Kinetic energy of asteroid impacts in TESB

[Mr. Oragahn]

Gots links to more or less exact figures?

There's that small impact that vapourized an asteroid, whiel the ISD was shooting down others, and the famous one which obliterated the bridge.

[Mike DiCenso]

Well, there's really only two estimates. One can be found naturally on SDN, and the other here:

http://www.st-v-sw.net/STSWweakhull.html

There is also an estimate by Jedi Master Spock here:

http://www.starfleetjedi.net/f4.html

About 36 terajoules is a more than reasonable estimate.
-Mike

[Socar]

There is also an estimate by Jedi Master Spock here:

http://www.starfleetjedi.net/f4.html

Off-topic note to JMS: The first link on that page to SDN is broken. You accidentally typed in a second L in Impact-examples.htmll

[Mr. Oragahn]

36 terajoules (8.6 KT) looks ok to me.

Either that sector of the shields failed to stop that asteroid, or the armour is responsible.

As a wish to comment it for quite some time, I went to Wong's page. Here's what he says:

Written: 1998.08.01
Last Revised: 1999.10.06

Energy Handling

There are three common methods of estimating Star Destroyer shield strength, although accurate estimates are elusive:

• TESB asteroid field. The TESB novelization described a "steady rain" of asteroids, and Anakin Skywalker: The Story of Darth Vader said that "turbolaser gunners blasted the largest rocks; those they missed impacted against the bow shields like multi-megaton compression bombs." We can see from the film that the ships were taking impacts at the rate of at least 1 asteroid per second if not more, and we know from the above quote that the asteroids were striking with several megatons of energy each. Some Federation cultists dispute this figure by stating that we saw some slow-moving asteroids in the films, but this is a false dilemma fallacy: the existence of slow-moving asteroids does not prove that all of the asteroids (<99.99% of which would have impacted >off-screen) would have been slow-moving, particularly since typical asteroid speeds in the Earth's solar system have been observed to be much higher than this. Furthermore, the bombardment must have continued for at least 1 or 2 days because Vader had time to contact bounty hunters, who travelled from their various homebases to the Outer Rim while the fleet stayed in the field. Therefore, each ISD might have absorbed as much as 3E20 joules of kinetic energy while in the asteroid field.

First, the steady rain is relevant in the light of the total of supported impacts, covering the whole stay in the asteroid belt, instead of a minute by minute rate.
As we can see in the film, the rain is not that much steady, and most if nor all asteroids are blasted apart by TL batteries. Only a few manage to strike the ship. Existing examples show them either being too small and do nothing noticeable, or being much bigger and hit with the force of 8.6 kilotons.
As a whole, the concentration of impact is particularily low.

As such, it's totally unsurprising that Wong does not hesitate to literally rewrite Star Wars and serve us with an interpretation of events which he got from god knows where.
His claim, about more than one impact per second, should be another very illustrative proof of the lies he openly crafts, in order to paint a version of Star Wars that has nothing to do with reality.

A "rate of at least 1 asteroid per second if not more".
How can't we be bewildered by such a audacious claim!

He doesn't stop there. According to him, all of this concentrated rates happened off-screen, and the impacts we saw in the film represent less than 0.01% of the total number of impacts.

Obviously! How couldn't it be? It's just a miracle, or call it bad luck, that for all the times we saw the ships flying in the middle of the asteroid belt, we only got to see a total of two impacts, counting one which completely obliterates a whole section of a ship!

Of course, if you're going to confront them with their unsupported beliefs, they'll probably say that you're entitled to your own flawed interpretation of facts (as it recently happened with Poe when asked to defend in claims about asteroid vaporization here).

In the end, it helps to understand how the much mocked and completely outlandish wank, which mainly originated from Wong's site and its community, managed to grow to such a daring scope, steam rolling over logic and dragging a whole train of people who are just too happy to limit themselves to such a poor level of observation and reflexion.

It has the Wizard's 1st Rule written all over it, really. It's always a case where the bigger the lies, the more impressive, the more the people want to believe in them, the more they'll work into them.



On another of Wong's pages, geared towards physical impacts, we get to read the text, quoted below.
I added my own comments in orange.

Written: 2002-05-04
Last updated: 2003-04-12

Example #1: Hoth asteroid impact

Now that you've seen the pretty pictures, let's crunch some numbers. Let's suppose a 70 metre wide asteroid strikes a ship while moving at roughly 1 km/s (as all long-time Star Wars vs Star Trek people know, this is similar to the asteroid which hit an ISD bridge tower in TESB, as seen in this Divx5 video clip). Actually, it would seem that Wong added more than 20m out of nowhere, and got a speed that's roughly twice the real one. This is considered a benchmark for an ISD's resistance to physical impacts, albeit somewhat over-conservative. Remember that all the ships had already sustained damage beforehand (from prior asteroid impacts, and perhaps also from the Battle of Hoth and a near-collision with two other Star Destroyers) (that is an interesting concession from 2003, since many SDNetists love to argue that the ISDs were not damaged by asteroid impacts - and incidentally, spent time trying to find explanations to plaster upon the canon - that said, how could you disagree with them, since Saxton rates shield dissipation of much older warships as already being in the x teratons per second - it's an uphill battle of unification for a prosper continuity), the shields may have been down to permit the holo-transmission (this one was kindly enforced by Saxton in the E2-ICS - yet it's a claim which came out of nowherewe, and we have a formidable concession that hulls, no matter the neutronium, handwavium, fancy plating and reactive/ablative/suckative tech that's behind the thick layers of uber armour, still utterly fall against mere raw kilotons of kinetic energy), and neither the bridge tower or its shield generators would be as robust as the main hull and its defense systems (made up assertion - especially since the models show that the bridge structure is as heavily platted as the rest of the ship! - any shot from the production models will show that). As a slightly off-topic exercise, ask yourself what this incident tells us about the structural strength of the bridge tower (hint: does the asteroid pulverize against the tower's surface, penetrate deeply inside, or fly right through and out the other side?)

