Author
|
Topic: A question on Open Source... (Read 26880 times)
|
|
|
Neutrino 123
Zebranky food
 Offline
Gender: 
Posts: 35
|
Considering that the author of the SW technical manuals was a consultant for ILM when they were producing the prequels, and his technical manuals are considered canon, and happens to be a PhD in physics...
I'd say he knows a watt from a joule and his material is relevant.
"Ah," though I, "a physicist. He should know what he is talking about and have good calculations."
I found that he actually has a web site, which I looked at.
http://www.theforce.net/swtc/index.html
Unfortunately, he seems to make mistakes. Also, he seems to use everything related to Star Wars including the books and comics. This is no good. Why should anything but the movies be used? It doesn't even matter what is consulted by the writers, only the movie things are part of the actual movies.
On to his mistakes, he seems to not understand what "vaporization" of an astoroid would look like (the astoroid seems to disappear in a manner not known to physics, not be vaporized). Also, he seems to assume that the Death Star II is not mostly hollow when he calculated the "Ewok extermination". Other errors that I caught after a skim include an assumption that even the individual chuncks were solid (they would be composed of decks with equipment if that large), and that a mass extinction even would NOT be visible from the shield generator area where everyone was partying at the end.
That's what he gets for not having peer review!!! 
|
|
|
|
|
Logged
|
-Neutrino 123 (pronounced Neutrino One-Two-Three)
|
|
|
Death 999
Global Moderator
Enlightened
Offline
Gender:
Posts: 3876
We did. You did. Yes we can. No.
|
Also, he seems to use everything related to Star Wars including the books and comics. This is no good.
Why not? It's canon under LFL's canon policy. What part of 'considered true unless contradicted by movies' bothers you?
On to his mistakes, he seems to not understand what "vaporization" of an astoroid would look like (the astoroid seems to disappear in a manner not known to physics, not be vaporized).
Not really. If you vaporize an asteroid that violently in a total vacuum, it will expand and adiabatically cool to low temperature very quickly. Also, a diffuse monatomic gas of nickel is transparent. So, it disappears. That does not mean that nothing is there.
Also, he seems to assume that the Death Star II is not mostly hollow when he calculated the "Ewok extermination".
Not at all. Suppose that metal in the 900 km wide DS2 is only 100m, mostly near the surface. In other words, we assume a filling fraction of about one part in 1500. Compare this to the Graf Zeppelin filling fraction: about one part in 2300. Is that empty enough for you?
Total mass: 254 thousand cubic kilometers of metal.
(compare to 382 million cubic kilometers of metal in a solid sphere that size)
Now, only consider the 15.4% of that that is directed towards Endor. Let's round that off to 40 thousand cubic kilometers of metal.
If we were to wrap that up in a ball, we'd get an impactor of radius 21 kilometers. Ouch! That's over twice the mass of the asteroid that is hypothesized to have wiped out the dinosaurs. Of course, this didn't get to fall from such great height. On the other hand, it was actively hurled at the ground at several times escape velocity. That's not better, that's worse.
Or, assume that most of the mass fell gently. Then let's figure out how thick the debris would fall on Endor, shall we?
15.4% (450 km/5200 km) ^2 *100 meters = an average of 12.5 cm of debris, or around 5 inches.
Ouch again!
it's easy to say he seems to have made a mistake. It's not so easy to actually make sure he made a mistake.
|
|
|
|
« Last Edit: September 01, 2006, 06:03:57 pm by Death 999 »
|
Logged
|
|
|
|
Arne
Enlightened
Offline
Gender:
Posts: 520
Yak!
|
What if the debris was dust small enough to burn up in the atmosphere? Lot's of heat I guess.
I remember the episode with Voyager and the nukes. Single nukes are not a threat to Voyager. I think it got in trouble because it got hit by many in a very short period of time (time speedup thing).
It'd be interesting with a program that estimates the volume of an arbitrary spaceship and suggests typhical subsystem ratios aswell as space efficiency and structure material. It'd output volumes and values for like hull structure, shield gens, main cannon, turrets (surface area), energy generators, fuel store, engine, hangar, storage, bridge, medical, prison, living quarters, recreation, life support, suggested crew compliment, etc etc.
|
|
|
|
|
Logged
|
|
|
|
Data
Frungy champion
Offline
Gender:
Posts: 76
|
What if the debris was dust small enough to burn up in the atmosphere? Lot's of heat I guess.
