet is a sphere. This sphere is spinning on an axis. You are standing on the outside of this sphere. ONLY GRAVITY keeps you on the surface of this sphere! If gravity were removed from the equation, then the energy of the planet's spin would be imparted to YOU, and you would fly away from the planet IN THE DIRECTION OF THE ROTATION (NOT straight up!) at the speed of the rotation. In physics this is called Centripital Force (NOT Centrifigal, which is when you are INSIDE the object rotating, not OUTSIDE).

For the effect I was describing, the AG Landmine would have to COMPLETELY cancel 100% of the gravity in its area of effect. If even a TINY fraction of micro-gravity were in there, then you would just get a "bouyancy", or balloon-like effect. It would still fling you into the air, just at a lower base speed.

And yes, it is POSSIBLE for Centripital Force to overcome Gravity -- but the planet would have to be spinning so fast, that a Day-Night Cycle would be only several minutes long.

 

[LordVince]

Originally posted by Lionel Deffries:
Hello.
Two points (both of which i probably have wrong).
1 - Nul grav mine = wouldn't you rise at 32feet per sec not squared(on earth) until you left the nul grav field then gravity would slow you down and then pound you into the ground at 32 feet per sec/per sec (1g).

32 feet per second-squared is the Accelleration value imparted to a falling object by the influence of Gravity. Without the influence of Gravity that accelleration has no hold on you, and you would be flung away from the surface of the planet you stand on at the speed of it's rotation. You are correct, however, in that, once you are out of the AG field -- and back into the influence of Gravity -- you will FALL at the rate of 32 feet per second-squared. This will vary planet-by-planet, because 32 feet per second/second is the accelleration from Earth's 1 G.

2 - With contra grav you could set up a force field around your ship that would keep out material objects (missiles, PA's, gamma radiation), this would also allow you to get up to near light speeds, yes we are probably talking shit loads of power hear but in combat is it better to end the battle with low power reserves or to win.
Also if contra grav will stop particules will it stop or divert mesons????? ( i assume that a meson screen is just the aiming fields for a meson gun without the generator (you retarget or reenergise the mesons or divert them)).
Just thinking please replie.
Bye.

This technology might count as the 4th Gravitic Technology, because you are talking about using an artificially generated gravitic force AS a shield. That is, instead of an area of effect -- in which EVERYTHING inside the area is being influenced by the gravity effect -- a gravitic shield would be a PLANE of force. Objects on either side of the plane are unaffected, but anything trying to intersect the plane (pass thru it) would be influenced. This would be VERY difficult to achieve. Gravity doesn't work like Magnetism -- never make that mistake! A magnet can generate a field around itself that is relatively "weak" in the center, but stronger away from the magnet (we've all seen magnet-under-the-paper science experiment; you then drop iron filings on the paper, and they settle into a sorta-circle formation around the magnet, clumping at the "poles").

But Gravity doesn't work that way. Whether you're at the North Pole, the Equator, the South Pole, or somewhere in the middle, the pull of gravity is constant (more or less), and straight down to the center of mass. Thus, even with artificial generators, the gravity you generate will ALWAYS propagate from, or to, the emitter and ALL THE SPACE IN BETWEEN. It would be almost impossible to create a "shield" of gravitic force without that same effect existing in all the space between the emitter and the "edge" of the shield.

Now, I suppose you could cover the hull of your ship with Repulsor emitters, then activate them all at once, and create a gravitic "wave" effect that pushes things away from your ship in all directions at once. The problem with this, however, is Newton's 3rd Law. As those Repulsors are PUSHING in at your ship from all directions, it would make steering pretty hard.

 

[Drakon]

Couple of points:
1) Gravity is now largely believed, (according to Einstein) to be a "psuedo-force" Not a real force like the push of a rocket engine. It is the result of the geometry of the underlying dimensional manifold.

If a piece of paper is curved, then a line drawn on it will also curve, unless you leave the manifold (paper) altogether.

2) For planets and stars, the mass of the object alters the curvature of the manifold, the space AND time of the underlying space. This curvature is actually quite slight. For the earth, it works out to something like curving a straight line into a loop about a light year in diameter. The mathematics used to describe the curvature of the space-time manifold references it to a flat one.

