Library of Congress cards

If anyone is going to be in Washington and plans to visit the Library of Congress, my friend who was there recently has some advice. He went into the LoC, then found out that ANYONE can get a library card, especially if they state that there’s something that they are researching, (e.g. anti-intellectualism in American politics). You don’t even have to be American.

However, the building where you join is across the street from the main library building and often has a line-up for entry; and if you go outside you have to leave security, line up, and enter security again (bag check?). However, the two buildings are connected by an underground tunnel. You can stroll over via the tunnel, staying within the secure area and skipping the line.

Second, he said that if you are reading something and want to continue the next day, there’s a room where you can leave your book overnight; because if you put it in the “return to shelves” area it can take a few days to get back it its place.

So if you’re going to be in D.C., you might want to get library cards!

Discovery Channel: Daily Planet

Tonight’s Daily Planet: a rocket-powered school bus; virtual autopsies by combined MRI and X-Ray tomography; world’s most compact house (looks like a tool-trailer 2m on a side; whales sleeping while they breathe every 20 minutes. Software has identified the most boring (least eventful day in the last 110 years as 4 April, 1954). Someone has constructed a 3.5-tonne chocolate Christmas tree, modelling its inner structure on the membranes in human lungs for light-weight support.

Adverts: Tim Horton’s coffee shops are selling fudge!!

Roger Ebert on men with guns

Thanks, Cactus Wren!

Roger Ebert’s review of the movie Men With Guns: “I understand guns in war, in hunting, in sport. But when a man feels he needs a gun to leave his house in the morning, I fear that man. I fear his fear. He believes that the only man more powerless than himself is a dead man.”

What if God came down from heaven?

A god, gods, goddesses? In a discussion of “can there be evidence for god?” people are likening the question to “can there be evidence for any fictional character?” and A Ray in Dilbert Space had a great comment:

And as to the idea of the skies opening and a bearded man with 12 apostles…riding to the ground with a “heavenly host”, well, if you were part of an alien invasion, wouldn’t it behoove you to take advantage of old superstitions? So, while “notable”, this in itself would not budge my posterior probability for belief in Gods.

 

Simple organic compounds: alkanes

Methane (1 carbon), ethane (2 carbons)

In the previous post, I casually mentioned methane and ethane in the atmosphere of Saturn’s moon Titan. I’ve started with the terms in that post and worked back to the supporting concepts so you can read until you get to things you already know.

  • Methane and ethane are the simplest hydrocarbons.
  • Hydrocarbons are molecules that are comprised entirely of atoms of hydrogen and carbon. Specifically, they have no oxygen, which is the commonest other component of organic molecules.
    • Incidentally, a molecule that contains hydrogen, carbon, and oxygen is a carbohydrate, a completely different kind of molecule. In his book Chariots of the Gods, Emmanuel Velikovsky casually changed hydrocarbons (fuel) into carbohydrates (food) with a twist of the typewriter, demonstrating that he knew nothing about chemistry.
  • Organic molecules contain carbon and are more complex than carbon dioxide (CO2). They’re called organic because a hundred years ago, we thought that only biological processes could form them: that’s all that scientists had ever observed. Since then, we have learned to synthesize them step by step, observed them forming from inorganic compounds, and detected them in interstellar clouds. The chemistry of carbon is called organic chemistry.
  • The smallest alkane is methane, with one carbon. Ethane has two, propane has three, butane has four. After that they use Greek numeric prefixes pentane, hexane, heptane, octane, and so on.
  • Alkanes are saturated hydrocarbons: saturated means that every available bond is filled: the molecule is saturated with hydrogen and cannot take up any more. There are no double bonds on any of the carbon atoms in an alkane. They are sometimes said to have a carbon “backbone.” You can read more about alkanes. Hydrogen atoms tend to clutter up chemical structure diagrams, so they are often left out: just assume that a hydrogen atom fills every unspecified bond.
  • Carbon atoms can form four covalent (electron-sharing) bonds, so each carbon atom can connect to four other atoms. This is the secret to its success in building large, even gigantic molecules and why we think that other life might be “carbon-based.”
Tetrahedral structure of methane

Methane

  • The carbon bonds naturally radiate to the four tips of a triangular pyramid with the nucleus in the centre: carbon molecules are not flat. Methane is a tetrahedral molecule. molecules with carbon chains are, at the very least, crinkled. Thus, even the simple structure of a three-carbon molecule has two conformations, with the ends of the molecule bent towards or away from each other.

Carbon molecules showing "handedness"

  • If a carbon atom has different atoms attached to its bonds, it can form a molecule with mirror image versions like left-handed or right-handed mittens. No matter which way you turn them, you can’t superimpose them. This is called chirality (handedness) and the molecules are called enantiomers of each other.
  • Carbon has 6 protons in its nucleus; otherwise, it would be something else: the number of protons defines the element. If the nucleus has more or fewer neutrons, it’s an isotope of the element. A carbon atom usually has 6 neutrons but there’s an isotope with 8 neutrons, which is slightly less stable and decays over time. [Corrected as noted below.]
  • An atom has a nucleus surrounded by electrons. A nucleus is built of protons (positive charge) and neutrons (no charge) surrounded at some distance by electrons with negative charge.

Titan: rocky core, water crust, hydrocarbon atmosphere

funny pictures-Demonstrashun of Concept Kittehs:
See more Lolcats and funny pictures

Titan, Saturn’s largest moon, has been visited by a spacecraft, Cassini-Huygens. It appears to have a nitrogenous atmosphere with evaporated methane and ethane, oceans of methane and ethane, and a crust of water ice. It has features formed by wind and liquid erosion. Recently, slippage of the crust makes people think that there is liquid water below, as well. It’s altogether an interesting planet.

 

Symphony of Science: A Wave of Reason

Science’s “new wave of reason.”

Phil Plait says, “Teach a man to reason and he’ll think for a lifetime.”

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