Tuesday, June 26, 2012

Giant Hot Wheels Track

RT @wiredplaybook.

with double loop-the-loop AND life-size cars!  Warning:  This is a preview, the event is supposed to happen 30 June.

Image credit:  Artist rendering from Mattel

Apollo 17 at Shorty Crater

RT @hackernewsbot

[APOD Picture].

Man, was it really 1972?!

Image credit:  NASA

Introduction to Python descriptors

RT @NewsOfLinux

From IBM Developer Works.

This is Python's version of getters and setters.

Re-Tweeting Part 2

Whew!  Okay, that Twisted Light post just now took forever to do!  That's complex.  I don't know if I'll keep this up.

'Twisted light' carries 2.5 terabits of data per second

RT @LanceUlanoff

From BBC News.
Researchers have clocked light beams made of “twisted” waves carrying 2.5 terabits of data - the capacity of more than 66 DVDs - per second.

The technique relies on manipulating what is known as the orbital angular momentum of the waves.

Recent work suggests that the trick could vastly boost the data-carrying capacity in wi-fi and optical fibres.

Image credit:  Nature Photonics


Who do I recommend following on Twitter?  Recently I was talking to a co-worker about how I had switched from using RSS to Twitter for reading news a few years ago (meaning at least two, I'm not sure without checking).  That leads to the question, who would I recommend following.

In the past I would have said to just look at my re-tweets to gather a recommended list.  However, most recently I've taken to writing blog posts here instead of re-tweeting most of the time, though I'll still re-tweet short items of interest.   When I post, I usually just link back to the original article so there's not any mention of who I got the article link from on Twitter.

I'm going to experiment with ways to acknowledge the original tweets and Twitter account, starting with a classic RT at the beginning of the post.  However, if that's just too repulsive to look at on an otherwise nice looking blog post, the next idea will be some other Twitter acknowledgement, maybe at the bottom.

The nice thing about an RT is that it will show up in the Twitter feed that's reduced from my blog in the traditional way.  We'll see how this goes.

Saturday, June 23, 2012

Why we owe it all to Alan Turing

by Dan Crow on Gigaom.

…he, more than anyone, can be said to be the father of the computer. So what was his great insight? What is it he did that shaped our world so profoundly?

The Church-Turing Thesis has two very important implications.

First, it recognized the fundamental limitations of the system — for example, that there are some programs that are not computable by any machine.

But it was the second implication that was most profound: within its limitations, a Turing Machine can be programmed to run any piece of software. In fact, one of the programs that can be run on a Turing Machine is a simulation of a Turing Machine. And the simulated Turing Machine can itself run any program that a Turing Machine can run.

This is the genius of Turing’s work, his key insight. He has defined a “Universal Machine” — one that can run simulations so powerful they are themselves universal machines.

Are Bitcoins Becoming Europe's New Safe Haven Currency?

from Daily Finance.

 “Bitcoin is in some senses a financial island removed from the vicissitudes and consequences of a traditional banking system. It's neither controlled by central banks nor governments, and thus not vulnerable to larger-scale shifts like changing interest rates or the rampant inflation of countries in decline.”

Saturday, June 16, 2012

A Bit More on Bradbury

One of my favorite writers, Jerry Pournelle, wrote on his blog, “At one time the whole genre was dominated by ‘ABC’, Asimov, Bradbury, and Clarke, although usually someone would quickly add Robert Heinlein. Now the Big Four are gone. They will all be missed.”

Verified by Visa?

I was submitting an order on-line for refurbished electronics from a site I normally don't use.  A window popped up for Verified by Visa asking for the CVV code again, also the last four digits of my social security number and asking me to create a password.  It has our bank's logo on it.

Of course I was suspicious.  I poked around the web and found the actual Visa site as well as this article which pretty much explains what happened to me along with the program.

I also went to my bank's web site and found a discussion of the program there.

The bottom line:  This is a good thing.  It essentially adds a password to your credit card.  You have to supply this password when you use your card on-line.

I would have appreciated more warning but maybe there was something from the bank that I ignored.