3) Our experiences give us objects like spheres, which are two dimensional surfaces (or manifold) embedded in a 3 dimensional manifold. But what we can measure, with present technologies and information, is the "intrinsic curvature" of the manifold. This intrinsic curvature tells us NOTHING about the existence or dimensionality, or even the shape, of any higher dimensional manifolds that may or may not exist. They are unnecessary, (unless you want to make use of alledged shortcuts through higher dimensional space)

4) Instead of an umbrella, what you are looking for is a "lens". Something that will curve the manifold differently than what it is. To go up, instead of curving space-time one way, curve it the other, or flatten that curvature out.

5) Because of space-time's rather unique properties, it is not a "thing" like planets and stars. One has no reference point to base a measurement system on, if you refer to the space itself. You can't see it, or touch it, or differentiate one piece of space time from any other, without objects being embedded in that manifold, like rocks, planets, or stars.

6) Anti-gravity mines, or gravity nullification mines: As an object on the surface of the planet is travelling at about 1,000 miles an hour at the equator, any object tripping such a mine would find itself flung off into space, unless acted upon by some other force. At least until it cleared the field of the mine, then our regular gravity would take over, and adjust the flight path of the object.

6a) This would include air as well, which might make for some interesting weather patterns as air leaving the planet, causing a low pressure area in the mine blast zone, high winds, etc. Interesting adventure just turning the damn thing off.

7) At present it appears that the only way to get gravity to curve space the opposite way, to turn it into a repulsive force, requires "exotic matter/energy" Which means negative mass, which is not been found and may not be findable. Not because of its non-existence, but because, well think a minute.

Start off with two masses. Identical except we flip the sign of the mass for one of them. The negative mass object, A, will be repulsed by the positive mass, B. But B is attracted to A, causing it to move closer to A. Which causes A to be pushed further from B. Right now there is no end in sight for this arraignment. B will continue to chase A, forcing it to go faster and faster, and we will see if the speed of light holds as these two objects run away from each other.

8) My own ideas of how this might be doable, shields and even warp drive, have to do with modifying the space-time manifold in a particular way. It seems to me that using constructive and destructive interference might make such devices feasable, at least in theory. Pumping energy is the same as pumping mass, and you can beam energy, with a simple radio or laser. Getting the frequencies just right, to produce the size, shape and consequences of the desired field, that might prove tricky.

 

[Richard Saunders]

Hello.
Just an idea on the two atoms chasing each other, wouldn't they just spin in space as one tries to impact on the other but cant because of the repulsion field.
Instead of a force field you could just use it as a repulsor field (the incoming material would be slowed down until it couldn't hit the ship), missiles you hold them away until they run out of fuel, for PAWs you slow dpwn the particules and they do less damage if you slow them down enough no damage.
Now to stop a spinal mount PAWs you would need a spinal mounted pressor (equal and opposite reaction) now while the pressor is turned on its also accelerating your PAWs while decelerating the enemys, The optimum placement for the pressor would be around the mouth of the spinal weapon.
As a thought (just occured to me) if gravity changes space then a pressor would make messon guns harder to hit with (whats the range through a pressor field and is it activated).
Wouldn't you fly straight up from the core of the planet (it would just seam as if you where flying backwards).
About them mine - you would only need to turn it on for 2 seconds, dont know about you but i dont think my body could take 1000k/h acceleration in one sec, The atmosphere of a planet would rise maybe 10k then just settle back down.
Silly story.
Sargeant to General - sir we have just shot down our hatted enemys spy satelite sir, it's getting a little hard to breath sir, do you think we could turn of the generator now sir.
Bye.

 

[Drakon]

Originally posted by Lionel Deffries:
Hello.
Just an idea on the two atoms chasing each other, wouldn't they just spin in space as one tries to impact on the other but cant because of the repulsion field.

Assuming you are discussing the negative/positive matter runaway situation.

My understanding is no. They would not orbit around each other because there is not balance of forces (for lack of a better term). Also since we are dealing with gravity, a pseudo force, it is unclear that there is a speed limit.

You hold one part down, the other simply zooms away, or impact. (Hmmm... what effect would that produce. Where is my bottle of negative matter

) There is the whole question of being able to trap exotic matter in the first place. You let them go, they'll simply runaway, one chasing the other.

You may have a point about a pressor field making a meson gun harder hit their target. And I think you are correct about using pressor fields defensively.

