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• Shifting Sands of Far-Off Lands

  Posted by Ben Burress

  on Mar 12, 2010

  Martian dunes, captured by NASA's Mars Reconnaissance OrbiterWhat started out to be a workaday chore?replacing a broken motor in an exhibit?panned out to be a voyage of discovery to the shifting sands of another world. This is an occupational hazard when working at a place like Chabot Space & Science Center?.

  The motor in question powers a fan in an exhibit built to demonstrate the physical processes of duning?the fluid transport and deposition of solid particulates into collections and patterns. The fan blows up a constant micro-gale within the exhibit enclosure, and visitors get to play Mother Nature by turning a handle and redirecting the wind. Meanwhile, a mass of tiny white glass beads is constantly whipped up into a fair recreation of a sand storm on planet Arakis?.

  After the chore of installing the new motor, I rewarded myself by enjoying the exhibit a bit. I piled up all of the sand on one side of the tank to see how the fan would redistribute it; I sent the wind from different directions, watching how the freshly blown grains were scattered across the pristine black undersurface; I placed all of the pyrite rocks, which serve as wind obstacles, in one pile. It was a lot of fun.

  One thing I noticed that I hadn't paid much attention to in the past was how the dune actually moved, or migrated. Maybe I hadn't watched long enough before, or maybe it was easier to witness because I had stacked the deck by mounding the sand all in one corner, but it was fascinating to see the process.

  On the windward side of the giant dune, the scouring wind picked up the sand and carried it racing to the top?slowly peeling away the front face of the dune. As soon as the sand-laden wind reached the crest and took a sudden turn downward, it was slowed a bit, becoming less able to support the sand grains, which then fell out onto the leeward side of the dune in a sandy-wind version of precipitation. The buildup of sand on the lee side eventually formed small avalanches that slid down the face in little dry floods.

  In this fashion, the dune moved along, slowly being erased on its windward side and formed on the lee.

  Almost coincidentally, a few days later I read a report from NASA about sand dunes on Mars. In some areas, dunes have been observed to migrate over time, while on others the patterns have remained stock-still?some of them for perhaps thousands of years, or longer.

  So I had successfully created the right conditions for a migrating sand dune. What about static dunes? Well?I had noticed already that some of the pyrite rock obstacles that I placed in the sand stream formed small dunes in the wind-shadows of their leeward sides. The rocks weren't moving, and so the dunes they were nurturing and protecting remained in place.

  Some of the static dune ripples observed in Meridiani Planum?where the rover Opportunity is exploring?have been explained as possibly being protected by the presence of "blueberries": tiny nodules of gray hematite that have eroded out of Martian rocks, but which themselves are erosion-resistant, and too large (1-3 millimeters) to be carried by the wind. The blueberries, as the explanation goes, embed in the sand and form a protective "armor" layer for the dune ripples, which remain safe and still in their lee.

  Where else do we find dunes, other than Earth? Well, you need wind of sufficient strength and sand of sufficiently small size, for starters. We don't know about dunes on Venus; Venus has a thick enough atmosphere, but the winds may be too sluggish to whip up much of a sand storm. The only other object with a thick enough atmosphere and a solid surface is Saturn's moon Titan?and in fact we have pictures of Titanian dunes taken by Cassini.

  Now I'm feeling that old itch to make another trip to my favorite place in the Solar System, Death Valley, to explore the macroscopic dunes of Stovepipe Wells . I'll send a postcard?.

  
  Tags: chabot, death valley, dunes, mars, sand, wind
  
  
  

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• Reporter's Notes: Battle Over Public Power

  Posted by Amy Standen

  on Mar 12, 2010

  Three months before the state election, Prop 16 has made headlines in every major state newspaper.

  At first glance, Proposition 16 might appear to lack a certain splash-factor — at least compared to other initiatives – like 8 or even 71 – that have appeared on recent California ballots. In short, the proposition would require a two-thirds super majority election by voters before a local government could pool the buying power of consumers to secure energy contracts. (Oh, are you still reading this? Good.)