I remember the episode with Voyager and the nukes. Single nukes are not a threat to Voyager. I think it got in trouble because it got hit by many in a very short period of time (time speedup thing).
It'd be interesting with a program that estimates the volume of an arbitrary spaceship and suggests typhical subsystem ratios aswell as space efficiency and structure material. It'd output volumes and values for like hull structure, shield gens, main cannon, turrets (surface area), energy generators, fuel store, engine, hangar, storage, bridge, medical, prison, living quarters, recreation, life support, suggested crew compliment, etc etc.
Well, I beileve that such a thing would be nearly immopossible considering all the sources you could be getting information from and that info itself is heavily modified throuought any series, Star Trek, Star Wars and that in Star Control there aren't any real information of that tipe. Besides, when a scriptwriter writes some episode/film, I seriosly doubt that every time he runs to check if that is phisically plausible or not and otherwise.
Oh, and www.irregularwebcomic.net has some great comics about Star Wars plausibility, I'm just too lazy too check which one.
|
|
|
|
|
Logged
|
Sig fixed at Shivers request.
|
|
|
Arne
Enlightened
Offline
Gender:
Posts: 520
Yak!
|
I wrote the program. Needs a lot of tweaking, there's probably a lot of ship systems I haven't thought of, like shields and quasiplex portal flux capacitators... I just set some values (hierarchical, as indicated by --) and the program does math stuff with the volume. The square floor data is calculated with a 2.5m roof height, ^2 would give the amount of square meters (right now it's the side of the floor/room). I'm not sure if all the math is correct though.
Length: 300.00m
Cube: 2.66
Total volume: 1434560.31cu.m (100.00%, 112.78m cube, 757.51m square floor)
--Hull & structure volume: 573824.13cu.m (40.00%, 83.10m cube, 479.09m square floor)
--Drive and fuel systems volume: 573824.13cu.m (40.00%, 83.10m cube, 479.09m square floor)
--Other volume: 286912.05cu.m (20.00%, 65.96m cube, 338.77m square floor)
----Weapons volume: 172147.23cu.m (12.00%, 55.63m cube, 262.41m square floor)
----Hangars volume: 57382.41cu.m (4.00%, 38.57m cube, 151.50m square floor)
----Systems volume: 28691.20cu.m (2.00%, 30.61m cube, 107.13m square floor)
----Crew compliment: 386.67 (74.20cu.m per crew)
----Crew total volume: 28691.20cu.m (2.00%, 30.61m cube, 107.13m square floor)
------Quarters volume: 7733.48cu.m (0.54%, 19.78m cube, 55.62m square floor)
------Corridors volume: 13146.91cu.m (0.92%, 23.60m cube, 72.52m square floor)
------Lifesupport volume: 3093.39cu.m (0.22%, 14.57m cube, 35.18m square floor)
------Recreation volume: 386.67cu.m (0.03%, 7.29m cube, 12.44m square floor)
------Medical volume: 386.67cu.m (0.03%, 7.29m cube, 12.44m square floor)
------Quarantine volume: 38.67cu.m (0.00%, 3.38m cube, 3.93m square floor)
------Prison volume: 38.67cu.m (0.00%, 3.38m cube, 3.93m square floor)
------Lifeboat volume: 773.35cu.m (0.05%, 9.18m cube, 17.59m square floor)
------Workstation volume: 1933.37cu.m (0.13%, 12.46m cube, 27.81m square floor)
------Sanitation volume: 386.67cu.m (0.03%, 7.29m cube, 12.44m square floor)
------Dining hall volume: 386.67cu.m (0.03%, 7.29m cube, 12.44m square floor)
------Kitchen volume: 386.67cu.m (0.03%, 7.29m cube, 12.44m square floor)
A 1600m star destroyer would have a crew compliment of 58659.87, but I'm sure they would settle for a lot less and waste a lot more space in general due to the size. A 150m ship would have 48.33 crew, but might waste less space and skip things like prison cells etc. It would be cool to get some real data from a naval vessel to put into the program.
