B5 superweapons vs. Death Star

[Durandal]

Bah, I meant change in velocity.

[Connor MacLeod]

This third point is kinda flaky: The SPKs are also said to hide their actual physical structure in hyperspace. The one in "Call to Arms" says otherwise, but that SPK was built by the Drakh, who really had no idea what they were doing when they built the thing. Is this true?

Go digging on Hyperion or Google groups. JMS specifically stated that the ACTA missile swarm was identical to the swarms used by the Shadows themselves.

The ACTA novelization supports it even more strongly by linking what the Drakh did at Daltron 7 (by Sheridan's observations) to what was done by the SHadows with the prior PK. I'll see if I can find and post some of it later.

[Enlightenment]

Why am I continuously contradicting myself!?

Because arguing about B5 canon is a matter of arguing fifty thousand different explanations, all of which are true?

[Connor MacLeod]

Why am I continuously contradicting myself!?

Because arguing about B5 canon is a matter of arguing fifty thousand different explanations, all of which are true?

Thats because most of the fanatics keep changing tactics, rules, evidence, whatever they need to to win. These are people that take pride in likening themselves to Rebel Guerilla fighters, remember.

[Connor MacLeod]

Not in my recollection. IIRC, Sheridan said that one of the Shadow planet-killers was left behind, and the Drakh knew how to operate it. It was never even hinted that they actually knew how to build one (which would explain why they never built another).

The Drakh were finishing one up in one of the post-series books. I don't recall which book it was, but most of the books after the series are based on JMS outlines so they may be considered canon. Still, I'm not sure they knew how to build one from scratch or if they knew how to opperated the equipment left behind to finish building one that was already started.

This is true to an extent (Armies of light and Dark, second Centauri Prime book) - the Drakh had found one nearly built or already built (I think) and started construction on another couple.

Incidentally, some of them like to claim that this incident describes production rates for the shadows, but never acknowledge some of the ambiguities of the situation (or the fact that alot of it occurs from Virs viewpoint, etc.) or that it conflicts with KNOWN production rates in the very same B5 Wars sources they like citing.

A handful (one named Elizar who's true identity as I recall is Dark Lord - someone who likes to snipe at Mike IIRC) even claim that there is proof that the Shadows can spontaneously and instantaneously convert energy into matter (and thereby not need resources) - yet this is ALSO a gross exaggeration of the sources they quote, and in contradiction with the same B5 Wars materials they love to cite.

[Connor MacLeod]

This third point is kinda flaky: The SPKs are also said to hide their actual physical structure in hyperspace. The one in "Call to Arms" says otherwise, but that SPK was built by the Drakh, who really had no idea what they were doing when they built the thing. Is this true?

Go digging on Hyperion or Google groups. JMS specifically stated that the ACTA missile swarm was identical to the swarms used by the Shadows themselves.

I don't mean the missiles, I mean the actually skeleton-like superstructure that the Death Cloud is built on. Does it stay in normalspace or is it hidden away in hyperspace?

To my knowledge, no, there is no evidence of any ability to do so (and I own a substantial amount of B5 Wars material, novelizations, and such. I can be just as certain as any Fiver could.)

The closest they come is the "half-phasing" ability, and this does not render the ship completely invulnerable, nor does it selectively phase PART of the vessel into hyperspace (it phases the whole thing into a halfway state supposedly.) BEsides which, how do they keep the "cloud" intact with the structure in hyperspace (or how do they launch missiles, for that matter.)

[Connor MacLeod]

You can "crack" a planet with relatively small energy cost. This does not imply the ability to overcome its gravitational potential energy deficit and blow it apart, Death Star-style.

If their entire argument is based upon the semantics of "cracking open a planet", they're fucked. If you crack a planet in half, you'll kill everyone on the surface, but the two halves will simply slam back together again from gravity. And (here's the fun part) the energy requirement of this process is zero, since the final energy state of the planet is the same as its initial state.