Oh that's simple. It completely destroys a huge section of the bridge tower, if not the whole protruding superior structure. Really, what can it tell?
Maybe that shields are the be and end all in Star Wars, and that sheer armour is not oh so fantastic as they think?

In any case, given nickel-iron composition and roughly 7000 kg/m³ density, this asteroid would have roughly 1.25 million tons mass, therefore its momentum would be 1.25E12 kg·m/s and its kinetic energy would be 6.25E14 J (roughly 150 kilotons). Please notice how he immediately decides to go with the heaviest composition. Not only asteroids containing significant amounts of iron are likely to look redish, which isn't the case as far as the bridge killer is concerned, but such asteroids do not represent the majority of asteroids. Why immediately aim for the highest figures possible? We might leap to the conclusion that a Star Destroyer's shields must be limited to 150 kilotons for any weapon regardless of whether it possesses mass or not (assuming its bridge shields were, in fact, up at the time despite the holo-transmission which normally requires shields to be lowered), but this conclusion is oversimplistic and wrong. The dilemna is rather simple here. It's either the shields or the armour that is faulty. It is not unthinkable that the ship would have seen its shields weakened, but then, how such mere impacts ever threaten a ship, which all of these wankers happily rate in the up-up teraton range? (Or maybe more in fact, I'm just lost on the absurd figures they sprout, they seem to get bigger month after month, for no apparent reason.) Knowing what we know about collision physics, we know that the shields must apply enough reaction force to reduce the asteroid's velocity to zero before impact. From another scene in ROTJ where a stricken fighter explodes against an ISD bridge tower's shields, they appear to be less than 10 metres away from the hull. This would give them less than 0.02 seconds to stop the asteroid, and the reaction force would be at least 6.25E13 N (note that we are ignoring the fact that no shield interaction was visible in the asteroid impact, so we are humouring the common Trekkie belief that the shields were up). This defines the physical stress applied to the shield generator's mounts, and stress causes structural failure. Sure, you can pump up the destructive incident's wattage, but unless you think in terms of a billionth of a second, at the very least, you are never going to ever meet their much beloved and extrapolated ISD shield figures, indirectly derivated and boosted from the already made up numbers attributed to Acclamators, Venators and other major ships by Saxton.

Now, let us consider an equivalent turbolaser blast (again, speaking from a structural perspective). We know that turbolaser bolts do not arc measurably downward in gravity even over distances where it should be obvious (eg- the ground battle at Hoth, the space battles in low orbit over Endor and Tatooine), so they appear to be massless (and the SW2ICS provides official confirmation of this interpretation). No, this EU source provides a conflicting and hugely absurd theory, about overcomplicated spinning light conundrums, to actually reduce the speed of a beam! And nevermind the same beams, either fired from space ships of any tonnage, or ground and atmospheric vehicles, which routinely burst in the strictest flak fashion. So no, they are clearly not lasers. It is even more funny to see how these EU-phile people dismiss the fact that tibanna gas, which is used for many energy weapons in Star Wars, is also attributed anti gravitational abilities. Don't ask, it's just the way it goes. Of course, insisting that it's pure light lets them boost their firepower calculations up by calculating how much energy would be necessary to rock spaceships with light. From TESB's pursuit sequences for example, nevermind if, again, the destroyers' bolts act as flak, as properly described by the novelisation. In fact, almost all, if not simply all of the six novelizations do come with numerous mentions of flak weaponry or weapons behaving like flak weaponry, that is, bolts which are apparently "timed" to explode at a certain moment. This would seem wise, in fact, to maximize efficiency, when you see how bolts often miss their targets. At least, if they explode in the target's vicinity, they're ought to deal some damage, instead of completely missing it. That would also fit with the sources George Lucas took his inspiration from, mostly WWII battles as far as mechanized units are concerned. Moreover, we know (from the TESB asteroid vapourization scene) that a long turbolaser bolt takes roughly 2 frames at 24 fps (0.08 seconds) to impart its energy to the target. Since the time duration is 0.08 seconds instead of 0.02 seconds, it needs 4 times as much momentum as the asteroid (ie- 5E12 kg·m/s) in order to subject the bridge tower to the same stresses. Therefore, since the momentum of a massless particle is U/c, this means that its energy yield would have to be 1.5E21 J, or 350 gigatons. In short, you would need to hit an already-damaged ISD's bridge tower with a 350 gigaton laser or turbolaser blast in order to cause the same physical impact damage we saw in TESB (assuming its shields are up, otherwise the sheer energy transfer would overwhelm the ship's armour regardless of the physical impact). And here we see just absurd it is. Using his probably reliable knowledgable technical background in sciences, he disguises his logical flaws and made up asumptions behind a curtain of nice sounding technobabble and numbers... and ends finding that a bolt's yield would need to be about 350 gigatons, when a mere asteroid finely manages to do the same, with a very low kiloton level of energy, imparted only 4 times faster than a bolt!

Considering that his comments postdate the release of the E2-ICS, there's just no excuse here. He's openly lying through his teeth.