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Science and Technology "Somewhere, something incredible is waiting to be known." - Carl Sagan.

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Old September 15 2012, 08:50 AM   #31
RB_Kandy
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Re: About planetary gravity

sojourner wrote: View Post
Piece of advice. Youtube is NOT the place to learn new "theories".
Well it can't be worse than everything on The History Chanel being about Aliens. Did you know, every historical event we've ever had, might have had extra terrestrials?

Is there any reason why this new theory doesn't work?
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Old September 15 2012, 09:08 AM   #32
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Re: About planetary gravity

RB_Kandy wrote: View Post
sojourner wrote: View Post
Piece of advice. Youtube is NOT the place to learn new "theories".
Well it can't be worse than everything on The History Chanel being about Aliens. Did you know, every historical event we've ever had, might have had extra terrestrials?

Is there any reason why this new theory doesn't work?
I wouldn't call it a theory, I'd call it a brain fart with really dramatic music.

I assume you know quite well how your car engine works. The pistons go up and down (or at some angle if you have a V engine, or sideways if you have a horizontally opposed engine). Your crankshaft is then driven in a purely circular motion, centered on the crankshaft main bearings mounted in the engine block. That drives your cam sprocket (for an overhead cam) or lifters, and also your fan belt, and possibly accessory belts.

That's what you think you know. (insert dramatic music with chanting choir). Once you take your car out on the road, those motions are false, because your pistons are moving up and down as you travel down the highway at 88 mph, so they're sine waves, and your crankshaft turns in a helix. But then you go around a turn, so the motion is even more complex! And as you go around a turn, your car tilts a little, and then you hit a bump.... So the crankshaft bearings can't possibly explain the incredibly intricate curve followed by the crankshaft, and thus can't explain the motions of the pistons, much less the intake and exhaust valves.

There must be unknown, magical forces at work.

Or a complete idiot making videos with really cool, ominous choir music.

ETA: I think the trouble your having is with seperating motions based on influences. When a body is subject to gravity, it accelerates, as does everything around it, since those things are subject to the same gravitational field. If you were holding hands with a bunch of people in a space ship and gravity suddenly changed, you'd still be holding hands, and wouldn't even notice any tugs or yanks, and wouldn't notice any forces from the floor or ceiling, because the spaceship would feel the same pull.

You, your friends, the ship, and your breakfast trays are all moving together, and though your course might change due to gravity, it affects all of you at the same time, and all equally, so that you actually have absolutely no way to detect that anything changed.

This is different from a car on a bumpy road, a train going around a curve, or an airplane flying trhough turbulence, because in those cases an external force was applied externally to wheels or wings, not to the occupants directly, so they slam into the seats or doors. Gravity isn't like that.
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Old September 15 2012, 09:41 AM   #33
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Re: About planetary gravity

Christopher wrote: View Post
^Just try to imagine learning sex education from a sardonic, middle-aged mortician who sounds like Fat Albert's Mushmouth without the speech impediment.
Hey, my Sex Ed teacher told us that the only people who masturbate are homosexuals. Kind of a weird thing to hear as a 12-year old.
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Old September 15 2012, 10:13 AM   #34
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Re: About planetary gravity

Re Betsy Ross myth: that she made the first American flag, which, like so many historical legends, fails to tell the interesting actual story of people in favor of a mythologized version of events.
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Old September 15 2012, 11:24 AM   #35
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Re: About planetary gravity

RB_Kandy wrote: View Post
First, I would like to start off by explaining that my school was a very stupid school that made no effort to educate.
We noticed.
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Old September 15 2012, 12:58 PM   #36
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Re: About planetary gravity

Was that necessary?
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Old September 15 2012, 03:54 PM   #37
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Re: About planetary gravity

Probably not.
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Old September 15 2012, 06:56 PM   #38
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Re: About planetary gravity

RB_Kandy wrote: View Post
Is there any reason why this new theory doesn't work?
Well, the easiest way to point out that it's wrong is the fact that all the planets orbiting our sun are on the same elliptic plane as the galaxy. Not perpendicular as the video shows it. That's the point where you can stop the video and dismiss it entirely.
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Old September 15 2012, 07:02 PM   #39
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Re: About planetary gravity

RB_Kandy wrote: View Post
It's like learning HTML, skipping the year they teach you Java, and going right to PHP and MySQL, and it is assumed you know Java. You'd never pass, because every time they'd ask you to write a Java script to defer to the MySQL data base, you'd just sit there like WTF!?
Java != Javascript
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Old September 15 2012, 07:21 PM   #40
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Re: About planetary gravity

sojourner wrote: View Post
Well, the easiest way to point out that it's wrong is the fact that all the planets orbiting our sun are on the same elliptic plane as the galaxy. Not perpendicular as the video shows it. That's the point where you can stop the video and dismiss it entirely.
Sorry, but that's not right. The ecliptic plane (the plane in which the Earth orbits the Sun) is tilted at 60.2 degrees relative to the galactic plane. It's closer to perpendicular than parallel.