PS. Why the fuck are they too stupid to notice things like this? Are they allergic to elementary thermodynamics or something?

Mike -

I suppose we should post the actual reference they use when claiming that the VPK can do what it can. Feel free to nitpick it as you wish:

Note that the source it comes from is, supposedly per JMS, canon (which I generally believe)

This is a tremendous weapon which only appears on Vorlon planet-killer ships. It has only one use: total annihilation. There is no target and no roll to hit - if the unit is in arc and in range, the weapon hits automatically!

The firing arc is the row of hexes directly in front of the ship, from 1 to 4 hexes out, not including the firing vessel’s hex. Any ship, moon, planet, or other object in one of these hexes is destroyed. No damage needs to be rolled - destruction is automatic. The beam is capable of cracking planets as large as Jupiter, though it will have no appreciable effect on stellar bodies (even brown dwarfs or black holes, which are to massive to be broken apart by the weapon).

(Source: Rules Compendium 2nd Edition, The Coming of Shadows sourcebook.)

(I cringe at teh thought of "breaking apart" black holes... Mike is SO going to have a field day with that one)

Basically, by the quote itself, I cannot see any particular reason this means "DS-style destruction". Even if we assume it is so, we have no knoweldge of the characteristics of said weapon, and this also neglects the fact its a HIGHLY SPECIALIZED platform dedicated to killing planets - despite being smaller it is VERY easily damaged (quite possibly even by the Younger Races) - The ship is designed to be and HAS to be escorted by another fleet for protection - and the Vorlons sent THOUSANDS of ships with the VPK at Coriana 6 IIRC.

Contrasted with the Death Star (designed to operate independently, able to fend for itself in combat against whole fleets, as well as to be self-sufficient, garrison/invade planets, act as a super-carrier, etc...) Well, you get my meaning.

[Connor MacLeod]

The VPK is immensely hard to quantify. While the Rabid Fivers are somewhat correct in that nothing explicitly contradicts the VPK being able to destroy planets, but they make a staggering number of incorrect assumptions in their own right regarding the vessel.

Simply put, they largely ASSUME on the basis of implied evidence that the ship CAN destroy planets DS-style, yet its quite clear (as Ossus mentions) that we have no proof of it doing so. We have no visual equivalent ot Alderaan in B5 canon form which to accurately gauge firepower (Remember that the Death Star's capabilities are FROM observation, whihc makes a huge difference.) All the Fivers have are alot of references that imply the capability to do so, but give us nothing to derive calcs on. We know nothing of the size/nature of the planet Invaonva mentions (only that it supports a rather large population, but that doesnt mean that its an Earthlike planet neccesarily). We know nothing of the amount of time to recharge between firings. We know nothing of even HOW it might destroy planets (if it simply does not achieve what the SPK does.)

There is some indirect evidence that there exist planetkillers that can shatter planets, but again this isn't specific, and it doesn't really add anything to what we already know.

And of course, even if it DOES destroy planets - so what? Its nothing at all like the Death Star, and is in no way a combat vessel - its a dedicated weapon of mass destruction meant to be protected by other ships.

The SPK of course we now the capabilities of canonically. Supposedly in B5 Wars there exists a version called an "energy cloud" that CAN destroy planets also by using missiles, but this ship has a LARGE number of characteristics that distinguish it from the onscreen planetkiller, and I treat it as a completely separate vessel. (It, like the VPK, is hideously vulnerable to weapons fire and not meant to be employed directly in combat). The "CAnon" PK the Shadows employ cannot destroy planets at all, and is merely a dedicated BDZ/TError platform.

[Shinova]

You can "crack" a planet with relatively small energy cost. This does not imply the ability to overcome its gravitational potential energy deficit and blow it apart, Death Star-style.

If their entire argument is based upon the semantics of "cracking open a planet", they're fucked. If you crack a planet in half, you'll kill everyone on the surface, but the two halves will simply slam back together again from gravity. And (here's the fun part) the energy requirement of this process is zero, since the final energy state of the planet is the same as its initial state.

