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Post by Count Zero on May 22, 2007 1:54:59 GMT -4
Oh yeah, don't forget to kick a large clump of non-billowing "wet sand" with every step!
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rocky
Earth
BANNED
Posts: 212
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Post by rocky on May 22, 2007 7:07:27 GMT -4
The clearest footage of the rover that I know of is here. video.google.es/videoplay?docid=4135126565081757736&q=apollo(21 minute 14 second mark) It's not a frontal shot but the curvature of the arcs the soil makes when thrown up is clear enough. In a vacuum there should be a symmetrical parabola. This is far from a symetrical parabola. If something is that obvious, there's no need to do any calculations. You people are trying to change the laws of physics.
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Post by Grand Lunar on May 22, 2007 7:36:19 GMT -4
Yes, emphasis on footage you know of. A lot of footage exists elsewhere. It seems you only wanted to show that from your precious hoax video. Did it occur to you to try the Apollo Lunar Surface Journal? About your complaint of a symmetrical paraboloa. You said it yourself, its not a frontal shot. It doesn't look symmetrical because you're viewing it from an angle! It's called "foreshortening". Also, you're watching a low res clip of a few seconds of video. My collegues here have DVDs that show much longer periods. Also, as stated, the sped-up look doesn't hold for the hours of footage (which you'll likely never see on YouTube or Google Video). Also consider the uneven terrain. The dust is being kicked up along an undulating surface. So, you wind up with multiple trajectories that clump together. You're ignoring the facts. Still waiting for your comment to this. Gillian posed a similar, shorter version of what I ask. So, you have two people asking you the same question. Pressure's on, booby.
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Post by PhantomWolf on May 22, 2007 8:14:54 GMT -4
The clearest footage of the rover that I know of is here.
The clearest footage of the rover that I know of is sitting on my bookcase and I can play it on a 28" screen. You're wrong.
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Post by tofu on May 22, 2007 9:15:59 GMT -4
I love how an HB will make me download an hour-long video, who knows how many gigabytes, so that I can watch about 2 seconds of rover footage. And what do I see? Lo and behold, it looks to me like every grain of dust is following a parabola.
Me thinks rocky has never used a garden hose. If you flick a garden hose you make what looks like a wave propagating through the air. In fact, every drop of water is following a parabola and the wave is just an illusion.
--edit to add the word "illusion"
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Post by Jason Thompson on May 22, 2007 9:17:13 GMT -4
The clearest footage of the rover that I know of is here. The clearest footage I know of is available on DVD in superb quality. If you want to do proper analysis of moving images at least get the best quality you can to do it with. All projectiles, in a vacuum or otherwise, follow a parabolic trajectory. Yet that's what you claimed to have done earlier. You said you had calculated trajectories. Now, confronted by people who are demanding you show your calculations you claim they are unnecessary. Remind me again why we should take you seriously? No, we're trying to show you where your understanding of the laws of physics is in error. Now, explain to us again what it is that stops the dust from creating huge billowing clouds as it is thrown up by the wheels of the rover....
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Post by sts60 on May 22, 2007 9:18:40 GMT -4
That's because for rocky/david, "research" begins and ends with YouTube and Google Video.
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Post by sts60 on May 22, 2007 9:22:56 GMT -4
All projectiles, in a vacuum or otherwise, follow a parabolic trajectory.
Jason, I assume you're simplifying here. Certainly, particles in a sensible atmosphere will follow only an approximately parabolic trajectory, depending on the drag on and mass of the particle. (It goes without saying that we're not considering escape trajectories.)
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Post by Grand Lunar on May 22, 2007 9:31:18 GMT -4
Tofu, to avoid the long wait, just move the track button to the time desired (or near it) and hit pause. It loads from that point. You don't even have to wait for the whole thing to download. Just the to the part our intrepid "invesigator" mentions.
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Post by Grand Lunar on May 22, 2007 9:33:44 GMT -4
That's because for rocky/david, "research" begins and ends with YouTube and Google Video. I can only wonder: how would Rocky get by in a time before YouTube and Google Video? Say it was 1912, and Rocky wanted to expose that the govt. was responsible for the Titanic disaster. He'd be lost! Closest I can imagine would be for him would be to splice together some film that he recovers. Even then, he'd be laughed at.
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Post by JayUtah on May 22, 2007 9:41:56 GMT -4
In a vacuum there should be a symmetrical parabola.
