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How Beauty Is Making Scientists Rethink Evolution: The extravagant splendor of the animal kingdom can't be explained by natural selection alone -- so how did it come to be?
"Symmetry is a vast subject, significant in art and nature. Mathematics lies at its root, and it would be hard to find a better one on which to demonstrate the working of the mathematical intellect."
It's sometimes funny, or jolting, when symmetry breaks down:
But, as David noted, there was a certain "organized asymmetry" to what Fred and Ginger were doing here, which was beautiful in its own way.
A phenomenal scientist and artist, Ernst Haeckel, discovered and documented many of the radiolaria, such as this one (Spumellaria):
These have a beautiful three-dimensional rotational symmetry - and we're headed into three-dimensions today!
It can be used to make fancy dances more interesting, by copying movements across the dance floor (translational symmetry) -- e.g. contra or square or line dances.
Today we consider the Platonic solids, which possess a great deal of symmetry: they're super-symmetric solids.
"A regular polygon is a polygon which is equiangular (all angles are equal in measure) and equilateral (all sides have the same length). Regular polygons may be convex or star."
Bees have the same idea:
A cube is an example of a Platonic solid. It's the one we're most familiar with, so let's start with that.
A Platonic solid is a solid for which
They're super-symmetric!
The Five Convex Regular Polyhedra (Platonic solids) -- thanks Wikipedia! | ||||
---|---|---|---|---|
Tetrahedron | Hexahedron or Cube |
Octahedron | Icosahedron | Dodecahedron |
fire | earth | air | water | universe |
Some nice illustrations from Weyl's book.
The answer involves Euler's formula, as Weyl discusses.
The Platonic solids allow us to make "flat spheres" (sort of!):
"The six spheres each corresponded to one of the planets (Mercury, Venus, Earth, Mars, Jupiter, and Saturn). The solids were ordered with the innermost being the octahedron, followed by the icosahedron, dodecahedron, tetrahedron, and finally the cube. In this way the structure of the solar system and the distance relationships between the planets was dictated by the Platonic solids."
And then Uranus was discovered, and there was not a sixth Platonic solid. And so science evolves....
From Pauling's paper:
Molecular architecture may be said to have originated in 1874, when J. H. van't Hoff and J. A. le Bel independently formulated the brilliant postulate that the four valence bonds of the carbon atom are directed approximately toward the corners of a regular tetrahedron. It was extended into inorganic chemistry in 1893, when A. Werner suggested that in many inorganic complexes six atoms are arranged at the corners of a regular octahedron about a central atom, and that other geometrical structures are represented by other complexes.
These are some higher quality images than my scans:
"An array of viruses. (a) The helical virus of rabies. (b) The segmented helical virus of influenza. (c) A bacteriophage with an icosahedral head and helical tail. (d) An enveloped icosahedral herpes simplex virus. (e) The unenveloped polio virus. (f) The icosahedral human immunodeficiency virus with spikes on its envelope."
# of Vertices | Edges | Faces | faces at each vertex | sides at each face | |
Tetrahedron | |||||
Cube | |||||
Octahedron | |||||
Dodecahedron | |||||
Icosahedron |
What conclusions can we draw from this data? Is there a pattern? (Of course there is!:) The pattern leads to the concept of "Duality":
Here's nature being all dual: This pastel drawing of a compound of Molybdenum Dichloride is from Pauling's book:
Because the above written pair in the first month bore, you will double it; there will be two pairs in one month. One of these, namely the first, bears in the second montth, and thus there are in the second month 3 pairs; of these in one month two are pregnant and in the third month 2 pairs of rabbits are born, and thus there are 5 pairs in the month; ...
there will be 144 pairs in this [the tenth] month; to these are added again the 89 pairs that are born in the eleventh month; there will be 233 pairs in this month.
To these are still added the 144 pairs that are born in the last month; there will be 377 pairs, and this many pairs are produced from the abovewritten pair in the mentioned place at the end of the one year.
You can indeed see in the margin how we operated, namely that we added the first number to the second, namely the 1 to the 2, and the second to the third, and the third to the fourth and the fourth to the fifth, and thus one after another until we added the tenth to the eleventh, namely the 144 to the 233, and we had the abovewritten sum of rabbits, namely 377, and thus you can in order find it for an unending number of months.