PS. Why the fuck are they too stupid to notice things like this? Are they allergic to elementary thermodynamics or something?

Mike -

I suppose we should post the actual reference they use when claiming that the VPK can do what it can. Feel free to nitpick it as you wish:

Note that the source it comes from is, supposedly per JMS, canon (which I generally believe)

This is a tremendous weapon which only appears on Vorlon planet-killer ships. It has only one use: total annihilation. There is no target and no roll to hit - if the unit is in arc and in range, the weapon hits automatically!

The firing arc is the row of hexes directly in front of the ship, from 1 to 4 hexes out, not including the firing vessel’s hex. Any ship, moon, planet, or other object in one of these hexes is destroyed. No damage needs to be rolled - destruction is automatic. The beam is capable of cracking planets as large as Jupiter, though it will have no appreciable effect on stellar bodies (even brown dwarfs or black holes, which are to massive to be broken apart by the weapon).

(Source: Rules Compendium 2nd Edition, The Coming of Shadows sourcebook.)

(I cringe at teh thought of "breaking apart" black holes... Mike is SO going to have a field day with that one)

Basically, by the quote itself, I cannot see any particular reason this means "DS-style destruction". Even if we assume it is so, we have no knoweldge of the characteristics of said weapon, and this also neglects the fact its a HIGHLY SPECIALIZED platform dedicated to killing planets - despite being smaller it is VERY easily damaged (quite possibly even by the Younger Races) - The ship is designed to be and HAS to be escorted by another fleet for protection - and the Vorlons sent THOUSANDS of ships with the VPK at Coriana 6 IIRC.

Contrasted with the Death Star (designed to operate independently, able to fend for itself in combat against whole fleets, as well as to be self-sufficient, garrison/invade planets, act as a super-carrier, etc...) Well, you get my meaning.

VPS = WC's Behemoth, so to speak.

But it still took several shots from the First Ones ships to destroy the VPK, which is no indication that the younger Races could do it just as easily.

[Shinova]

typo

VPS => VPK

[Enlightenment]

Thats because most of the fanatics keep changing tactics, rules, evidence, whatever they need to to win. These are people that take pride in likening themselves to Rebel Guerilla fighters, remember.

Yes, that too, but I was thinking more of the nature of the B5 canon itself: it is rather like the Christian bible, with multiple, mutually incompatible, tellings of the same events, all of which are fundamentally canon but also fundamentally irreconcilable.

Indeed, the responses from the B5 fanatics when called on the contraditctions are rather similar to the responses of the fundies when they are called on biblical contradictions. Both fictions must appeal to the same anti-logic centers in the zealot brain or something...

[Connor MacLeod]

Yes, that too, but I was thinking more of the nature of the B5 canon itself: it is rather like the Christian bible, with multiple, mutually incompatible, tellings of the same events, all of which are fundamentally canon but also fundamentally irreconcilable.

Canon has never been firmly established like it was with STar wars and Trek. A good example is the contention over the status of the "Tim Earls" size charts most often cited on the B5tech.com site.

Indeed, the responses from the B5 fanatics when called on the contraditctions are rather similar to the responses of the fundies when they are called on biblical contradictions. Both fictions must appeal to the same anti-logic centers in the zealot brain or something...

I tend to liken Rabid Fivers as being adequate competiton for Rabid Trekkies. You'll notice alot of their "logic" and arguments have gradually grown to duplicate what Rabid Trekkies have done in the past (IE as an example, note that certain Rabid Fivers have taken to arguing that Shadow weapons would ignore shields and armor of ANY universe because they do so to YR ships in the B5 universe, as per B5 Wars materials. Not even bothering to verify that any sort of connection CAN be made - very analogous to what Trekkies tried doing with the "frequency" myth stuff.)

