Saturday, February 14, 2015

Physics behind airplanes vs rockets

Fr. Cedric makes common mistake of conflating physics behind airplane motion, i.e. Bernoulli's equation, with that of rockets, i.e. Newton's 2nd law of Motion:

Father Cedric: All the possibilities. Think about airplanes. A hundred years ago, nobody flew. We've been to the moon and back many times. This is the world that we live in. I remember what Fulton Sheen said about TV. I'm fascinated by TV.  I love to watch it. I'm so glad I get to reach out to people on TV.  And Fulton Sheen said, "that some say  that we live in the atomic age." But he said, "We live in the age of television. Newton knocked out the boundaries of space.  Einstein knocked the boundaries out of time. But television has annihilated space and time." And I love TV because what a way to reach out.

Bishop Sheen quote can be found in Ladd, Gregory J. Archbishop Fulton J. Sheen: A Man for All Media. San Francisco: Ignatius Press, 2001. Print.

"Our era has been misnamed the 'atomic age': it is rather the 'television age.' Television influences human brains a thousand times more than the fission and the fusion of atoms.  Television is the newborn babe of the Fourth Dimension of Space-Time. Newton knocked the boundaries out of space; Einstein knocked the boundaries out of time, but television has annihilated space and time."  

I appreciate Bishop Sheen was speaking metaphorically, but his metaphysical analogy isn't apt because he inaccurately summarizes the contributions of Newton and Einstein, but I'll address this in a later post.

Rocket propulsion uses Newton's 2nd Law of Motion: Law of Conservation of Linear Momentum, and thus can operate in the vacuum of space. From a standard introduction to physics text:  Serway, Raymond A., Robert J. Beichner, and John W. Jewett, Jr. Physics For Scientists and Engineers. Fifth ed. New York: Saunders College, 2000. 

Conversely, aeroplanes operate under Bernoulli's principle and require the presence of a fluid, as scientists would say, or air, as common folks would, and thus planes can't fly in the vacuum of space:

Additionally, whilst on physics, the moon is neither a planet nor a star but is a natural satellite. Even Dish Nation goofs on the lack of scientific knowledge of their home shopping network compadres:

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