Cosmic egg

The world egg, cosmic egg or mundane egg is a mythological motif found in the cosmogonies of many cultures that is present in Proto-Indo-European culture and other cultures and civilizations. Typically, the world egg is a beginning of some sort, and the universe or some primordial being comes into existence by "hatching" from the egg, sometimes lain on the primordial waters of the Earth. Typically, the upper half of the egg, or its outer shell, becomes the heaven (firmament) and the lower half, or the inner yolk, becomes the Earth. The motif likely stems from simple elements of an egg, including its ability to offer nourishment and give rise to new life, as is reflected by the Latin proverb omne vivum ex ovo ('all life comes from an egg').

The modern cosmological versions of this idea are called the emergent Universe scenarios.