edit: Millenium Falcon only gets 0.88 crew with my program, but since it's such a small ship there won't be any elaborate crew areas, and ship structure can be lighter.
edit: pretty close crew number on the star destroyer though, only 10k off. However, the hangar and weapons on the star destroyer seems to be low. Hundreds of meter between each turret, compare that to the armament of a naval ship. The hangar is either small or inefficient spacewise. Makes me wonder what's actually inside the ship. It would be interesting to do a ship-volume vs weapons or hangar comparison and see how it changes with ship sizes. I predict that maybe the volume relative power of a ship will go down with like an inv.sqrt or something..
|
|
|
|
« Last Edit: September 02, 2006, 11:37:02 pm by Arne »
|
Logged
|
|
|
|
Neutrino 123
Zebranky food
Offline
Gender:
Posts: 35
|
Death 999, sorry for writing “seems” so much in my posts. I needed to prepare some things, so was typing too quickly, and thus, the general structure of my post was lacking in elegance… 
As for the “canon policies”, I guess that is a matter of personal opinion. For myself, I don’t like the idea of some things in one story being “true” and some being “false” based on a weird set of priorities, which can be further compounded by “greater” sources “implying” things while a lesser source “states” a “fact”. I would take only take original material of various shows and movies to be canon. Hell, I would even ignore the Star Control 2 manual as a source of “facts” (though in that special case, perhaps accept its explanation for a know phenomena if there are no better explanations more consistent with anything else).
If you deliver energy from one point on an asteroid, I am not even sure if it will vaporize. It would probably melt/vaporize a small part and then cause the rest to explode.
At any rate, it is extremely unlikely that the asteroid was mostly nickel. Asteroid compositions are somewhat unknown, but it would probably be mostly iron and silicates, though nickel could certainly be a notable part of it.
For the Death Star impact on Endor, why assume any filling percentage? It is easily big enough to be incredibly massive without needing to assume the filling of even blimp. We know from the final scenes that a cataclysmic event did not occur (there would have been visible effects, even if the Calamari Cruisers blocked debris near the shield generator). Thus, either the Death Star has less mass then thought and/or the Calamari ships somehow blocked more debris (but we didn’t see this on the screen).
If the 80km/sec estimate of the speed is correct, though, then the Debris WAS moving about three times faster then the dinosaur impact, according to rough estimates.
Arne, on the matter of volume and crew considerations, there should be considerable resources available to you about various ships of the last century or two.
A naval ship design program (1850-1950) you might find interesting is Springsharp:
http://www.springsharp.com/
I have done a brief search, but have not been able to find a page with volumes for warships. However, if you input the mass, draft, freeboard, width, and length of a known warship into Springsharp, you can get a rough estimate of the volume.
This is done by using the block coefficient that Springsharp will give you from the above.
http://en.wikipedia.org/wiki/Hull_(watercraft)
The block coefficient is the ships total volume divided by the volume of a block with lengths equal to the ships length, width, and draft (NOT total height, which would include parts above the surface).
Thus, to find the volume of a ship, you should just have to multiply length*width*draft*block coefficient.
I hope this is using the proper clock coefficient definition. I have seen a few different ones across the internet.
Here are some good sites for naval information:
http://www.fas.org/main/home.jsp
http://www.hazegray.org/
http://navalhistory.flixco.info/
Finally, just convert tons (I’m pretty sure that warships are given in long tons) to kilograms by using 1016kg/long ton.
Edit: I found some additional volumetrics information here for Star Trek Ships and Star Wars ships:
http://www.st-v-sw.net/STSWvolumetrics.html
I would generally ignore the analysis on the third crew density page, though, and consider things independantly.
|
|
|
|
« Last Edit: September 03, 2006, 12:45:09 am by Neutrino 123 »
|
Logged
|
-Neutrino 123 (pronounced Neutrino One-Two-Three)
|
|
|
|
|
Culture20
Enlightened
Offline
Posts: 917
Thraddash Flower Child
|
Regarding Nukes and Federation (ST) shielding, does anyone remember how close the runabout got to the nuclear bomb test in the episode of DS9 where Quark & Odo (and someone else) went back in time on Earth? That should be pretty conclusive; if memory serves, they needed to be in the blast to irradiate their engines.