[His Divine Shadow]

Did we see this happen, or was it another one of those "interpret from dialogue" things?

I'm paraphrasing heavily but it went like:
Ivanova: Smack-fu Prime is gone! The vorlons blew it away!
Sheridan: what joo yapping 'bout woman? The colony is gone?!!
Ivanova: No, not the colony, the planet, the planet is gone! *starts sobbing*
Sheridan: This is a job for... Blessed nukes of sufficient yield!

[Durandal]

How could the planet be gone if the "survivors" needed atmospheric evacuation craft?

And, one more thing...

How does one go about "cracking" a giant fucking ball of gas? Planets as large as Jupiter are all gas giants. That's like saying I can "crack" the air.

And, for fuck's sake, there's no way to "crack" a black hole. It's a fucking singularity, OK? It's already as small as it can possibly get. It exists in zero space.

Firing a beam into it will only make it more massive, and the beam would, to an outside observer, appear to freeze once it breached the event horizon.

God, are these people really that fucking stupid?

[seanrobertson]

You can "crack" a planet with relatively small energy cost. This does not imply the ability to overcome its gravitational potential energy deficit and blow it apart, Death Star-style.

That's a superb point. I'm almost certain that's what their
Holy text, B5Wars, says of the Vorlon Planet Killer: "has
the ability to crack planets as large as Jupiter," or the
like.

If their entire argument is based upon the semantics of "cracking open a planet", they're fucked. If you crack a planet in half, you'll kill everyone on the surface, but the two halves will simply slam back together again from gravity. And (here's the fun part) the energy requirement of this process is zero, since the final energy state of the planet is the same as its initial state.

Indeed, my lord

Semantics is all they have. When we see the Shadows fire on
a Narn colony, with three spiders joining in on the attack, we're
told it's not a good example of firepower because the Shadows
were trying to "imitiate a Centauri attack." They claim the
only difference between that "staged" attack and the Centauri
doing the same thing is "time." I point out that time has
just a little to do with firepower; next thing I know, I'm
the Anti-Fiverchrist.

Also, WRT planet cracking, their response will be, "But the planet
must have been shattered because after an attack, asteroids
are seen in the 'hexes' surrounding the target." Apparently
ejecta doesn't exist in the B5 continuity.

Most also refuse to acknowledge that this damn game depicts
planet killers altogether differently than what we see on the
show itself. The Shadow version can also "shatter" a planet
with hundreds of missiles. They'll whine that this isn't contradicted
by the show since the "Shadows were holding back."

Yeah, surrrrrrrrrrre. The Shadows were holding back when they
were trying to kill all life on a planet!

PS. Why the fuck are they too stupid to notice things like this? Are they allergic to elementary thermodynamics or something?

Yes. Some of them seem to break out with a form of Tourette's
Syndrome when anything is mentioned of actual physics.

And talk about semantics...

I was involved in a debate with several Fivers a few months ago
concerning what the VPK does to planets. They all quibbled
about the use of "survivors" in an effort to show that there
were in fact none on a planetary surface. The excuses
ranged from:

1--These survivors are only such in the sense that they
were off-world when their planets were attacked. One
could be a "survivor of Alderaan" if he wasn't on the planet
when the DS blew it up.

2--These survivors were in orbit of the planet as it blew up.

3--Survivors who needed medical attention doesn't mean
they were hurt in the attack itself. They might be "shell-shocked."
Or their ships' supplies were running out or nonexistent.

4--The survivors had taken off from an attacked planet
and landed elsewhere, only to require being picked up
again (?). (I never got that one at all. The others were
totally ridiculous, but the one-way space trip was never
really explained to me.)

5--Survivors might've had space-capable craft, and didn't actually
need assistance from hospital ships to get back into space
per se, but they DID need help because the local jumpgates
were destroyed (and, presumably, all of these ships lacked
the ability to make a jump pt.).

