Paradoxes and Dilemmas

Jeremy
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21 years 10 months ago #3987 by Jeremy

Replied by Jeremy on topic Reply from

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
Then I like to congradulate you for inventing a massless car speedometer. I like to see something like that. Maybe then I can understand how to make a square out of a circle or even how to take derivatives of S without resorting to the concept of infinity or zero that Patrick is concerned with.
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The point I was trying to make was that your definition of velocity as a list of dimensional parameters is handy but doesn't substitute for understanding. No physicist I know would define velocity by throwing mass into the description or teach his students without starting with V = L/T for UNDERSTANDING. I don't recall making any comments about infinity or zero but I'll take the standard mathematical treatment of them over the Pythagorean way of thinking that Patrick uses.

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
I have a suggestion for you. Read first. Read well to understand that what you take for granted today, like 1+1=2 and V = ds/dt, have been debated for such a long time and NO rigid solutions or answers exist. Texts avoid the issues, the same way they avoid the action on a distance notion of Newton. Texts are intellectual garbage written, or better copied, one from the other.
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I read quite a bit actually and I dare say that there are not hoards of engineers and scientists waking up in the middle of night troubled by the validity of 1+1=2, perhaps you are a victim of a new kind of phobia. Texts are intellectual garbage? Surely not the ones you read of course.

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
I can define speed anyway I want:

speed= unicorns/temporals and mass = fatso

I can build a whole physics around this and NO ONE will be able to challenge it in lieu of anything else since it will work.
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Give me a break. The speedometer in my car can be adjusted to count nonexistent unicorns and still give me a reliable readout so that I don't get a speeding ticket? Think I find V = L/T far more credible than what you've just given me.

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
...I can even go further and challenge your basic perception of the world, which is just your perception and you cannot even know if the person sitting next to you has the same perception.
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This is pure solipsistic nonsense. If I am a figment of your imagination than why even respond to me? The fact that human mental states are roughly similiar is proven by a consistent body of experimentation that shows people reacting similarly to similar phenomena. Human factors engineers do this for a living. You and I couldn't even communicate using this messageboard without pretty good correspondence of internal world views of the meaning of the words that we are using. Do you think it is pure randomness that people can speak and understand one another?

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Read the posts carefully. Do it several times. Before you blast out ink to gain posting momentum understand what it is written there.
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This is nothing more than the appeal to authority that you were deprecating. How am I to regard a response that I am just gaining "posting momentum"? You have a much higher output of verbiage on this board than I do. What about your "posting momentum"?

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
NO ONE claimed that C is not the speed of light. Patrick claimed C^2 may also be speed. That is wrong in the current system of defining dimensions. It may be right in another system in which dimensions are structured in such a way as to allow C^2 to be speed. That system may not be practical or realistic. That's not the point.
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That IS the point Makis, you can't just invent bizarre concepts that are different from everything that one works with without carefully defining your terms and making a decent argument for them. There is nothing that justifies calling C^2 a velocity other than a basic conceptual error which is all that Patrick is guilty of. You know better, what is your excuse?

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
When Lobochevsky proposed an alternative geometry, many laughed. It took several generations and hard work to prove that his system is consistent
and actually both Euclidean and Lobachevsskian geometries are both consistent:

Euclidean: Given a line and a point not on the line there exist one and only one line through the point parallel to the line.

Lobaveskian: Given a line and a point not on the line, there exist at least two lines through the point that are parallel to the line.

Does this latest statement maybe violate your basic understanding of the world you think you perceive as such?
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Not really, all it shows in my mind is the degree to which mathematicians don't concern themselves with what occurs in reality. Obviously only one of these geometries can physically exist since they are mutually incompatible. This simply is a good example of how one cannot examine the universe through pure metaphysics but must go out and see what it actually does.

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Because of that you will call Lobavesky a metaphysician and make a naive joke?
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No, Lobachevsky made an important mathematical discovery akin to what Godel did in showing the limits of mathematical deduction. I really don't have any idea of whether he regarded his geometry as being real or just a head game. If he thought it was real then further research into Euclidean geometry would be pointless wouldn't it?

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
You better save the jokes my friend if you lack basic knowledge of what's the story in physics and math. That's what is a joke, the metaphysician did the right thing because he was honest. Being honest is better that being ignorant, or an "infidel mathematician", as many of his times called Newton, your inventor of Calculus and physical units, everyone accepts as universal truths today.
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I would say that getting practical results that conform to reality are more important than endless philosophical discussions about whether reality is real. The engineers seem to produce useful results like cancer drugs and automobiles using their biased garbage textbooks and 1+1=2; whereas I am unawa

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tvanflandern
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21 years 10 months ago #3947 by tvanflandern

Replied by tvanflandern on topic Reply from Tom Van Flandern

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>Why isn't earth going right into the moon? I understand that if the moon has appropriate velocity, the pushing action on it will create a central force that will result in an elliptical or circular path. But with respect to the moon, earth is stationary and also receives a pushing force (or pulling in the case of Newton). Wouldn't that force make earth move? What would stop earth from falling right on the moon? Is there another medium in between that prevents that?<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

The Moon has a velocity relative to the Earth, which means the Earth has the same relative speed, but opposite direction, relative to the Moon. So Earth is not "stationary with respect to the Moon".

