Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?
DEAL: For $25 - Add A Second Phone Number To Your Smartphone for life! Use promo code SLASHDOT25. Also, Slashdot's Facebook page has a chat bot now. Message it for stories and more. Check out the new SourceForge HTML5 Internet speed test! ×

Comment Physicist's commentary and original article (Score 4, Informative) 460

For those who are interested, the scientific journal has a companion article here. It describes the design and sensitivity of the experiment, as well as some of the context. There is also a link to the actual journal article to the right, but you may need institutional access to download it.

Comment Re:Man-portable supercooling? (Score 1) 298

The basic technique is called a Magneto-Optical Trap, or MOT for short, although they probably use a few extra steps to create a Bose-Einstein condensate. As an atomic physicist, I have a couple of MOTs in my lab, and the whole thing will easily fit in a 1-meter long box. These things are actually being miniaturized quite effectively, and sensor packages using cold atoms are being built that fit in your hand. I bet a government-sponsored project could get them a bit smaller still. For example, here's a story about a DARPA project that's working to make a cold-atom based inertial guidance package for missiles that will be 20 cm^3.

Comment Re:this article doesn't have enough posts yet... (Score 4, Informative) 230

we know that simply observing an experiment can change the outcome. We don't know why that is either, AFAIK ... So it seems that consciousness and attention can have effects in the physical world, the mechanism of which we cannot explain.

We most certainly *do* know why observation affects an experiment. It's the Heisenberg uncertainty principle in action - if you make a measurement of the state of a system, that variable is known to some degree of precision. Its conjugate variable is thus made uncertain to a degree prescribed by the uncertainty principle. This has nothing to do with consciousness or a living observer.

A simple double-slit experiment works because of the uncertainty in the position of the particle. The wavefunction interferes with itself as it comes out of both slits and affects the possible positions it can be observed at on the detector. If you measure whether the particle passes through one of the slits, it's position is no longer uncertain, the wavefunction changes, and the experiment reflects that. This is well-understood quantum mechanics, although the popular press likes to pretend we don't know anything about it. And yes, IAAP (I am a physicist).

Comment Re:"the math of GR" -- how much math is that? (Score 1) 358

I can second the recommendation for Hartle (the title is Gravity: an Introduction to Einstein's General Relativity). It's a great introduction that I used as an undergrad, but be warned - it's still pretty complicated, even as an introduction. The nice part about it is that it develops the concepts of curved spacetime as you need them to investigate interesting physical systems, like the geometrized version of Special Relativity (which gets you time dilation and the Twin Paradox) or Schwarzschild black holes. My favorite section is where it discusses the metric of the entire universe, which describe the expansion of space and what happens to spacetime in the distant future.

As to Misner, Thorne, and Wheeler - avoid it until you've gone through some more introductory texts. It's really easy to get in over your head and get discouraged in that text, as they dive in head-first with hard-core math.

Comment Re:The First Amendment is Obsolete (Score 2, Informative) 141

If you think that a "fat slob" paying more for his insurance means that you'll pay less, you have a very naive view of insurance companies. Or companies in general. Also, how diligent do you think they'll be to check that you're not a fat slob? Remember that banks have been foreclosing on houses that weren't even in default!

Comment Re:PSA (Score 1) 125

I'm a physicist; I work in a laser lab. I never capitalize 'laser', and I've never seen it capitalized in any contemporary publication. Frankly, explicitly capitalizing acronyms gets really annoying once they enter common usage. It just gets in the way of effective communication.
Lord of the Rings

Submission + - Peter Jackson Will Produce "The Hobbit" (nytimes.com)

Soldrinero writes: After years of bitter fighting with the studio and nail-biting by the fans, the word has come out that there will be a "Hobbit" movie and it will be produced by Peter Jackson. Actually, the story will be split into two movies, to be released in 2010 and 2011. Time to start getting your costumes ready for the premier!

Submission + - OLPC News: OLPC Give 1 Get 1 Program: XO-1 Laptop (olpcnews.com)

wayan writes: "Oh My God! The event every geek has dreamed about for the last year is now here: OLPC XO laptop sales will start November 12th with promised delivery by Christmas in a Buy 1 Get 1 program from OLPC. $399 buys a XO laptop for you and one for a child in the developing world — Nicholas Negroponte's way to keep OLPC demand going when he's not getting government orders to fill Quanta's production line."

Submission + - iPhone Lives Up To Hype

soldrinero writes: The New York Times columnist and Missing Manual writer David Pogue has had his hands on an iPhone for the past few weeks, and is ready to give us mere mortals an early glimpse of its features. The verdict? It lives up to its hype.

Submission + - Hybrid Cars No Better than 'Predicting' Cars

eldavojohn writes: "There's no doubt been a lot of analysis done recently on energy consumption, especially on the road. Now, a study released today reveals that cars with traffic flow sensors built into them can perform just as efficiently as hybrids. The concept of an 'intelligent' car that communicates with the highway or other cars is an old idea but the idea of them using sensors to anticipate braking could vastly reduce fossil fuel consumption. From the article, "Under the US and European cycles, hybrid-matching fuel economy was reached with a look-ahead predictability of less than 60 seconds. If the predictability was boosted to 180 seconds, the newly-intelligent car was 33 percent more fuel-efficient than when it was unconverted." Now, the real question will be whether or not you can convince consumers that the three minutes of coasting up to a red light or halted traffic is worth the 33 percent less gas and replacing your brake pads/cylinders less often."

Submission + - Intel Debuts New Centrino Duo Chipset

DigitalDame2 writes: "Intel's latest Centrino Duo chipset, released today, gives you GMA X3100 graphics, support for Draft-n Wi-Fi, better battery life, and front-side bus speeds of up to 800 MHz. Along with the release, of course, comes a host of new laptops sporting the chipset, including offerings from Dell, Fujitsu, HP, and Lenovo. PC Mag has complete coverage of this new technology with reviews, news, and more."

Slashdot Top Deals

Suburbia is where the developer bulldozes out the trees, then names the streets after them. -- Bill Vaughn