6--Not all of the planets attacked were specifically said
to be the targets of planet killers. (IMO, this is by far
the best monkeywrench thrown into the works yet. The
person that mentioned this is pretty reasonable, though,
and not prone to the nitpicking that's typical of others.)

7--Survivors who report "mass destruction on a planetary
scale" had seen a planet shattered out the back window
as they hauled ass away from the scene. (LOL.) Or
had heard rumors or the like, or were reporting about
the attacks of Vorlon battleships (6).

Usually most of these are thrown at you, along with a hurl
of rather poor flaming from a select few.

[seanrobertson]

The asteroids it was flying through may have been there before the planet was destroyed. In fact, their relative velocity is far too low to have escaped the gravity of an Earth-type planet. See Mike's excellent discussion of this incident on his Planet Killer page.

Head of. Nail. Hit HARD!

Yes, exactly. I mentioned this in a 15 page brawl at Spacebattles.
Those asteroids weren't glowing, weren't moving at thousands
of km/sec. (relative to the PK, anyway)...weren't really doing
anything.

I can't remember who I was arguing with at first--I actually
found the guy who first pointed that out otherwise pretty
tenacious and smart--but somehow, it was turned around
such that *I* had to prove there was an asteroid field
close to the target planet!!!!!

God am I glad to be finished with that particular thread.

[seanrobertson]

The ACTA novelization supports it even more strongly by linking what the Drakh did at Daltron 7 (by Sheridan's observations) to what was done by the SHadows with the prior PK. I'll see if I can find and post some of it later.

Your resourcefulness never ceases to impress me.

Usually, RFs claim that the Drakh-operated PK was a "cheap
knock-off," incapable of doing what the Shadows' "really
real" version could.

Are the Drakh that damn stupid? I never understood why
they couldn't operate a planet killer efficiently. They *were*
the Shadows hand-picked minions after all.

[Connor MacLeod]

Also, WRT planet cracking, their response will be, "But the planet
must have been shattered because after an attack, asteroids
are seen in the 'hexes' surrounding the target." Apparently
ejecta doesn't exist in the B5 continuity.

Actually the only way they can prove the existence of "debris scattering" is more or less with in-game rules/details (its actually an OPTIONAL rule concerning debris, which includes planet destruction) - but this also of course opens the door to pointing out the utter VULNERABILITY of such craft in combat situations - even to younger race vessels. Of course as we know they like to ignore the in game mechanics, so why should anyone accept that part?

And this still doesn't address the fact that we know absolutely nothing about the rest of the VPK's capabilities (recharge rate, planet size, speed of the debris, etc.) And the only way one COULD derive such is to use the ingame details - but if one did - these vessels become easy even for the YR to destroy, to say nothing of other FO's or other universes.

Most also refuse to acknowledge that this damn game depicts
planet killers altogether differently than what we see on the
show itself. The Shadow version can also "shatter" a planet
with hundreds of missiles. They'll whine that this isn't contradicted
by the show since the "Shadows were holding back."

Yet as I pointed out, Sheridan noted simliarities in what the Drakh did at Daltron 7 to what the Shadows did with THEIR PK. He seemed to think that THEY weren't going about blowing up planets (and he'd very likely be in a position to know, being a president of the IA and all)

We can also point out that both canonically and officially, nothing has established a firm "upper limit" regarding the capabilities of the superlaser. In fact there ar ea number of superlaser platforms that IMPROVED the overall destructive capability of the weapon (DS2, Darksaber, etc.)

[Slartibartfast]

If you crack a planet in half, you'll kill everyone on the surface, but the two halves will simply slam back together again from gravity. And (here's the fun part) the energy requirement of this process is zero, since the final energy state of the planet is the same as its initial state.

This confuses me a little. If you have a smaller superlaser, with enough power to crack a planet in half which will then reform, and I fire it at a planet, the requirement is zero? Does that mean that I get my energy back? I would think that the energy was still transferred to the planet... probably during the process of getting back together it would turn into heat or kinetic energy or whatever.

