Missing the missiles

**DONOTDELETE** · Feb 1, 2002

<BLOCKQUOTE>quote:<HR>Originally posted by bakana:
Nope. A 1 ton rock falling from orbit hits with as much impact as a small Nuke whether you slam it out of orbit with a Mass Driver or just nudge it gently.

The extra enegy added by the Mass Driver is negligible in comparison to the kinetic energy the rock gets falling from 50 - 100 miles up.

The reason they used the Mass Drivers is not to increase the Impact, but to Aim the rocks.

It takes more energy to grab the rock and bring it aboard the Centauri ship than it does to throw it at a planet.
<HR></BLOCKQUOTE>

You didn't contradict me at all. I said that if there is acceleration, it needs a lot of energy. You claim there isn't, but agree that grabbing the rock would cost energy. But here's something else: Back when they used the mass drivers, people complained about "glowing rocks" and it was said to be attributable to them being loaded with quite a bit of energy in the shooting process. Second, gravity decreases quite drastically with distance. Meaning if you launch these rocks without acceleration from quite a distance, they will take quite a bit of time until they reach their target. Unless you have hundreds of them, that can be enough time for fighters to crunch them into pieces tiny enough to be eaten by the atmosphere.

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If I tell you my name is Lorien, what good is that?

(Whatever happened to Mr. Garibaldi?)

**DONOTDELETE** · Feb 1, 2002

<BLOCKQUOTE>quote:<HR>Originally posted by Lennier:
How fast do beam weapons reach you?

1. Weapons which use particles with no standing mass travel at the speed of light. The first shot of a laser can't be intercepted, it hits before your sensors can detect it. Heavier particles (it has been mentioned that Minnbari weapons are based on accelerating neutrons) travel at near-light-speed.

This serves two purposes: due to time dilation, the "aging" of particles slows and their lifetime grows. This allows to use particles which would, under normal conditions, be incredibly short-lived. Secondly near-light speed makes them *very* difficult to counter.

Can you intercept them?

Yes. Interceptor for a laser: a cloud of crystal particles which refract or reflect it. Interceptor for antimatter: any kind of matter. Interceptor for plasma: anything which absorbs its energy and makes the projectile disintegrate.
<HR></BLOCKQUOTE>

I guess a cloud of sand would be quite effective against lasers. As far as antimatter and other particle accelerators go, the best defense against charged particles is to provide an electromagnetic field, I guess, to splatter the beam so much that the amount of energy delivered per area is perfectly tolerable.

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If I tell you my name is Lorien, what good is that?

(Whatever happened to Mr. Garibaldi?)

**DONOTDELETE** · Feb 1, 2002

<BLOCKQUOTE>quote:<HR>Originally posted by Lennier:
What would a Minbari cruiser do against a squadron of Starfuries equipped with missiles?

Nothing.

Nothing at all. It would sit there, switch on its defense grid and destroy the Starfuries. Unable to track the Minbari cruiser, the missiles would miss. Space is big. If you are unable to track something, you will miss.

Now let us assume that of the 100 missiles fired, 10 would accidentally home in on the cruiser. Naturally, its fighter wing would destroy them. Unlike piloted fighters, missiles fly in a straight line. They don't have the fuel or intellect to manouver. For a Minbari fighter, intercepting an Earth missile would be crushing a snail which tried to crawl past you.
<HR></BLOCKQUOTE>

I disagree. Missiles don't have to fly in a straight line. Cruise missiles most certainly don't. With enough brain (read computer) power, they can very well be seen to fly erratic patterns while still travelling in the same overall direction.

<BLOCKQUOTE>quote:<HR>
Should the fighters fail, there will be other means. The warcruiser would focus its ECM on the missiles and accelerate. Given that it has excellent gravity engines, missiles with ion or rocket engines would quickly be left behind.
<HR></BLOCKQUOTE>

Not by definition. A gravitic engine is still and engine by any means and has to accelerate a certain mass. It might be able to do that far more efficiently (but heck, not having a gravitic engine, we have no idea if it would), but the basic laws of physics are not suspended. The missiles being much smaller than the cruiser, they need much less energy to accelerate. The question will therefore be how much energy the Minbari reactors provide for the engine re:the energy needed to accelerate a huge ship

<BLOCKQUOTE>quote:<HR>
----------

Example:

An Earth Force battle group is defending a space station. A Minbari warcruiser jumps *into* the station at full speed, tearing it apart with a jump point. Earth ships fire their missiles. Unfortunately, as the Minbari cruiser was moving at full speed, the missiles fail to catch up. It destroys two more ships with beam weapons and jumps out.

