Structure formation

In physical cosmology, structure formation is the formation of galaxies, galaxy clusters and larger structures from small early density fluctuations. The universe, as is now known from observations of the cosmic microwave background radiation, began in a hot, dense, nearly uniform state approximately 13.8 billion years ago.^[1] However, looking at the night sky today, structures on all scales can be seen, from stars and planets to galaxies. On even larger scales, galaxy clusters and sheet-like structures of galaxies are separated by enormous voids containing few galaxies.^[2] Structure formation attempts to model how these structures were formed by gravitational instability of small early ripples in spacetime density^[3]^[4]^[5]^[6] or another emergence.^[7]

The modern Lambda-CDM model is successful at predicting the observed large-scale distribution of galaxies, clusters and voids; but on the scale of individual galaxies there are many complications due to highly nonlinear processes involving baryonic physics, gas heating and cooling, star formation and feedback. Understanding the processes of galaxy formation is a major topic of modern cosmology research, both via observations such as the Hubble Ultra-Deep Field and via large computer simulations.

^ "Cosmic Detectives". The European Space Agency (ESA). 2013-04-02. Retrieved 2013-04-15.
^ Einasto, J.; Longair, M.S. (1978). "The Large Scale Structure of the Universe Symposium". Large Scale Structures in the Universe. 79. Reidel: 247. Bibcode:1978IAUS...79..241J.
^ Dodelson, Scott (2003). Modern Cosmology. Academic Press. ISBN 978-0-12-219141-1.
^ Liddle, Andrew; David Lyth (2000). Cosmological Inflation and Large-Scale Structure. Cambridge. ISBN 978-0-521-57598-0.
^ Padmanabhan, T. (1993). Structure formation in the universe. Cambridge University Press. ISBN 978-0-521-42486-8.
^ Peebles, P. J. E. (1980). The Large-Scale Structure of the Universe. Princeton University Press. ISBN 978-0-691-08240-0.
^ Ben-Amots, N. (2021). "Helium as a major portion of the dark matter and the cell structure of the universe". Journal of Physics: Conference Series. 1956 (1): 012006. Bibcode:2021JPhCS1956a2006B. doi:10.1088/1742-6596/1956/1/012006.

[1] "Cosmic Detectives". The European Space Agency (ESA). 2013-04-02. Retrieved 2013-04-15.

[2] Einasto, J.; Longair, M.S. (1978). "The Large Scale Structure of the Universe Symposium". Large Scale Structures in the Universe. 79. Reidel: 247. Bibcode:1978IAUS...79..241J.

[dodelson-3] Dodelson, Scott (2003). Modern Cosmology. Academic Press. ISBN 978-0-12-219141-1.

[liddle-4] Liddle, Andrew; David Lyth (2000). Cosmological Inflation and Large-Scale Structure. Cambridge. ISBN 978-0-521-57598-0.

[padmanabhan-5] Padmanabhan, T. (1993). Structure formation in the universe. Cambridge University Press. ISBN 978-0-521-42486-8.

[peebles-6] Peebles, P. J. E. (1980). The Large-Scale Structure of the Universe. Princeton University Press. ISBN 978-0-691-08240-0.

[7] Ben-Amots, N. (2021). "Helium as a major portion of the dark matter and the cell structure of the universe". Journal of Physics: Conference Series. 1956 (1): 012006. Bibcode:2021JPhCS1956a2006B. doi:10.1088/1742-6596/1956/1/012006.

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