Physics
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Item Reorganizing Nothingness(2017) Misner, Charles WThis note is directed to scientists who intend to help wide audiences better understand current science progress. It sketches, in mostly qualitative descriptions, what is known about simple black holes. It describes black holes when they are no longer importantly interacting with other astronomical objects. Thus, it does not explore black holes seen to be currently acquiring mass by absorbing ordinary matter in accretion disks. Nor do I try to explain how matter just outside the black hole horizon can be expelled in violent jets powered by the energy stored in the gravitational fields of rotating black holes. Brief descriptions of simple black holes explain that BHs can be formed from ordinary matter in large stars that find no non-gravitational forces sufficient to overcome the intense gravity of extremely large masses at extreme densities. Where this note differs is when the simple descriptions suggest that, after forming and entering beyond the BH horizon, the collapsing matter is crushed beyond the scope of current physics nearly into a point, inside the BH, that we can’t observe. I insist that, instead, the matter is crushed and then disposed of by being flushed out of our universe in a tube of huge and increasing spatial length. A mathematical appendix explores this idea in a little detail. I suggest that many low curvature spacetime regions inside the BH are very robust consequences of Einstein’s equations and require a new vocabulary in their description. There I choose analog words to present my viewpoint. I find a use for phrases such as: nothingness; enzymatic matter; phase transitions; recuse; autonomic spacetime creation.Item Submillimeter Test of the Gravitational Inverse-Square Law Using a Superconducting Differential Accelerometer(2007-11-21) Prieto, Violeta A; Paik, Ho Jung; Physics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The inverse-square law of gravitation is tested at submillimeter distances. To minimize Newtonian errors, the experiment employs a near null source, a circular disk of large diameter-to-thickness ratio. Two test masses, also disk-shaped, are suspended on the two sides of the source mass at a nominal distance of 180 micrometers. The source mass amplitude of motion is 16.1 micrometers. The signal is detected by a superconducting differential accelerometer. Careful matching and alignment makes the detector highly immune to platform vibrations. To reduce the thermal Brownian motion noise as well as the temperature noise of the instrument, the experiment is cooled to 1.7 K by pumping on liquid helium. In this dissertation, I discuss the assembly, design, and design improvements of the inverse square law experiment. I perform a comprehensive analysis of the errors, identify the problems with the apparatus, and show ways to improve the design of the experiment. With the improved design, it will be possible to achieve a sensitivity of |alpha| = 2 x 10^-3 at lambda = 150 micrometers, which will improve the current experimental limits by one order of magnitude at 150 micrometers and by over two orders of magnitude at shorter distances.