Ok, from here on I am going to try to turn this to a more constructive direction, instead of stupidly defending my original paper which has been shot full of a number of holes by my own blindness... To this end I will strive to account for all the evidence (including the rebel display which I still think is just a glorified alarm clock, but you wont hear me call it that from now on) beginning -- hopefully -- with this post.
Darth Wong wrote:
As LOTF pointed out, this comes from the movie. WATCH THE MOVIE. How can you produce these detailed screenshots and be so goddamned unfamiliar with the movie from which they came? First you produce a screenshot from the scene in which Y4 seems to be moving at >1000km, and you use it as proof that it can be moving at 50km/s or less(!!!) Then, you act as though this line from the movie is ONLY found in the screenplay. Didn't you ever WATCH it, in real-time complete with audio? Or is your entire concept of Star Wars based on static screenshots taken out of context?
no Mike, it isnt based on that... but I honestly did not remember hearing the line 'we are approaching the planet Yavin' in the movie (it might be the version I have, a faulty copy whatever, but I swear to you that 'we are approaching the planet Yavin' is not in it, although 'preparing to orbit the planet' is. as to the moon's velocity, I just dont see where you are getting that 1000km/sec figure, as (yes using Curt's data) all the orbital elements come together nicely with a calculation of about 42km/sec at that point in the orbit. if you or anyone else has any actual element data which allows for a different result for Y4's orbit that fits with the observed visuals, please let me know.
No, it doesn't. The scenario only fits the math if you throw out most of the evidence, and seize upon ONLY the parts of the evidence which DON'T make sense. You use screenshots such as the ones I showed in order to show that Y4 is very close to the edge and about to pass through. However the velocity of Y4 in that scene is ridiculously high; so high that 30 minutes is a HUGE overestimate. So it is OBVIOUSLY a PROJECTION for Tarkin's benefit. It is not showing Y4's current status; it is showing him what they INTEND to do (unless you seriously think their rate of closure was that high).
so basically you (et al) are saying that I am indeed suffering from a massive case of GIGO (bad premise + bad initial data + good math =
very bad result), and that all of the orbital elements of Y4 established for the calcs are wrong -- all the masses, eccentricites, inclinations etc are invalid. Ok... fine.
I suppose then someone wont mind if I ask for some info, such as:
1) concerning the rate of closure, do we actually really know if the range was decreasing, was it just the angular separation for LOS purposes, translated to look like distance on the rebel display, or both (and to what extent)? (I would prefer not to just blindly accept the rebel representation without a second source to confirm)...
2) I need to add a piece of evidence from the rebel side here as well... when the DS acheived LOS on Y4, the rebel announcer stated either 'the death star has cleared the planet' or 'the death star is clear to fire' twice (repeated it for emphasis I suppose) I just cant remember the wording exactly... now I know what I think it means: 'the DS has the angle on us!'; at the same time, the DS controller states 'rebel base in range' (but what is the superlaser's range?) what do you all think?
3) I know which evidence I counted in the original text: all the displays from the DS overbridge; all the evidence which I interpreted differently: the 'orbiting the planet at maximum velocity' statement (which I applied to Y4, as it was apparently at or near perigee itself) and the evidence I discarded or failed to consider: the rebel display, the 'approaching the planet, preparing to orbit' statement. am I missing anything else?
The fact is that given the high velocity on the DS display, the Rebel display is MORE reliable, not less. And your attempt to pretend the math cannot possibly work out is a joke; you are still starting from a groundless assumption, namely that the DS comes out of hyperspace with no initial velocity to worry about. Suppose it comes out of hyperspace with such a velocity that it's basically moving around Yavin in the same direction as Y4? In that case, it would have to accelerate in the opposite direction at a prodigious rate and continue accelerating until it nullifies its velocity in one direction and begins counter-rotating back toward Y4.
Ok, I fully admit to falling into the '
absence of evidence' fallacy, and that I wantonly failed to take that possibility into account. However, what we really need to determine is in what direction the moon and DS are in fact moving at the start of the countdown, and the distance from the DS to Yavin at the 'max velocity' statement, which
should be perigee... we can already infer from the initial targeting screen on the DS what the angular separation is between the 2 bodies, but once again we (or rather I) need better data apparently than curt's numbers to work it out...
This would explain the initial viewscreen, the acceleration on the Rebel display, the positioning, etc. It would explain everything, except for the DS display which shows them closing at >1000km/s, and which must therefore be a time-compressed projection for Tarkin's benefit, unless you choose to believe that the DS had LOS in less than one minute (extrapolated from the velocity in the scene), and spent the remaining 29 minutes just sitting around.
so, we have gone from my ignoring the rebel display because it is inaccurate wrt scale, distances, and proper motion (at least so far as I know, given that all my previous orbital data for Y4 has been dismissed)... to your ignoring the DS targeting display because it is supposedly time compressed... what a wonderful bit of progress... is there any way we can meet in the middle here?
Face it; your math is based upon deliberate exclusion of evidence with nothing but flimsy excuses to back it up, and you seize upon a display which obviously says something COMPLETELY different from what you claim with your out-of-context static screenshot. I provided two time-indexed screenshots and even a video clip for evidence, and you chose to answer everone's posts but mine.
darnit guys... I give up on the initial scenario ok, but just humor me for a minute while I propose a new one:
given recent events, I propose that the DS had in fact established a para- or hyperbolic orbit, with perigee occuring during the same timeframe as the phrase 'orbiting the planet at maximum velocity'... since we cannot know just what the DS's initial elements were upon coming out of hyperspace, I dont think it is wise (or fair, as you could give it all sorts of boons, while I would choose not to) to speculate what it did to get to that point, so we can concentrate on what it did from the start of the countdown on. first, are there any issues with this premise?
now there are some concerns here:
1) regarding Y4, this has the potential to end up skewing Y4's orbit even more towards an
e of 1, and shifts its other elements such that it is going even faster during the scenario than originally calc'd... this even opens up the possibility that the moon is actually moving
away from the DS... a possibility which I think you all might really like.
2) can we agree that huge accelerations on the DS's part are not required -- that is, after the 'orbiting the planet at maximum velocity' phrase is uttered? in fact the phrase would seem to disqualify the possibility of further acceleration, unless the DS broke orbit to pursue a powered intercept (a presumption for which there is no evidence AFAIK)