Friday, June 08, 2012


After James Spann appeared on this week's TWiG, I was delighted to have learned about Weatherbrains, “The official netcast for people who love weather.” I'm subscribing to the audio podcast and the quality is quite good. Recommended!

Note:  Here's the RSS link for subscribing to the podcast, which I only found by a Google search.

James Spann

Images credit:  From weatherbrains.com

Thursday, June 07, 2012

So Long Ray Bradbury

I enjoyed many of his short stories, particularly in high school.  This is a very nice video of him at JPL on the eve of Mariner 9 entering Mars orbit in 1971.  He's sitting next to Arthur C. Clarke.  There's a quick shot of Carl Sagan, too, who was on stage.   Good grief, Bradbury was younger than me there.

My Favorite Venus Transit Video

It's pretty clear that NASA's Solar Dynamics Observatory (SDO) has stolen the show, at least on Youtube and Twitter, with it's videos of the recent Venus transit.  However, my favorite video is not the popular, creepy (yet beautiful!) extreme ultraviolet images of a flat-looking black circle moving across amazing prominences and other features in the hot solar corona.  

My favorite is this video in orange light where you can clearly see sunlight scattered around Venus' atmosphere as it moves in front of the Sun.  The limb of the Sun also seems to be refracted by the planet's atmosphere.

These images were made by the SDO's Heliocentric and Magnetic Imager (HMI) which observes at a wavelength of an Fe I (unionized iron) absorption line at λ6173.

Tuesday, June 05, 2012

Live Stream of Venus Transit

There are several live streams of the Venus transit.  Here's one from Mt. Wilson.


Friday, June 01, 2012

Melancholia Misses the Physics

Melancholia was a dark and slightly depressing movie but with some interesting special effects.  I watched it on a recommendation from Hal.  However, they got the science wrong on a couple of basic accounts and I think I know why.

If a terrestrial planet (dirt and rock) came that close to the Earth, there would be two major effects.  First, the tidal force on the Earth would be extreme.  The Moon's diameter is more like the size of the United States and look at it's tidal force.  Such an approaching big planet as the fictional Melancholia would basically put the Earth's surface through a food processor before any collision ever occurred.  I'm not sure if the tidal force would be enough to completely destroy the Earth, but anything and anyone on or near the Earth wouldn't know the difference.

Tidal force is caused by the difference in gravitational force between the closest and farthest parts of one body caused by another.  This effect of the Moon on the Earth causes it's ocean surface to bulge toward and away from the Moon.  The Earth's crust also does the same but to a lesser and non-catastrophic extent.

Second, the two bodies would move about their mutual center of gravity.  The Earth would be perturbed completely out of it's orbit by the encounter in some crazy way.   It could still involve a single close encounter, again with both planets being destructively disturbed by the tidal forces of each on the other, followed by a later, final impact, but there's no telling what their mutual trajectory would look like.  What is nearly certain is that the Earth would not continue on it's nearly-circular orbital path.

So surely they had a science/astronomical advisor for the movie.  Why such fundamental mistakes?  I propose that when they consulted their expert, they were thinking of a small asteroid collision with a body more the size of a large metropolis or a state.  A small  body wouldn't perturb the Earth from it's orbit and wouldn't have much tidal effect.  However, the impact would be catastrophic.

Later, because they had brilliant ideas about the look and effect of a  giant planet approach and final impact, they changed the threatening body but they didn't go back and consult the expert.  They just kept the path from the previous discussions.

Dragon Spash Down

[VIDEO] from a NASA chase plane.

How to Make Coffee with Minimal Equipment and Maintenance

from Life Hacker.

Image credit:  by ketrin/Pond5.com

Amazon $5 Albums This Month

Alert:   Some of the MP3 albums in this month's Amazon collection of 100 albums for $5 each.

The Definitive Collection - Litter River Band (19 songs, many digitally remastered).
We're An American Band - Grand Funk (1973)  (12 songs, all remastered)
Money Jungle - Duke Ellington (1963)  (15 songs, almost all remastered)
The Classical Summer Collections (29 pieces)

and more.