Topic
Particle horizon
About: Particle horizon is a research topic. Over the lifetime, 2096 publications have been published within this topic receiving 69137 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this paper, an empty Kantowski-Sachs universe model with cosmological constant Λ was studied and the characteristic feature of an inflationary era was found, and the model emerged from a pointlike, stringlike, membranelike singularity and developed toward an isotropic de Sitter universe.
Abstract: We study an empty Kantowski-Sachs universe model with cosmological constant Λ. The characteristic feature of an inflationary era is found. This universe model emerges from a pointlike, stringlike, membranelike singularity and develops toward an isotropic de Sitter universe.
7 citations
TL;DR: In this article, the authors examined the validity of first and second laws of thermodynamics on apparent and event horizons for three different types of dark energy models and found that on the apparent horizon, the laws are always valid.
Abstract: We have considered the flat FRW model of the universe which is filled with only dark energy. The general descriptions of first and second laws of thermodynamics are investigated on the apparent horizon and event horizon of the universe. We have assumed the equation of state of three different types of dark energy models. We have examined the validity of first and second laws of thermodynamics on apparent and event horizons for these dark energies. For these dark energy models, it has been found that on the apparent horizon, first and second laws are always valid. On the event horizon, the laws are break down for dark energy models 1 and 2. For model 3, first law cannot be satisfied on the event horizon, but second law may be satisfied at the late stage of the evolution of the universe and so the validity of second law on the event horizon depends on the values of the parameters only.
7 citations
TL;DR: In this article, the phase transition from the decelerating universe to the accelerating universe, which is of relevance to the cosmological coincidence problem, is possible in the semiclassically quantized two-dimensional dilaton gravity by taking into account the noncommutative field variables during the finite time.
7 citations
Book•
01 Jan 1999TL;DR: Black holes More to light than meets the eye! Invisible stars Beyond the horizon A hole that can never be filled Spinning black holes Falling into a black hole To see a hole Not so black after all White holes Time Times are Changing What is time? Who invented time? The first moment Does time flow? Something called entropy Arrows of time Stephen Hawking gets it wrong A possible solution Einstein's Time What is so special about special relativity? The two faces of light Thought experiments and brain-teasers Slowing down time Shrinking distances Light-the world speed record When time runs
Abstract: SPACE The 4th Dimension To do with shapes What is space? 2Dworld and 2D'ers Curved space Is there really a 4th dimension? Matters of Some Gravity Apples and moons Einstein's gravity Free fall Rubber space Twinkle, twinkle Cooking the elements Champagne supernova in the sky The Universe The night sky How big is the Universe? The expanding Universe Hubble, bubble ... Space is stretching Did the Big Bang really happen? The edge of space A closed universe An open universe What shape is the Universe then? Invisible matter 1998: a big year in cosmology Is the Universe infinite? Why is it dark at night? Before the Big Bang? Summary Black Holes More to light than meets the eye! Invisible stars Beyond the horizon A hole that can never be filled Spinning black holes Falling into a black hole To see a black hole Not so black after all White holes TIME Times Are Changing What is time? Who invented time? The first moment Does time flow? Something called entropy Arrows of time Stephen Hawking gets it wrong A possible solution Einstein's Time What is so special about special relativity? The two faces of light Thought experiments and brain-teasers Slowing down time Shrinking distances Light-the world speed record When time runs backwards Little green men Fast-forward to the future Spacetime-the future is out there Gravitational times Time Travel Paradoxes The Terminator paradox Trying to save the dinosaurs Mona Lisa's sister No way out? Parallel universes Where are all the time travelers? TIME MACHINES Wormholes A bridge to another world Alice through the looking glass When science fact met science fiction Wormholes-keeping the star gate open Visiting a parallel universe How to Build a Time Machine Time loops The Tipler time machine Cosmic string time machines A recipe for a wormhole time machine Insurmountable problems? What Do We Know? The mother of all theories The end of theoretical physics What might new experiments tell us? Astronomy versus astrology The fascination of science Suggestions for Further Reading Index
7 citations