Ion thrusters don't depend on chemical reactions. Ionization is through colliding a high-energy electron with the propellant, and then the ionized propellant is accelerated.

Using hydrogen is pretty dumb because you're trying to generate thrust. F=ma. Hydrogen has low mass.

They've been testing this for awhile. AFF (Autonomous Formation Flight) from 2001 is the first project I know about. The challenge is in the guidance and control system - it must be able to keep the trailing aircraft within inches of the desired position (12 inches for AFF) and maintain position through maneuvers and disturbances.

One study disagrees: http://www.sciencedaily.com/releases/2012/04/120429085411.htm Phone up or down made no difference, at least with this sample of teenagers.

Where are you in LA? I've been in LA area the past 5 years. Live in West LA and I've gone to just about everywhere as far east as San Gabriel Valley. The only place I've had terrible T-mobile coverage is Palos Verdes, but my understanding is that all the carriers suck there since no one wants cell towers cheapening their property.

You're forgetting the purpose of a rocket: to put something useful into space. Getting a rocket and a bunch of fuel into space is worthless by itself. More fuel means less payload.

I agree with you about Finder, but for home/end of a line, just press CMD+Left/Right. This just an idiosyncrasy of the OS, like pressing CMD+Down/Up to navigate folders instead of Enter and...is there even a "up one folder level" shortcut in Windows?

Those are patents, not copyright. Copyright is intended to help content creators profit from their work so they can make a living and create more content.

SEP has been in regular use for over a decade now...first EP-powered deep space mission was in 1998 (Deep Space 1), and just about every Earth-orbiting satellite relies on EP.

Anandtech mentions that the 520 went through a year of testing, so it should be much more reliable than other SF-2200 SSDs. Also fixed a BSOD issue in one of their systems, which was also using SF-2281.

It's not about what's good for the consumer, it's about what's good for non-Chinese economies. China did the same thing with rare earths – undercut all competitors and eventually produce more than 90% of the world's rare earth supply. Then they used that to control prices and where the refining and production takes place (hint: not anywhere overseas). They basically control the high-tech economy and wind turbine production (which need rare earth magnets). Who wants that for soloar panels too?

Opening new mines or even just re-opening the old mine in Mountain Pass, CA, can't happen "overnight." It will take at least seven years to open a new mine (http://www.gao.gov/new.items/d10617r.pdf).