AffiliationUniv Arizona, Dept Phys, Appl Math Program
Univ Arizona, Dept Astron
MetadataShow full item record
PublisherAMER ASSOC PHYSICS TEACHERS
CitationAmerican Journal of Physics 86, 585 (2018); doi: 10.1119/1.5045333
JournalAMERICAN JOURNAL OF PHYSICS
Rights© 2018 American Association of Physics Teachers
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractIn general relativity, a gravitational horizon (more commonly known as the "apparent horizon") an imaginary surface beyond which all null geodesics recede from the observer. The Universe has an apparent (gravitational) horizon, but unlike its counterpart in the Schwarzschild and Kerr metrics, it is not static. It may eventually turn into an event horizon-an asymptotically defined membrane that forever separates causally connected events from those that are not-depending on the equation of state of the cosmic fluid. In this paper, we examine how and why an apparent (gravitational) horizon is manifested in the Friedmann-Robertson-Walker metric, and why it is becoming so pivotal to our correct interpretation of the cosmological data. We discuss its observational signature and demonstrate how it alone defines the proper size of our visible Universe. In so doing, we affirm its physical reality and its impact on cosmological models. (C) 2018 American Association of Physics Teachers.
VersionFinal accepted manuscript
SponsorsChinese Academy of Sciences [2012T1J0011]