----------

<HR></BLOCKQUOTE>

You assume the missiles have to catch up with the cruiser. That depends on the bearing from which they were fired. The cruiser might be running straight into them. Aside from that, I wouldn't consider opening a jump point into solid matter a very safe procedure. Who knows the details of such jump points.

<BLOCKQUOTE>quote:<HR>

Advantages of beam weapons:

1. Weapon travels at light speed or near-light speed. Enemy speed it irrelevant. Evading a beam weapon is much more difficult than evading a missile.

<HR></BLOCKQUOTE>

Enemy speed is not irrelevant, since you still have to aim the thing. And depending on what kind of beam weapon you have, evading it might be very simple.

<BLOCKQUOTE>quote:<HR>
2. Great range, no need for fuel, no need for continuous guidance. Once the shot has been fired, it is invulnerable to ECM. It will hit or miss, but it can't be jammed.

------------
<HR></BLOCKQUOTE>

Wrong on several accounts. The range of a charged particle beam will be anything but great, since the particles will unfocus due to repulsion. Second, the matter and/or energy still has to come from somewhere, thus need for fuel is very much given. Continuous guidance is very much necessary for moving targets, otherwise the target will move out of the beam. That requires specific knowledge of speed and bearing.

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If I tell you my name is Lorien, what good is that?

(Whatever happened to Mr. Garibaldi?)

**DONOTDELETE** · Feb 1, 2002

Irmo: thanks for comments. Most adequate on some accounts, wrong on others.

Yes, missiles can try to fly in a complicated pattern, but that would waste fuel. This fuel could be spent on gaining more speed, which is usually considered important.

Comparison with cruise missiles is inadequate. A cruise missile knows where its target it, conforming to terrain to avoid detection. Space has no terrain. You are out in the open, relying on speed, stealth and the enemy not being faster/undetectable.

A ship-to-ship missile can't afford fancy manouvers. After its next elaborate loop or spiral, it might no longer acquire a target. Also, by showing its engine exhausts, it would betray itself even to the most primitive sensors.

<BLOCKQUOTE>quote:<HR>The missiles being much smaller than the cruiser, they need much less energy to accelerate.<HR></BLOCKQUOTE>

Their engines are less efficient, and they use a small conventional power source (chemical fuel, assuming that no nuclear reactos are that small).

Minbari engines would be much more efficient, a warcruiser would be large enough to have *at least* thermonuclear reactors. Also, gravity engines would render the concept of acceleartion-related stress meaningless. Minbari ships, even large ones, could easily be faster than Earth missiles.

<BLOCKQUOTE>quote:<HR>Enemy speed is not irrelevant, since you still have to aim the thing. And depending on what kind of beam weapon you have, evading it might be very simple.<HR></BLOCKQUOTE>

True. Relevant for aiming, irrelevant for interception. If something approaches at near-light speed, early detection would require a huge distance.

<BLOCKQUOTE>quote:<HR>Wrong on several accounts. The range of a charged particle beam will be anything but great, since the particles will unfocus due to repulsion.<HR></BLOCKQUOTE>

Using charged particle beams is questionable. Neutron, photons or other electrically neutral waves/particles are preferable over large distances.

<BLOCKQUOTE>quote:<HR>Second, the matter and/or energy still has to come from somewhere, thus need for fuel is very much given.<HR></BLOCKQUOTE>

In a missile, it has to come from a spatially limited supply of chemical fuel. In a ship, it can come from a much larhger nuclear reactor.

<BLOCKQUOTE>quote:<HR>Continuous guidance is very much necessary for moving targets, otherwise the target will move out of the beam.<HR></BLOCKQUOTE>

Continuous aiming is not equal to continuous guidance. Aiming is something your ship does, something you are more likely to have under control. Guidance is what a missile requires, and often does on its own. If the enemy has superior ECM systems, they will easily blind the missile. A ship with powerful computers, shielding and versatile sensors is much less vulnerable to electronic attack.

