Saturday, December 30, 2006

Warning: Gravity is “Only a Theory” - Reply

This is my reply to the previous post(this article), it became rather long so that’s why I made a new post. You sure don’t have to read it, I foremost wrote this for myself. I quickly wrote it and didn't reread so don't expect well formulated sentences eek.

I do agree with the text that textbooks should be clearer in explaining the philosophy of science. There is no such thing as absolute facts within science. This also is the only thing I agree with….

"If the theory of gravity were true, it would show that the sun's gravitational force on the moon is much stronger than the earth's gravitational force on the moon, so the moon would go around the sun." I recalculated that and the gravitational force between the sun and the moon is indeed twice as large as the gravitational force between the earth and the moon, but this does not mean that the theory of gravity is not "true".

The moon does(read: can be explained according to the simple theory of Newton) orbit the sun if we use the sun as fixed frame of reference. The moon does orbit the earth if we use the earth as our fixed frame of reference.

I actually made a model of the solar system in Java for our project with only the simple laws of Newton and within that model the moon does what it does in reality. This means that Newtons model/theory is very accurate in modeling reality and therefore is a useful scientific theory. There is not a point of accuracy within science that makes something a fact. It’s just easy to call it a fact.

“Because if the moon's “gravity” were responsible for a bulge underneath it, then how can anyone explain a high tide on the opposite side of the earth at the same time?” That sure is a good question, but it also has an answer and it can be explained using Newtons Theory. From wiki: “On the opposite side of the Earth, facing away from the Moon (the antipodal point), the water is farther from the moon than the solid earth, so it is pulled less and effectively moves away from Earth (i.e. the Earth moves more toward the Moon than the water does), rising as well.”

“astronomers, who seem to have a fetish for gravity, tell us that the moon rotates on its axis but at the same time it always presents the same face to the earth. This is patently absurd.” LOL, come on! This is perfectly possible within Newtons model. It all depends on the frame of reference, which is a very important(and hard) concept to understand within physics. You can also say that all planets and the sun orbit the moon in very weird orbits if you take the moon as fixed frame of reference, but we try to search for elegant models in physics.

“which wholly contradicts the Second Law of Thermodynamics. Since everything in the Universe tends to disorder according to the 2nd Law, orderly orbits are impossible.” The second law of thermodynamics is not so easy to explain in words. What does order and disorder mean? This again is a very difficult concept to fully grasp. I have read a good argument against this in a book by Brain Greene, but I can’t clearly reproduce it.

“This cannot be resolved by pointing to the huge outpouring of energy from the sun. In fact, it is known that the flux of photons from the sun and the “solar wind” actually tends to push earth away.” True, photons do exert a force on earth, but Newton tells us: F=m*a. Because the mass, m, of the earth is enormous, it’s change in velocity, a, is very small for a very small force F caused by photons. “For example, the observed behavior of the earth revolving around the sun can be perfectly explained if the sun has a net positive charge and the planets have a net negative charge, since opposite charges attract and the force is an inverse-square law, exactly as the increasingly discredited Theory of Gravity.” I don’t really understand this theory, but I do know that science tries to find elegant generalizing theories that cover a large part of reality. It is more general to say that all mass exerts the same force on other mass then to make the sun positive and planets negative. “According to natural law and homeopathy, everything exists in opposites: good-evil; grace-sin; positive charges-negative charges; north poles-south poles; good vibes-bad vibes; etc. We know there are anti-evolutionists, so why not anti-gravitationalists?” Go ahead and be an anti-gravitationalist, but don’t make it part of science; homeopathy is not science. It has nothing to do with the scientific method and any major scientific philosophy.

“so he invented a whole new branch of mathematics, called fluxions, just to “prove” his theory. This became calculus, a deeply flawed branch having to do with so-called “infinitesimals” which have never been observed.” Hahaha, “just to prove” lol. That’s a decent reason to invent a new branch of mathematics if you ask me. The application of Calculus is so easy to observe. Distance, velocity and acceleration are beautifully defined by Calculus. Calculus is relatively simple and so beautiful in its ability to model reality as we observe it. There is no such thing as a mechanical engineer without Calculus and I don’t think I have to explain why we need engineers ;)

Newton, by the way, was far from a secular scientist, and the bulk of his writings is actually on theology and Christianity.” True, but that doesn’t say anything about his theories.

“And even children can see how ridiculous it is to imagine that people in Australia are upside down with respect to us, as gravity theory would have it.” Huh? Does he imply a flat-earth theory?

“Adherents have a hard time explaining, for instance, why airplanes do not fall.” I can do that, like most people who have an interest in physics. If I remember correct, Bernoullis theory that more or less explains this, can be directly derived from Newtons laws.

“The theory of gravity violates common sense in many ways.” Science have shown us that the world isn’t as common as we might think. It’s a freaky weird thing that can’t be explained using common sense. “It violates common sense” is definitely no argument.

“It is not even clear why we need a theory of gravity -- there is not a single mention in the Bible, and the patriotic founding fathers never referred to it.” Why do we need it? First of all because we are curious about the world around us and we try to model that world to get a better understanding of how things might work. Second, it's this curiousity that has brought us TV, computers, Internet, cars, planes, etc,etc... Go fuck that Bible please! Thank you! Gravity is a weird thing and it is true that Newton had a hard time defining gravity, but his model is pretty neat. The arguments in this article don't focus on real problems with the Theory of Gravity.

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