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Post by jaydeehess on Feb 20, 2006 17:51:50 GMT -4
I did a search of the forums going back 100 days and did not find a reference to this. However if it has been posted before accept my apologies for doing it again. intuitor.com/moviephysics/
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Post by Kiwi on Feb 21, 2006 6:25:11 GMT -4
Thanks for that link -- I've filed it for future reference.
Just last week I was wondering whether I should buy the DVD of "The Core," mainly because Leonard Maltin gives it three stars and a good write-up. (I hardly ever go to the movies these days, and am not in a position to rent many either.) Anyway, one of our TV stations showed "The Core" last night, so I sat down to watch. It wasn't long before I thought "stupid movie" and started to wander off and do other things. Watched now and then and kept thinking, "very stupid movie," and that I definitely won't be buying the DVD.
This morning I looked up your link to see what they had to say, and it was pretty much the same as what I thought. It blows me away that Hollywood gets so unreal, when reality itself can be so intriguing. Granted, a science fiction movie like that has to take liberties with the truth, but do they have to get so absurd?
I always remember as a kid in the late 50s to early 60s, wondering why, when cannon balls hit the ground, I never saw the balls but they threw a thin column of dirt vertically into the air, with a small burst of blue smoke. It didn't seem right to me, and later I realised that this was Hollywood SFX people getting it wrong. Nowadays, of course, a cannon ball hits a wooden structure with a massive explosion and a great big conflagration of flames too. At least when I was a kid they simply smashed things they hit.
My other frustration with movies is that we rarely ever see real-looking stars. I've only ever seen recognisable constellations about five or six times.
A few months ago I happened to catch part of a New Zealand soap opera I don't usually see, and there was a scene of a couple smooching outside in the dark. They commented on the beauty of the stars, and then I was both amazed and very pleased to see a shot of Orion, with the stars twinkling naturally. I later checked my star maps and found that the angle of it was the same as after evening twilight about four to six weeks before, so it seemed that someone had taken the trouble of going outside and filming real stars instead of shooting random pinholes in black paper.
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Post by gwiz on Feb 21, 2006 8:33:56 GMT -4
I always remember as a kid in the late 50s to early 60s, wondering why, when cannon balls hit the ground, I never saw the balls but they threw a thin column of dirt vertically into the air, with a small burst of blue smoke. It didn't seem right to me, and later I realised that this was Hollywood SFX people getting it wrong. "Master and Commander" did a pretty good job on this, lots of wood fragments going everywhere but no explosions or flames. If you're into historical fiction, I can recommend the rest of the film, too.
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Feb 21, 2006 9:31:26 GMT -4
"Master and Commander" did a pretty good job on this, lots of wood fragments going everywhere but no explosions or flames. If you're into historical fiction, I can recommend the rest of the film, too. Master and Commander is one of my favorites.
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Post by snakeriverrufus on Feb 21, 2006 22:56:02 GMT -4
Thanks for the link
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Post by PhantomWolf on Feb 21, 2006 23:05:25 GMT -4
Just one minor grrrrr I tend to have. Why do people always assume that space ships are orbiting planets when they are above them? I know that this is how our ships currently do it, but if you have the fuel to manage it and want to stay at a low altitude and above a certain spot, then you have to use station keeping techniques rather than orbit. The ships seen in the battle at the start of SW 3 are obviously station keeping, not orbiting, but they still get critised for falling after a lose of power. This is exactly what would happen to a station keeping ship because its velocity is simply not enough to keep it in orbit without its engines. It would also require the ship's enegines to continue to run.
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Post by jaydeehess on Feb 22, 2006 2:11:26 GMT -4
"The Core", a truly bad movie as far as the science goes. Ranks up there with ,,, uhh, whatever the movie with Bruce Willis fending off an asteroid was.
My wife has told me not to point out the crap science in movies anymore but she knows what it means when I snort or laugh out loud.
Master and Commander was good and I too was pleased to see wildly flying shards of wood with no explosions. The scene in which an officer gets shot by an onboard Marine is true to science as well as he gets struck and just stands ther with a pained look on his face. He does not get thrown back by the force of a small round pellet to the abdomen.
KIWI, nice catch on a correct appearance of Orion.
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Post by jaydeehess on Feb 22, 2006 2:19:33 GMT -4
PhantomWolf, how quickly would a station keeping craft fall after loosing power? Dependant on altitude, I would think.
There is an exotic style of weapon that would shoot(actually , release with a slight push in the right direction) a simple dumb chunk of mass from a satellite in order to have it fall onto an enemy. the material and the geometry of the mass would be chosen to allow it to survive re-entry at the highest velocity possible and thus the KE would be equivalent to small nukes but with no fallout and little evidence even of the 'bomb'.
