Tuesday, August 4, 2015

Physics (part 2) - Flat Earth? It depends ...

Flat Earth/Wikidpedia

Flat Earth?

That's a throwback to medieval science, isn't it?  And didn't Columbus debunk the "flat Earth" when he "discovered" America? Or so says the myth.

But actually, the ancient philosophers and learned understood that the Earth was round, at least as far back as the ancient Greeks. [reference: Who Discovered The Earth is Round?]

Today, the term Flat Earther has become an epithet for someone who adheres to outmoded beliefs and ideas. And there really exists such a groups  as The Flat Earth Society.  And they still make the case ... you guessed it ... for a flat Earth.

Some may laugh. Flat Earth? That can't possibly be.  Well, ...

It depends ....

According to Einstein and the great scientists before him, such as Lorentz and Maxwell, the length - including the "flatness" of the Earth, for example - is not absolute, but depends on your reference frame.

The video below take a serious scientific look at the flat Earth:

Indeed, our latest knowledge of physics indicate, if you are going near the speed of light, the Earth is flat as a pancake.  And that point was made about 7 minutes into the video.

Again, here are the numbers, which could be the answers to homework problems given in any college modern physics course:

* For cosmic ray protons, for example, moving at 99.9999999999991% of speed of light, the Earth only appears 17 meters thick, essentially flat

But to us Earthlings, our reference frame, the Earth is ball shaped.  Yet, to cosmic travelers zipping along near light speed, it's a flat Earth. At least in their direction of motion.

Why does length contract?

I had a physic professor who said - and rightly so - there is no answer to why nature behaves as it does. All we have are descriptions.  And that's what all those equations are about. They describe phenomenon, make predictions of their behavior, and can be reproduced with the same results.  If they fail to do so, it's back to the drawing board. (And that can be a subject of another post.)

As for length contraction, here is a mini-lecture from a modern physics class describing its observed behavior: Physics: Length Contraction

Ball or Sphere?

But what of the claims of a Flat Earth, regardless of our reference frame?  Consider the philosophy of Ockham's Razor:

The salient point is this:

"when you have two competing theories that make exactly the same predictions, the simpler one is the better."
  [reference: What is Occam's Razor? ]

Simply put. Keep It Simple. And a spherical Earth does just that.


Previous post in the series:

Physics (part 1) - Picking Feynman's Brain (2013)


Photo from: Flat Earth/Wikidpedia

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