Did Man Invent the Straight Line?

[notmydesk]

Are there straight lines in nature? Or did man have to invent one? And if so, how did he know it was straight with nothing straight to compare it to? And what was the first straight line that was invented, exactly? And when? Huh?

[According to Pliny]

I suppose even an ape could pull a strand of hair taut and create a straight line.

[Czarcasm]

Of course Man invented the straight line. Do any other species tell jokes?

[Polycarp]

A straight line is the shortest distance between two puns.

Did you by any chance ever run into Spider Robinson's science fiction novel Lifehouse in which this precise question is asked with the connotation implied in these posts. (I.e., as seen by the character, the Universe is God's "setup" for the ultimate joke.)

[Nickrz]

To which of Cecil's columns does this question refer?

[notmydesk]

Oh crap. I'm sorry, I guess I posted this in the wrong section. I didn't have any particular column in mind. Sorry!

nmd

[JillGat]

[[Oh crap. I'm sorry, I guess I posted this in the wrong section. I didn't have any particular column in mind. Sorry!]]

I can move it if anyone wants me to.. I'm guessing there isn't much more to say about it anyway? Let me know.
Jill

[JillGat]

Moved from "Cecil's Columns" forum to here.

[Crafter_Man]

While nothing in nature is *perfectly* straight, there are things that approximate straightness over a short distance, including:

* Light ray
* Surface of water (or any liquid)
* A hanging rope with a weight tied to it


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Crafter
Dayton, OH

"Don't be so open-minded your brains fall out."
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[pluto]

Some crystals which occur naturally have straight lines and planes. Large examples are rare but smaller ones are plentiful.

Any view of the horizon over water would be, for all practical purposes, a straight line.

That said, one of the characteristics used by military radar systems to detect man-made objects is the existence of planes and angles. These are so rare in nature that detection of them is the defining criterion for man-made vs. natural objects.

Pluto
Bombs 'R Us

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"non sunt multiplicanda entia praeter necessitatem"
-- William of Ockham

[ChiefScott]

A straight line is the shortest distance between two points.

We live in a three dimensional world.

Everything occurring in nature has length, width and depth.

A line is purely theoretical since it has no width or depth. It only has length.

Mankind "created" the straight line.

[NanoByte]

Does a straight dope have any width? Breadth? Girth? Or is it purely theoretical. . .all real dopes being somewhat distorted?

Ray (Lost my geometer.)

[Steve-o]

I was watching Animal Planet this morning, and saw the eyes of an octopus. Sure, I’ve seen an octopus before, but never a close-up of its eyes. If they ever show any close-ups of any of its parts, it’s always its mouth, or its tentacles. The eyes were amazing. The pupils were “perfect” horizontal rectangles. Four 90 degree angles, and straight lines between them. Does anyone know of any other animals with similar pupils?

I made this post in this old thread because I also want to know about straight lines in nature, and didn’t want to create two threads that could be covered in one. If anyone knows of any others not listed here… well… list them please.


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Things are random only insofar as we don’t understand them.

[handy]

There really is no such thing as a straight line dude.

There is only a collection of dots giving an appearance of such.

[Dystopos]

some 'apparent' straight lines occuring in nature (all could be argued, but the theoretical invention of 'straightness' for the purposes of measuring distance and 'geometrical linearity' for the purposes of mathgematic ideals could be widely separate endeavors)

the segments of a tight spider web
the cleft surface of slate
the sunbeams through the clouds
some of your more rigourous tree trunks
the path of a rolling snowball on a smooth berm
a fold
a meteroite
a daddy long-legs' legs
a bee-line (?)
any thread or filament pulled taut
a frozen lake
the pull of gravity

more?

[rowrrbazzle]

A stretched cord is not theoretically straight because gravity always pulls it a little.

The first linkage capable of perfectly converting circular motion into linear motion (and therefore capable of drawing a theoretically straight line) was invented in 1864 by a Frenchman named Peaucellier.

He knew the motion was perfectly straight because he used geometry to prove it.

There are a number of pages on the web related to this. Here's a page that has an interactive demonstration.
http://forum.swarthmore.edu/sketchpa..._linkages.html

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...this is another Moebius sig...b!s sn!qaoW jay+oue s! s!y+...
(adaptation of a WallyM7Sig™ a la quadell)

For business reasons, I must preserve the outward signs of sanity. - Mark Twain

[KarlGauss]

The straight line is but one example of a whole host of ideals that seem NOT to be present in nature. Things like perfect triangles, circles, etc. don't exist in nature.

Even the concepts of one, two, etc., seem not to be present in nature - what you see as a "oneness" is a matter of learned perception. Any object you see as unique has molecules which merge and mingle with the atmosphere's. How did you know the object was separate?

[Surgoshan]

The edge of a perfect crystal.

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I sold my soul to Satan for a dollar. I got it in the mail.