Editing Dark Energy (section)

=== Alternative Cosmological Models ===

'''Lemaitre-Tolman-Bondi (LTB) Model:'''  
The LTB model is a solution to Einstein's field equations that describes an inhomogeneous, spherically symmetric universe without assuming isotropy. In this model, the universe is allowed to have varying densities and expansion rates at different points, which could explain observations without invoking Dark Energy. For instance, if we live near the center of a large underdense region (a "void"), the apparent accelerated expansion could be a result of local inhomogeneities rather than a true cosmological constant.

For more on the LTB model:
* [https://arxiv.org/abs/0803.3688| Exploring the LTB Model as an Alternative to Dark Energy - arXiv]

'''Anisotropic Universe Models:'''  
There are cosmological models that relax the assumption of isotropy, allowing for different expansion rates or gravitational effects along different directions. These models can incorporate anisotropic stress or anisotropic Dark Energy, which could lead to observable effects such as differences in the expansion rate when viewed from different directions or variations in the CMB.

For further reading on anisotropic models:
* [https://journals.aps.org/prd/abstract/10.1103/PhysRevD.85.123518| Anisotropic Dark Energy: Observational Constraints and Stability - Physical Review D]