If you shut it off after the two seconds, then the atmosphere would just settle down. It would still be a heck of a storm until you did. It depends on the shape of the field as to whether it would settle back down, or simply be ejected out into space. That is one way to conquer a planet. Remove the atmosphere for a little while, then bring it back after the people have all died.

 

[Richard Saunders]

Originally posted by Drakon:

Assuming you are discussing the negative/positive matter runaway situation.

My understanding is no. They would not orbit around each other because there is not balance of forces (for lack of a better term). Also since we are dealing with gravity, a pseudo force, it is unclear that there is a speed limit.

You hold one part down, the other simply zooms away, or impact. (Hmmm... what effect would that produce. Where is my bottle of negative matter

) There is the whole question of being able to trap exotic matter in the first place. You let them go, they'll simply runaway, one chasing the other.

------------------------------------------------
We shouldn't call them positive and negative matter sound to much like matter and antimatter.
If matter has a finite speed of the speed of light then negative matter either will be limited to light or it will only travel faster than light ??????.
-------------------------------------------------

You may have a point about a pressor field making a meson gun harder hit their target. And I think you are correct about using pressor fields defensively.

If you shut it off after the two seconds, then the atmosphere would just settle down. It would still be a heck of a storm until you did. It depends on the shape of the field as to whether it would settle back down, or simply be ejected out into space. That is one way to conquer a planet. Remove the atmosphere for a little while, then bring it back after the people have all died. [/QB][/QUOTE]
-------------------------------------------------
Yes a huricane would look like a gentle zephyr, Most of the earths atmosphere is in the first 10miles but atmosphere reaches about 100miles up so in 2 seconds no atmosphere would get up to escape velocity.
An antimatter bomb would be quicker and probably cheaper.

Gurps has pressor beams as weapons but only at Tl15.
Bye.

 

[Drakon]

Originally posted by Lionel Deffries:

------------------------------------------------
We shouldn't call them positive and negative matter sound to much like matter and antimatter.
If matter has a finite speed of the speed of light then negative matter either will be limited to light or it will only travel faster than light ??????.
-------------------------------------------------

You are probably right, but the terms have already been established, so changing them will be even more confusing. I agree, better terms should be sought.

Negative matter/energy has the opposite sign mass, rather than charge, as in anti-matter.

As for whether it will break the light barrier, well, that gets tricky. First off, it depends on the frame. Because of nature of curvature, with space contraction and time dilation, the speed as measured outside that local frame will change.

This makes energy calculation dicey at best. And the energy calculations of a gravity field, or as a result of space-time curvature, unclear.

The reason why an object cannot cross the light barrier is that it would require an infinite amount of energy. But energy is linked to the local inertial frame, what the clocks and rulers end up being in size. When you are dealing with gravitation, it gets very messy.

So, whether, via only the influence of gravity alone, an object can cross the light speed barrier, that is the 64,000 credit question. Like what happens behind the event horizon of a black hole.

At least that is my understanding.

 

[Richard Saunders]

Hello.
How does gravity get out from a black hole.
I can understand how gravity can be equal at all points in the universe (no light speed problem), but i cant understand how it can seem to escape from a black hole, but obviously it can.
Have several probably erronious thoughts but i gota go.
Bye.

 

[Whipsnade]

Lionel Deffries wrote:

"How does gravity get out from a black hole.
I can understand how gravity can be equal at all points in the universe (no light speed problem), but i cant understand how it can seem to escape from a black hole, but obviously it can. Have several probably erronious thoughts but i gota go."


Mr. Deffries,

As far gravity is concerned, everyone has erroneous thoughts about it! While gravity still pokes us in the eyes everytime we try to describe it, there have been some intriguing developments of late. I'm just a simple nuclear engineer and know enough to say that the physics is beyond me but a recent NOVA(1) series made me want to try and tackle the physics again.

First, a proviso: I may not have fully comprehended the descriptions and I may not present them entirely accurately. Hopefully, the more physics savvy CotI members will be able to correct my mistakes and further illucidate Our Olde Hobby. Now, on with the conjectures!

String theory is currently the odds on favorite for the GUT title, the Grand Unified Theory or the Theory of Everything. String theory holds that all those quarks and other sub-sub-atomic particles are really made up of eensy-weensy vibrating loops of string. One of the problems with string theory was that there were FIVE different versions, all of which seemed as plausible as the next!

