Recent content by keithdow

"Good! That brings us closer to the OP question. Does subjectivity require consciousness?" Since machines can make measurements and do calculations, the whole question is meaningless. Everything involved here can be done by a machine. In fact, since physicists use diverging integrals and...

Mermin didn't establish if Feynman did or didn't say it. Feynman's approach was clear though. He said he didn't understand quantum mechanics, but he did know how to calculate,

Feynman said the Copenhagen interpretation of quantum mechanics was simple, "Shut up and calculate."

"I've no clue what you want to tell me." The wave function collapses when a measurement is made. For the external observer, it collapses when he checks to see if the cat is dead. For the internal observer it is collapsing all the time because the internal observer is making a continuous...

You should look up Wigner's friend. Simply stated, put someone inside a space suit next to Schrodingers cat. It won't affect the outcome of the experiment. For the external observer, the wave function only collapses when he looks. For the friend, the observation in continuous.

If you want to consider why or why not something was used, the first consideration often is money.

I believe a simple chart is the following: (xe^z, ye^z)

I am looking at the classic paper Israel and Khan "Collinear Particles and Bondi Dipoles in General Relativity" Nuovo Cimento 33 (1964) 331. The basic question is how to go from equation 2.9 to 2.10? a_i is the center of rod i and b_i is the mass of rod i. The attached file has the details...

Thank you sir. You are correct. I am reading it now.

I have a question about equation 10.21 in "Exact Space-times in Einstein's General Relativity" by Griffiths and Podolski. The equation is the well know standard metric for multiple extreme Reissner Nordstrom black holes. It has the below term: (1+ sigma(mi/ri)) The point ri = 0 is of course...

Thanks! Now how do I show that?

Here is a simple one. An observer far away from a black hole emits a light pulse every second. A second observer has just crossed into the event horizon and received one of his pulses. How many additional pulses will the second observer receive before he is crushed at pi*m proper time. Thanks.

Thanks. So the easy way is for the external observer to keep sending signals to the in falling frame of reference.

Thanks. It is obvious that I will have to write the computer program and run the simulation myself to get the answer. I can probably get a paper out of it.

Actually the idea of global simultaneity is fundamental to 3+1 formalism. Let me quote from "Introduction to 3+1 Numerical Relativity". Page 65. "Let us start by considering a spacetime with metric gαβ. As already mentioned in Chapter 1, we will always assume that the spacetimes of interest...