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30 June 2007

Chomsky on Missile "Defense"

More total insanity from the Bush administration, building on the Clinton administration's stupidity.

AFRICA: Food for 12 Billion. So Why Did 854 Million Go Without?

Good question, no?

Here's another excellent piece on water, to wash down this one on food. Ah, yes, "free trade" -- subsidies for the North; "discipline" for the South. Nice little murderous racket we got going.

IPS is a consistently excellent source of news. Bookmark it; syndicate it; subscribe.

29 June 2007

Rainbows: The Inside Story

This is from an e-mail Q&A with a physics friend that was inspired by a perfect rainbow I saw yeseterday.

I'll reorder it so you don't have to read from bottom up...

Physics is just damn cool. Unless you're falling off a building. Anyway, maybe it's just me, but this is far more fascinating to me than any myth I've ever heard. And I like myths!

Of course, if any physicists/scientists/whatever disagree with the analysis below, comment away! Any other comment welcome, too, of course.

Question:

Why are rainbows bows? That is, why doesn't every single droplet show the prismatic effect? And those that don't (or don't show it to an observer in a given position -- ?); well, why do those that do arrange themselves in a hemisphere?

Answer:

OK, each water droplet in the sky: Think of each droplet as a sphere. Light from the sun impacts the air/water boundary of the droplet. A significant amount of the white (i.e., "contains all colors") light refracts into the droplet. However, the light ray contains different wavelengths of light (different colors), and a law of optics called Snell's Law tells us that the angle of refraction depends on the wavelength of the light. Simple version of the effect: the different colors refract at slightly different angles into the droplet.

[Harder physics version:] Light strikes the air/water boundary at an angle to the "normal" of the surface, the line that is perpendicular to a plane that is tangent to a surface. In the case of a sphere, at each point on the surface, the "normal" is the line that points directly away from the center. Because the index of refraction (the degree to which light is slowed when traveling through a material) is higher for water than for air, Snell's Law implies that the light will bend upon entering the water, bend toward the normal (tend to pass more closely to the center of the sphere than it would if it had kept traveling in the same direction). That explains why light bends. Different colors bend slightly different amounts by this logic: light of different colors has differing wavelength and frequency. Fact of a light wave: frequency times wavelength in a medium = speed of light in that medium. The energy of a light wave is directly proportional to frequency. The energy of the wave doesn't change when it enters a new medium (which means frequency is constant), however the wavelength of the wave does change. (Why? Argh. Fermat's Principle of Least Time is the short answer.) Frequency x reduced wavelength = reduced speed of light. Light of different wavelengths means different speeds means different refraction angles. [End of harder physics version.]

The diverging colors reflect off the back end of the droplet, strike the front end again (light enters droplet from upper right, refracts through to left side of sphere, and refracts out of sphere on the lower right), but the different colors of light strike in different places, and leave the droplet at different angles.

So, white light enters every droplet in the sky, and light of different colors leaves in different directions.

Now, the "right" geometry happens when the angle between the sun's incoming rays and the rays leaving the droplets (angle ABC, where A = sun, B = droplets, and C = you) is about 42 degrees. ABC for the sun's blue light is 40 degrees. ABC for red light is 42 degrees.

Droplets that are slightly farther away and higher in the sky will reflect the red light into your eyes. Different drops that are slightly closer, and slightly lower, will reflect blue light into your eyes. Intermediate colors will reflect at intermediate angles...and you will see a rainbow.

"That is, why doesn't every single droplet show the prismatic effect?" Every droplet DOES show a prismatic effect. But the sun-droplet-you angle has to be about 42ish degrees, and you'll only be able to see ONE of the colors from that drop. Other droplets provide other colors...the combined effect being the rainbow.

Why the hemisphere?

A rainbow would be the base of a cone, if the Earth didn't get in the way. The vertex of the cone is the sun, the center line of the cone passes from the sun through your eyes to the shadow of your eyes (head) on the ground, and the base of the cone (the rainbow) is formed where the sun(vertex)-droplet (base)-eye angle is between 40 and 42-ish degrees. Technically, there is a red cone with one angle, a yellow cone with a slightly different angle, ..., a blue cone with a slightly different angle. You see all the cone bases as a rainbow.

Question:

Interesting twist: a friend of my bro's saw a circular rainbow in a plane! Also, I've seen double-rainbows -- I assume that's just a situation in which there are two "sets" of bows at the proper angles?

One thing that blew me away was the compound nature of the illusion. First, for a creature that doesn't register our visual spectrum, that bow ain't there. I assume bees see UV bows; and so on. Second, unless I misunderstood, the bow itself does not literally exist one color on top of another in a certain place: each color is separated (by miles, feet...?) and only seems to be "stacked" when seen at the proper angle.

Is this correct?
Answer:
I'm guessing bees don't have the visual acuity to see that far away...unless it's mini-rainbow from a sprinkler. :)

You're correct about the "stacked" nature of rainbows. However -- "Also, I've seen double- rainbows -- I assume that's just a situation in which there are two 'sets' of bows at the proper angles?" -- is interesting.

When light rays strike a boundary between different media (air/water), part of the ray reflects (bounces off) and part of it refracts (traverses the boundary and bends). We see a strong single rainbow with the 40-42 degree big arc because much of the light refracts into the droplet, reflects off the back side, then refracts back into the air. However, some of the light will bounce inside the droplet twice: refract in, reflect off the back, reflect off the front, reflect off the back, then refract out of the droplet.