No. Each grain of dust should follow its own parabola. That doesn't mean that many thousands of grains should all appear to follow the same parabola. You're trying to generalize what's true for one object to the appearance generated by many such objects with different departure conditions.
A dust plume is not one single object that obeys the simple rule you learned in high school. You can't let your eye and intuition fool you into misinterpreting the behavior of an aggregate.
In my work I am often called upon to assist in the computation of behavior that is governed by extremely simple rules at the small scale (e.g., pressure versus temperature) but when extended to thousands or millions of examples generates complex patterns of behavior in aggregate effect. This is, frankly, one of the joys of what I do.
If something is that obvious, there's no need to do any calculations.
The battle cry of the ignorant.
A conspiracy theory works by dumbing down the expectations until they fit within a conspiracist's lay intuition. No education necessary. But of course the universe doesn't often conform to oversimplified expectations, otherwise there would be no need for expertise beyond high school. It doesn't often obey only the simple classroom rules, or the ones invented on the spot by the nice man who's trying to sell you a video.
Wheelfuls of dust don't collectively follow tidy parabolic trajectories, even in a vacuum. Reflections in visors don't follow scatter-free optical paths. Air resistance doesn't act only horizontally.
And of such things "anomalies" are made. They aren't a problem with the data; they're a problem with the expectations against which the data are measured.
If the rover footage doesn't obey the proper laws of physics, where are the legions of worldwide physics teachers? Why aren't they descending on NASA to punish them for the crass display of "obviously" wrong behavior? Why aren't they all pounding their podiums demanding that a dust plume create a "symmetrical parabola?" Or to put it more succinctly: why do these objections always originate from the enclaves of conspiracy theorists who've "had a little physics?"
You people are trying to change the laws of physics.
By your own admission you only have a rudimentary education in this field. I, however, do physics for a living, and from that basis I've given you a more thorough explanation of the physics involved. It's not as if I'm just making idle claims to expertise. You've received a fairly thorough discussion, as well as some suggestions for principles you could test yourself.
You're like a high-school biology student accusing a practicing physician of abusing the simple laws of biology he learned in the classroom, simply because the physician has a broader, more sophisticated, and more experienced perspective and from that perspective accomplishes things that don't fit into the student's beginner's knowledge.
You ignored all the answers to your questions you thought would be rhetorical, but which instead turned out to be more complicated than you imagined. That says you're aware of the possibility of sophistication, but simply choose to look only at your grossly formulated version. Trollish behavior, I think.
The laws of physics include not only ballistics but fluid mechanics. In your mad rush to accuse us of failing to respect simple ballistics, you've stumbled headlong over fluid mechanics. You say the dust doesn't behave in a ballistically correct manner, so it therefore must be affected by an atmosphere. But in trying to elucidate that claim, you rely upon the completely wrong notion that fluid resistance occurs only horizontally. And you ignore aerosolization altogether. Your own theory fares atrociously according to the laws of physics.
Just as your knowledge of ballistics is oversimplified, your knowledge of fluid mechanics is just wrong. Your theory doesn't derive from a knowledge and application of those principles. It merely handwaves toward them in a feeble attempt to connect what you see with what you desperately desire to believe about it.
So kindly dispense with trying to lecture everyone on laws you neither understand nor appreciate.
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Post by JayUtah on May 22, 2007 9:50:49 GMT -4
You said it yourself, its not a frontal shot.
It's important to remember that both front and rear wheels of the rover turn for steering. It's therefore important not to try to infer the orientation of the rear wheels from the apparent orientation of the rover body.
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Post by tofu on May 22, 2007 10:21:12 GMT -4
Tofu, to avoid the long wait, just move the track button I was on a wireless network. It took about 15 minutes to download.
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Post by Jason Thompson on May 22, 2007 10:57:25 GMT -4
Jason, I assume you're simplifying here. Certainly, particles in a sensible atmosphere will follow only an approximately parabolic trajectory, depending on the drag on and mass of the particle. (It goes without saying that we're not considering escape trajectories.) Maybe I am oversimplifying. I admit to not being totally versed in such matters. However, my understanding was that all ballistic flight was along a parabola. Am I not correct?
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Post by JayUtah on May 22, 2007 11:03:17 GMT -4
All ballistic flight is a parabola, but not all flight is ballistic. If the flight is through an atmosphere, its path and rate will be a combination of ballistics and aerodynamics, the combination to be determined by the precise parameters of each case.
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