Explains expanding space, redshift, and the hot early universe leading to the standard model.

Presents the steady state alternative, its perfect cosmological principle, and the rise of observational tests.

Introduces cyclic models and ekpyrotic brane scenarios as attempts to avoid a single beginning.

Explores string theory-based bounce ideas, extra dimensions, and a landscape of possible universes.

Describes pillars like redshift, CMB, nucleosynthesis, and large-scale structure that support or challenge cosmology.