Midway through the Nineties, one of the real genius types stepped outside the box proposed a sixth string theory. He suggested that the five theories were just different ways of looking at the one actual theory. The five theories were the particle physics equivalent of an optical illusion. You've all seen them. Is it a vase or two people kissing? A young girl combing her hair or an old women? Stuff like that. This suggestion sent all the physics boffins scurrying about wearing out blackboards and using up tons of chalk.

The original five string theories had assumed that a certain number of dimensions existed co-equally within the universe. The sixth theory held that 11 dimensions were needed.

Within all these dimensions; including our familiar ones, a different kind of string existed; strings that weren't looped but rather open ended. These open strings formed membranes, or 'branes', and our universe fits neatly onto one. All sorts of other 'branes' co-exist with ours along all the different 'angles' that 11 dimensions provide. You've all seen 3D snowflake ornaments, now imagine an 11D one!

According to this sixth string theory, there are other universes operating under other physical contraints on other branes along these other dimensions. Please note; these other universes aren't of the 'Nazis Win WW2' variety, the physical laws that exist there; things like the strong and weak nuclear force, electromagnetism, and so forth, are completely different from our universe's versions or may not exist at all.

If all of this isn't 'funny' or 'weird' enough, there exists the possibility of particles 'leaking' from one dimension's brane to another dimension's brane! Imagine a 2D universe on a 2D brane, a particle there could 'leak' out by entering another dimension, just as a mote of dust floats up from a sheet of writing paper.

This is where gravity comes into the picture. Gravity is very weird. When compared to other forces we know about, gravity is absurdly weak and yet gravity has no drop off due to distance. All the other forces weaken across distances, yet the puny strength of gravity stays the same whether you're talking about 1 angstrom, 1 AU, 1 lightyear, or 1 universe.

With the sixth string theory as a springboard of sorts, some theorectical theorists have proposed that the force we call gravity is not really part of our universe at all! Rather, gravity is the observed result of particle 'leakage' from another 'nearby' brane! Gravitons are merely passing through our universe after leaking from another. This suggestion 'explains' why gravity is weak; whatever it is at home we are just observing the miniscule portion of it that is leaking out of another brane. The suggestion also 'explains' why gravity's effect does not drop off with distance; the leakage rate from gravity's home brane and passage rate through our brane is uniform regardless of the 'distance' between two objects in our universe.

Naturally, all of this is naught but theory, supposition, and suggestion. SLAC in California, Fermi in Illinois, and CERN along the Franco-Swiss border are gearing up to search for gravitons and hopefulyl provide experimental proof of certain parts of the sixth string theory. The smart money is on CERN winning the race. With the decision to abandon construction of the USA's SSC, SLAC and Fermi Lab have a serious handicap when their energy levels are compared with CERN's soon-to-occur upgrades.

Stepping back into Our Olde Game, IF what we call gravity is really leakage from another brane in another dimension and IF we can somehow shield, shunt, redirect, mask, fill-in-the-blank that leakage, than we MAY be able to control gravity in some manner. I quite like the idea of gravity being nothing but the leakage from some other, more powerful force operating in another universe stretched across the brane in another dimension. The suggestion that gravity may be nothing but the scent of woodsmoke on an autumn day, or the aroma of coffee perking in the kitchen downstairs, or the delightful lavender scent worn by a woman waltzing nearby makes the withered Whipsnadian ticker excitedly flutter and the weary Whipsnadian wetware tick over with renewed fervor.

The universe is weirder than we can ever imagine. So many things left to learn and discover, and so little time in which to do so.


Sincerely,
Larsen

1 - For those CotI members not lucky enough to reside in the World's Biggest Banana Republic, NOVA is a long running PBS science series in the USA.

 

[Tobias]

BTW, just to burst the bubbles of those who envision grav weapons utilizing hundreds of gees: Traveller Grav Technology seems to have its limits at 6Gs. Furthermore, I wholeheartedly agree with whoever first said that the "grav weapon" should be post-TL-16. Tractors are TL 16 and their remote manipulation of gravitic force is very basic and primitive.
IMTU, basically, with TL 15 or lower Grav Tech, you can only push. Grav Plates on Starships thus work by being mounted in the ceiling, not in the floor.

Regards,

Tobias

 

[Richard Saunders]

Hello.
My two stuppid and rediculous theories.