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"We are the universe, trying to figure itself out.
Unfortunately we as software lack any coherent documentation."
-- Delenn

**DONOTDELETE** · Feb 1, 2002

Minbari warships carry 6missiles with 20 megatons each.

**DONOTDELETE** · Feb 1, 2002

<BLOCKQUOTE>quote:<HR>Originally posted by Lennier:
Irmo: thanks for comments. Most adequate on some accounts, wrong on others.

Yes, missiles can try to fly in a complicated pattern, but that would waste fuel. This fuel could be spent on gaining more speed, which is usually considered important. <HR></BLOCKQUOTE>

I don't consider gaining more speed as of superior importance to arriving at the target.

<BLOCKQUOTE>quote:<HR>
Comparison with cruise missiles is inadequate. A cruise missile knows where its target it, conforming to terrain to avoid detection. Space has no terrain. You are out in the open, relying on speed, stealth and the enemy not being faster/undetectable.
<HR></BLOCKQUOTE>

That's not the point. The point is that a missile can perform maneuvers. Stealth, in any way, is a given for small objects in space. Especially if you paint them in a matte black to avoid optical detection.

<BLOCKQUOTE>quote:<HR>
A ship-to-ship missile can't afford fancy manouvers. After its next elaborate loop or spiral, it might no longer acquire a target. Also, by showing its engine exhausts, it would betray itself even to the most primitive sensors. <HR></BLOCKQUOTE>

Hardly. A clean burning process will be next to invisible in space. The infrared radiation will be visible mainly from behind the missile, which is not where you'd expect the enemy to be.

<BLOCKQUOTE>quote:<HR>
Continuous aiming is not equal to continuous guidance. Aiming is something your ship does, something you are more likely to have under control. Guidance is what a missile requires, and often does on its own. If the enemy has superior ECM systems, they will easily blind the missile. A ship with powerful computers, shielding and versatile sensors is much less vulnerable to electronic attack.
<HR></BLOCKQUOTE>

It depends entirely on what kind of guidance you assume. We're not talking about 20th century missiles here. Short of a Klingon/Romulan cloaking system, there is little possibility to shake off good image recognition, at least at shorter ranges. That's sufficient. The missile can approach the general area of the enemy, then a target is picked from the launching ship, the missile acquires the target and follows it.

<BLOCKQUOTE>quote:<HR> Their engines are less efficient, and they use a small conventional power source (chemical fuel, assuming that no nuclear reactos are that small).

Minbari engines would be much more efficient, a warcruiser would be large enough to have *at least* thermonuclear reactors. Also, gravity engines would render the concept of acceleartion-related stress meaningless. Minbari ships, even large ones, could easily be faster than Earth missiles.
<HR></BLOCKQUOTE>

Again, that's speculation. We have no idea how efficient gravitic engines operate.

<BLOCKQUOTE>quote:<HR> True. Relevant for aiming, irrelevant for interception. If something approaches at near-light speed, early detection would require a huge distance. <HR></BLOCKQUOTE>

Well, we still have the good old "They're powering up their weapons systems." Depending on what kind of weapon you're talking about, magnetic coils would have to be powered etc... and given the vaccuum of space, a cloud of sand is easily dispersed. All you need is a bag of sand in a pressurized compartment. When the time comes, open the hatch and have some explosive decrompression.

<BLOCKQUOTE>quote:<HR>
Using charged particle beams is questionable. Neutron, photons or other electrically neutral waves/particles are preferable over large distances. <HR></BLOCKQUOTE>

But much more difficult to handle, since harder to manipulate. And at least today's lasers aren't 100% parallel. They will eventually lose focus, too. Though that doesn't mean that that is a problem that can't be tackled. In any way, antimatter will be near impossible to handle unless it is charged, because you need touchless containment. As such, I would see antimatter as very likely charged.

In a missile, it has to come from a spatially limited supply of chemical fuel. In a ship, it can come from a much larhger nuclear reactor.

Yes. But the missile doesn't need to be able to handle the energy as energy. The ship weapon does. Thus, the destructive energy, in whatever form, is always much more efficiently and safely stored in a missile. On the ship, you have to handle the raw energy, which usually is less efficient. As the ultimate example, imagine a matter/antimatter torpedo. It has matter and antimatter stored and on impact loses containtment of the antimatter. Voila, we have production of a whole lot of energy, and half of our torpedo was simply a bottle of some matter. Matter is a very efficient way to store energy, if you can get it out of there again. The amount of plasma you need for the same energy is much more voluminous. Not to mention that the gun has to survive the firing, the missile doesn't.

