What happens if 2 black globes touch?

[AnotherDilbert]

Given that a ship doesn't change velocity when it activates its black globe, leads me to believe normal gravitational forces act on the generator.

Sorry? Gravity is acceleration, lack of acceleration is constant velocity.

Anyway:

Gravity. Gravity is stopped by the globe barrier. The interior of the globe is unaffected by gravity.

Similarly globes in planetary labs, or orbital labs, can be turned on or off, and don't drift off into space burning a hole through the lab in the process when they become immune to orbital forces. The techs can continue to stand around outside the field, trying to poke it to work out what it is.

Activating a black globe on a planet is a bad idea.

On Worlds. A Black Globe activated on a world surface or in atmosphere receives damage at a rate equal to world size plus atmosphere per turn as it absorbs ambient energy from the environment.

Of course black globes don't have to make sense so who knows?

They have never made sense, but is kind a preview of "magic" super-tech beyond Imperial standard. The first ones were Ancient artefacts, IIRC.

[Linwood]

So - with a globe inside a globe, can the same ship project both globes? That would be an interesting twist on layered defense.

[Reynard]

What is it with gamer dreams of layering armor?!

[PsiTraveller]

I got to thinking about how long before someone tries to build a Black Globe generator to power a planet. As AnotherDilbert points out the globe absorbs planet + atmosphere per turn when a globe is activated on a planet. You could store up a lot of power in surface capacitors and use the power for the local grid.

Not effectively as it turns out. Planets and atmosphere would not generate enough to cover the energy needed to run the globe. Earth would generate 14 points. The globe uses 30. Oh well. I had visions of some Rube Goldberg device attached to an Ancient device.

Unless smarter folks than I could come up with a way to keep the lights on for free? Be a nice trick to have long term power for one of those really long low berth scenarios in the other thread.

[Moppy]

Given that a ship doesn't change velocity when it activates its black globe, leads me to believe normal gravitational forces act on the generator.

Sorry? Gravity is acceleration, lack of acceleration is constant velocity.

Anyway:

Gravity. Gravity is stopped by the globe barrier. The interior of the globe is unaffected by gravity.

Similarly globes in planetary labs, or orbital labs, can be turned on or off, and don't drift off into space burning a hole through the lab in the process when they become immune to orbital forces. The techs can continue to stand around outside the field, trying to poke it to work out what it is.

Activating a black globe on a planet is a bad idea.

On Worlds. A Black Globe activated on a world surface or in atmosphere receives damage at a rate equal to world size plus atmosphere per turn as it absorbs ambient energy from the environment.

This is inconsistent with itself but that’s ok because it is magic.

if gravity can’t pass the generator, a ship will change velocity when the gravity on it is negated. Extreme example if orbiting it will cease and fly off into space. A globe on a stand on airless plant will also shoot away harmlessly, not burrowing into the ground.

If instead gravity is removed by absorbtion,and increases the energy in the field you could detect at least the magnitude of other masses outside your globe, and this way and the globe would also gradually fill up on regular use. Edit: and the ship still changes velocity when activating.

Edit 2: and of course, just waking up, I forget to discuss what I actually wanted to, what happens if the user of a globe, from inside the field, picks it up the generator and moves it. We could say “it can’t move” but gravity does move it, because our ship doesn’t change velocity when activating a globe.

[Condottiere]

1. It sucks up all energy within it's vicinity, except apparently batteries.

2. Of course, sucking energy from capacitors and batteries would create a feedback loop.

3. Can't recall what powers a Black Globe - dark matter?

4. Speaking of feedback loops, a Black Globe should be the perfect solar cell.

[AnotherDilbert]

So - with a globe inside a globe, can the same ship project both globes? That would be an interesting twist on layered defense.

Certainly you can, but the inner globe will have no effect.

If they are turned on so that they intersect the Globes have no effect in the intersecting volume, at least if one Globe is within the other.

[AnotherDilbert]

This is inconsistent with itself but that’s ok because it is magic.

Not really, if you think it through. A "force-field" with the stated properties are of course pure pixie-dust magic, but it can behave logically with those properties.

if gravity can’t pass the generator, a ship will change velocity when the gravity on it is negated. Extreme example if orbiting it will cease and fly off into space. A globe on a stand on airless plant will also shoot away harmlessly, not burrowing into the ground.