The video is basically right about its facts, but completely wrong in how it interprets them. The key is to understand that all motion is relative, and how the motion of an object is perceived depends on what frame of reference you're observing it from. For instance: Imagine you're sitting on a moving train, playing with a yo-yo. From your perspective, it looks like the yo-yo is moving straight up and down, because you're defining your coordinate system relative to the train itself. But to an outside observer standing in the station and watching the train go by, it looks like the yo-yo is moving in a sine-like wave, not just moving up and down but moving sideways. That's because that observer is defining her coordinate system relative to the station, which isn't moving with the train. Which one is right? Both of them are! It all depends on how you're measuring it. There is no frame of reference that's more right than another.

This is the exact same situation. If you're standing still relative to the Sun and watching the planets go around it, you see them following elliptical paths. But if you're in a different coordinate system, say, one that's motionless relative to a distant galaxy, then you see the Sun moving in its orbit around the center of our galaxy and the planets moving around it at roughly 60-degree angles (since the different planets are all in slightly different orbital planes, not perfectly in the Earth's ecliptic). So if you drew out their paths in that frame of reference, they would be lopsided helices (not spirals, since a spiral is a path that increases in radius as it goes around; a helix is more like a Slinky, maintaining its radius but changing position perpendicular to that, or nearly so).

But this is a trivial distinction, because both are equally correct ways of defining the motion. The only difference is in what coordinate system you're using. And changing the coordinate system does not invalidate the underlying physics. The planets are still being drawn toward the Sun by its gravity, and the combination of that attraction and their momentum produces the paths we observe. You get that same result regardless of which coordinate system you use and how you define their motion. It's just that choosing a coordinate system that treats the Sun as motionless is the simplest way to solve the equation, because that way you get to ignore terms (like the effect of the galaxy's gravity on both the Sun and its planets) that would cancel out of the equation anyway and don't make any difference to the result.

So this video makes a common mistake of a lot of Internet charlatans -- taking some scientific facts that are basically correct in isolation, yet completely failing to understand how to interpret their meaning.
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Old September 15 2012, 08:19 PM   #41
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Re: About planetary gravity

^ People have trouble thinking about motions in space, since they're used to having a nice stretch of terra firma as their absolute reference.

They know that when they roll their car, the bystanders, sidewalks, and trees aren't really aren't spinning around in crazy circular paths, their head is.

People can think of their airplane flight as the Earth falling away, tipping up at an angle, moving way down, spinning slowly around as they line up on the runway, then coming back up to kiss the plane's wheels as they land, but they know that's not a good way to describe things. But in an aircraft centered coordinate system, that's actually a pretty good way to think about it, where the pilot can work to keep the planet level, not the plane, and it's equally valid.

I wonder if we should tell him about shooting a monkey with a blowgun, and how changing a reference frame can turn mathematically difficult problems into trivial ones?
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Old September 15 2012, 09:12 PM   #42
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Re: About planetary gravity

Christopher wrote: View Post
sojourner wrote: View Post
Well, the easiest way to point out that it's wrong is the fact that all the planets orbiting our sun are on the same elliptic plane as the galaxy. Not perpendicular as the video shows it. That's the point where you can stop the video and dismiss it entirely.
Sorry, but that's not right. The ecliptic plane (the plane in which the Earth orbits the Sun) is tilted at 60.2 degrees relative to the galactic plane. It's closer to perpendicular than parallel.
Well, that's one on me.
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Old September 15 2012, 10:26 PM   #43
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Re: About planetary gravity

^ When you view the night sky, the Milky Way is all cockeyed to the ecliptic where the planets and moon travel.
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Old September 15 2012, 10:48 PM   #44
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Re: About planetary gravity

Technically, only the Earth travels in the ecliptic plane. It's called that because it's the plane where eclipses happen, where the Moon passes directly between the Earth and the Sun -- which, naturally, would correspond to the plane of the Earth's motion around the Sun. Naturally the Moon doesn't orbit exactly in the ecliptic (it's off by about 5 degrees), or there'd be a solar eclipse every four weeks and a lunar eclipse midway between each one. And all the other planets' orbital planes range from about 3/4 of a degree (Uranus) to over 7 degrees (Mercury) off of the ecliptic.
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Old September 15 2012, 11:23 PM   #45
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Re: About planetary gravity

Reading this thread i'm actually frightened to see how other school systems educate their kids

I know that teachers are still humans and you get good ones and bad ones ( i once had a teaches in French who was unanimously voted as the worst teacher in school but he still was very good at French.. he just sucked as a person) but i never encountered a stupid teacher.

Honest to god.. if this was the standard i could sit myself in these classes and teach from the get go and i'm almost 20 years out of school and have forgotten much about the details of science (especially the math).
Would probably need a few weeks to brush up again.
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