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Roger's Equations

This blog is all about science and technology (with occasional math thrown in for fun). The goal of this blog is to try and pass on the sense of excitement and wonder I feel when I read about these topics. I hope you enjoy the posts.

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Absurd Geometry by Roger Pink

Posted February 19, 2014 2:39 PM by Bayes

Menger Sponge

The Menger Sponge has an infinite surface area and yet has zero volume.

The construction of a Menger sponge can be described as follows:

  1. Begin with a cube (first image).
  2. Divide every face of the cube into 9 squares. This will sub-divide the cube into 27 smaller cubes.
  3. Remove the smaller cube in the middle of each face, and remove the smaller cube in the very center of the larger cube, leaving 20 smaller cubes (second image). This is a level-1 Menger sponge.
  4. Repeat steps 2 and 3 for each of the remaining smaller cubes, and continue to iterate ad infinitum

Koch snowflake

The Koch snowflake has infinite circumference yet finite area.

The Koch snowflake can be constructed by starting with an equilateral triangle, then recursively altering each line segment as follows:

  1. divide the line segment into three segments of equal length.
  2. draw an equilateral triangle that has the middle segment from step 1 as its base and points outward.
  3. remove the line segment that is the base of the triangle from step 2.

Gabriel's Horn

Gabriel's Horn has infinite surface area yet finite volume.

How to construct Gabriel's Horn.

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#1

Re: Absurd Geometry by Roger Pink

02/19/2014 9:59 PM

Just a few more examples of how not using actual numbers in mathematics causes problems with how things fit into reality.

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#2

Re: Absurd Geometry by Roger Pink

02/19/2014 10:52 PM

Unfortunately the described method for making a Menger sponge will never yield zero volume, even with an infinite growth in surface area.

Continually subtracting any given percentage ratio apart from 100% can never result in zero- just a proportionately lessening convergence.

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#3
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Re: Absurd Geometry by Roger Pink

02/20/2014 12:07 AM

I think you can argue the exact opposite as well...that you will never get an infinite area with a proportionately expanding divergence.

Jon.

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#4
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Re: Absurd Geometry by Roger Pink

02/20/2014 7:12 AM

True but it will take forever to prove it!!!

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#5

Re: Absurd Geometry by Roger Pink

02/20/2014 9:45 AM

Looks like Fractal Geometry.

Which Benoît Mandelbrot is a pioneer. Of which we own allot to for entertainment such as animated graphics among other things.

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#6

Re: Absurd Geometry by Roger Pink

02/20/2014 10:42 AM

Do these things really have infinite surface area or circumference?

When the phrase ad infinitum is used to describe the construction it takes it away from reality. It's not possible to do any of the steps to infinity from a time perspective. Furthermore, one can not do it from a physical perspective because at some point you are at the atomic level and you begin to split atoms and deal with fractions of atomic size.

In the end, you do end up with something finite.

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#7
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Re: Absurd Geometry by Roger Pink

02/20/2014 11:02 AM

There's fields of mathematics that can take these to their convergence and prove what Roger is presenting.

Once you get to the atomic level you transfer to the mathematicians' universe where they all walk around with long capes and hoodies and mutter about partial derivatives and triple integrals and the limits as N approaches infinity....

Jon.

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#8
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Re: Absurd Geometry by Roger Pink

02/20/2014 11:07 AM

And that's kind of my point. It's only a mythical world where it exists. But it's presented to us and others in the non-mathematical world as something real (horn or box or star or whatever) with finite this but infinite that. It's only a mental construct, not something real.

Don't get me wrong, I think these things are cool, interesting and have a place.

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#9
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Re: Absurd Geometry by Roger Pink

02/20/2014 12:46 PM

But the real world is annoyingly populated with theoretical building blocks.

How long is a coastline? Putting aside the shear impossibility of two "points" in the real world, the answer depends on the resolution of your measurement. If you trace the outlines of all the sand grains at the water's edge (assuming an artificially static interface), you'll get a number much higher than taking a straight-line path.

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#15
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Re: Absurd Geometry by Roger Pink

02/21/2014 12:21 AM

You would have to put an imaginary sea level in there first. Last I looked the ocean moved around a fair bit!

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#10
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Re: Absurd Geometry by Roger Pink

02/20/2014 3:08 PM

It's only a mythical world where it exists.

If its a fractal, I have to disagree, What I understand Fractals are in nature......

And to answer Lynn W. here is Fractal Dimension of Coastlines with the accuracy is determined by the number of iterations in this case (∞) infinity number of iterations would do it.

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#11
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Re: Absurd Geometry by Roger Pink

02/20/2014 6:18 PM

I disagree.

Even if it's fractal, it's still finite in that as you zoom in on the coastline you will get to the point that your scale is on the atomic level and you will now be dealing with discrete points as opposed to distances that can be zoomed in on. The practical implementation is that we are not able to measure any smaller than a certain value. Are there things smaller than the smallest thing we know of? Possibly, but we don't know. Is it possible to find such a thing? Maybe, be again we do not know.

My point is that even in nature, the leaf or coast line still has a finite number of atoms which make it up.

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#12
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Re: Absurd Geometry by Roger Pink

02/20/2014 6:28 PM

True

Than not use infinity amount of iterations, and use the among of iterations necessary to match our capacity to be able to measure.

And as our ability to measure to a smaller value, add to the iterations,..... Because we do have an infinity amount.

;)

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#13
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Re: Absurd Geometry by Roger Pink

02/20/2014 6:31 PM

Ow...that made my head hurt.

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#14
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Re: Absurd Geometry by Roger Pink

02/20/2014 6:44 PM

I edited post #12 using my iPad and accidentally dragged my finger across 'post anon'

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#17
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Re: Absurd Geometry by Roger Pink

02/21/2014 10:53 AM

I knew that was you.

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#16
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Re: Absurd Geometry by Roger Pink

02/21/2014 10:36 AM

Then zoom in further, inside the electron cloud and the nucleus. Then to the subatomic level. I may be wrong, but I think the latest LHC results indicate that we still can't say we've measured the smallest thing(s) in existence.

Reality is an approximation. (c)

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#18

Re: Absurd Geometry by Roger Pink

03/03/2014 11:15 PM

The fact that ''Gabriels' Horn'' has finite volume but infinite surface area merely points to the fact that taking the limit of something out to infinity demonstrates that there is a flaw in the logic of doing so. Otherwise, they would both be equal quantities.

Starting with the fact that ''infinity'' is that which can never really be reached...

(except by Buzz Lightyear who does reach it, but keeps coming back, so he says...)

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