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Post by Count Zero on May 21, 2007 5:31:14 GMT -4
No, because the dust is not billowing.
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Post by Grand Lunar on May 21, 2007 6:57:19 GMT -4
But-but.....he preformed calculations! And if its on the internet, is MUST be true! ;D I recall Rocky's standard answer. He believes that colored, washed sand was used. I assume, then, that close ups of the ground that show it as compacted powder must be of something different. Rocky, and thoughts on what I presented to you here?
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Post by Jason Thompson on May 21, 2007 9:07:57 GMT -4
Translation: I don't know how to do it, but I did it according to my own preconceptions which must be right.
However, I doubt very much you did any calculation whatsoever. If you did, post it here. It seems more likely all you did was look at it, decide it didn't look right, and then conclude based on your own limited understanding of actual science.
Not necessarily true. If an atmosphere does slow a particle down there is no guarantee it will actully stop its lateral motion altogether. Have you ever, say, thrown a tennis ball in such a way that it travels laterally and hits the ground vertically? In my experience they always bounce on in the direction I threw them. The only time I ever got a tennis ball to bounce vertically was when I threw it vertically upwards in the first place.
However, even granting that an atmosphere does produce a drag that slows the lateral motion, the slowing will simply turn the trajectory into another parabola.
Why are you asking that question when you claim to have already done it? Why have you drawn a conclusion if you are as uncertain as this qiestion makes you appear?
No, it would form a different parabola.
This seems like something pretty basic to me.[/quote]
Then there is a good chance you have oversimplified. How have you determined the initial upward velocity of the dust to determine its ballistc course? How have you accounted for the fact that the view you have of the dust is not side-on but from an angle? How do you account for the fact that the uneven surface contributes to the direction the dust flies in?
Proof please.
Rubbish. The loose and fine dust should be suspended by the atmosphere if it was there and would form great clouds whatever speed it starts at. This dust doesn't, so is not moving in an atmosphere.
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Post by petereldergill on May 21, 2007 11:02:12 GMT -4
Assuming you could have an accurate height scale on the photo, couldn't you measure the heights of the dust particles and plot them vs time, find the equation of the parabola, and find the second derivative to show the acceleration is that of the moon? Then it wouldn't matter if you're on an angle or not. Or am I oversimplifying/missing something
Pete
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Post by Jason Thompson on May 21, 2007 12:06:05 GMT -4
Assuming you could have an accurate height scale on the photo, couldn't you measure the heights of the dust particles and plot them vs time, find the equation of the parabola, and find the second derivative to show the acceleration is that of the moon? Then it wouldn't matter if you're on an angle or not. Or am I oversimplifying/missing something Pete Whilst you probably could do something like that (remembering you need to know the frame rate of recording to get the time correctly), there seems little point. For all their professing to have done some calculations, HBs almost certainly don't understand how to do it, and wouldn't get it if you actually put the numbers up anyway. Save your effort, and don't go jumping through their hoops. Get them to grasp the qualitative before digging into the quantitative. Remember, the burden of proof is on THEM, not you.
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Post by JayUtah on May 21, 2007 12:18:29 GMT -4
Also--doesn't the footage look just like earth conditions when played at double speed?
Begging the question.
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Post by scooter on May 21, 2007 12:46:25 GMT -4
Frankly, I've never seen footage of the LRV driving around on Earth, spinning it's wheels going over bumps, throwing up dust...what should it look like?
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Post by JayUtah on May 21, 2007 13:42:57 GMT -4
When something is thrown in a vacuum, it's forward speed never changes. Its downward speed keeps increasing unitil it hits the surface but the forward speed isn't changed at all.
Simplistic.
Calculus is helpful here because it involves rates of change. But the important concept here is vector analysis.
A velocity is a vector. We express vectors as scalar quantities relative to a basis. Any vector can be reckoned simultaneously in any number of bases, giving any number of components. If the basis is orthonormal, we can treat each component as an independent quantity.