The light that does this double bounce is lower in intensity (quantum mechanics: individual photons are more likely to refract-reflect-refract than refract-reflect-reflect-reflect-refract). The double bounce causes a different geometry: the sun-droplet-eye angle will be bigger by a few degrees...and that's why the second rainbow appears elsewhere in the sky: the color cones whose bases make up the second rainbow have a different angle (probably 48 or 50 degrees or something like that).

How to Destroy an African-American City in Thirty-Three Steps - Lessons From Katrina

Two years later, and NOLA has to go abroad to find funds for reconstruction!

I think the "No one could have imagined..." lie is a bit threadbare now, no? I mean, we have the president on tape being briefed on the incipient disaster, of course. I refer to the day after the disaster to the present day. It's appalling, uncivilized, and a good preview of the world and country the Right would like to see.

How very Christian of them! More from Democracy Now.

Bush, Mideast Wars and End-Time Prophecy

Why the term "theofascists" should be on everyone's lips.

28 June 2007

EXXON HACKS THE YES MEN

This is not a joke. Read on, and shudder for truly free expression in this country.

June 28, 2007

FOR IMMEDIATE RELEASE

EXXON HACKS THE YES MEN
Yes Men badly need sysadmin, server co-location

Contact: mailto:people@theyesmen.org

One day after the Yes Men made a joke announcement that ExxonMobil plans to turn billions of climate-change victims into a brand-new fuel called Vivoleum, the Yes Men's upstream internet service provider shut down Vivoleum.com, the Yes Men's spoof website, and cut off the Yes Men's email service, in reaction to a complaint whose source they will not identify. The provider, Broadview Networks, also made the Yes Men remove all mention of Exxon from TheYesMen.org before they'd restore the Yes Men's email service.

The Yes Men assume the complainant was Exxon. "Since parody is protected under US law, Exxon must think that people seeing the site will think Vivoleum's a real Exxon product, not just a parody," said Yes Man Mike Bonanno. "Exxon's policies do already contribute to 150,000 climate-change related deaths each year," added Yes Man Andy Bichlbaum. "So maybe it really is credible. What a resource!"

After receiving the complaint June 15, Broadview added a "filter" that disabled the Vivoleum.com IP address (64.115.210.59), and furthermore prevented email from being sent from the Yes Men's primary IP address (64.115.210.58). Even after all Exxon logos were removed from both sites and a disclaimer was placed on Vivoleum.com on Tuesday, Broadview would still not remove the filter. (The disclaimer read: "Although Vivoleum is not a real ExxonMobil program, it might as well be.")

Broadview did restore both IPs on Wednesday, after the Vivoleum.com website was completely disabled and all mention of Exxon was removed from TheYesMen.org.

While this problem is temporarily resolved, the story is far from over. Meanwhile, though, two bigger problems loom, for which we're asking your help:

1. THE YES MEN'S SERVER NEEDS A NEW HOME.

Broadview Networks provides internet connectivity to New York's Thing.net and the websites and servers it hosts, including the Yes Men's server. Thing.net has been a host for many years to numerous activist and artist websites and servers.

At the end of July, Thing.net will terminate its contract with Broadview and move its operations to Germany, where internet expression currently benefits from a friendlier legal climate than in the US, and where baseless threats by large corporations presumably have less weight with providers. At that time, the Yes Men and two other organizations with servers "co-located" at Thing.net will need a new home for those servers. Please write to us if you can offer
such help or know of someone who can.

2. THE YES MEN NEED A SYSADMIN.

The Yes Men are desperately in need of a sysadmin. The position is unpaid at the moment, but it shouldn't take much time for someone who knows Debian Linux very well. It involves monitoring the server, keeping it up-to-date, making sure email is working correctly, etc. The person could also maintain the Yes Men's website (which will be updated next week), if she or he wants.

Thing.net also needs a sysadmin: someone living in New York who knows Linux well. The Thing.net position involves some money and the rewards of working for an organization that has consistently and at great personal risk supported groups like the Yes Men over the years.

THE YES MEN AND THING.NET THANK YOU!

Vidal Tackling the Mexican War...

Let's hope he finishes it! Will cap off his Narratives of Empire series, which is our Decline and Fall.

Some other goodies in this recent Guardian piece.

27 June 2007

"You Kent Always Say What You Want," The Simpsons 400th Episode

In three acts. It gets funnier and funnier as it progresses; the end is priceless.

I

II

III

Kicked in the Family Jewels: CIA Nastiness FOIA-ed

Amazing. Here's the DN! report.

Here's the actual report from the National Security Archive.

Yeah, they don't do this anymore. Thank you, Gen. Hayden. I feel so much better now that these illegal moves have been normalized, spread throughout the executive branch (DoD, NSA), and, what's worse, outsourced to unaccountable private mercenary corporations (Blackwater, among many others). Here's Robert Parry on this issue. And here's a three-parter on Robert Gates from TomDispatch by Roger Morris, who was on DN! today.

Oh, the progress we've made! If I hear one more self-congratulation on the elite media...

"The Tragedy That Remains," Thus Spoke The Spectacle

Another clip from the great multimedia piece...just in time for the splashback, tenth-anniversary, magazine-sales-booster known as "Princess Diana." Dig the first clip here; dig the TSTS site here.

26 June 2007

Spanish Civil War: Some Videos

"Spanish Civil War," Part 1

"Spanish Civil War," Part 2

"Anarchists in the 1936 Spanish Civil War"