Wednesday, July 28, 2004

WorldNetDaily: Israeli invention sees through walls

7/2/2004 by Aaron Klein (pointed out by the IEEE Signal Processing Newsletter received via e-mail)
This article discusses using an ultra-wideband radar system to image through a wall. Helpful for rescuers of earthquake victims. Similar to another article IEEE pointed out recently on using terahertz technology for security screening and yielding results like the original Airplane movie (remember what happened when people walked through the x-ray on that movie?). What does this all mean for our ability to hide?

Tuesday, July 27, 2004

World Year of Physics/Einstein Year 2005

Did you remember that 1905 was the year that Einstein published 3 groundbreaking papers in Physics? IOP, AIP, APS, and others are all sponsoring activities to commemorate. In fact, they're calling 2005 the World Year of Physics and working to get a UN resolution on it. The two main sites with events, facts, activities are: (primarily US), (British)

Monday, July 26, 2004 : Ship-Sinking Monster Waves Are Widespread -- ESA

(warning: Pop-ups galore)
7/24/04 Found via Topix
"Rogue waves that rise as high as 10-story buildings and can sink large ships are far more common than previously thought, imagery from European Space Agency (ESA) satellites has shown."

This is a little disconcerting. I've spent many a day on the ocean and have never seen a wave like this (even in hurricane sorties, thank goodness). If you read the press release from the ESA you can learn a little more about this. Susanne Lehner from the University of Miami is working this so we'll look out for more from her.

Friday, July 23, 2004

Hawking and Black Holes

Brief background: Stephen Hawking, the famous physicist from Cambridge and author of A Brief History of Time among others, contacted the organizers of a conference to submit a paper at the last minute. Why so important? Apparently he now has reversed his theory on black holes and information and lost a bet. In the past he maintained that black holes sucked in everything around them without so much as a thank you. Now he says some of the information about the creation of the black hole actually hangs out near the event horizon and can influence radiation emitted by the black hole. Listen to Sean Carroll and Juan Maldacena discuss it here (real required).

There are plenty of articles on this in the media (like
About Those Fearsome Black Holes? Never Mind by Dennis Overbye, NY Times 7/22/04) and many scientific bloggers have weighed in (here and here)

The problem is that just because Hawking says it doesn't make it a done deal. Physics is rarely revolutionary (or at least as much as people think); instead, it's evolutionary. Good scientists who have carefully studied this subject disagree and it isn't proven -- there are only thought experiments. I do think that it's great that Hawking can generate this much media attention and I look forward to more discussion.

Thursday, July 22, 2004

The New York Times > Technology > Circuits > What's Next: For Doctored Photos, a New Flavor of Digital Truth Serum

7/22/04 by Noah Schachtman
Another article discussing issues around doctoring of digital photographs. Dr. Farid, who is cited in this article, had a nice article in New Scientist (v. 179 no. 2411 (9/6/2003): 38, here for Academic Search Premier subscribers) on this same subject. You can read his other academic papers on his Dartmouth site.

An Intuitive Explanation of Bayesian Reasoning

Pointed out on Furl as one of Today's Popular Items
"Bayes' Theorem for the curious and bewildered; an excruciatingly gentle introduction. By Eliezer Yudkowsky"
If you, like me, kind of get Bayesian Reasoning but wonder why everybody's so excited about it... read through this lengthy explanation. Ok, so I'm still not excited but now I remember how to read p(X|A). It's a nice resource either way.

Thursday, July 15, 2004 > Revolutionary Steel

"Scientists at the University of Virginia have announced the discovery of a non-magnetic amorphous material that is three times stronger than conventional steel and has superior anti-corrosion properties." The scientists say it's somewhat brittle right now but they're working on that. Apparently it can be molded and shaped like plastic.
See V. Ponnambalam, S. Joseph Poon, and Gary J. Shiflet. "Fe-based bulk metallic glasses with diameter thickness larger than one centimeter" Journal of Materials Research v19 no5 (May 2004): 1320-1323. (DOI: 10.1557/JMR.2004.0176, PDF for subscribers).

Wednesday, July 14, 2004> High society (engineering of new skyscrapers)

7/9/2004By Christopher Sell
"Once complete, Burj Dubai will claim the title of the world's tallest building. At over 2,000ft it will be almost twice as high as the Empire State Building and over 500ft taller than the current record holder, the Petronas Towers in Kuala Lumpur, Malaysia. But to reach such dizzying heights, unique engineering design challenges have presented themselves." Innovation had a really neat episode on the engineering of new skyscrapers. Most observers won't realize how much these buildings move. You can get sea sick! The article linked above discusses how the engineers for the Dubai building went back to wind tunnels and other standard approaches because the computer models doen't adequately predict the microscale wind turbulence. It also discusses vortex shedding (see Tacoma Narrows Bridge). The article also mentions the materials to be used which are much stiffer than older materials. The Innovation episode also discusses the change in attitude or lack of real change in attitude toward skyscrapers since 2001.
Update:  NYT has a nice article on an exhibit of skyscrapers.  It's more on the art than the engineering but still worth a visit.  (Herbert Muschamp, "Skyscraping Around the Urban World" July 16, 2004, free registration required or contact your library to find out how to get access through their databases) (7/16/04)

Thursday, July 08, 2004

Slate: Science as Metaphor: Where does Brian Greene stand in the pantheon of physicists?

7/6/04 by Amanda Schaffer
"His celebrity can be attributed to a widespread popular appetite for avant-garde science dressed in neat metaphorical packages: The universe is elegant; the cosmos is like a string symphony. Yet there is plenty to be suspicious of in Greene's unself-conscious romanticism—his unnuanced use of terms like elegance and beauty—and his teleological approach to the history of physics. Where, exactly, does he stand in the pantheon of physicists?"
Sean Carroll points out and discusses this article on his blog, Preposterous Universe. He also points to several other people who are commenting on this article.
I have my own opinion. First, a disclaimer: I only have a BS in physics so am not the one to really poke holes in the actual theory. My opinion: The best physics and math is elegant, simple, and yes, beautiful. Mathematics is beautiful. The power to describe the world in terms of equations is amazing. I've tried to explain this to people who got turned off of math and science by high school teachers who couldn't actually explain their subjects. I like Brian Greene and I like what he's trying to do. I think he does a good job of making this information more accessible to the public. For all of you doing government funded research, this is important! Greene also gives some disclaimers and problems of the theory, but maybe he doesn't go far enough. I think he does. I had a middle school age kid come up to me at a public library and ask for a copy of Fabric. I asked him and he read, understood, and enjoyed Elegant and he wants to be a physicist. That's what I'm talking about.
So, to answer the question, where does Brian Greene stand? He's respected in his field. He is respected and liked outside of his field.

Tuesday, July 06, 2004 New twist on fibre optics

by Josh Chamot, 6/2/2004
"By twisting fibre optic strands into helical shapes, researchers have created unique structures that can precisely filter, polarise or scatter light. Compatible with standard fibre optic lines, these hair-like structures may replace bulky components in sensors, gyroscopes and other devices.
While researchers are still probing the unusual properties of the new fibres, tests show the strands impart a chiral, or 'handed,' character to light by polarising photons according to certain physical properties." The author discusses an article originally published in Science (DOI: 10.1126/science.1097631). This is a pretty cool way to do this plus it's pretty simple... elegant even. For a really nice explanation of how fiber optics work, see the PBS Innovation episode "Light Speed". These scientists use a rectangular internal core, pop it into an oven, and give it a twist. The amount of twist decides if the photons of the same handedness are reflected backward, trapped in the cladding, or escape the cladding into space.