horizon problem


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horizon problem

See inflation.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

horizon problem

[hə′rīz·ən ‚präb·ləm]
(astronomy)
The problem of explaining the observed uniformity of the universe, and in particular of the cosmic background radiation, when, according to the standard big-bang theory, sources of radiation coming from opposite directions in the sky were separated by manyfold the horizon distance at the time of emission, and thus could not possibly have been in physical contact.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
If such signals are discovered, it would provide an incontrovertible proof of cosmic inflation, solving, among other things, the (http://www.ibtimes.com/light-may-have-outpaced-gravity-early-universe-researchers-say-2450790) horizon problem , which deals with the fact that the universe has a uniform temperature even though heat-carrying particles would not have had enough time to reach all the corners of the cosmos.
These situations are dubbed "the horizon problem" when current owners cannot capture the value of investments that will benefit the next-generation of owners.
Inflation also solved the horizon problem, or how very distant regions on opposite sides of the sky today can look nearly alike even though in an uninflated Big Bang, nothing can ever have had any common influence on them at all.
The short time horizon problem is the tendency to extrapolate whatever is going on recently into the indefinite future, and making decisions accordingly.
While Obama's plan wouldn't grant any new leases until 2012, the Deepwater Horizon problem is casting a long shadow over the public comment process now going on in Virginia and other coastal states otherwise ready to sign on the dotted line for exploratory wells to go into their offshore waters.
Inflation is not needed because there does not exist the horizon problem. Monopoles should not be created because it is not hot enough.
The infinite horizon problem is undecidable, as it is for the single agent case (i.e., solving a regular POMDP) (23).
This issue is often avoided by representing the investment decision as an infinite horizon problem, but this is not very realistic.
For example, if it had been lower in the past, meaning a higher speed of light, it would solve the "horizon problem." Cosmologists have struggled to explain why far-flung regions of the universe are at roughly the same temperature.
Indeed, opportunistic reductions in R&D spending become more likely when: (1) the CEO approaches retirement (Dechow and Sloan 1991)--the horizon problem, and (2) the firm faces a small earnings decline of a small loss (Baber et al.
In the fifth chapter, Earman discusses the (particle) 'horizon problem' in standard big-bang models of the universe as an interesting case of the more general philosophical question of what counts as a good explanation.