Moreover, both Earth and Moon move relative to the "Earth-Moon barycenter", which is in effect the center of mass between these two bodies. The period of this motion is identical -- 27.3 days. The Moon's orbit around the barycenter has a radius of nearly 400,000 km, whereas the Earth's orbit around the barycenter has a radius of about 5,000 km (because the Moon's force is much weaker). The latter radius is a but less than Earth's radius, so the Earth-Moon barycenter is always inside the physical body of the Earth.

More generally, chapter 6 of Dark Matter, Missing Planets and New Comets explains why bodies orbit at all, why planets do not fall into the Sun, etc.

In connection with Pushing Gravity, it is useful to note that there is no difference between the predictions of LeSage-type pushing gravity and Newtonian pulling gravity until one gets into very small effects, such as possible gravitational shielding (different from "shadowing") or the finite speed or range of LeSage gravity. -|Tom|-

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tvanflandern
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21 years 10 months ago #3948 by tvanflandern

Replied by tvanflandern on topic Reply from Tom Van Flandern

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>I understand why planets do not fall into the sun. What I do not understand is why the sun is not pulled right onto the planets.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

If the planet moves relative to the Sun, then the Sun is moving relative to the planet. So the direction to the planet keeps changing. That, in turn, causes the direction of the force to keep changing.

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>I specifically do not care about the barycenter concept. It was used by Newton to "cheat" on kepler's third law. Please let's not introduce fanthom points, exactly the same point you were making regarding phantom units.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

Good instincts. The barycenter is almost always a "red herring", much like "pseudo-forces". But I was not sure which motion you were speaking about.

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>In the case of pulling gravity, there is a force from the planet on the sun. Newton's second law says that in the presence of a force, a body moves with appropriate acceleration towards the direction of the force. It does not matter how small the force is. In the case of earth, that force causes changes of orbital velocity directed towards the center of forces, resulting in a centripetal acceleration that keeps the earth around the sun. What is the motion of the sun in reference to that force? What stops the sun from moving and increasing it's velocity towards earth? If the force is attractive, every time the sun got "an impulse" from the earth it should move in some fashion, otherwise, Newton's second law is violated.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

In December, Earth pulls the Sun toward Gemini. In June, Earth pulls the Sun away from Gemini, reversing the previous fall of the Sun in that direction. Because one force ends up canceling the other, there is no net fall toward Earth after one year.

Instead, the Sun also orbits, but its orbit is miniature because the forces acting on it are so small. From Earth alone, the Sun falls only 500 km before that fall gets reversed, so the radius of the Sun's orbit around Earth is only 500 km (out of 150,000,000 km distance between them).

If Earth were held in place, perhaps by taut ropes from distant quasars, and the Sun had no transverse motion relative to Earth, it would indeed fall onto the Earth. But whereas Earth could fall into the Sun in just over two months, the Sun would take more than a century to fall onto a fixed Earth because Earth's pull is so much weaker. So the Sun doesn't get very far at all before the real Earth dances off into some other direction and starts to reverse the pull that has already happened. -|Tom|-

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AgoraBasta
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21 years 10 months ago #4362 by AgoraBasta

Replied by AgoraBasta on topic Reply from

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>The barycenter is almost always a "red herring", much like "pseudo-forces".<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>Sure. But it's still a usefull concept. It's actually a kinda "partial centre of masses", so that you can always consider a barycenter of only a few masses of a system instead of counting them all for centre of masses.

(sorry for interrupting)

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tvanflandern
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21 years 10 months ago #3988 by tvanflandern

Replied by tvanflandern on topic Reply from Tom Van Flandern

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>it's still a usefull concept. It's actually a kinda "partial centre of masses", so that you can always consider a barycenter of only a few masses of a system instead of counting them all for centre of masses.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

I agree that the barycenter is useful to establish a reference point with zero or constant momentum. However, attaching physical significance to it will quickly get one into trouble.

For example, consider the solar system barycenter which is sometimes inside and sometimes outside the physical body of the Sun. Now add Alpha Centauri (AC) to the dynamical system. AC is too far away to have any detectable gravitational effect on the Sun or any planets in our lifetimes. Yet the barycenter would be shifted completely out of the planetary region, roughly half way to AC. -|Tom|-

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AgoraBasta
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21 years 10 months ago #3949 by AgoraBasta

Replied by AgoraBasta on topic Reply from

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>For example, consider the solar system barycenter which is sometimes inside and sometimes outside the physical body of the Sun. Now add Alpha Centauri (AC) to the dynamical system. AC is too far away to have any detectable gravitational effect on the Sun or any planets in our lifetimes. Yet the barycenter would be shifted completely out of the planetary region, roughly half way to AC. -|Tom|-<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>A thing is useful just as long as it's appropriately used, I fathom. <img src=icon_smile_big.gif border=0 align=middle>

Hope you had a Merry Xmas and wish you a Happy New Year!

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