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

[mike wightman]

The "Laws" of gravity are well understood, but thr jury is still out on what exactly causes gravity. Is it the curvature os spacetime due to mass or is it due to the exchange of graviton particles or ...
Then there's the interesting question of how to explain the observed fact that our universe is expanding faster and faster, as if due to some form of unknown repulsive force or antigravity, istead of slowing down due to the effect of gravity as those "laws" predict?
The final question is, of course, how can electrical energy be "converted" directly into antigravitational energy?
It could be that the repulsor is invented first because it is a variation of the grav module which pushes against things (maybe grav plates should be in the ceiling pushing people to the floor?). In the weapon version the field or particles are focused and collimated to produce a narrow beam rather than a cone, and you only use them against targets smaller than you.
The tractor is based on the production af a true artificial attractive gravity field or graviton particles, and requires higher TL understanding.

 

[Doyle Hunt]

Okay, I'll admit that the gravitons vs. space-time curvature jury is still out. It's kind of like the turn-of-the-last-century argument about the luminiferous ether to act as a medium for light waves, before photons were discovered as distinct particles with wavelike properties. My reason for supporting the existence of gravitons IMTU is that creation of virtual particles (gravitons or anti-gravitons) for grav modules, acceleration compensators, etc. sounds less far-fetched than creating extremely localized (and directional!) space-time curvature by means of those devices, which would not only affect gravity, but also light and other electromagnetic phenomena.

As for the air/raft, g-carrier, etc. not creating a downdraft, I do take your point about helicopter lift. However, merely negating the effects of gravity doesn't provide thrust, so it doesn't provide deliberate movement. That would make an air/raft work more like a hot-air balloon. Which is fine as far as it goes - TNE used this concept for contra-grav "lift", but then didn't use it for acceleration compensators or internal grav fields.

To get gravitic thrust, you would still have to throw something away from the vessel, i.e. anti-gravitons (to coin a term - if gravitons pull, anti-gravitons would push). That means that the air under an air/raft would be pushed downward as the air/raft is pushed upward, and considering the relative differences in mass, the air would be pushed very far and very fast compared to the air/raft itself. Of course, grav modules on the bottom of the air/raft don't have to push against air to provide lift, pushing against the mass of the planet does that, whether you have an atmosphere or not. The downdraft is just an undesirable side effect.

Another consideration - Since the inverse-square law governs the force of gravity, regardless of arguments between gravitons and space-time curvature, and your air/raft's lift depends on gravitic thrust away from the planet, most gravitic vehicles would have a definite service ceiling, above which the force of gravitic thrust between the air raft and the planet becomes too small to keep the air/raft aloft. This ceiling should be all the way out to low orbit to stay in line with canon, but the ceiling should be there. That could make an interesting malfunction for a gravitic vehicle, loss of gravitic thrust that restricts the service ceiling. Older gravitic vehicles nearing the end of their useful lives may find that simple wear has reduced their ceilings as well.

By the way, for present-day aircraft, a "service ceiling" is measured as the altitude beyond which there is not enough lift to maintain a climb rate greater than 100 feet per minute at cruising speed. A plane can climb above that altitude, but it takes a long time to do it. Since an air/raft need not have aerodynamic lift, and need not be in an atmosphere at all, the service ceiling could be defined as the altitude above which the air/raft's gravitic thrust cannot maintain a vertical acceleration greater than 0.05g, or something. YMMV.

 

[Straybow]

Originally posted by Doyle Hunt
To get gravitic thrust, you would still have to throw something away from the vessel, i.e. anti-gravitons (to coin a term - if gravitons pull, anti-gravitons would push). That means that the air under an air/raft would be pushed downward as the air/raft is pushed upward, and considering the relative differences in mass, the air would be pushed very far and very fast compared to the air/raft itself. Of course, grav modules on the bottom of the air/raft don't have to push against air to provide lift, pushing against the mass of the planet does that, whether you have an atmosphere or not. The downdraft is just an undesirable side effect.

aragraph: No, because the anti-gravitons need only counter the effects of gravity they need be no stronger than the local gravitation. For individual gas molecules an acceleration of 9.81m/s² is small compared to gas molecule velocities. The result would be a pressure increase, but it would be small and generate very little wind.