Gravity will change the objects velocity, absence of gravity will not change its velocity.

An orbit depends on being constantly accelerated (change of velocity) by gravity, so of course an object not affected by gravity will continue in a straight line according to Newton's first.

If instead gravity is removed by absorbtion,and increases the energy in the field you could detect at least the magnitude of other masses outside your globe, and this way and the globe would also gradually fill up on regular use.

Sorry, I have no idea what that means.

Edit 2: and of course, just waking up, I forget to discuss what I actually wanted to, what happens if the user of a globe, from inside the field, picks it up the generator and moves it. We could say “it can’t move” but gravity does move it, because our ship doesn’t change velocity when activating a globe.

The globe will be a half-buried ball. If we try to move it sideways it will collide with the rest of the planet and stop.

If we start it at the top of a high building it will slice off a bit of planet and continue in a straight line while the rest of the planet accelerates in an orbit around the star.

If we activate it at ground level any imperfections such as a hill would trap the globe like a ball more than half buried in the surface of the planet and be dragged along.

[Moppy]

The problem is we are told that ships under a black globe cannot manoeuvre and that gravity is negated by the device.

Therefore either activating a black globe in orbit results in gravity negation, which means you leave orbit, so you have made a manoeuer under black globe - or the planets gravity is not negated in which case it is affecting the englobed ship by holding it in place (this also means you could move an englobed ship with a repulsor from outside the field).

I admit one of the points was badly written but it’s difficult to write clearly about magic. What I meant is that, does the black globe negate gravity by absorbing gravitional energy (whatever that is)? If so, it places a timer on the operation of the device, since it must eventually fill.

Why would a black globe stop permanently when it collided with an object? It will distintegrate what it touches, and then you can move it again. The generator is able to operate while moving (a ship is always moving with with respect to something) and should be movable from inside the field by picking it up, so long as you don’t use a gravitational drive.

Edit: but obviously the rules for magic take preference, just wanted to say the device rules are inconsistent but that’s ok. They’re supposed to be.

[Rikki Tikki Traveller]

I have always read this as Gravity doesn't affect what crosses a BGG. Therefore, if a ship is in orbit and activates its generator, it will begin moving in a straight line, per the exact velocity vector it had at the instant the generator was activated. It moves out of orbit at a tangent to its orbit. It moves in a straight line, regardless of what is in the way; absorbing energy until it can't anymore.

There is no maneuvering with the BGG activated, it just retains its initial momentum.

[AnotherDilbert]

Therefore either activating a black globe in orbit results in gravity negation, which means you leave orbit, so you have made a manoeuer under black globe - ...

You did not make any manoeuvre, you continue on you present course (vector) as the planet accelerates away from you under the influence of gravity. There is no contradiction.

I admit one of the points was badly written but it’s difficult to write clearly about magic.

Try quantum mechanics sometime, it's far more magical than black globes, but can still be precisely described, at least in mathematics.

What I meant is that, does the black globe negate gravity by absorbing gravitional energy (whatever that is)? If so, it places a timer on the operation of the device, since it must eventually fill.

Ah, I understand.

Well, apparently not. Gravity is not radiated energy, it's considered a force (Newton) or geometry (Einstein). Like a rope it can be used to drag an object and let both ends of the rope exchange energy state, but it is not energy radiation like a photon (as far as we know, pending finding the graviton).

Why would a black globe stop permanently when it collided with an object? It will distintegrate what it touches, and then you can move it again.

It absorbs energy, not matter. If an object hits a globe there is an inelastic collision and the globe can absorb the object's kinetic energy (its speed).

The generator is able to operate while moving (a ship is always moving with with respect to something) and should be movable from inside the field by picking it up, so long as you don’t use a gravitational drive.

Agreed, there is no absolute reference for position, and hence no absolute reference for movement.

You can move in space, but not while the globe is trapped in a planet's surface.

Edit: but obviously the rules for magic take preference, just wanted to say the device rules are inconsistent but that’s ok. They’re supposed to be.

There is no inconsistency or magic in it's operation, as far as I can see.

