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:
“His life was gentle, and the elements
So mixed in him that nature might stand up
And say to all the world “This was a man.””
—William Shakespeare (1564–1616)
“We must not inquire too curiously into the absolute value of literature. Enough that it amuses and exercises us. At least it leaves us where we were. It names things, but does not add things.”
—Ralph Waldo Emerson (1803–1882)
“The whole world of thought lay unexplored before me,—a world of which I had already caught large and tempting glimpses, and I did not like to feel the horizon shutting me in, even to so pleasant a corner as this.”
—Lucy Larcom (1824–1893)