What was the universe like when it was very young? From a high‐energy physicist’s dream world it has evolved through many eras to its present state of comparative darkness and emptiness.
IN RECENT YEARS the active frontiers of cosmology have widened and certain aspects of the subject are attracting more attention from physicists. Growing emphasis on physics has been stimulated by discovery of the universal black‐body radiation and by growing realization that the composition of the universe was once extremely complex.
3. G. Lemaître, Revue des Questions Scientifiques, November 1931, quoted in ref, 6.
4. G. Lemaître, The Primeval Atom, Van Nostrand, New York (1950).
5. G. Lemaître, “The Primaeval Atom Hypothesis,” p. 1 in La Structure et l’Evolution de l’Universe, Institut International de Physique Solvay, Brussels, Belgium (1958).
21. R. A. Alpher, G. Gamow, R. Herman, Proc. Nat. Acad. Sci. 58, 2179 (1967).https://doi.org/PNASA6
22. G. Lemaître, Annales de la Société Scientifique de Bruxelles 47A, 49 (1927); G. Lemaître, Bulletin of the Astronomical Institutes of the Netherlands 5, no. 200 (1930); https://doi.org/BAINAO G. Lemaître, Monthly Notices of the Royal Astronomical Society 95, 483 (1931).https://doi.org/MNRAA4
24. W. de Sitter, Bulletin of the Astronomical Institutes of the Netherlands 5, no. 193 (1930); https://doi.org/BAINAO R. C. Tolman, Relativity, Thermodynamics and Cosmology, Clarendon Press, Oxford (1934), pp. 404–411; R. A. Alpher, R. C. Herman, Phys. Rev. 75, 1089 (1949).https://doi.org/PHRVAO
25. R. C. Tolman, Phys. Rev. 37, 1639 (1931); https://doi.org/PHRVAO Relativity, Thermodynamics and Cosmology, Clarendon Press, Oxford, (1934), chap. 9.
27. P. G. Roll, D. T. Wilkinson, Phys. Rev. Letters 16, 405 (1966); https://doi.org/PRLTAO G. B. Field, J. L. Hitchcock, Phys. Rev. Letters 16, 817 (1966); https://doi.org/PRLTAO P. Thaddeus, J. F. Clauser, Phys. Rev. Letters 16, 819 (1966); https://doi.org/PRLTAO T. F. Howell, J. R. Shakeshaft, Nature 210, 1318 (1966); https://doi.org/NATUAS W. J. Welch, S. Keachie, D. D. Thornton, G. Wrixon, Phys. Rev. Letters 18, 1068 (1967); https://doi.org/PRLTAO D. T. Wilkinson, Phys. Rev. Letters 19, 1195 (1967); https://doi.org/PRLTAO R. A. Stokes, R. B. Partridge, D. T. Wilkinson, Phys. Rev. Letters 19, 1199 (1967).https://doi.org/PRLTAO
28. R. H. Dicke, P. J. E. Peebles, P. G. Roll, D. T. Wilkinson, Astrophys. J. 142, 414 (1965).https://doi.org/ASJOAB
49. R. B. Partridge, D. T. Wilkinson, Phys. Rev. Letters 18, 557 (1967).https://doi.org/PRLTAO
50. H. Reeves in Steller Structure, (L. H. Aller, D. B. McLaughlin, eds.) University of Chicago Press, Chicago (1965), p. 150.
51. A. S. Eddington, Fundamental Theory, Cambridge University Press, Cambridge (1953), pp. 9, 10.
52. D. Layzer in Annual Reviews’ of Astronomy and Astrophysics? 2, 341 (1964); Ya. B. Zeldovich in Advances in Astronomy and Astrophysics 3, 242 (1965); https://doi.org/AAYAAK E. R. Harrison, Rev. Mod. Phys. 39, 862 (1967).https://doi.org/RMPHAT
53. E. R. Harrison, Memoires Société Royale des Sciences de Liège 15, 15 (1967).
54. J. H. Jeans, Astronomy and Cosmogony, Cambridge University Press, Cambridge (1929), p. 352.
Amid growing investment in planetary-scale climate intervention strategies that alter sunlight reflection, global communities deserve inclusive and accountable oversight of research.
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As conventional lithium-ion battery technology approaches its theoretical limits, researchers are studying alternative architectures with solid electrolytes.
November 10, 2025 10:22 AM
This Content Appeared In
Volume 21, Number 6
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