Oh, and regarding Trek vs. Wars vs. Control: I'd say Trek wins hands down; I forgot how easy it was for Federation ships to travel through time (and wipe out the beginnings of life in a galaxy far far away or in an alternate reality where big bugs replace the borg).
|
|
|
|
|
Logged
|
|
|
|
Arne
Enlightened
Offline
Gender:
Posts: 520
Yak!
|
Thanks Neutrino! I'll try to compile that info into little cute diagrams. Maybe it would be cool to plot the correlation between length and volume (my cube value), aswell as volume and crew (density). The color of the plots could depend on the universe (StarTrek, StarWars, Submarines, Naval ships, Airplanes)
I made this little tutorial for quick volume estimation. It's about as accurate as you are careful when making the model. Tut Pic stuff
|
|
|
|
« Last Edit: September 03, 2006, 06:18:36 pm by Arne »
|
Logged
|
|
|
|
Death 999
Global Moderator
Enlightened
Offline
Gender:
Posts: 3876
We did. You did. Yes we can. No.
|
If you deliver energy from one point on an asteroid, I am not even sure if it will vaporize. It would probably melt/vaporize a small part and then cause the rest to explode.
Pushing on something with a force large enough to deform it heats it. If the force is large enough, it can be vaporized.
At any rate, it is extremely unlikely that the asteroid was mostly nickel. Asteroid compositions are somewhat unknown, but it would probably be mostly iron and silicates, though nickel could certainly be a notable part of it.
Fine, replace all instances of 'nickel' with 'any atom at all, period'. Doesn't change the result.
For the Death Star impact on Endor, why assume any filling percentage? It is easily big enough to be incredibly massive without needing to assume the filling of even blimp.
1) Because we saw ships flying through the thing, and it was nothing close to empty.
2) Because we can see the interior structure to some extent, and it's actually got quite a bit of stuff
3) are you REALLY trying to say there isn't even 100 meters of stuff on the surface? That'd be thinner than the super star destroyer.
4) Anyway, if we scale down the hull thickness to a mere 20 meters, we still get a whole inch of metal dust coating the surface of Endor. That'd still be a major catastrophe.
We know from the final scenes that a cataclysmic event did not occur (there would have been visible effects, even if the Calamari Cruisers blocked debris near the shield generator). Thus, either the Death Star has less mass then thought and/or the Calamari ships somehow blocked more debris (but we didn’t see this on the screen).
This is a fairly good point, except that Dr. Saxton addresses it, and, IMO, adequately (i.e. the dust has not yet settled; the large bits were blasted by the Mon Cals, but it still landed as dust). Don't forget, the mass of the DS and ecological catastrophe on Endor is a subpoint of a subpoint: whether Dr. Saxton's site is riddled with inaccuracy and ignored issues is the subpoint of what we were talking about, on the general subject of ST vs SW superiority.
|
|
|
|
|
Logged
|
|
|
|
Neutrino 123
Zebranky food
Offline
Gender:
Posts: 35
|
If some small bit with depth of the asteroid is given a lot of energy quickly, then it will push the other parts apart in an explosion in this situation. This would most probably happen before those parts could be vaporized.
If iron and many other elements in an asteroid were vaporized, they would be greatly lit up.
We saw ships fly through the Death Star, but that doesn’t mean it isn’t mostly empty. There would need to be something connecting the surface area with the center area, and the Death Star was still under construction too.
What I’m saying, is that is was thin enough (and/or ‘something’ blocked much of the debris) to have no noticeable effect on Endor celebrations at the end. Lots of dust in the atmosphere would have blocked out the sun in a highly noticeable way. If the dust had magically settled instantly, then the atmosphere would look fine, but we would notice dust… 
Anyway, I am not saying the site is “riddled” with errors (I’m sure he has most things right, especially things that don’t involve super-technology such as ship lengths  ), just that it has at least a few important ones. The other problem is the weirdness of the “canon”, which I don’t agree with as mentioned in my previous posts.
|
|
|
|
|
Logged
|
-Neutrino 123 (pronounced Neutrino One-Two-Three)
|
|
|
Death 999
Global Moderator
Enlightened
Offline
Gender:
Posts: 3876
We did. You did. Yes we can. No.
|
If some small bit with depth of the asteroid is given a lot of energy quickly, then it will push the other parts apart in an explosion in this situation. This would most probably happen before those parts could be vaporized.