1 - You realy do want grav plates on the floor and the ceiling, on the ceiling to give artificial grav, on the floor to give acceleration relief for your feet (imagine 2g's for 2 days, ow my falled arches).

Realy silly theory
2 - Gravity is the same everywhere in the universe because at the big bang all matter and energy where present (no new creation of either) since then the universe has expanded but so has gravity (at the same rate).
At this point visualize a ballon the pressure inside is the same at all points if you blow it up bigger the pressure is still the same at all points (could anyone tell if the pressure changed, what do you compare it to ).

Totaly stuppid theory.
The gravity at the even horizon of a black hole is high enough to destroy the structor of any matter (gravity shear), also because of the speed of anything falling into a black hole time dilation will hold anything at the even horizon basicaly forever.

Well i think that will hold me for today 2 stupid theries and 1 good idea.
If somone feels like throwing maths at me 2*a = 3 Bananas or yellow.
BYE.

 

[Drakon]

Originally posted by Lionel Deffries:
Hello.
How does gravity get out from a black hole.
I can understand how gravity can be equal at all points in the universe (no light speed problem), but i cant understand how it can seem to escape from a black hole, but obviously it can.
Have several probably erronious thoughts but i gota go.
Bye.

The reason why you have problems with it is you are thinking Newtonian. Don't sweat it, everyone does.

You are thinking of something, a particle, a "graviton" that flies from a mass, interacts with another mass, causing that mass to be pulled back toward the transmitter of the particle.

General Relativity does not work that way. Take a sheet of rubber, and pull on the middle of it, pull it up or just gather it together in the middle. The rest of the sheet becomes stressed, deforms, as a result of you pulling it in the middle.

Mass stresses space-time here, which causes stresses on space-time outside of the black hole, just as well.

Also, there is a theory advocated by Tom Van Flandern that proposes the universe is filled with gravitons, that are all out there buzzing and banging into things. Gravity is more like brownian motion in this model. A massive object shields other objects from some of these particles, creating a net pressure on that object to close the distance toward the other. (It should be pointed out that both objects sheild each other, thereby causing the distance to decrease between them, due to the net pressure of the remaining gravitons.)

 

[Drakon]

Originally posted by Lionel Deffries:
Hello.
Totaly stuppid theory.
The gravity at the even horizon of a black hole is high enough to destroy the structor of any matter (gravity shear), also because of the speed of anything falling into a black hole time dilation will hold anything at the even horizon basicaly forever.

This is only true for small black holes which has a very high gradient close to the horizon. Large balck holes, such as sit at the center of most galaxies have far less of a gradient and don't get spagettified until well after passing through the horizon.

The event horizon is more a mathematical boundary rather than a physical barrier. It is the point where space and time are such that excape velocity exceeds light, but crossing the horizon is, well kind of weird. The original equations indicate that space and time switch roles behind the horizon, whatever that means phsyically is somewhat of a guess at this point. Mathematical studies do indicate that if you drop a particle into a black hole, it will impact the singularity in it, in a finite amount of time as measured by the particle itself. It may be strung out due to tidal stresses, but it still hits the singularity.

 

[Commander Drax]

I've read all of this and my brain is hurting! but I'll have a go...

I envisige, space-time as a type of substance that is bent by mass, the curvature of which causes the mutual attraction of massess (i.e Gravity).

In the traveller universe, gravity manipulation begins at late tl-8 (grav modules) I use the rational that these grav modules generate a field that bends the fabric of local space-time so that normal gravitational attraction can be used to create thrust in any direction (as per the Traveller canon), Likewise I envisage the development of the Starship Thruster unit as a larger more energy consuming artificial gravity generator that instead of interacting with a local gravity field, generates its own by compressing space before the thruster plate whilst simultaneously expanding it behind the plate, allowing movement and accelleration in any direction independant of gravitational masses being nearby. In a sense then space-time would behave like air being sucked through a jet engine providing thrust by being expelled out the back of the assembly.

Like I say, I am not a scientist, just an enthusiastic amatuer, I would be very interested to know if this drive could actually work in terms of real world physics should the technology become available. I personally feel that it doesnt break the law of the conservention of momentum as per the TNE explanation of why they dropped thruster plates from the TNE canon. As far as I can see this type of drive does have a respectable scientific following as it was reported as a theoretical warp drive in Focus Magazine.