That's why explosives work so well: They release a whole lot of volume, and thus, through the expansion, a whole lot of energy, from a comparatively small volume of matter in explosion.

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If I tell you my name is Lorien, what good is that?

(Whatever happened to Mr. Garibaldi?)

Click to expand...

Cern · Feb 1, 2002

<BLOCKQUOTE>quote:<HR>Originally posted by Lennier:
A reminder that even the simplest weapons are
capable of causing more loss than ever needed.

Our species is just as destructive without advanced weapons.
Which was this case, a rocket or an AT mine?

<HR></BLOCKQUOTE>

AT mine.

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**DONOTDELETE** · Feb 1, 2002

<BLOCKQUOTE>quote:<HR>Originally posted by bakana:
Yes, the Warship equivalent of stopping at Wal Mart to buy groceries. <HR></BLOCKQUOTE>

Yeah, 50 times on one day. That is, provided there is an asteroid belt at all.

<BLOCKQUOTE>quote:<HR>Well, they were wrong. That was Atmosperic Friction.
These rocks are, in essence artificial Meteors.
They are moving so fast that friction with the air Heats them to a nice Bright Red Glow which is exactly the same thing that happens when you see a "shooting star".
<HR></BLOCKQUOTE>

Precisely what kind of atmosphere do you postulate inside the launch mechanism?

"They", btw, being JMS.

[Edited to add: "As for the mass drivers, the amount of energy required to move something that big would generate huge amounts of heat, possibly making them even white-hot hence the glow." http://www.midwinter.com/lurk/guide/042.html Not that I think he understands the concept, but he's the guy who calls the shots in his universe]

<BLOCKQUOTE>quote:<HR>

32Ft/Sec Squared. How's your Basic Physics?

<HR></BLOCKQUOTE>

Better than yours, apparently. The acceleration is defined by the gravitational force. The gravitational force is defined as F= G M1 M2/D^2. Restated, the force exerted by gravity between two objects is found by the (G) gravitational constant multiplied by the mass of the first object times the mass of the second object divided by the square of the distance between the objects.
Now when dealing with planets on the one side and artificial constructs on the other, we can usually neglect the influence of the artificial construct. What we can't neglect is that the the force declines with the square of the distance. That means that while your equation is correct close to the planet, the further you get out, the smaller the acceleration will be.

The moon, for example, only experiences an acceleration of 0.00273 m/s^2. at its distance of 60 radii of earth compared to 9.80 m/s^2 at the surface (which is your 32Ft/sec squared). That value is only valid on the surface of the planet.

<BLOCKQUOTE>quote:<HR> Given a one ton chunk of Granite or Iron Ore (depending on your asteriod belt) moving Down at several hundred miles per hour, the best that fighter can hope to do is knock it Sideways.
Shattering rocks with explosions only works if you can drill Holes in them to get the explosives Inside the rock.
Otherwise, the rock reacts like a Baseball hit with a Very large Bat.
It lands in left field instead of where it was Originally aimed.
And that's only if it can Hit it in the first place. <HR></BLOCKQUOTE>

Wrong. All you need is to impose enough stress on it. An asteroid is not an elastic and regularly shaped body as a baseball is. And orbit isn't a ballpark. If the asteroid doesn't hit the atmosphere at the right angle, it will shatter. If there are two explosions on sufficient force on opposite sites of the asteroid, it will shatter. Even if it is just knocked out of its path enough to have a longer trajectory, enough of it can be eaten up by the atmosphere.

<BLOCKQUOTE>quote:<HR>Landing in "left field" may not be so good when the target is a City.
Left field may be the Suburbs or Factory district instead of Downtown, but it's still part of the City.<HR></BLOCKQUOTE>

Wrong. Given the distance traveled, left field is several hundred miles away. Take your broomstick at one end. That's where the meteor is. The other end is where it would impact. Now tilt your hand by 2 to about a 1o'clock position of where it was before. Your hand isn't a lot different from where it was. But the other end of the broomstick sure is.