If you supply enough energy, it will be vaporized. Or do you think that the outer casing of your average hydrogen bomb emerges in solid state from its use?
If iron and many other elements in an asteroid were vaporized, they would be greatly lit up.
Why, yes, they would be lit up, in the incandescent period before they adiabatically cooled. And, what do you know, this is observed in the GFX. A ball of incandescent gas which expands rapidly and then disappears. The only mechanism capable of cooling it quickly is the adiabatic expansion that we incidentally know that it is undergoing.
What I’m saying, is that is was thin enough (and/or ‘something’ blocked much of the debris) to have no noticeable effect on Endor celebrations at the end.
Just as long as you realize that being 'thin enough' would mean making it only a couple meters thick on average.
I'd personally go with the 'blocking' theory since the cruisers could deflect large chunks out in some other direction.
Lots of dust in the atmosphere would have blocked out the sun in a highly noticeable way.
I don't know of any endor-based shots on the order of minutes after the death star's destruction, until after sundown, except for one (with the fireworks), which IIRC does not do much either way for clean/dirty sky, since we're at an unknown point during sunset.
|
|
|
|
|
Logged
|
|
|
|
Neutrino 123
Zebranky food
Offline
Gender:
Posts: 35
|
A nuclear bomb will vaporize its case because the case is much smaller then an asteroid, and it explodes in the center of the case. If you had a super-duper-mega amount of energy in the turbolaser blast, it might be able to vaporize the asteroid, but exploding a large part of it without vaporization is much more likely.
It can be confirmed, however, that the asteroid is not vaporized.
The asteroid shows no signs of glowing bits moving in large expansion, only a small puffing effect for the glowing stuff. Also, unless the frames on Saxton’s website are a long time apart, the glowing stops very quickly, so either the asteroid disappeared, or its pieces are no longer glowing.
If the pieces were really really hot, they would not stop glowing in under a second. Just consider some thin liquid (or hot solid) iron in a factory with no atmosphere. It would not stop glowing in under a second, despite the fact that it would radiate very quickly at higher temperatures (but as it cools, it radiates more and more slowly…). Vapor would be similar, just a bit faster, not orders of magnitude faster.
On the Death Star, I would think that the Rebel cruisers would be busy fighting the imperials, who wouldn’t surrender until the Death Star was destroyed. We didn’t see any deflection at all in the explosion picture. Still, some might have been deflected (especially the nasty pieces) in the last seconds, but we don’t see any kind of decisive impact. However, we don’t see much debris moving toward the planet in the first place…
You are right in that the Death Star might not have its decks evenly distributed under its surface. Still, one should be able to get a reasonable number of decks total, at least a few dozen Executer super star destroyers worth. Remember though, that a certain thickness is not that of solid material. In fact, due to futuristic material technology the Empire no doubt has, the decks are probably very thin (except the armor deck, of course!).
Another way to reduce the size of the debris is to reduce the size of the Death Star itself. However, this isn’t really a good method…
Using my super knowledge of advanced classical mechanics, I have determined by examining the characters (and other objects) motion that the gravity on Endor is exactly one times the gravity of Earth . This means that Endor will have a radius fairly close to that of Earth, which is 6378km. Using the following picture, I roughly calculated:
Endor: 136 pixels
DSII: 14 pixels – scales to 1313km
Since the Death Star is closer, this is an upper limit, and there is some uncertainty in it since Endor probably isn’t the exact size of Earth.
However, the following two pictures but a monkey wrench into this calculation.
It is clear in the first picture that the Death Star scales to be much smaller relative to the planet. Similarly, it is clear in the second picture that the death star is far larger then a mere1313km since the super star destroyer is in the high teens kilometers long (I am too lazy to get the exact figure). By some very rough eyeballing, the sizes are an order of magnitude smaller and larger then what I originally calculated. Clearly, the producers made mistakes in scaling the different things, but where does that leave us?
…
That’s not a rhetorical question!
