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Comment Re:Physics time! You misunderstand ion drives (Score 1) 473 473

The most popular theory is that it's transferring momentum via virtual particles. That has some startling implications, but it's less physics shaking than violating conservation of momentum. I'm not sure anyone has come up with any solid testable hypotheses yet, but it seems to be something that is likely to be testable in principle.

You'd have to work out the math, but I'd be cautious being too aggressive with relativistic reasoning. Conservation of energy and momentum in special relativity are a bit tricky to start with, and don't hold when you start jumping between reference frames.

Comment Re:Physics time! You misunderstand ion drives (Score 1) 473 473

If it's not reactionless then you're transferring momentum and energy and momentum are conserved in the same way they are in a regular rocket. If it's actually reactionless then presumably you would find you were harvesting energy from the spatial differences in the laws of physics. Either way, you wouldn't have a perpetual motion machine.

Comment Re: Looking more and more likely all the time... (Score 2) 473 473

Noether's theorem doesn't "fall." In this context it says (roughly) that if the laws of physics are the same in all places then linear momentum is conserved. We believe that the laws of physics don't vary with position, but they could.

Also, there are various explanations for how the drive could work without violating conservation of momentum. They require some other interesting violations of things we currently believe to be true, but aren't necessarily.

Comment Re:Blimey (Score 2) 473 473

For outer system stuff you'd use a nuke.

"Fuel" in terms of energy isn't the problem in a rocket. The problem is the requirement to haul around reaction mass: stuff to throw out the back. If you don't need to do that, the tyranny of the rocket equation goes away and space travel suddenly becomes a much different proposition.

Comment Re: What about the rest of it? And Firefox? (Score 1) 143 143

Hm... I took my six year old macbook pro in to an Apple Store the other day. They were happy to work on it. They ran a 24 hour diagnostic, free, after which I took it home and fixed the problem (they would have happily done so). My friend took in his 5 year old one, and they replaced the mainboard in it for free because it was one of the first lead free batches that had known faults.

Comment Re: What about the rest of it? And Firefox? (Score 1) 143 143

OS X is a unix-alike. Most of the software that runs on Linux will run on a Mac without a problem.

Your idea of open source seems to be of the double-click variety. There's a LOT of open source software that requires a ./configure; make to install. That works on Linux and Mac. If one of the developers is a masochist there might be a way to build it using Visual Studio on Windows, or more likely a way to build it under Cygwin.

Comment Re:shorts (Score 2) 467 467

While sweltering at an outdoor summer wedding wearing a jacket, pants and socks (!) I ended up in a conversation with a woman wearing some kind of sheer silk dress and sandals about how men don't understand the social pressure on women to appear a certain way. I told her I would love to wear what she was. She gave me this strange look and excused herself.

"Everything should be made as simple as possible, but not simpler." -- Albert Einstein

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