swansont

Explain why.

I took a break between undergrad and grad school. At first I was just going to get my MS, but my two best friends (both were in grad school) convinced me that I was not likely to go back to school yet again, so if I was going to go for a PhD I should do it all in one shot, which is what I ended up doing. In retrospect, they were right, and I'm glad I took their advice. It's hard enough being an impoverished and overworked grad student once; it would be really hard to readjust one's life to do it twice.

I don't know if I can cover all the possible scenarios (as I've stated a number of times, my expertise in GR is limited). I was thinking of the "straight-line" (as described in recent posts) motion at constant speed. If the space is curved, there is a force, or what would classically be called a force, acting on the object. As for other cases, straight-line freefall in a gravitational field is an inertial frame - that's the standard example in equivalence principle argument. But I was discussing things in context of the given scenario.

It is my understanding that inertial space has to be flat.

V=IR The current is going to depend on the voltage, which is given, and the impedance. What is the impedance of the circuit?

As is mentioned in a few other posts, the hypersphere does not constitute an inertial frame, which means you can't blindly apply SR to it. As Tom Mattson suggested, one should work out the case of two travellers who, in flat space, travel away from each other, turn around, and return. It seems to me that this shows the dynamics of the issue more clearly. They hypersphere scenario is similar, but has a small acceleration over the whole trip, and it makes it harder to see what's going on. Though once you've solved the simpler case, it will make the hypersphere case a little easier to understand. Walk before you run, and all that.

How does one manage a round trip, travelling in a straight line? Either one or both of them have to accelerate, or you have to have curved space, which AFAIK is going to act like an acceleration (and was the point of the OP)

They would both be travelling at the same v wrt the observer, and have the same dilation.

As I understand it the curvature changes only if there is an acceleration. So for a single mass, moving at a constant v, there is no radiation. It looks completely static in its own frame. A binary system (or bigger) will radiate, but if one mass is large compared to the others, the acceleration is very small. Since the scaling factor is related to G you need really large accelerations to give off appreciable radiation. This is why binary pulsars are one target of investigation. The binary stars will accelerate a lot (e.g. center of mass outside the star) and the fact that they are pulsars gives an easy thing to measure. Solar systems such as ours would be a much weaker source.

Actually, as the mu gets higher, it saturates more easily, because you are concentrating the field more.

If it's cheap you want, soft iron is the way to go, or steel as YT said. (mu metal isn't cheap)

5614 is right. The particles have to interact. Neutrinos interact via the weak force, so cross sections are extremely small.

The solution to Maxwell's equations, which is a wave equation for EM radiation, fails if c depends on the speed of the source or observer. It doesn't matter if the difference is small - the solution fails. We see EM waves with high speed devices/particles as well as low speed ones. Another implication of constant c is time dilation. This is also observed for high speed particles and lower speed devices.

If EM radiation doesn't travel at c, Maxwell's equations don't work: you don't satisfy the wave equaton. I think we can safely say that radio waves are still waves even if the car is in motion.

No. Gravity waves travel at c. Van Flandern is misrepresenting or misinterpreting the physics. There are other speed of gravity threads. Speed of gravity faster than light? How fast is gravity? Kopeikin's experiment isn't the only one. There are binary pulsar orbital decay observations, too.

The kind of detailed "which path" experiments they are describing aren't really introductory QM. I've looked at a few of the pages on the site and I'm not convinced they are describing experiments accurately.

Civilization III, Heroes of Might and Magic III (I thought IV was lousy), Railroad Tycoon II and III. I like turn-based games as opposed to ones that require good hand-eye coordination and visual skills. I mean, if I had those skills, I'd be out playing real games instead of sitting at my computer

I did, and I have to call BS on this. Can you post a link to anyone who has a working device, anywhere, in use? Sr-90 does not alpha decay, and neither does its daughter in the decay process, Y-90. That is the least of the problems. The claim here is that the battery would produce 7500 W per g of Sr-90. That's some trick, considering that the decay to stability (Sr-> Y -> Zr, all betas) releases about 2.8 MeV of energy (.546 MeV for Sr, and 2.28 MeV for Y), and that the total power you could get (assuming 100% efficiency) is about 2.3 W per gram. The rest of the explanation in the link is perpetual motion/quantum snake oil mumbo-jumo. This link explains how Brown's company had been sued for fraud. Nobody could come up with a working device. I'm shocked, shocked to find gambling going on in this establishment.