In the party scenes, a massive amount of dust in the atmosphere would be clearly visible (probably with structure too), and some would have reached near the ground (also visible), making the characters most uncomfortable. As if the smell of Vader’s ‘open-air’ funeral wasn’t bad enough…
On another note, I calculated the length of the Earthling Cruiser in the “Earthling Cruiser” thread, and confirmed it by looking at the Vindicator picture. I used the site http://www.merzo.net to get some relative lengths and added the Cruiser in. Thus, I can now present two images with a bunch of popular ships in 1 pixel = 1 meter and 1 pixel = 2 meters scaling.
|
|
|
|
|
Logged
|
-Neutrino 123 (pronounced Neutrino One-Two-Three)
|
|
|
Death 999
Global Moderator
Enlightened
Offline
Gender:
Posts: 3876
We did. You did. Yes we can. No.
|
Vapor would be similar, just a bit faster, not orders of magnitude faster.
But that's the thing! When you have liquid or a solid experiencing an explosion, it does not obey the ideal gas law; its parts have temperature defined in respect to each other, and not to the overall volume over which the liquid or solid is distributed.
On the other hand, vapor does obey the ideal gas law, and as it expands rapidly, it cools rapidly.
On the Death Star, I would think that the Rebel cruisers would be busy fighting the imperials, who wouldn’t surrender until the Death Star was destroyed. We didn’t see any deflection at all in the explosion picture. Still, some might have been deflected (especially the nasty pieces) in the last seconds, but we don’t see any kind of decisive impact. However, we don’t see much debris moving toward the planet in the first place…
yes, the 'they got lucky and the explosion was anisotropic' argument works fine, I'll grant. Saxton could very well have missed that one.
You are right in that the Death Star might not have its decks evenly distributed under its surface. Still, one should be able to get a reasonable number of decks total, at least a few dozen Executer super star destroyers worth. Remember though, that a certain thickness is not that of solid material. In fact, due to futuristic material technology the Empire no doubt has, the decks are probably very thin (except the armor deck, of course!).
Their support beams and such do not seem thin, really. We get to see lots of macroscopic structures in Ep 4.
Using my super knowledge of advanced classical mechanics, I have determined by examining the characters (and other objects) motion that the gravity on Endor is exactly one times the gravity of Earth .
My similarly highly sophisticated analysis also came to that conclusion. Brilliant!
This means that Endor will have a radius fairly close to that of Earth, which is 6378km.
Actually, this is a weak dependence because increasing the radius also increases the separation from the center of mass.. So surface gravity varies as radius to the 1/3. The gravity depends more straightforwardly on the density, which is free to vary substantially.
Endor: 136 pixels
DSII: 14 pixels – scales to 1313km
Since the Death Star is closer, this is an upper limit, and there is some uncertainty in it since Endor probably isn’t the exact size of Earth.
900 km is the figure I've been using. If you include the height the station has above the surface, it's a fairly substantial part of this, so the upper-limit-ness is important here.
However, the following two pictures but a monkey wrench into this calculation.
It is clear in the first picture that the Death Star scales to be much smaller relative to the planet.
Kind-of. I took the first picture, moved over the DS to the edge of the planet, and scaled it up until the DS was the same size as in this shot. The curvature was not all that much greater.
As further support, if you draw the tangents of the rim of Endor near the edges of this shot, you get around a 12 degree angle, over a length of about 7.5 DS2 diameters. 12 degrees = 1/30 of a circle, or around 0.2 radians, or 0.4 of a diameter. Thus, this shot supports a diameter of the DS2 which is around 0.4/7.5 = 1/18.75 of that of Endor.
Similarly, it is clear in the second picture that the death star is far larger then a mere1313km since the super star destroyer is in the high teens kilometers long (I am too lazy to get the exact figure).
If you have a graphing calculator, graph y = sqrt(90^2 - x^2) and zoom in on the peak of this graph. It's awfully flat even compared to a single unit line segment. I think this is consistent with a ~tens kilometers SSD and 900 km DS.
In the party scenes, a massive amount of dust in the atmosphere would be clearly visible (probably with structure too), and some would have reached near the ground (also visible), making the characters most uncomfortable.
I agree that this is odd.
|
|
|
|
|
Logged
|
|
|
|
|