This is similar to a falling craft with no power.
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Post by PhantomWolf on Feb 22, 2006 9:16:03 GMT -4
PhantomWolf, how quickly would a station keeping craft fall after loosing power? Dependant on altitude, I would think.Well physics would say that as soon as the force opposing gravity was removed it would start to fall, so immediately. Whether you would notice it immediately, and whether it would tip nose down or just fall directly down is another story though.
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Al Johnston
"Cheer up!" they said, "It could be worse!" So I did, and it was.
Posts: 1,453
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Post by Al Johnston on Feb 22, 2006 11:51:40 GMT -4
Just one minor grrrrr I tend to have. Why do people always assume that space ships are orbiting planets when they are above them? I know that this is how our ships currently do it, but if you have the fuel to manage it and want to stay at a low altitude and above a certain spot, then you have to use station keeping techniques rather than orbit. The ships seen in the battle at the start of SW 3 are obviously station keeping, not orbiting, but they still get critised for falling after a lose of power. This is exactly what would happen to a station keeping ship because its velocity is simply not enough to keep it in orbit without its engines. It would also require the ship's enegines to continue to run. I think what most people criticized about the opening battle in Revenge of the Sith, was the way that Grievous' ship tipped over on one end and everything within it slid to that end, as if the external gravity had more influence than the onboard artificial gravity.
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Post by iamspartacus on Feb 22, 2006 12:26:29 GMT -4
I think what most people criticized about the opening battle in Revenge of the Sith, was the way that Grievous' ship tipped over on one end and everything within it slid to that end, as if the external gravity had more influence than the onboard artificial gravity. I think it was supposed to be the onboard artificial gravity that was swinging about. In Matthew Stover's "Revenge of the Sith" (the book of the film of the screenplay and original story by George Lucas) he writes, "Before Anakin could answer, the erratic gravity swung like a pendulum; while they both clung to the railing, the room seemed to roll around them."
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Post by thestargazer on Feb 23, 2006 9:28:45 GMT -4
On explosions, I can tell you that saving private ryan and Full Metal Jacket are the only two films to get bullet sounds right. If you hear them coming it, it's like a zipper sound followed by a flat dull "smack" when they hit things.
Inside (esp. in a largely concrete structure) it's a flat slapping sound as a weapon is fired.
I have friends in the two "industries" concerned: filmmaking and the military. Since I've had firefights described to me first-hand, movies - even those with good stories - where combat noises are all "PWEEON! PWEEON! artilleryBOOM!" for gunfire just fall flat.
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Al Johnston
"Cheer up!" they said, "It could be worse!" So I did, and it was.
Posts: 1,453
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Post by Al Johnston on Feb 23, 2006 12:48:56 GMT -4
And as rifle bullets are supersonic, mostly you don't. David Niven in his autobiography was quite emphatic: "They go CRACK!" Presumably the sonic boom after they've missed...
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Post by jaydeehess on Feb 23, 2006 23:45:28 GMT -4
PhantomWolf, how quickly would a station keeping craft fall after loosing power? Dependant on altitude, I would think.Well physics would say that as soon as the force opposing gravity was removed it would start to fall, so immediately. Whether you would notice it immediately, and whether it would tip nose down or just fall directly down is another story though. Bad phrasing on my part. I have been in a small aircraft that had one tank run dry(DeHavilland Beaver) and the engine sputtered out. The plane immediatly nosed down and started going down. No surprise, and no biggee since we were 8,000 ft agl. The pilot quickly switched tanks, pumped the primer and restarted the engine(though I would have preferred he switched over prior to runing dry one tank). A craft holding station above the earth would have gravity pulling down on it but would not suffer drag and loss of airspeed and thus loss of lift that the aircraft did. That leads me to believe that the spacecraft would start plummeting faster than the aircraft except that the accelleration due to gravity would decrease the further from the surface it is. Thus my questioning. Would the vertical accelleration I felt as the plane nosed down be less, or more, than that in a spacecraft at say 150 miles up?
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Bob B.
Bob the Excel Guru?
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Post by Bob B. on Feb 24, 2006 1:15:53 GMT -4
Would the vertical accelleration I felt as the plane nosed down be less, or more, than that in a spacecraft at say 150 miles up? If I understand the scenario correctly, we have a spaceship stationary above the Earth holding its position by thrusting downward. Is this correct? In this case the astronauts would be feeling gravity just like they would if they were standing on Earth, except at an altitude of 150 miles the force is only 0.93 g. If the thrusting ceased, then the spaceship would immediately begin to fall straight down just likely dropping a rock. At this time the astronauts would be in free-fall and therefore experiencing weightlessness.
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