期刊
CLASSICAL AND QUANTUM GRAVITY
卷 31, 期 23, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.1088/0264-9381/31/23/234003
关键词
general relativity; cosmology; backreaction
类别
资金
- NSF [PHY 12-02718]
- NSERC
- CITA National Fellowship at the University of Guelph
- Industry Canada
- Province of Ontario through the Ministry of Research Innovation
- Division Of Physics [1202718] Funding Source: National Science Foundation
Extremely well! In the Lambda CDM model, the spacetime metric, g(ab), of our Universe is approximated by an FLRW metric, g(ab)((0)), to about one part in 10(4) or better on both large and small scales, except in the immediate vicinity of very strong field objects, such as black holes. However, derivatives of g(ab) are not close to derivatives of g(ab)((0)), so there can be significant differences in the behavior of geodesics and huge differences in curvature. Consequently, observable quantities in the actual Universe may differ significantly from the corresponding observables in the FLRW model. Nevertheless, as we shall review here, we have proven general results showing that-within the framework of our approach to treating backreaction-the large matter inhomogeneities that occur on small scales cannot produce significant effects on large scales, so g(ab)((0)) satisfies Einstein's equation with the averaged stress-energy tensor of matter as its source. We discuss the flaws in some other approaches that have suggested that large backreaction effects may occur. As we also will review here, with a suitable 'dictionary,' Newtonian cosmologies provide excellent approximations to cosmological solutions to Einstein's equation (with dust and a cosmological constant) on all scales. Our results thereby provide strong justification for the mathematical consistency and validity of the Lambda CDM model within the context of general relativistic cosmology.
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