(astro-ph): Dark Matter, Dark Energy and Fundamental Physics
Mike Turner
Author(s): Michael S. Turner
More than sixty years ago Zwicky made the case that the great clusters of
galaxies are held together by the gravitational force of unseen (dark) matter.
Today, the case is stronger and more precise: Dark, nonbaryonic matter accounts
for 30% +/- 7% of the critical mass density, with baryons (most of which are
dark) contributing only 4.5% +/- 0.5% of the critical density. The large-scale
structure that exists in the Universe indicates that the bulk of the
nonbaryonic dark matter must be cold (slowly moving particles). The
SuperKamiokande detection of neutrino oscillations shows that particle dark
matter exists, crossing an important threshold. Over the past few years a case
has developed for a dark-energy problem. This dark component contributes about
80% +/- 20% of the critical density and is characterized by very negative
pressure (p_X < -0.6 rho_X). Consistent with this picture of dark energy and
dark matter are measurements of CMB anisotropy that indicate that total
contribution of matter and energy is within 10% of the critical density.
Fundamental physics beyond the standard model is implicated in both the dark
matter and dark energy puzzles: new fundamental particles (e.g., axion or
neutralino) and new forms of relativistic energy (e.g., vacuum energy or a
light scalar field). A flood of observations will shed light on the dark side
of the Universe over the next two decades; as it does it will advance our
understanding of the Universe and the laws of physics that govern it.
Paper: astro-ph/9912211
Dated: Thu, 9 Dec 1999 22:48:30 GMT (82kb)
Comments: 15 pages LaTeX with 6 eps figures. To be published in The Proceedings
of Physics in Collision (Ann Arbor, MI, 24 - 26 June 1999), edited by M.
Campbell and T.M. Wells(World Scientific, NJ)
URL: http://xxx.lanl.gov/abs/astro-ph/9912211