Thus every arbitrary velocity vector in a plane can be decomposed along a orthonormal basis defining the plane that establishes one axis as the local gravity force vector (if any), and the other one perpendicular to it -- the local horizontal. And of course each component of that vector can be treated physically in that basis as having either the full effect of gravity or none. If none, Newton's first law holds and the velocity does not change -- that applies to the horizontal component of the velocity vector. The vertical component is affected by gravity integrated over time. The sum of those components is the final velocity vector, and itegrating it over time gives the means of discovering the object's trajectory in that space.
But that does not mean that every external force acting upon the object aligns to the gravity basis. As I said, there are infinitely many bases upon which we can reckon a vector.
If there is atmospere, the forward speed slows until there is no forward speed. The object finally just falls straight down.
False. Air resistance in still air always acts in a direction that opposes the object's motion, whatever that direction is. If you're going horizontally north, air resistance acts as a force pushing south. If you're falling, air resistance acts as a force pushing upward. If you're rocketing upward, air resistance acts as a force pushing downward.
The conspiracy theorists all propopse the same simplistic formulation, the one that comes from having a "little calculus" but omits the generalized discussion of reference frames that are the foundation of Newtonian dynamics. The trajectories people messed with in high school assumed only the one reference frame, and therefore failed to convey the notion that others exist. And so the common novice mistake is to reckon all forces only in that frame.
The reference frame for air resistance is aligns its cardinal axis with the direction of movement, and rotates as that direction rotates. The important concept is that air does not merely slow objects in the horizontal direction; it slows them also in the vertical direction according to how fast they're moving in that directon.
When conspiracists attempt to argue that the rover dust "hits a wall of air," and stops, but then fail to account for that dust not hitting a "floor" of air on its way down, they demonstrate their lack of sophistication in discussion dynamics at the real-world level.
Doesn't this aply to what dust does in an atmpsphere and doesn't do in a vacuum too.
Not as simplistically as you've formulated it, no.
Wouldn't that be noticable?
It may be noticeable under certain conditions. If you assert that those conditions hold in this case, you have the burden of proof for that. As for now, you're just begging the question.
Wouldn't it be possible to examine footage and determine whether there is an atmospere or a vacuum just by looking at the trajectory of the soil thrown up by the tires?
Not by an analysis of trajectory, since we would need to know precise departure conditions in order to derive a ballistic model along which to measure the object's observable path.
However, since dust aerosolizes profusely in atmosphere, the visible lack of aerosolization can be taken as evidence of a lack of atmosphere.
In a vacuum, shouldn't the soil just follow the parabolic trajectory that could be easily calculated?
Each dust grain should follow a ballistic trajectory. That doesn't mean every grain of dust should follow the same ballistic trajectory. Since each grain has a slightly different departure conditions, the particles will tend to diverge over time. They will, however, remain ballistically "related," meaning that they will exhibit a certain complex coherence based on the differences being only slight ones.
If there is atmosphere, wouldn't it slow down significantly so that it doesn't form a perfect parabola?
Not universally. There is a problem of scale.
As the size of a particle increases, its mass increases faster than its aspect from which drag is computed. Consider a simple solid sphere of uniform density. It's aspect is always a circle of radius R. That is, as seen from any one direction a sphere always looks like a circle. And the drag on an object is proportional to how it is "seen" in the direction of the fluid flow -- specifically its cross-sectional area. The area of a circle is proportional to the square of its radius.
The mass of a solid, unformly dense sphere is proportional to its volume, which is in turn is proportional to the cube of its radius. Galileo's principle says that inertial mass and gravitational weight cancel either other out so that acceleration doesn't change with mass. However a more massive object requires more force in the form of air resistance to slow it down, because of the conservation of momentum principle. It doesn't get more force, because momentum increases an order of magnitude faster than drag as radius increases.
Thus smaller particles are more proportionally susceptible to air resistance, entrainment, and aerosolization than are large particles. Not all particle motion in an atmosphere will therefore exhibit similar behavior. If you pick up a handful of random dust and throw it, you'll find that the heavier rocks follow almost pure ballistic trajectories while the fine dust particles aerosolize almost immediately.
This seems like something pretty basic to me.
Most oversimplified questions do indeed seem basic. The question is not how easy it is to grasp your explanation, but how correct your explanation is. You have the burden to show it's correct, but you have simply begged the question.
