2007/06/26 by Michael S. Turner, Dragan Huterer · 2 citations
Physics and Astronomy · #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Relativity and Gravitational Theory #astro-ph #gr-qc #hep-th
paper · pdf · doi:10.1143/jpsj.76.111015
published as J.Phys.Soc.Jap.76:111015,2007 · 10 pages, 8 figures, invited review for Journal of the Physical Society of Japan, in press
arxiv created 2007/06/26 · openalex publication_date 2007/11/12 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
A web of interlocking observations has established that the expansion of the Universe is speeding up and not slowing, revealing the presence of some form of repulsive gravity. Within the context of general relativity the cause of cosmic acceleration is a highly elastic (p∼ -rho), very smooth form of energy called ``dark energy'' accounting for about 75% of the Universe. The ``simplest'' explanation for dark energy is the zero-point energy density associated with the quantum vacuum; however, all estimates for its value are many orders-of-magnitude too large. Other ideas for dark energy include a very light scalar field or a tangled network of topological defects. An alternate explanation invokes gravitational physics beyond general relativity. Observations and experiments underway and more precise cosmological measurements and laboratory experiments planned for the next decade will test whether or not dark energy is the quantum energy of the vacuum or something more exotic, and whether or not general relativity can self consistently explain cosmic acceleration. Dark energy is the most conspicuous example of physics beyond the standard model and perhaps the most profound mystery in all of science.