Cosmic inflation

In physical cosmology, cosmic inflation, cosmological inflation, or just inflation, is a theory of exponential expansion of space in the very early universe. Following the inflationary period, the universe continued to expand, but at a slower rate. The re-acceleration of this slowing expansion due to dark energy began after the universe was already over 7.7 billion years old (5.4 billion years ago).^[1]

Inflation theory was developed in the late 1970s and early 1980s, with notable contributions by several theoretical physicists, including Alexei Starobinsky at Landau Institute for Theoretical Physics, Alan Guth at Cornell University, and Andrei Linde at Lebedev Physical Institute. Starobinsky, Guth, and Linde won the 2014 Kavli Prize "for pioneering the theory of cosmic inflation".^[2] It was developed further in the early 1980s. It explains the origin of the large-scale structure of the cosmos. Quantum fluctuations in the microscopic inflationary region, magnified to cosmic size, become the seeds for the growth of structure in the Universe (see galaxy formation and evolution and structure formation).^[3] Many physicists also believe that inflation explains why the universe appears to be the same in all directions (isotropic), why the cosmic microwave background radiation is distributed evenly, why the universe is flat, and why no magnetic monopoles have been observed.

The detailed particle physics mechanism responsible for inflation is unknown. A number of inflation model predictions have been confirmed by observation; for example temperature anisotropies observed by the COBE satellite in 1992 exhibit nearly scale-invariant spectra as predicted by the inflationary paradigm and WMAP results also show strong evidence for inflation.^[4] However, a some scientists dissent from this position.^[5]^[6]^[7] The hypothetical field thought to be responsible for inflation is called the inflaton.^[8]

In 2002, three of the original architects of the theory were recognized for their major contributions; physicists Alan Guth of M.I.T., Andrei Linde of Stanford, and Paul Steinhardt of Princeton shared the Dirac Prize "for development of the concept of inflation in cosmology".^[9] In 2012, Guth and Linde were awarded the Breakthrough Prize in Fundamental Physics for their invention and development of inflationary cosmology.^[10]

^ "First Second of the Big Bang". How The Universe Works 3. 2014. Discovery Science.
^ "2014 Astrophysics Citation". The Kavli Foundation. Archived from the original on 14 July 2014. Retrieved 27 July 2014.
^ Tyson, Neil deGrasse and Donald Goldsmith (2004), Origins: Fourteen Billion Years of Cosmic Evolution, W. W. Norton & Co., pp. 84–85.
^ Tsujikawa, Shinji (28 April 2003). "Introductory review of cosmic inflation". arXiv:hep-ph/0304257.
^ Cite error: The named reference Steinhardt2011 was invoked but never defined (see the help page).
^ Cite error: The named reference Earman-Mosterín was invoked but never defined (see the help page).
^ Cite error: The named reference Hložek was invoked but never defined (see the help page).
^ Guth, Alan H. (1997a). The Inflationary Universe: The quest for a new theory of cosmic origins. Basic Books. pp. 233–234. ISBN 978-0201328400.
^ "The Medallists: A list of past Dirac Medallists". ictp.it.
^ "Laureates of the Breakthrough Prize in Fundamental Physics in 2012". breakthroughprize.org. Breakthrough Prize in Fundamental Physics.

[1] "First Second of the Big Bang". How The Universe Works 3. 2014. Discovery Science.

[KavliPrize-2] "2014 Astrophysics Citation". The Kavli Foundation. Archived from the original on 14 July 2014. Retrieved 27 July 2014.

[3] Tyson, Neil deGrasse and Donald Goldsmith (2004), Origins: Fourteen Billion Years of Cosmic Evolution, W. W. Norton & Co., pp. 84–85.

[4] Tsujikawa, Shinji (28 April 2003). "Introductory review of cosmic inflation". arXiv:hep-ph/0304257.

[Steinhardt2011-5] Cite error: The named reference Steinhardt2011 was invoked but never defined (see the help page).

[Earman-Mosterín-6] Cite error: The named reference Earman-Mosterín was invoked but never defined (see the help page).

[Hložek-7] Cite error: The named reference Hložek was invoked but never defined (see the help page).

[8] Guth, Alan H. (1997a). The Inflationary Universe: The quest for a new theory of cosmic origins. Basic Books. pp. 233–234. ISBN 978-0201328400.

[Dirac_Prize-9] "The Medallists: A list of past Dirac Medallists". ictp.it.

[Breakthrough_Prize-10] "Laureates of the Breakthrough Prize in Fundamental Physics in 2012". breakthroughprize.org. Breakthrough Prize in Fundamental Physics.

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