Cosmology

This page features an overview of all our Spotlights dealing with cosmology. In the category Basics, you will find some more information about the big bang models, their predictions and cosmological observations, notably about the cosmic background radiation. Under Cosmology and quantum gravity there are some texts about the cosmological consequences of the current attempts to describe quantum theory and general relativity in a unified setting. Physics in the background features a Spotlight giving background information that is useful for a deeper understanding of the Spotlight texts presented on this page.

Useful background information can be found in our introduction Elementary Einstein, especially in the chapter Cosmology.

Basics

	The shape of space The different space geometries allowed by the big bang models - do we live on a hypersphere?
	Cosmic Sound: Curvature and the cosmic background radiation How the spatial geometry of the universe can be derived by observing the cosmic background radiation
	A tale of two big bangs In cosmology, "big bang" has two different meanings - and if you want to understand what's going on, you should be aware of that difference.
	Big Bang Nucleosynthesis How the first nuclei of helium, lithium and other light elements were cooked up shortly after the big bang
	Equilibrium and Change The physics behind Big Bang Nucleosynthesis, the period shortly after the big bang that saw the first production of light elements such as helium and lithium
	Elements of the past How to reconstruct the abundances of light elements shortly after the big bang, and thus test some important predictions of the big bang models against observation
	The mathematical universe Why cosmology is not only a matter for astronomers and physicists, but also for mathematicians
	Of gravitational waves and spherical chickens (also in Gravitational waves)    Information about a class of simple model universes, each an expanding cosmos filled with gravitational waves

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Cosmology and quantum gravity

More information about possible cosmological consequences of the attempts to formulate a theory of quantum gravity.

	Avoiding the big bang (also in Relativity and the quantum) The collapsing and then re-expanding quantum universe that loop quantum gravity offers as a replacement of the standard big bang models
	Taming infinity with loops (also in Relativity and the quantum) How loop quantum gravity could replace the absurd state of infinite density, the big bang with which, according to Einstein's relativity, the universe began.
	Searching for the quantum beginning of the universe (also in Relativity and the quantum) About attempts to understand the beginning of our universe using different approaches to quantum gravity

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Physics in the background

	Heat that meets the eye (also under Black Holes & Co.) The connection between temperature and the emission of electromagnetic radiation, as well as the consequences for stars, matter disks around black holes, and cosmology

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