Many Thanks,

 

[Straybow]

Horse of Another Color

Originally posted by Lord Vince:
Out in space this would mean nothing, but on the surface of a planet, suddenly losing the pull of gravity meant that anything inside the area of effect would be affected ONLY by the spin of the planet -- thus you would be flung into the air at the rotational speed of the planet -- with, for Earth, is, like, 25 miles per second. Imagine, you're walking along and suddenly -- pop! -- the AG Landmine activates, and you are flung up into the air at 25 mi/s. However, you are flung off at a TANGENT -- NOT straight up! So, a few seconds later, you slow down enough for gravity to once again start pulling you down -- from about a half-mile up! Can you say "Squish"?

No, the closest one can come to that effect would be instantaneous cancellation of momentum wrt the planet. If on the "trailing side" of the planet you would fly up at an initial velocity equal to the atmospheric drag limit. If on the equator at the leading side of the planet, you wouldn't even know anything happened, because the force required to keep you where you are is exactly equal to the force of gravity. At other places on the surface there could be odd effects mostly falling "down" (suddenly pivoting around your point or points of contact with the surface) or falling "up" at an angle.

I don't imagine that will appear in Traveller, instantaneous changes in momentum being a wee bit hard to arrange.

Gravitional mass nullification without nullifying inertial mass would have a similar but far less dramatic effect. Whatever could do that (a technology indistiguishable from magic, hmmm?) would have to stick to its target. You would retain your rotational vector but suddenly lose your centripetal acceleration. The resulting velocity isn't 25 mi/s (escape velocity), but about 1040 mph diminished in proportion to sin(latitude).

However, the ground beneath you is also rotating at the same velocity, only its vector is changing. So you would appear to rise at a rate (initial vector)·(1-cosecant) if I remember my trig correctly. That is, you would initially rise very slowly as your constant vector changed in relation to the curved surface of the earth. Adding orbital effects don't matter as much because the vector changes very slowly, less than 1° per day instead of ~360° per day.

Winds would probably become the dominant control over your vector after rising a short distance (100m or so) above the surface. It would be a frustrating experience until somebody with an air/raft caught up to you, or the device ran out of juice. With magical tech, who knows how long that could be.

If your gravitational and inertial mass were cancelled (they are probably one and the same intrinsic property, or external effect a la Mach's Principle) you wouldn't fly off the surface because you don't have any particular momentum at all. You would drift with the slightest breeze, etc.

Cancelling gravity would only cause you to bound upwards at the F=ma provided by your leg muscles when they can't instantly react to the instantaneous lack of downward pull. You might find yourself then falling from an uncomfortable height at an awkward angle due to uncontrolled spin induced by off-center application of that initial force.

A repulsor mine would cause you to fall up, at whatever gee rating it has, while you remain within its field. The effective gee of the field would weaken with distance by some mathematical relation, probably 1/r³ since gravitonics is envisioned to be a very short distance effect. Also the power source would be limited, otherwise your mine detector would spot it a long way off. Still, you find yourself hurled up against ceiling, branches, etc, then dropping a substantial distance afterwards. Not fun.

 

[mike wightman]

I don't imagine that will appear in Traveller, instantaneous changes in momentum being a wee bit hard to arrange.

Isn't that what starship inertial compensators do all of the time, produce instantaneus momentum changes to counteract the accelerations of the maneuver drive?

I like the repulsor mine idea, by the way

 

[LordVince]

Originally posted by Straybow:
A repulsor mine would cause you to fall up, at whatever gee rating it has, while you remain within its field. The effective gee of the field would weaken with distance by some mathematical relation, probably 1/r³ since gravitonics is envisioned to be a very short distance effect. Also the power source would be limited, otherwise your mine detector would spot it a long way off. Still, you find yourself hurled up against ceiling, branches, etc, then dropping a substantial distance afterwards. Not fun.

Yeah, that's what I was trying to say! I just didn't have the Math ^_^
And, while that might be dsiconcerting for a Trooper walking into the AoE, just imagine the kind of los of control you'd get for a vehicle suddenly racing into the AoE.