For example, I have an electric heater in the bathroom 'coz the tile gets too cold. If there weren't a fan in it the only circulation would be provided by the expansion of the heated air. Not much, even though the air is being heated by 100° C or more.

But when a column of air 12km high gets heated or cooled by only a few degrees the cumulative effect is a measurable change of air pressure on the ground surface and winds that may reach very high speeds.

Unless you have a grav vehicle several km across there won't be enough air effected to create winds from a very localized gravitational force.

aragraph: Second, the point I made about the gravitational stress on the fabric of space is analogous to magnetic fields. A vehicle can use generated magnetic fields to "push" against the ambient magnetic fields to generate thrust. Since the interaction between two magnetic fields is weak it take a very strong localized field to generate a very small acceleration. It is, however, very efficient. NASA has considered using the effect to maneuver probes travelling over interplanetary distances.

This doesn't have to be so for grav tech. The interaction could be strong, in which case the generated grav-field would provide significant acceleration against the ambient grav field. This doesn't require spitting out "things" to create exchange of momentum, just field interactions.

Such activity would expend energy from the power source and drain energy from the ambient gravity field. That could mean gravity in the general area surrounding an operating grav vehicle would experience a diminution proportional to the mass ratios (which would be roughly 10^-18 gee around an Air/Raft, if I remember my mass figures correctly). I doubt anything but the most sensitive experiment could detect it.

 

[aramis]

Extant canon gives us at least 6 G's of gravitic hrust, and it is some ofrm of off-axis thrust, as it is for intertial compensators... (MT, TNE, T4) It appears to generate accellerations nerarlyt instantly, but said accellerations seem to work at "Normal" rates for Traveller (The OTU G is 10m/s^2, not 9.8... see FF&S1)...

Also, since there are repulsors AND tracttors mentioned in CT bk 5, we need rules for what they do besides cting aains missiles.

Now, I would assume that since AG and IC appear to be non-globular, then gravitic tech can create non-spherical areas of effect.

Hence linearity/conality of Repulsor weapon area of effect. Inverse square law probably applies just as it does for other "Lights"...

I would assume that tractor and repulsors provide accelerations to the target when they hit... for missiles, that is clearly a very useful bit... provided the acceleration is greater than the drive's rating.

Now, the other possibility is that they create a situation where the two objectts climb/dive each other's graity wells...

if the former, even a 2G off-axis, off-plane thrust is a great anti-personel weapon... if applied in a semi-random manner.

If the latter, the "damage" is going to be minimal, but the ships will either be forced apart or brought together...

Perhaps the "graviton pressure" theory makes the possibility of a non-graviton particle which produces gravitons (and hence localized graviton pressure increase) when it decays... so repulsors are esentially equivalent to meson guns in function, just different in on-target effect...

 

[far-trader]

Originally posted by Aramis:

<snippage>

Perhaps the "graviton pressure" theory makes the possibility of a non-graviton particle which produces gravitons (and hence localized graviton pressure increase) when it decays... so repulsors are esentially equivalent to meson guns in function, just different in on-target effect... [/QB]

Hmm, or, and its just a germ of an idea here, maybe meson guns are actually gravity guns (aka Gravy Guns) and meson screens are gravity screens (Gravy Strainers?).

We know that somewhere it was decided that mesons wouldn't actually work and that it was suggested that the name was a dodge by the Solomani to protect the nature of the weapon. Hmm, it might be counter to the old Solomani tech being weak in gravity manipulation though.

Anyway if you will imagine for a minute that a "meson" gun is in fact a massive graviton pulse then perhaps the effect is more understandable.

It would be a useful space weapon since it "decays" inside the target due to interacting with the targets own local mass, typically at the targets center of mass. Hence it ignores armor by being attracted inside, past the armor. Once it interacts with the gravity field, boom!

The "meson" screen acts by countering or randomly moving the ships apparent mass so the incoming gravitons scatter (no boom) or converge outside the ship (boom miss).

Gravy Guns would be similar in ways to Repulsors but much less finely tuned and with lots more power. Like a water ballon instead of water pistol.

Gravy Strainers would be grossly similar to Tractors in much the same way. The first makes gross uncontrolled fields of gravity around your ship the second refines it to a variable and directional beam.

That leaves "meson" communicators. Same kind of an idea here. Instead of mesons you have graviton pulses and the reciever side is a Tractor, the transmitter is a Replusor.