<BLOCKQUOTE>quote:<HR>BTW, have you ever read about the Meteor that hit Russia in the early 1900s??
It devastated about 100 Square Miles.
Luckily for the Russians, most of that was uninhabited Forest.<HR></BLOCKQUOTE>

You're speaking of the Tunguska incident. Incidentally, you demonstrate how much of empty space there is for an asteroid to hit, and how localized the damage can be.

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If I tell you my name is Lorien, what good is that?

(Whatever happened to Mr. Garibaldi?)

[This message has been edited by Irmo (edited February 01, 2002).]

[This message has been edited by Irmo (edited February 01, 2002).]

Wanderer · Feb 1, 2002

well, this is certanly interesteng...

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jnk5y · Feb 2, 2002

ok if a beam weapon is a sorta like a laser why don't they just stick mirrors on the outside of their ships and send the beams back at the shadow ships that sent them. If it were only so easy.

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bakana · Feb 2, 2002

Ok, you say you understand the basic physics.

So, calculate the kinetic energy of that 1 ton rock dropping from a geostatioary orbit into the atmosphere.
No big Delta V.
Just enough to ensure it Enters the atmosphere and makes it to the ground.
The Trip may take a Week or more, depending on how much of a nudge you gave it.

While it may not be moving very fast when it Starts that journey, the Terminal Velocity is going to be sufficient to generate a very large BOOM.

Make it simple. Use Earth gravity.

As I said before, The Mass Driver isn't so much about making the impact bigger as it is about Aiming. And cutting the trip down to a couple hours instead of a week.

As far as Intercepting the thing on the way down, Even if the Narn have aircraft Capable of doing it, the Centauri are going to be Shooting them Down as fast as they can lock on a weapon.

Destroying them in mid air isn't a much better option than letting them hit the ground anyway.
They are Still going to release Kinetic Energy equivalent to a small Nuke.

While an Air Burst isn't Quite as destructive as a ground burst, with that much energy, it's still going to knock down a lot of buildings.

Sorry, but the Large Rock from orbit scenario works just fine for destroying cities.

And picking up 50 - 100 rocks out of an asteroid belt is a Lot less expensive than manufacturing a nuke.

The Warship is a "Sunk Cost". They are going to be paying the bills for it whether they stop at the nearest Asteroids'R'Us or not.

The Nuke, OTOH, requires an Expensive factory, a source of expensive Fissionables and a lot of security to make sure no one wanders off with samples.

Who's going to steal a Big Rock?

That's the reason the Centauri used the mas driver in the first place.
Ammunition is Dirt Cheap.
Literally.

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Do not ascribe your own motivations to others:
At best, it will break your heart.
At worst, it will get you dead."

bakana · Feb 2, 2002

BTW, do we really need that old photo array of the Personnel carrior getting blown up?

All it does is force horizontal scroll without contributing to the discussion in any way.

------------------
Do not ascribe your own motivations to others:
At best, it will break your heart.
At worst, it will get you dead."

bakana · Feb 2, 2002

<BLOCKQUOTE>quote:<HR> You didn't contradict me at all. I said that if there is acceleration, it needs a lot of energy. You claim there isn't, but agree that grabbing the rock would cost energy.<HR></BLOCKQUOTE>

Yes, the Warship equivalent of stopping at Wal Mart to buy groceries.

<BLOCKQUOTE>quote:<HR>
But here's something else: Back when they used the mass drivers, people complained about "glowing rocks" and it was said to be attributable to them being loaded with quite a bit of energy in the shooting process.
<HR></BLOCKQUOTE>
Well, they were wrong. That was Atmosperic Friction.
These rocks are, in essence artificial Meteors.
They are moving so fast that friction with the air Heats them to a nice Bright Red Glow which is exactly the same thing that happens when you see a "shooting star".

<BLOCKQUOTE>quote:<HR>
Second, gravity decreases quite drastically with distance. Meaning if you launch these rocks without acceleration from quite a distance, they will take quite a bit of time until they reach their target. Unless you have hundreds of them, that can be enough time for fighters to crunch them into pieces tiny enough to be eaten by the atmosphere. <HR></BLOCKQUOTE>

32Ft/Sec Squared. How's your Basic Physics?

Given a one ton chunk of Granite or Iron Ore (depending on your asteriod belt) moving Down at several hundred miles per hour, the best that fighter can hope to do is knock it Sideways.
Shattering rocks with explosions only works if you can drill Holes in them to get the explosives Inside the rock.
Otherwise, the rock reacts like a Baseball hit with a Very large Bat.
It lands in left field instead of where it was Originally aimed.
And that's only if it can Hit it in the first place.