  And yet, three months before the state election, Prop 16 has made headlines in every major state newspaper. The LA Times, the Chronicle, the San Jose Mercury News, and the Sacramento Bee, to name just a few.

  From the standpoint of Prop 16's backers, these are not the good kind of headlines. With few exceptions, each article has put a spotlight on a dramatically lopsided campaign: One side of Prop 16 ? the "Yes" camp ? is funded entirely by a single company, PG&E, which has said it's prepared to spend $35 million on the campaign. The "No" camp has scraped together less than $25,000, nearly all of it from an advocacy group with a staff of 15.

  When I asked a Yes On 16 spokesman whether he was concerned that his camp's financial muscle might turn off voters, he said that the issues at hand are simply too important not to put on a ballot. But "important" how? To PG&E's profit margin? Or to the communities interested in pursuing public power? That may be the key distinction guiding voters on June 8.

  To view the complete Campaign Finance reports of Proposition 16 opponents and proponents (including details about where money comes from, and where it is spent), click here.

  
  
  Listen to Battle Over Public Power radio report online.

  
  Tags: CCA, charles mcglashan, cleanpower SF, community choice aggregation, greg larsen, marin clean energy, mindy spatt, PG&E, proposition 16, ross Mirkarimi, severin bornstein, the utilities reform network, TURN
  
  
  

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• Fighting Words

  Posted by Jim Gunshinan

  on Mar 05, 2010

  Words matter to scientists. The scientific method is a structure through which scientists test theories through experiment, and then share the results with other scientists.

  Do words matter? They matter to the world?s great religions. In the Book of Exodus in the Bible?sacred text for Jews, Muslim?s, and Christians?God speaks, and there is light. The Gospel of John begins with, In the beginning was the Word. The Buddhist Sutras lead followers to enlightenment. The epic poem Mahabharata is a central narrative for Hindus.

  And words matter to scientists. The scientific method is a structure through which scientists test theories through experiment, and then share the results with other scientists. Science moves forward inch by inch with every paper printed in a journal or delivered at a conference.

  Without words, we wouldn?t be human. Our great democracy is based on the    power of words?the Declaration of Independence, the Bill of Rights, the Constitution. We are inspired by words?the Gettysburg Address, Shakespeare. Lucille Clifton,  a poet that I got to know and love through the Squaw Valley Community of Writers, and who died recently at the age of 74, wrote short, simple, powerful poems that turned conventional interpretations of the Bible upside down. (In one poem she quotes from the Book of Samuel, David has slain his ten thousands?he was a mercenary before he was a king.)

  A recent Supreme Court decision that gave corporations the same free speech rights as individuals has me worried. It equates money with words. Is one person?s ability to persuade another, or a nation, equal to a corporation?s ability to flood the media with sound bites that tend to distort the truth as much as enlighten us? (?Heresy? means emphasizing one aspect of the truth to the exclusion of all others; it doesn?t mean an out-and-out lie as many people think. Just as pornography is emphasizing one aspect of our humanity to the exclusion of others. Pornography sells.)

  If you read all the Gospels you get a sense of what Jesus was about. He rarely mentioned sex, never talked about birth control; but he talked a lot about the danger of money and power. Jesus was harder on the religious leaders of his time than he was on tax collectors and prostitutes. (To the Pharisees he says You clean the outside of cup and plate [obey the letter of the law and what people can see] but inside you are all corruption.) He knew that wealth and the power it conveys corrupts. He stood for the power of persuasion and not force. He led by example and spoke of the power of love and forgiveness. Jesus became angry when he saw powerful people abusing the weak and vulnerable.

  Those of us who believe in the power of words?scientists included?have our work cut out for us. There?s a lot of money being spent to distort the truth. For example, ?death panels??the claim that the Obama health proposal advocates the government to pull the plug on Grandma?and the claim by some of late that the snow storms on the East Coast are proof against global climate change. But we have the power of words on our side. We?ll need it. A headline in Thursday?s New York Times online reads, ?Darwin Foes Add Warming to Targets.?

  
  Tags: KQED, Science
  
  
  

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