[Connor MacLeod]

The ACTA novelization supports it even more strongly by linking what the Drakh did at Daltron 7 (by Sheridan's observations) to what was done by the SHadows with the prior PK. I'll see if I can find and post some of it later.

Your resourcefulness never ceases to impress me.

Usually, RFs claim that the Drakh-operated PK was a "cheap
knock-off," incapable of doing what the Shadows' "really
real" version could.

Are the Drakh that damn stupid? I never understood why
they couldn't operate a planet killer efficiently. They *were*
the Shadows hand-picked minions after all.

Here are the quotes I was talking about:

Babylon 5, A call to arms novelization,

Page 131:

"It was capable of engulfing whole worlds," Sheridan went on, seeing it happen again, seing the cloud, inky black and still expanding to fill all the visible horizon. And then the missiles began to pour in, thousands of them, a silvery rain of missiles."

- Sheridan describing the effects of the SPK and its mechanism. Note that this is entirely consistent with what we know from both B5 and ACTA. Note the repetition of the notion of "thousands" of missiles, lending credence to Ericsson's statements.

page 173:

"The display shifted to a computer enhancement. It gradually peeled away the cloud layer to reveal thousands of craters all over the planet's surface. Dureena saw this and came up alongside Sheridan.

She said. "This - this is what they did to my world."

-- Note two details: One is that there are "thousands of craters all over the planet's surface." This puts to rest any claims that there were millions of craters or missiles and Ericsson only saw part of the planet, since this is a computer-enhanced scan that was showing the ENTIRE planet's surface, minus cloud cover (interesting that there was cloud cover present... remember that the Computer analysis indicated there WAS still an atmosphere?)

The other is that Dureena confirms that what the SPK did during the Shadow War is identical to what was done on Daltron 7, further reinforcing the notion that both PKs were similar.

Page 174-175

"It was a nightmare scene. Once-fertile land had been subjected to an endless rain of heat and explosives, leaving everything a wasteland. During the attack, some deep-burrowing missiles must have penetrated to the planet's core, for there were great plains of shiny black volcanic material. It was apparent that underground explosions of stupendous force had occured, literally blowing out the inside of the planet."

Description of the effects of the PK. Some of the details are questionable I suppose, but they seem to attribute the "deep burrowing to the core" elements as being atypical or random, rather than applying to all missiles. There are possibly other explanations for the description, but the overall context fits with what we already know of the PK.

Page 176:

"Look," Anderson said, "I wasn't involved in the Shadow War, you were... So I didn't see these deathclouds. But... Are you sure this was done by a Shadow Planet Killer?"

"Positive," Sheridan said. "Nothing else leaves a pattern of craters like we saw from above. I've never seen anything like it before or since."

"And that was six years ago, right?"

"Correct. Then the Shadows left and took it with them."

Sheridan reinforces the prior connection by Dureena that the SPK used in the Shadow war basically rendered a planet uninhabitalbe rather than blasting it apart. Since Sheridan seems so certain, and he is definitely in a position of authority to recognize such effects, we have no reason to disbelieve this particular claim.

Interestingly enough, he seems to also indicate that WHAT the SPK did was beyond anything he had ever seen or known the YR to be capable of and what the FO's had ever demonstrated. This seems to infer some interesting "upper limit" capabilities of what the other races are capable of (and what individual shadow vessels are capable of.)

Page 200:

"You haven't seen what a deathcloud can do. I have. It'll wipe out all life on Earth unless we can stop it."

this reinforces the idea that the SPK causes massive extinction without survivors, although this may be something of an exaggeration if it is considered an "off the cuff" statement (although Ericsson I believe made a similar claim.)

[Connor MacLeod]

If you crack a planet in half, you'll kill everyone on the surface, but the two halves will simply slam back together again from gravity. And (here's the fun part) the energy requirement of this process is zero, since the final energy state of the planet is the same as its initial state.

