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Comment Re:Location (Score 1) 560

Well, it does, actually. If you intercept a signal, you absorb part of it, so you are changing the electromagnetic field. If you are changing the electromagnetic field, you can be tracked (in principle). Of course you're not going to track a portable radio for reasons of practicality, but that's an issue of scale, and not something fundamentally inherent to the theory. In some circles it goes by the name of radar :)
Science

Invisibility Cloak Created In 3-D 113

An anonymous reader writes "Scientists have created the first device to render an object invisible in three dimensions. The 'cloak,' described in the journal Science (abstract; full text requires login), hid an object from detection using light of wavelengths close to those that are visible to humans. Previous devices have been able to hide objects from light travelling in only one direction; viewed from any other angle, the object would remain visible. This is a very early but significant step towards a true invisibility cloak." The "object" hidden in this work was a bump one micrometer high. The light used was just longer than the wavelengths our eyes detect. To get a visible-light cloak, the features of the cloaking metamaterial would need to be reduced in size from 300 nm to 10 nm.

Comment Re:Not same as elevator (Score 2, Interesting) 296

Actually, "out of Earth's gravity well" would truly be the "edge of space", i.e., infinitely far away. As I understand, the biggest problem in getting to space is to spend as little time as possible in the deepest part of the well, because, going straight up, maintaining that altitude costs a lot of power. But if the structure is self-supporting, then you can hoist up your fuel and payload using more efficient means, since you don't have to actively maintain your altitude. It's called "gravity drag". I'm not really up on the numbers, but the first 10% costs you a helluva lot more fuel than the "last" 10%, for most values of $destination.

Comment Re:string analogues (Score 3, Interesting) 236

Well this is closer to "universality", which is a concept in field theory and condensed matter physics, in which the "atomic" characteristics of a system are largely irrelevant to its macroscopic properties, save for specifying a few parameters like viscosity or resistivity. Unlike your differential equation example, the equations for both are very different and non-trivial. When you start enumerating differential equations starting from the simplest you can write down, the harmonic oscillator, heat equation, diffusion equation and so forth pop out right away. You'll be writing for a long time before 11D supergravity equations of motion pop out.

Comment What women want (Score 1) 349

Many women are interested in using technology, they just don't want to dive in to quite the same depth. Or they may not be interested in the way most men approach it.

Or... and I'm going out on a limb here... many women don't want men telling them what they want. "Just don't want to dive into quite the same depth"? Dear lord.

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