today
8:30 a.m. Audubon Society Field Trip See Event Description
read >9 a.m. Arcata Farmers' Market Arcata Plaza
read >9:30 a.m. Discovery Walk: Unknown Waterfront See Event Description
read >9:30 a.m. Manila Dunes Restoration Manila Community Center
read >10 a.m. Manila Dunes Guided Walk Manila Community Center
read >10 a.m. Library Book Sale Humboldt County Library
read >10 a.m. Dia de los Muertos and Mexican Folk Art Sale Private Eureka home
read >10 a.m. Final Arcata Farmer's Market Arcata Farmers' Market (off the plaza)
read >11 a.m. Donlin Foreman Dance Workshop Dell'Arte
read >2 p.m. Humboldt Coastal Nature Center Draft Trails Plan Walk Stamps House
read >5 p.m. Bati Zado and Show Redwood Raks World Dance Studio
read >6 p.m. The Tumbleweeds Chapala Cafe
read >6 p.m. Ali Chaudhary (jazz duo) Libation
read >6:30 p.m. Not Evil, Just Wrong Humboldt Area Foundation
read >7 p.m. Guitar Stan (country) Old Town Coffee & Chocolates
read >8 p.m. Guitar Orchestra of Barcelona Arkley Center for the Performing Arts
read >8 p.m. Stones in His Pockets Arcata Playhouse
read >8 p.m. A Christmas Carol North Coast Repertory Theater
read >8 p.m. Donna Landry Swing Dance Moose Lodge
read >8 p.m. North Coast Wind Ensemble Fulkerson Recital Hall at HSU
read >8:30 p.m. The Last Minute Men (international) Cafe Mokka
read >9 p.m. Ian McFeron Band (folk rock) Six Rivers Brewery
read >9 p.m. The Michael Paul Band WAVE @ blue lake casino
read >9 p.m. The Generatorz (classic rock) Central Station Cocktail Lounge
read >9 p.m. Taxi Bear River Casino
read >9 p.m. VJ Itchie Fingaz Pearl Lounge
read >9 p.m. Jack Ruby Presents + Blue Street + Acufunkture (DIY rock) Jambalaya
read >9 p.m. 2nd Annual Scorpio Bash The Red Fox Tavern
read >10 p.m. Music by DJ Sidelines
read >10 p.m. DJ Icy Hot Aunty Mo's Lounge
read >10 p.m. Jemimah Puddleduck (rock) Humboldt Brews
read >10 p.m. White Manna + Midday Veil + The King Salmon Duo (rock) Jambalaya
read >11 p.m. Radio Moscow (psychadelic blues) + Mosquito Bandito (one-man surf/garage) The Alibi Lounge and Restaurant
read >previous columns
April 24, 2008
Rogue Waves
Waves are intimately connected to everything, even electrons and such, ...
read >April 17, 2008
Designer Fruit
Preparing a bowl of fruit for lunch reminded me of ...
read >April 10, 2008
Sailing
The physics of sailing is outlined in the first diagram, ...
read >Photos
Symmetry
By Don Garlick
Crystal faces reveal symmetries which reflect the geometric arrangements of their constituent atoms. All inorganic solids are crystalline, except glass. The concepts of symmetry are essential also to the understanding of life's architecture.
Your right hand has no symmetry. Two hands in prayer are related by a mirror symmetry (biology's bilateral symmetry). Rotate one of those hands 180 degrees, palms together, and you have created a center of symmetry. A cube has a center, three axes of fourfold rotational symmetry, four axes of threefold, six axes of twofold, and nine mirror planes. The big diagram shows the symmetry of a soccer ball and the famous 60-carbon hollow "buckyball" molecule. The envelopes (capsids) of most kinds of virus resemble this same icosahedral symmetry. Such viruses use multiples of 60 protein molecules in constructing their capsids, which enclose infective genomes.
The most common symmetry among macroscopic animals is bilateral. Clams and tuna are bilateral, but snails and flounders have abandoned their ancestral symmetry. A few of your internal organs depart from the beautiful bilateral symmetry of your skeleton and muscles. The liver is almost always on the right.
The starfish appears to have fivefold radial symmetry with five mirror planes, but its off-center "madrepore" betrays its true bilateral symmetry. That spot provides filtered water to its plumbing system and hundreds of hydraulic tube-feet. Sand dollars and sea urchins are likewise bilateral echinoderms. Each urchin spine is a single crystal of calcite as revealed by its cleavage planes.
Anemones and jellyfish usually have radial symmetry.
Some comb-jellies sport two mirror planes (which generate one twofold axis).
Observe and ponder the symmetries of nature, and be amazed that any symmetry can be constructed from a right-handed DNA blueprint.





















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