Nature of The Absolute Horizon
The definition of an absolute horizon is sometimes referred to as teleological, meaning that it cannot be known where the absolute horizon is without knowing the entire evolution of the universe, including the future. This is both an advantage and a disadvantage. The advantage is that this notion of a horizon is very geometrical, and does not depend on the observer, unlike apparent horizons, for example. The disadvantage is that it requires the full history (all the way into the future) of the spacetime to be known. In the case of numerical relativity, where a spacetime is simply being evolved into the future, only a finite portion of the spacetime can be known.
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Famous quotes containing the words nature, absolute and/or horizon:
“From cradle to grave this problem of running order through chaos, direction through space, discipline through freedom, unity through multiplicity, has always been, and must always be, the task of education, as it is the moral of religion, philosophy, science, art, politics and economy; but a boy’s will is his life, and he dies when it is broken, as the colt dies in harness, taking a new nature in becoming tame.”
—Henry Brooks Adams (1838–1918)
“The Prime Minister has an absolute genius for putting flamboyant labels on empty luggage.”
—Aneurin Bevan (1897–1960)
“However closely people are attached to one another, their mutual horizon nonetheless includes all four compass directions, and now and again they notice it.”
—Friedrich Nietzsche (1844–1900)