[Moppy]

I don’t understand why leaving orbit is not a maneuver. It is something you can do to move out of the path of an unguided projectile. They aim, they fire, you see the bullet, you globe up, you move out of orbit because gravity no longer holds you there, you unglobe, you watch them miss. Maybe the rule should be written as you cannot perform an arbitrary maneuver?

@anotherdilbert: I do not understand your explanation of what a black globe is absorbing and why a planet stops it. My understanding is that the device converts to energy any matter (and it’s associated kinetic energy) it contacts directly and stores that in capacitor; if not bullets just hit it, stop and fall to the ground. However we are told objects are disintegrated by the globe. Hence, if it were to strike a planet only the matter directly touching the shell would affect it. It is not going to try to absorb the kinetic energy of the entire planet.

Edit: actually I am beginning to doubt this. Do bullets that hit a black globe stop, or are they converted to energy and stored? I am just reading old CT books and it does not specify.

[AnotherDilbert]

I don’t understand why leaving orbit is not a maneuver.

Think of a stone (ship) on a string (gravity). As you whirl it around you head it moves in a circle (orbit). If you cut the string (negate gravity) the stone flies away in a tangent as Rikki Tikki explained.

It's gravity that keeps us in orbit, without gravity there can be no orbit.

Manoeuvre in this case means using the Manoeuvre Drive, i.e. accelerating. Moving out of the way of a speeding bullet using the globe is a nice stunt, but not manoeuvring.

@anotherdilbert: I do not understand your explanation of what a black globe is absorbing and why a planet stops it. My understanding is that the device converts to energy any matter (and it’s associated kinetic energy) it contacts directly and stores that in capacitor; if not bullets just hit it, stop and fall to the ground.

That might be a bit unclear, but I don't think any edition actually said matter is absorbed, only the object's kinetic energy (speed). If matter were converted into energy, rocks would be just as good as nuclear missiles at overloading the globe.

T5 is rather clear that matter is not absorbed.

Hence, if it were to strike a planet only the matter directly touching the shell would affect it. It is not going to try to absorb the kinetic energy of the entire planet.

We can't stop a part of the planet without stopping all of it or breaking it apart.

Just like a tennis racket hitting a ball only a very small area of the racket will be touching the ball, yet the entire ball will change velocity

[AnotherDilbert]

Edit: actually I am beginning to doubt this. Do bullets that hit a black globe stop, or are they converted to energy and stored? I am just reading old CT books and it does not specify.

T5 specifies inelastic collision, i.e. the object and the globe equalise momentum and they continue together with equal velocity.

Only the kinetic energy is absorbed, not the matter.

[Moppy]

@AnotherDilbert

Ok i understand your planet comments now. I had them as spheres of annihilation that would disintegrate through matter, so i couldn't understand what you were saying. Instead you're staying they collide and stop, then resist movement by stealing the kinetic energy.

[AnotherDilbert]

Instead you're staying they collide and stop, then resist movement by stealing the kinetic energy.

Quite, or at least try. TNE FFS has this to say:

Important Note: If an erected force field comes into contact with large quantities of matter (a vehicle of 50 displacement tons or greater, a large asteroid, planet, etc.), the generator is immediately overloaded and destroyed, and its HPC sink immediately suffers a catastrophic detonation, causing 1D20 critical hits. As the field attempts to drain all of the kinetic energy of the large mass, cooling it to absolute zero, energy is drawn from the entire mass to be drained by the globe, rapidly overloading the generator, as it cannot possibly contain all of the energy in a system that large.

[Linwood]

I am beginning to think the true strategic purpose of a BGG is to induce confusion and chaos in the minds of your enemies as they try to figure how it works and what it can do....

[Condottiere]

I'm pretty sure I read somewhere that they're used dirtside as a defensive measure, so one would assume that any ambient energy they pick up from intervening planetary surface is minimal.

[Sigtrygg]

Yes, there is a canonical example of Imperial personnel retreating inside a black globe 'shelter' when the Zhos invade. I'll dig out the reference.

[AnotherDilbert]

Yes, there is a canonical example of Imperial personnel retreating inside a black globe 'shelter' when the Zhos invade.

Wouldn't that be rather silly? Just keep the "shelter" under fire and it will explode sooner or later...