The identification of black holes is one of the most important tasks of modern astrophysics. Candidates have been selected among binary stars based on a high mass function, and seriously considered when the lower mass limit exceeds ∼ 3M⊙. More recently the absence of (Type I) thermonuclear bursts has been advanced as an additional criterion in favor of the black hole interpretation, since the a...

The Bondi-van der Burg-Metzner-Sachs (BMS) group is the asymptotic symmetry group of asymptotically flat spacetime. It is infinite dimensional and entails an infinite number of conservation laws. According to the black hole membrane paradigm, null infinity (in asymptotically flat spacetime) and black hole event horizons behave like fluid membranes. The fluid dynamics of the membrane is governed...

In a recent paper [13] the author and Rick Schoen obtained a generalization to higher dimensions of a classical result of Hawking concerning the topology of black holes. It was proved that, apart from certain exceptional circumstances, cross sections of the event horizon (in the stationary case) and outer apparent horizons (in the general case) in black hole spacetimes obeying the dominant ener...

We present a Dirac quantization of generic single-horizon black holes in twodimensional dilaton gravity. The classical theory is first partially reduced by a spatial gauge choice under which the spatial surfaces extend from a black or white hole singularity to a spacelike infinity. The theory is then quantized in a metric representation, solving the quantum Hamiltonian constraint in terms of (g...

We measured the modulation of pupil size (in constant lighting) elicited by observing transparent surfaces black and white moving dots, perceived as a cylinder rotating about its vertical axis. The direction rotation was swapped periodically flipping stereo-depth two surfaces. Pupil modulated in synchrony with changes front-surface color (dilating when black). magnitude pupillary larger for hum...

We consider a spherically symmetric line element which admits either black hole geometry or wormhole and show that in both cases the apparent horizon throat is partially characterized by zero-set of single curvature invariant. The detection this invariant consistent with geometric conjectures implies it hole, while presents conceptual problem for conjectures. To distinguish between these surfac...

Blackening was observed on the surfaces of Mesopotamian clay tablets from Umma, Dilbat, Larsa, Ur, Babylon, Uruk, Sippar, and Nippur produced between the Third Dynasty of Ur and the Early Achaemenid Dynasty. Portable X-ray fluorescence analysis revealed that manganese was concentrated on the blackened surfaces. Rod-shaped materials with a length of 100 200 nm and a width of 30 nm were observed ...

In this study, we present several demonstrations of color averaging between luminance boundaries. In each of the demonstrations, different black outlines are superimposed on one and the same colored surface. Whereas perception without these outlines comprises a blurry colored gradient, superimposing the outlines leads to a much clearer binary color percept, with different colors perceived on ea...

Knowledge of cells' interactions with nanostructured materials is fundamental for bio-nanotechnology. We present results for how individual mouse fibroblasts from cell line NIH3T3 respond to highly spiked surfaces of silicon black that were fabricated by maskless reactive ion etching (RIE). We did standard measurements of cell viability, proliferation, and morphology on various surfaces. We als...

Lubricants ordinarily operate by keeping two sliding surfaces separated. The efficiency of a lubricant may be expressed by equations of hydrodynamics where the mechanical properties of the films of lubricants are adequately defined by the properties of bulk lubricant. In the case of water lubrication of black rubber at slow speeds and low pressures the lubricating ability of water is shown to b...