I'm a big fan of Gravitic Weapons, myself. In Traveller Canon, the Mastery of Gravity begins early on the Tech Tables. I find it odd that at Tech 12-14 there aren't more of them. I. myself, usually explain that Gravitic Weapons are "energy hogs", but that doesn't invalidate them completely! A Gauss gun is less "energy intensive" than a Gravgun that could do the same thing -- on a Personal Weapons scale. But gimme a 6G GravPulse Mass Cannon Spinal Mount anyday ^_^

 

[Straybow]

Math can be a humbling taste of reality. Let's look at the acceleration of the slug in a high-powered rifle barrel, such as a 30-06 or M-16:

m·a·d = ½mv²
a = v²/2d
a = (900m/s)²/(2·0.6m)
a = 675,000 m/s² = 67,500 gee

Do you think 6 gee gravitics can compete with that??

As for Gauss guns, the EM force is something like 10^30 times more powerful than gravitation. So a gravitics gun would be a very expensive spitwad shooter, a harmless TL 12 high school science project.

 

[Doyle Hunt]

My unsolicited opinions, in response to the whole thread rather than to a specific post--

Gravity works by well-known laws, and whatever is used in the game should follow those laws, within reason. Gravity works by the inverse-square law: The gravitational force between two objects is directly proportional to the sum of their masses, and inversely proportional to the square of the distance between them. The force of gravity at an arbitrary range of 2 "units" (whatever range intervals you use) would be one-quarter the magnitude that it was at a range of 1 "unit". At three units, the magnitude would be one-ninth, etc.

Tractors (which "pull" objects toward themselves) should be lower-tech than repulsors (which push, opposite to the way gravity normally works). It only makes sense that we learn how to artificially create what's found in nature before we learn to create its opposite.

Any kind of graviton emitter would only be able to push things directly away from itself, or pull things directly toward itself. It couldn't "grab" anything, just add an acceleration vector either directly toward or away from the emitter. Furthermore, the emitter, or the vehicle it is attached to, would have to be more massive than the target. Both the attacker and the target would move, unless one is so much larger than the other that the mass of the smaller object could be ignored (say, maybe two orders of magnitude, i.e. a factor of 100) A vehicle massing only one ton, and having a tractor or repulsor beam, targeting a vehicle massing two tons, would be moved twice as far as its target!

A tractor or repulsor beam would be a narrow cone, which widens out at increased distance, much like the beam of a flashlight, so fine control of a target's movement is not possible except at very close ranges. At higher tech levels, graviton streams might be controlled as precisely as a laser, but would still be subject to the inverse-square law. Using electric lights as a model (Tech level 4 for introduction of electric light, tech level 7 for laboratory laser propotypes, tech level 8 for commercial laser availability), precision control of a gravitic beam would require about three tech levels of development after discovery before precise control is possible, with another level before it's commercially available.

Veering away from the technical pedantry into a cultural side-topic, here's another potentially interesting concept regarding repulsors that provide gravitic lift. Anything below the vehicle would be repelled, including the air between the air/raft and the ground, so an air/raft could create the same type of down-draft as a helicopter flying overhead - if it's close to the ground, there would be a definite wind felt by anyone below, and a massive vehicle like a grav tank would literally be able to create hurricane-force winds directly downward. Flying over a bird would force the poor critter to crash into the ground if it was too low to recover in time. Environmentalists would be up in arms about flying grav vehicles over nature preserves, and municipalities would restrict grav vehicle use over parks and other pedestrian areas to high altitudes where the gravitic thrust can dissipate to a a level not harmful to people on the ground.

 

[Straybow]

It's never clear whether grav tech is graviton based or distorted-fabric-of-space based. Either way I don't think they'd generate significant down-draft in the air. The helicopter achieves lift by propelling a large mass of air at a high velocity

helicopter weight = airflow through blades
m·1 gee = dm/dt·v

Air doesn't have much mass, therefore velocity v has to be quite high. The acceleration of the air through the blades is far higher than 1 gee. So accelleration of air below a grav vehicle would be mild.

Grav tech is sometimes pictured as negating gravity's effect upon the vehicle, or whatever is contained within a field generated by the equipment. In this case there would be no acceleration of the air. The machinery is also presumed to divert/reflect/transmit a fraction of the energy available for vertical and horizontal acceleration.

I think of this as akin to the way a superconductor repells a magnetic field. The fabric of space is stressed by gravity, and grav tech enables the device or field to "float" at any arbitrary potential energy level. The energy cost of such an effect is likewise arbitary, since we're making all this up as we go.