List of estimates of the age of the universe

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Since the concept of an expanding universe was first introduced, there have been many estimates of the age of the universe that have evolved with scientific discoveries and developments. Many early estimates used the recessional velocities of distant galaxies to calculate the age of the universe, often getting results of about 2 Gyr (2 billion years) or less. Because this was less than calculations of Earth's age at the time, which were considered more accurate, doubt was cast upon the theory of expansion. This problem was resolved in 1952 when Walter Baade discovered that distances to neighboring galaxies, which were being used in the calculation of the age of the universe, were larger than previously thought; this brought the estimated age of the universe to about 4 Gyr.[1]

As time went on and observations improved, estimates for the age of the universe rose, with most estimates in the 1970s through 1990s in the range of 8–20 Gyr. Many of the higher estimates were due to the age of the oldest globular clusters, which had been estimated to be as high as 16 Gyr; these ages were later revised lower after new data revealed that they were further than previously thought.[2]

The launch of the Wilkinson Microwave Anisotropy Probe (WMAP) in 2001 and the Planck spacecraft in 2009, both measuring anisotropies in the cosmic microwave background, allowed astronomers to make more precise measurements of the age of the universe. The first year of WMAP data resulted in an estimated age of 13.7 ± 0.2 Gyr by two independent research groups.[3][4] As of 2026, the accepted age of the universe is 13.787 ± 0.020 Gyr, based on data from the Planck spacecraft analyzed in 2018.[5]

List

Estimate Year Method Authors References
10 Gyr 1922 Mathematical derivation of the Friedmann equations Alexander Friedmann [6][7]
1.8 Gyr 1929 Recessional velocity, Cepheid variables Edwin Hubble [8][9][10]
>2×105 Gyr 1930 Gravitational collapse of nebulae James Jeans [11][12]
<2 Gyr 1931 Mathematical derivation from relativity Arthur Eddington [13][1]
1–10 Gyr 1935 Recessional velocity Edwin Hubble, Richard Tolman [14][1]
5–10×103 Gyr 1936 Orbits of binary stars James Jeans [15]
0.75–1.5 Gyr 1937 Recessional velocity, positive cosmological constant Edwin Hubble [1][16]
0.7 Gyr 1938 Recessional velocity Paul Dirac [17][1]
<1 Gyr 1942 Recessional velocity Edwin Hubble [10][1]
3.64 Gyr 1949 Recessional velocity, nonhomogenous cosmology Guy Omer [18]
3.5 Gyr 1952 Revised distance calculations, recessional velocity Walter Baade [1][19]
4.1 Gyr 1956 Dirac large numbers hypothesis C. Gilbert [20]
13.0 ± 4.3 Gyr 1958 Redshift–magnitude relation Allan Sandage [21][22]
17.7 Gyr 1972 Cepheid variables Allan Sandage [23]
8–18 Gyr 1974 Oldest globular clusters Icko Iben Jr. [24][25]
13-20 Gyr 1974 Deuterium-limited density, oldest globular clusters, nucleochronology, galactic evolution J. Richard Gott, James Gunn, David Schramm, Beatrice Tinsley [24][26]
6–20 Gyr 1977 Nucleochronology, galactic evolution Kem Hainebach, David Schramm [24][27]
13.5–15.5 Gyr 1978 Oldest globular clusters, nuclear chronology Demosthenes Kazanas, David Schramm, Kem Hainebach [24]
12+3
−2 Gyr		 1980–1981 Nuclear chronology William Alfred Fowler, David Schramm, Sidney van den Bergh [28]
10.3 ± 2.2 Gyr 1987 White dwarf luminosity distribution Don Winget et. al [29]
13–18 Gyr 1992 Nucleochronology, oldest globular clusters Sidney van den Bergh [30]
>16 Gyr 1992 RR Lyrae stars, oldest globular clusters Young-Wook Lee [31]
>13 Gyr 1994 Cosmic microwave background anisotropies Marc Kamionkowski, David Spergel, Naoshi Sugiyama [32]
≥12.07 Gyr 1996 Oldest globular clusters Brian Chaboyer, Pierre Demarque, Peter Kernan, Lawrence Krauss [33]
9.7–15 Gyr 1998 Oldest globular clusters Lawrence Krauss [34]
≥9.5 Gyr 1998 Oldest globular clusters Brian Chaboyer [35]
13.4 ± 1.6 Gyr 1999 Literature review Charles Lineweaver [36]
<14 ± 2 Gyr 2000 Literature review Wendy Freedman [37]
14.0 ± 0.5 Gyr 2001 Cosmic microwave background anisotropies Lloyd Knox, Nelson Christensen, Constantinos Skordis [38]
13.2+1.2
−0.8 Gyr		 2001 Cluster ellipticals, cosmic microwave background, type Ia supernovae Ignacio Ferreras, Alessandro Melchiorri, Joseph Silk [39]
13.7 ± 0.2 Gyr 2003 Wilkinson Microwave Anisotropy Probe data David Spergel et. al [4]
13.7 ± 0.2 Gyr 2003 Wilkinson Microwave Anisotropy Probe data Charles Bennett et. al [3]
13.73+0.16
−0.15 Gyr		 2007 Wilkinson Microwave Anisotropy Probe data David Spergel et. al [40]
13.1+0.96
−0.87 Gyr		 2008 Data from Wilkinson Microwave Anisotropy Probe, Sloan Digital Sky Survey, Hubble Space Telescope Francesco De Bernardis, Alessandro Melchiorri, Licia Verde, Raul Jimenez [41]
13.31+1.0
−0.91 Gyr		 2008 Data from Wilkinson Microwave Asinotropy Probe, Sloan Digital Sky Survey, Hubble Space Telescope, high-resolution CMB experiments, two degree field galaxy redshift survey, type 1a supernovae Francesco De Bernardis, Alessandro Melchori, Licia Verde, Raul Jimenez [41]
13.772 ± 0.059 Gyr 2013 Wilkinson Microwave Anisotropy Probe data Charles Bennett et. al [42]
13.817 ± 0.048 Gyr 2014 Planck data, WMAP polarization low-multipole likelihood Planck collaboration [43]
13.798 ± 0.037 Gyr 2014 Planck data, WMAP polarization low-multipole likelihood, high-resolution CMB experiments, baryon acoustic oscillation Planck collaboration [43]
13.813 ± 0.038 Gyr 2016 Planck data Planck collaboration [44]
13.787 ± 0.020 Gyr 2020 Planck data Planck collaboration [5]