The soil in the footage isn't following the trajectory that it should follow in a vacuum.
Begging the question. You haven't shown that you understand how trajectories behave in a vacuum or in air.
The point is that the trajectory of the soil is not what it would be if it were in a vacuum.
No, the problem is that the trajectory is not what you expect, and you handwave wildly trying to claim that this is because there is an atmosphere, although you can't come up with an accurate physics explanation why. You don't consider that your expectations are just too simplistic to be useful in determining authenticity and that therein lies the "anomaly."
In other words, you fabricate some wild accusation of anomaly based on your ignorance and jump to the conclusion that the evidence is fake. That makes you a fairly unremarkable conspiracy theorist and hardly worth anyone's attention.
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Post by sts60 on May 21, 2007 14:43:01 GMT -4
I would correct Jay's last paragraph as follows: rocky/david already had his conclusion - that the evidence is fake. He didn't need to jump to a place he already was; his task was simply to wave his hands and try to make it sound like the evidence supported him, which it doesn't. But that's OK, because he has his universal fall-back position that all evidence was faked and everybody who says otherwise is a liar or dupe.
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Post by gillianren on May 21, 2007 15:15:32 GMT -4
No. However, even if it were, would that be conclusive evidence that that was what was going on? What prevented them from actually landing on the Moon? Why did the landings have to be faked?
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reynoldbot
Jupiter
A paper-white mask of evil.
Posts: 790
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Post by reynoldbot on May 21, 2007 15:46:40 GMT -4
it's been repeatedly shown on this and other forums that speeding up the footage only looks even the slightest bit normal (even that can be argued) in very short and selective segments taken completely out of their context. Watching any significant amount of footage sped up puts that ridiculous claim to rest very quickly. Even if it did look normal, do you really think it would be possible for the astronauts to run around in those heavy suits at top speed for hours on end? They'd collapse from exhaustion in only minutes if they actually tried that.
I have an idea. Why don't you go and strap 15 pound weights to your arms and legs and put on a 35 pound backpack then try running around as fast as you can for 8 hours?
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Post by twinstead on May 21, 2007 16:00:03 GMT -4
I have an idea. Why don't you go and strap 15 pound weights to your arms and legs and put on a 35 pound backpack then try running around as fast as you can for 8 hours? Well, they DID have those lounge chairs and the buffet in the green room between takes you know
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reynoldbot
Jupiter
A paper-white mask of evil.
Posts: 790
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Post by reynoldbot on May 21, 2007 16:19:23 GMT -4
I have an idea. Why don't you go and strap 15 pound weights to your arms and legs and put on a 35 pound backpack then try running around as fast as you can for 8 hours? Well, they DID have those lounge chairs and the buffet in the green room between takes you know Oh yeah, and plus they were held up by invisible cables for most of the time by an off-camera giant puppeteer
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Post by Count Zero on May 21, 2007 20:54:01 GMT -4
it's been repeatedly shown on this and other forums that speeding up the footage only looks even the slightest bit normal (even that can be argued) in very short and selective segments taken completely out of their context. Watching any significant amount of footage sped up puts that ridiculous claim to rest very quickly. Even if it did look normal, do you really think it would be possible for the astronauts to run around in those heavy suits at top speed for hours on end? They'd collapse from exhaustion in only minutes if they actually tried that. I have an idea. Why don't you go and strap 15 pound weights to your arms and legs and put on a 35 pound backpack then try running around as fast as you can for 8 hours? No, no running. Hopping, skipping, loping and sashaying, but not running. The kinesthetics of running the way we do on Earth are impossible in 1/6th G. The closest we can come is a lope, with the motion restricted by the pressurized suit. Attention would-be fakers: Try that for hours on end.
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Post by Cavorite on May 22, 2007 1:18:04 GMT -4
I suspect that the HB response to that would be that the astronauts didn't fake the footage in a period of several hours any more than a Hollywood movie is shot in real time - that they did it one scene at a time with a break between takes.
Of course, if you take the longest continuous bits of footage (ALSEP setup?) and ask them to do it for that long, they'd probably still fail.
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