Landing in "left field" may not be so good when the target is a City.
Left field may be the Suburbs or Factory district instead of Downtown, but it's still part of the City.

BTW, have you ever read about the Meteor that hit Russia in the early 1900s??
It devastated about 100 Square Miles.
Luckily for the Russians, most of that was uninhabited Forest.

------------------
Do not ascribe your own motivations to others:
At best, it will break your heart.
At worst, it will get you dead."

**DONOTDELETE** · Feb 2, 2002

<BLOCKQUOTE>quote:<HR>Originally posted by bakana:
Ok, you say you understand the basic physics.

So, calculate the kinetic energy of that 1 ton rock dropping from a geostatioary orbit into the atmosphere.
No big Delta V.
Just enough to ensure it Enters the atmosphere and makes it to the ground.
The Trip may take a Week or more, depending on how much of a nudge you gave it.
<HR></BLOCKQUOTE>

You're claiming the centauri will stick around for a week?

<BLOCKQUOTE>quote:<HR> As I said before, The Mass Driver isn't so much about making the impact bigger as it is about Aiming. And cutting the trip down to a couple hours instead of a week.

As far as Intercepting the thing on the way down, Even if the Narn have aircraft Capable of doing it, the Centauri are going to be Shooting them Down as fast as they can lock on a weapon. <HR></BLOCKQUOTE>

As far as i see it, interceptors are close-range.

<BLOCKQUOTE>quote:<HR>
Destroying them in mid air isn't a much better option than letting them hit the ground anyway.
They are Still going to release Kinetic Energy equivalent to a small Nuke.

While an Air Burst isn't Quite as destructive as a ground burst, with that much energy, it's still going to knock down a lot of buildings.
<HR></BLOCKQUOTE>

Wrongo. You assume a)that the rock explodes all at once and b)at an altidue sufficiently low and at a location sufficiently close to a city. That's a whole lot of assumptions.

<BLOCKQUOTE>quote:<HR> Sorry, but the Large Rock from orbit scenario works just fine for destroying cities.
<HR></BLOCKQUOTE>

I never said anything against that. Just not within the parameters you cite.

<BLOCKQUOTE>quote:<HR>
And picking up 50 - 100 rocks out of an asteroid belt is a Lot less expensive than manufacturing a nuke.
<HR></BLOCKQUOTE>

That's a pretty bold assumption.

<BLOCKQUOTE>quote:<HR>
The Warship is a "Sunk Cost". They are going to be paying the bills for it whether they stop at the nearest Asteroids'R'Us or not.
<HR></BLOCKQUOTE>

So you say if a ship stationed in the mediterranean wants to attack a location in, say, Pakistan, it is perfectly acceptable for that ship to make a little detour to Australia to pick up ammunition, because none happens to be available anywhere near pakistan? More, the rock requires a much higher mass than the comparable nuke, meaning the transport swallows a whole lot of energy. You are assuming an asteroid belt within vicinity of the target. I would assume that at least 7 times out of ten, that's probably not given.

<BLOCKQUOTE>quote:<HR>
The Nuke, OTOH, requires an Expensive factory, a source of expensive Fissionables and a lot of security to make sure no one wanders off with samples.
<HR></BLOCKQUOTE>

Sorry, we're not talking 20th century earth here. A lot of that stuff is very likely all available on your average starship yard.

<BLOCKQUOTE>quote:<HR>

That's the reason the Centauri used the mas driver in the first place.
Ammunition is Dirt Cheap.
Literally.

<HR></BLOCKQUOTE>

If all of a half-dozen assumptions you are basing your conclusions on is a given. It is most certainly not cheap to carry a rock a couple of dozen lightyears around.

[Edited to add:] Not the least, one of your assumptions is that the rocks are not actively slung at the planet rather than just dropped, whereas JMS says they are pumped full of energy. While I think he misses the point that if you get them white hot even before they hit the atmosphere, they're even more likely to just burn up, we still can't ignore that.

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If I tell you my name is Lorien, what good is that?

(Whatever happened to Mr. Garibaldi?)

[This message has been edited by Irmo (edited February 02, 2002).]

**DONOTDELETE** · Feb 2, 2002

I did some calculations.

