Recent content by jbunch

I think you might want to go over the equations you wrote down. http://ned.ipac.caltech.edu/level5/March01/Carroll3/Carroll3.html If you were looking for the anti-symmetrical properties of Christoffel Symbols (ie torsion) and the commutation relations of the covariant derivative...here is a...

I believe I shouldn't be asking a question under another question but... since the discovery of g waves was brought up...I didn't see the point in opening another thread. My question is this: Why is the discovery of gravitational waves being considered irrefutable proof for the theory of...

thanks, hadn't heard of neutron drops. http://www.int.washington.edu/talks/WorkShops/int_13_1a/People/Gandolfi_S/Gandolfi.pdf

Here's a good paper showing a Gaussian distribution on Si with a length order of magnitude 10 minus 12. Looking for hard experimental data. http://arxiv.org/pdf/1210.0457v3.pdf

I don't get it. Are you saying that experiments haven't been carried out? And that there is not a limit to the experiments where we can verify in a lab a gravitational attraction? Doesn't sound crackpot to me. Just looking for the data.

It most certainly does. As I said, less than the Planck mass. Let's keep dividing that grain of sand by 2. Looking for a comprehensive list of experimental data that shows the experimental limit. thx

I should have been more explicit. I'm looking for verifiable info. on the limits of gravitational testability on a small scale. thx

Is there any experimental or observational evidence that conclusively shows gravitational forces acting on mass that is less than the Planck mass? thx

thank you all! extremely helpful Schwarzschild geodesics: http://en.wikipedia.org/wiki/Geodesics_of_the_Schwarzschild_vacuum

thanks PeterDonis. so if you establish a particular spacetime geometry, it's invalid to use the EFE as it is no longer background independent? Can you then use Special Relativity on this particular geometry? thanks

thanks

The Weyl Tensor governs tidal forces and gravitational radiation in free space devoid of matter and is not in Einsteins Field Equation. Still not sure how or why a star would orbit a black hole.

I think that brings me back to my original question. Or rephrasing: Is the black hole curving the space outside the event horizon and if not, how do stars orbit the black hole? thanks

thanks WannabeNewton! I appreciate your response. So, they are Ricci Flat? And the Ricci tensor vanishes but the Riemann Tensor doesn't. Does that leave us with the Weyl tensor which accounts for the tidal forces which aren't in the Einstein Field Equation? Is the spacetime outside the...

Hi, I'm new and uneducated. Would like to know how to reconcile space-time being considered asymptotically flat near the event horizon and beyond, with the observable fact that stars do indeed orbit the black hole. I understand those orbits are not near the horizon, and I believe all the...