Cosmology of Early Universe and Anisotropy

Recent advancements in theoretical, observational, and computational techniques allow us to address the foundations of cosmology. The early universe remains mysterious, with the Big Bang and the bounce scenario being key models. Bounce cosmology offers a way to resolve the singularity issue in the standard (inflation) model, proposing a smooth transition from contraction to expansion.

On local scales, the Cosmic Microwave Background (CMB) shows that the universe exhibits neither homogeneity nor isotropy, with galaxies, galaxy clusters, and large-scale structures such as cosmic filaments and voids contributing to these anisotropies. In this context, the underlying geometry can be anisotropic. An example is a directional dependence of cosmic expansion, driven by a primordial cosmic magnetic field. Over time, an intrinsic mechanism may reduce this anisotropy, resulting in a more isotropic appearance as the universe evolves. Understanding the connection between the universe's anisotropy and the CMB presents a significant challenge that could reveal unknown mechanisms.

Dark matter and dark energy represent two of the most profound mysteries in modern cosmology, accounting for up to 95% of the universe's total energy. Dark matter's gravitational influence, in the form of particles beyond the Standard Model, is key to our understanding of structure formation, galaxy dynamics, and cosmic evolution. Conversely, dark energy poses profound questions about modifications to general relativity and the physics of the vacuum. Recent advances, through next-generation CMB experiments, deep-field galaxy surveys, and gravitational wave observations, etc., provide new opportunities to constrain the behaviors of the two unknown components.

Exploring extended Friedmann equations and extra-dimensional gravity is vital for understanding spacetime and cosmological dynamics. Modifications to these equations, such as brane-world scenarios, offer frameworks to address early inflation, late-time acceleration, and dark matter and energy. To survey further insights into early universe dynamics and foundational cosmological models, we welcome colleagues to submit their articles addressing, but not limited to, the following themes:

• The role of novel cosmological models in avoiding initial singularities.
• Comparative analyses of Big Bang and bounce cosmologies.
• The impact of cosmic anisotropy on large-scale cosmological structures.
• Extensions to traditional cosmological models involving dark matter and dark energy.
• The implications of CMB temperature anisotropies for cosmological isotropy.

Article types and fees

This Research Topic accepts the following article types, unless otherwise specified in the Research Topic description:

• Brief Research Report
• Data Report
• Editorial
• FAIR² Data
• FAIR² DATA Direct Submission
• General Commentary
• Hypothesis and Theory
• Methods
• Mini Review
• ... View all formats

Articles that are accepted for publication by our external editors following rigorous peer review incur a publishing fee charged to Authors, institutions, or funders.

Article types

This Research Topic accepts the following article types, unless otherwise specified in the Research Topic description:

• Brief Research Report
• Data Report
• Editorial
• FAIR² Data
• FAIR² DATA Direct Submission
• General Commentary
• Hypothesis and Theory
• Methods
• Mini Review
• Opinion
• Original Research
• Perspective
• Review
• Study Protocol
• Technology and Code

Keywords: Bounce cosmology, dark matter, dark energy, modified gravity, anisotropic cosmology, gravitational waves, extra-dimensional gravity, M-theory

Important note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.