FEATURE ARTICLE
Observing the Beginning of Time
New maps of the cosmic background radiation may display evidence of the quantum origin of space and time
Craig Hogan
The Origin of Time
The quantum rules governing the hydrogen atom are very simple and compelling, but they would never have been guessed without detailed data on the rich and complicated spectra that reflect the energies of the discrete stable states of atoms. Perhaps we will similarly be able to peer into the quantum nature of spacetime with images of the microwave background anisotropy and use that to figure out how it all works.
Although the maps of the sky contain a great deal of information—and promise more with the forthcoming results—they may also contain profoundly little information in a technical sense. Simple models of holographic inflation suggest that the total amount of information available to the quanta that form the background may be relatively modest—perhaps the equivalent of less than a million pixels, or roughly the amount of information displayed in your personal computer display. It's a lot less information than the maps we will be making, so we may be able to notice the information limit imposed by the universe (Figure 9). If so, the graininess in the picture, or whatever special atom-like quantum patterns emerge, will be a direct sign of the holographic quantization of spacetime. For all practical purposes, we could accurately call this a view of the true beginning of time, since we would be penetrating beyond "ordinary" time to some more fundamental, discrete structure from which our apparently continuous time and space have emerged.
Full disclosure: We should not think of primordial discreteness as some sort of Holy Grail that will provide answers to all the mysteries of creation. Equating interest and information content, the beginning of time is actually a lot less interesting than what came after. The evidence we have already suggests that the universe began with almost no information, and all the complex structure within it has developed since the beginning, on its own, without external influences. If this is true, finding the beginning of time and even its detailed structure will not help us much to understand the interesting things that have happened within the universe since then.
Bibliography
- de Bernardis, P. et al. 2000. A flat universe from high-resolution maps of the cosmic microwave background radiation. Nature 404:955–959. [CrossRef]
- Bousso, R. In press. The holographic principle. Reviews of Modern Physics. Preprint: http://arXiv.org/abs/hep-th/0203101
- Hogan, C. J. 1999. The Little Book of the Big Bang: A Cosmic Primer. New York: Springer-Verlag (Copernicus).
- Hogan, C. J. In press. Holographic discreteness of inflationary perturbations. Physical Review D. Preprint: http://arXiv.org/abs/astro-ph/0201020
- Kolb, E. W., and M. S. Turner. 1990. The Early Universe. Reading, Mass.: Addison-Wesley.
- Linde, A. 1990. Inflation and Quantum Cosmology. Boston: Academic Press.
- Lyth, D. H., and A. Riotto. 1999. Particle physics models of inflation and the cosmological density perturbation. Physics Reports 314:1–146. [CrossRef]
- Rees. M. 1997. Before the Beginning: Our Universe and Others. Reading, Mass.: Addison-Wesley.
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