1. Energy delivered by a nuclear bomb.

As a basis of my calculations, I used a persumably correct fact from an encyclopedia: by splitting all atoms in 1 kg of U-235 you will get 8*10^13 joules of energy. Considering that a nuclear bomb splits/fuses only a fraction of its atoms, I assumed an average hydrogen bomb to be equal to 50 kilograms of fully split uranium. The energy released would be 4*10^15 joules.

2. Energy delivered by asteroid collision.

I made this assumption: the Centauri arrived at the asteroid belt and opened jump points to let the asteroids into hypespace. To conserve fuel, they manouvered them towards Narn in hyperspace. After arriving near Narn, they returned to normal space at a location on collision course with Narn. The additional "nudge" from mass drivers was needed to target a particular city.

I assumed that their average asteroid was equivalent to a cube of 100 meters, with a density of 10 tons per cubic meter. Hence its mass would be 10*100^3 tons or 10^10 kilograms. Assuming that the collision exploited the full orbital velocity of an Earth-class planet (the velocity at which Earth orbits the Sun), I made the following calculation to determine kinetic energy:

M = 10^7 tons = 10^10 kilograms.
V = 20 kilometers/sec = 2*10^4 meters/sec.

E(k) = (M * V^2) / 2
E(k) = (1*10^10 * (2*10^4)^2) / 2 = 2*10^18

-----------

Asteroid = 2*10^18 joules.
Nuke = 4*10^15 joules.

Unless I misconverted some numbers, a small asteroid colliding at 20 kilometers per second is 500 times more powerful than 50 kilograms of fully split uranium.

[This message has been edited by Lennier (edited February 02, 2002).]

bakana · Feb 2, 2002

Lennier, we were arguing about 1 ton rocks, not entire asteroids.

The rocks, at one ton, would be small enough to just load into a cargo hold, so the trip through Hyperspace would be a lot easier.

And, no, I didn't say that the Centauri would drop them from orbit, just that the final Energy delivered using mass drivers wouldn't be much Different than just dropping them from orbit.

The mass driver just makes it easy to Aim.

Depending on the Composition of the rocks, you'd get some variation.
Denser elements would be preferred so that physically smaller rocks could be used, saving cargo space.

The mass Driver is probably an Artificial Gravity device rather than a Magnetic device.

So, the visible Energy discharge in the launch phase might or might NOT be Heat.
I had originally thought the reference was to the rocks passing through the Atmosphere where it Would be Heat.

And, I'd seriously doubt any race as warlike as the Centauri would consider Nuclear bombs an "off the shelf" commodity.
Weapons would still be kept under strict security, not left just laying around the spaceport.

------------------
Do not ascribe your own motivations to others:
At best, it will break your heart.
At worst, it will get you dead."

**DONOTDELETE** · Feb 3, 2002

<BLOCKQUOTE>quote:<HR>Originally posted by bakana:
Lennier, we were arguing about 1 ton rocks, not entire asteroids.

The rocks, at one ton, would be small enough to just load into a cargo hold, so the trip through Hyperspace would be a lot easier.

<HR></BLOCKQUOTE>

The problem is what mass would arrive on impact. Most of it would be shed into the atmosphere.

<BLOCKQUOTE>quote:<HR>
And, no, I didn't say that the Centauri would drop them from orbit, just that the final Energy delivered using mass drivers wouldn't be much Different than just dropping them from orbit.
<HR></BLOCKQUOTE>

The discussion was about energy requirements. Accelerating a rock does require energy.

<BLOCKQUOTE>quote:<HR>

So, the visible Energy discharge in the launch phase might or might NOT be Heat.
I had originally thought the reference was to the rocks passing through the Atmosphere where it Would be Heat.
<HR></BLOCKQUOTE>

Well, JMS says it is heat.

<BLOCKQUOTE>quote:<HR>
And, I'd seriously doubt any race as warlike as the Centauri would consider Nuclear bombs an "off the shelf" commodity.
Weapons would still be kept under strict security, not left just laying around the spaceport.
<HR></BLOCKQUOTE>

I never said they would. You said it would be a comparative hassle to create a nuke and require dedicated plants and security. I said most of that will already be a given anyway through starship construction.

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If I tell you my name is Lorien, what good is that?

(Whatever happened to Mr. Garibaldi?)

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