So some questions:

What do you think of the idea?

What works, what doesn't?

Planetary Bombardment. Will it work? My opinion, no. The gravitons would be pulled to the center of mass and the boom would have little effect. This is I think a good thing, it leaves something for missiles to be good for, as well as troops and assault craft. I think I recall a published description of planetary assault by meson gun but I can rewrite that for mtu.

Deep Site Guns. Are they still valid? IMO, yes, and even more so. They are firing at valid targets and the bonus is its harder to be targeted. Makes planetary defense oh so much easier, once you have the tech, and that's why there are still armies and assault craft, and navies to get them there and keep them from getting there.

More questions?

 

[fredofmars]

Originally posted by Drakon:
<snip>
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.) [/QB]

This theory of gravity was proposed in the book "Recall Not Earth" by CC MacApp (published in the late 60s or early 70s I think). It's an interesting theory. In the story it turned out there was a fairly simple way to screen an area from this "push gravity" by a specially charged plate.
- Joseph

 

[Drakon]

Originally posted by Doyle Hunt:
Okay, I'll admit that the gravitons vs. space-time curvature jury is still out. It's kind of like the turn-of-the-last-century argument about the luminiferous ether to act as a medium for light waves, before photons were discovered as distinct particles with wavelike properties.

There is only one reason for this. Mathematically the two concepts, Aether and Curvature (and this is really where the graviton theory ends up, if you look at it. The Aether is essentially a "sea of gravitons) are identical. Aether theory, in its many varieties, including graviton sea, has been tweaked and fiddled with so much that it ends up producing the same mathematics as General Relativity.

Where the two depart is the nature of entities in question. Is the Aether separable from the dimensional manifold? You see, the problem is that while space acts as if it is curved, it was for the longest time assumed to be flat. This was Newton's big mistake.

[The difference between Standard Aether and gravitons is that the latter postulates this Aether as having a more granulated structure, instead of being a continuous fluid.]

Aether assumes the underlying dimensional manifold is flat, Euclidean. But this assumption is based on nothing more than simply we understood Euclidean geometry millenia before we understood non-Euclidean geometry. We accepted Euclids 5 postulates, including the troublesome 5th as, well, divine writ.

If the manifold is curved, any fluid or granular stuff in it to cause the effects of gravity, is superfluous.

 

[Drakon]

Originally posted by Commander Drax:

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.

So far things look positive. The only real critism I have seen have had to deal with Quantum Mechanics. Which have been dealt with in subsequent papers by Chris Van Den Brock et.al.

For manuvering or hovering, you don't need to compress space in front and expand it behind. (Or more exactly, compress space above and expand underneath) What you need to do is focus or "lens" the gravitational field (space-time curvature) that is already present.

 

[Drakon]

Originally posted by Straybow:
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.

For the record. Em is 10^41 times more powerful than gravity.

 

[Drakon]

Originally posted by far-trader:
So some questions:

What do you think of the idea?

What works, what doesn't?

Well, I see gravitons as little more than fiction. Mostly because I have my disagreements with Quantum Mechanics, which is where gravitons got resurrected.

Look, being alive and being dead are two mutually exclusive states. The cat only exists in one, or the other. It does not, nor cannot exist in both at once, or neither. The fact you DON'T KNOW what that state is until you open the box and look, was exactly why Shrodinger was torturing the poor kittens in the first place. To prove how Copenhagen offered a choice. Logic or its interpretation of QM? You can't have both.

Shrodinger did not intend to show how QM was weird. He attempted (and to me succeeded) in proving that the Copenhagen interpretation to QM is illogical.

What the wave equation is measuring is not so much the nature of the QM system, but our knowledge of that system. Which I think we can agree is limited as it is. It does not mean that the universe has a necessarily indeterminant nature. It simply means that we may not know just what that nature is exactly, in as many detail as we like.

So, do gravitons exist, like photons? Well, I don't know. I am not even sure if the photon exists. The dual nature of light (as well as other particles) is troubling, as again it appears we have two mutually exclusive states. Its a wave when its moving. But when it interacts with something, all of a sudden it becomes a particle. I don't think we know enough to figure out just what is going on at a subatomic level.

 

[Straybow]

meh. 10^30… 10^41… what's the diff?

As Sen. Dirksen said, "A billion here, a billion there, pretty soon you're talking big bucks."