Orestes wrote:Fucking nerds. I'm angry that I don't understand any of the above discussion.
The reason why earlier I asked about Leonardo is because he's mentioned in this article I've been reading, which argues against seeing Renaissance as that big of a breakthrough in scientific thought.
Also, all of the lists lack the Person of Jesus Christ - the greatest scientist of the human heart.
Speaking of debunking historical myths, and to get the thread back on topic.
Aristotle's physics is very interesting and partially correct. I've been trying to work out some of it in modern mathematical terms and doing so is really hard for very non-trivial reasons.
For example, it would seem that Aristotle was saying that effectively F = mv, since that equation would imply an absolute frame of rest. But the more you think about it, the less sense it makes. Except when you also consider the possibility that his physics not only requires an absolute frame of rest but also an absolute coordinate system. With that in mind, you can assume the newtonian definition of force, F_net = ma, but that there is always a resistive medium filling space. The resistance of this medium increases as you approach the center. This comes from the idea that the natural place of Earth (the densest medium) is below that of water (which is less dense) which in turn is below the natural place of air (even less dense) which is finally below the natural place of fire (the lightest medium). In that case, the force law becomes F_net = ma = F - hv, where h is the resistance of the medium.
Solving this equation for the velocity of a free particle gives v = v_0*Exp[-h(t-t_0)/m]. So a heavier object falling to the Earth with nonzero initial velocity will fall faster than a lighter object with the same velocity. Furthermore, it will slow down exponentially as it falls.
This is exactly what happens for objects falling through air (as opposed to vacuum). Error. See below. But from this discrepency one could deduce the existence of a force of gravity.
Now, if we assume that the resistance of the Earth is infinite, then, when the object hits the Earth its velociy goes to zero, exactly as observed.
EDIT: Actually, for the case of falling object you also have to take the force of gravity into account. Then, the equation of motion becomes ma = -mg - hv, and the solution is, the remarkably simple v = -mg/h. So an objet will fall to the Earth at a constant speed that is directly proportional to its mass (or rather weight = mg, which is the quantity that Aristotle refes to), and inversely proportional to the resistance of the medium. Thus, in Aristotle's physics, transitory acceleration phases disappear, and all objects fall at their terminal velocity. It also follows that vacuum cannot exist, since zero resistance would imply infinite velocity for a falling body.
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