See also

References

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  2. Chaboyer, Brian; Demarque, P.; Kernan, Peter J.; Krauss, Lawrence M. (1998). "The Age of Globular Clusters in Light of Hipparcos: Resolving the Age Problem?". The Astrophysical Journal. 494: 96–110. doi:10.1086/305201.
  3. Bennett, C. L.; Halpern, M.; Hinshaw, G.; Jarosik, N.; Kogut, A.; Limon, M.; Meyer, S. S.; Page, L.; Spergel, D. N.; Tucker, G. S.; Wollack, E.; Wright, E. L.; Barnes, C.; Greason, M. R.; Hill, R. S.; Komatsu, E.; Nolta, M. R.; Odegard, N.; Peiris, H. V.; Verde, L.; Weiland, J. L. (2003). "First-Year Wilkinson Microwave Anisotropy Probe ( WMAP ) Observations: Preliminary Maps and Basic Results". The Astrophysical Journal Supplement Series. 148: 1–27. arXiv:astro-ph/0302207. doi:10.1086/377253.
  4. Spergel, D. N.; Verde, L.; Peiris, H. V.; Komatsu, E.; Nolta, M. R.; Bennett, C. L.; Halpern, M.; Hinshaw, G.; Jarosik, N.; Kogut, A.; Limon, M.; Meyer, S. S.; Page, L.; Tucker, G. S.; Weiland, J. L.; Wollack, E.; Wright, E. L. (2003). "First-Year Wilkinson Microwave Anisotropy Probe ( WMAP ) Observations: Determination of Cosmological Parameters". The Astrophysical Journal Supplement Series. 148: 175–194. arXiv:astro-ph/0302209. doi:10.1086/377226.
  5. Planck Collaboration (2020). "Planck 2018 results. VI. Cosmological parameters". Astronomy & Astrophysics. 641. page A6. arXiv:1807.06209. Bibcode:2020A&A...641A...6P. doi:10.1051/0004-6361/201833910. S2CID 119335614.
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