In general relativity, a naked singularity is a hypothetical gravitational singularity without an event horizon. In a black hole, the singularity is completely enclosed by a boundary known as the event horizon, inside which the curvature of spacetime caused by the singularity is so strong that light cannot escape. Hence, objects inside the event horizon—including the singularity itself—cannot be observed directly. A naked singularity, by contrast, would be observable from the outside.
Jorge Pullin is an American theoretical physicist known for his work on black hole collisions and quantum gravity. He is the Horace Hearne Chair in theoretical Physics at the Louisiana State University.
Numerical relativity is one of the branches of general relativity that uses numerical methods and algorithms to solve and analyze problems. To this end, supercomputers are often employed to study black holes, gravitational waves, neutron stars and many other phenomena governed by Einstein's theory of general relativity. A currently active field of research in numerical relativity is the simulation of relativistic binaries and their associated gravitational waves.
A ring singularity or ringularity is the gravitational singularity of a rotating black hole, or a Kerr black hole, that is shaped like a ring.
Jozef T. Devreese is a Belgian scientist, with a long career in condensed matter physics. He is Professor Emeritus of Theoretical Physics at the University of Antwerp.
In loop quantum gravity, an s-knot is an equivalence class of spin networks under diffeomorphisms. In this formalism, s-knots represent the quantum states of the gravitational field.
Gravitational-wave astronomy is an emerging field of science, concerning the observations of gravitational waves to collect relatively unique data and make inferences about objects such as neutron stars and black holes, events such as supernovae, and processes including those of the early universe shortly after the Big Bang.
Patrick A. Lee is a professor of physics at the Massachusetts Institute of Technology (MIT).
Anzhong Wang is a theoretical physicist, specialized in gravitation, cosmology and astroparticle physics. He is on the Physics faculty of Baylor University. Currently he is working on cosmology in string/M theory and the Hořava–Lifshitz gravity.
Relativistic images are images of gravitational lensing which result due to light deflections by angles .
In physical cosmology, warm inflation is one of two dynamical realizations of cosmological inflation. The other is the standard scenario, sometimes called cold inflation.
A binary black hole (BBH) is a system consisting of two black holes in close orbit around each other. Like black holes themselves, binary black holes are often divided into stellar binary black holes, formed either as remnants of high-mass binary star systems or by dynamic processes and mutual capture; and binary supermassive black holes, believed to be a result of galactic mergers.
It was customary to represent black hole horizons via stationary solutions of field equations, i.e., solutions which admit a time-translational Killing vector field everywhere, not just in a small neighborhood of the black hole. While this simple idealization was natural as a starting point, it is overly restrictive. Physically, it should be sufficient to impose boundary conditions at the horizon which ensure only that the black hole itself is isolated. That is, it should suffice to demand only that the intrinsic geometry of the horizon be time independent, whereas the geometry outside may be dynamical and admit gravitational and other radiation.
Searches for Lorentz violation involving photons provide one possible test of relativity. Examples range from modern versions of the classic Michelson–Morley experiment that utilize highly stable electromagnetic resonant cavities to searches for tiny deviations from c in the speed of light emitted by distant astrophysical sources. Due to the extreme distances involved, astrophysical studies have achieved sensitivities on the order of parts in 1038.
James Michael Lattimer is a nuclear astrophysicist who works on the dense nuclear matter equation of state and neutron stars.
The first direct observation of gravitational waves was made on 14 September 2015 and was announced by the LIGO and Virgo collaborations on 11 February 2016. Previously, gravitational waves had been inferred only indirectly, via their effect on the timing of pulsars in binary star systems. The waveform, detected by both LIGO observatories, matched the predictions of general relativity for a gravitational wave emanating from the inward spiral and merger of a pair of black holes of around 36 and 29 solar masses and the subsequent "ringdown" of the single resulting black hole. The signal was named GW150914. It was also the first observation of a binary black hole merger, demonstrating both the existence of binary stellar-mass black hole systems and the fact that such mergers could occur within the current age of the universe.
Manuela Campanelli is a distinguished professor of astrophysics and mathematical sciences of the Rochester Institute of Technology, and the director of its Center for Computational Relativity and Gravitation and Astrophysics and Space Sciences Institute for Research Excellence. Her work focuses on the astrophysics of merging black holes and neutron stars, which are powerful sources of gravitational waves, electromagnetic radiation and relativistic jets. This research is central to the new field of multi-messenger astronomy.
Frans Pretorius is a South African and Canadian physicist, specializing in computer simulations in astrophysics and numerical solutions of Einstein's field equations. He is professor of physics at Princeton University and director of the Princeton Gravity Initiative.
Terry Schalk is an American physicist currently Professor Emeritus at University of California, Santa Cruz and an Elected Fellow of the American Association for the Advancement of Science.
Sydney Meshkov was a Theoretical Physicist who worked in gravitational wave, atomic, nuclear and particle physics.