This confuses me a little. If you have a smaller superlaser, with enough power to crack a planet in half which will then reform, and I fire it at a planet, the requirement is zero? Does that mean that I get my energy back? I would think that the energy was still transferred to the planet... probably during the process of getting back together it would turn into heat or kinetic energy or whatever.

No, I think he's referring to the fact that unless the debris is moving fast enough to escape the strength of the planet's gravity, it will remain more or less intact (think of it this way - once you achieve the minimum energy required to overcome the gravitational pull holding the planet together, the energy state of the entire mass has changed - or increased - but if you don't do this, the planet remains intact - going back to more or less the original "energy state" it had.

[Slartibartfast]

The Vorlon Planet Killer has completely destroyed at least one or two planets in season 4 (The TV show). So they don't just crack the planet.

The Shadow Planet Killer doesn't blow a planet outright but bombs it to death. Wasn't it said directly in the show that the missiles fired were gigaton range? And there's that bit where Sheridan's fleet was caught inside the SPK and their power got drained. They could still move around (A few ships fly in to intercept missiles headed for Sheridan's Whitestar), but they couldn't fire weapons. Marcus also said they would all freeze to death or something in a certain amount of time.

Well what makes these missiles so destructive is that they drill into the core of the planet and blow inside. The destruction is caused by extreme volcanic activity or something.

[Slartibartfast]

Did we see this happen, or was it another one of those "interpret from dialogue" things?

I'm paraphrasing heavily but it went like:
Ivanova: Smack-fu Prime is gone! The vorlons blew it away!
Sheridan: what joo yapping 'bout woman? The colony is gone?!!
Ivanova: No, not the colony, the planet, the planet is gone! *starts sobbing*
Sheridan: This is a job for... Blessed nukes of sufficient yield!

Well, as I remember she just said "gone", not destroyed, so it's perfectly possible that they just towed it away.

[SirNitram]

Okay, so it's canonical that the SPK is the equivalent of a ISD for bombardment(BDZ op!). The VPK can blow colonies away, but I find it hard to believe the tech difference between the Vorlons and Shadows is so massive they can field a DS-style superlaser in a compact form. Were this so, the Vorlons could have stamped out the Shadows like they were bugs.

[Durandal]

If you crack a planet in half, you'll kill everyone on the surface, but the two halves will simply slam back together again from gravity. And (here's the fun part) the energy requirement of this process is zero, since the final energy state of the planet is the same as its initial state.

This confuses me a little. If you have a smaller superlaser, with enough power to crack a planet in half which will then reform, and I fire it at a planet, the requirement is zero? Does that mean that I get my energy back? I would think that the energy was still transferred to the planet... probably during the process of getting back together it would turn into heat or kinetic energy or whatever.

No, there will still be an energy requirement. Mike was referring to the net energy change, which is indeed zero. Basically, the amount of useful work done is equal to the product of the displacement and force applied, or the equation W = Fd. Displacement is a vector quantity, so if you walk up the stairs and then back down, your total displacement is zero. Since your displacement is zero, the amount of work you did is zero. This same concept can be applied to "cracking a planet." If the two halves of the planet end up where they started, the change in energy state is zero, so as far as we're concerned, nothing useful really happened.

However, the caveat to this theorem -- called the Work-Energy Theorem -- is that is only applies if the only force present in the system is the force doing the work. If this condition is met, any energy input into a system will always increase the total kinetic energy state of that system.

However, since the planet's gravity is also a part of the system in addition to the planet-killing beam, the work-energy theorem doesn't apply. Think of it this way. If you pick up a ball, you do work on it, but its kinetic energy state does not change. This is because gravity is doing work on the ball as well.

So, since we have no idea of the total displacement of the two halves of the planet, there is absolutely no way to calculate the amount of work required. There was work done on the system, but we can't tell how much. If gravity slams the two halves back together, all we can say is that, on an Earth-sized planet, the total work done was less than 2.4E32J.