29,182 research outputs found
The Big Bang, Modern Cosmology and the Fate of the Universe: Impacts upon Culture
Cosmological discoveries over the past century have completely changed our
picture of our place in the universe. New observations have a realistic chance
of probing nature on heretofore unimaginable scales, and as a result are
changing the nature of fundamental science. Perhaps no other domain of science
has an equal capacity to completely change our perspective of the world in
which we live.Comment: Invited Lecture, UNESCO/IAU Meeting: The Role of Astronomy in Society
and Culture Jan 2009, to appear, IAU Proceedings, D. Valls-Gaubaud and A.
Boksenberg, eds.. (Several typos removed in this version
A New Cosmological Paradigm: the Cosmological Constant and Dark Matter
The Standard Cosmological Model of the 1980's is no more. I describe the
definitive evidence that the density of matter is insufficient to result in a
flat universe, as well as the mounting evidence that the cosmological constant
is not zero. I finally discuss the implications of these results for particle
physics and direct searches for non-baryonic dark matter, and demonstrate that
the new news is good news.Comment: 11 pages, latex, including 4 embedded figs. Based on invited lectures
at PASCOS98, Boston; Tropical Workshop on Particle Physics and Cosmology and
Particle Physics, San Juan; WEIN 98, Santa Fe. To appear in these proceeding
Space, Time, and Matter: Cosmological Parameters 2001
Over the past three years, our confidence in the inferred values of
cosmological parameters has increased dramatically, confirming that the flat
matter dominated Universe that dominated cosmological model building for the
past 20 years does not correspond to the Universe in which we live. I review
recent developments here and quote best fit current values for fundamental
cosmological parameters.Comment: 19 pages, figures included. (Invited Review Lecture: Third
International Conference on the Identification of Dark Matter, York, England,
Sept 2000 - to appear in Proceedings
The State of the Universe: Cosmological Parameters 2002
In the past decade, observational cosmology has had one of the most exciting
periods in the past century. The precision with which we have been able to
measure cosmological parameters has increased tremendously, while at the same
time, we have been surprised beyond our wildest dreams by the results. I review
here recent measurements of the expansion rate, geometry, age, matter content,
and equation of state of the universe, and discuss the implications for our
understanding of cosmology.Comment: 20 pages, To appear in Proceedings, ESO-CERN-ESA Symposium on
Astronomy, Cosmology and Fundamental Physics, March 2002. Typo in final table
fixe
Gravitational Lensing and the Variability of G
The four observables associated with gravitational lensing of distant quasars
by intervening galaxies: image splittings, relative amplifications, time
delays, and optical depths, provide separate measures of the strength of the
gravitational constant at cosmological distances. These allow one, in
principle, to factor out unknown lensing parameters to directly to probe the
variation of over cosmological time. We estimate constraints on
which may be derivable by this method both now and in the future. The limits
one may obtain can compete or exceed other direct limits on today,
but unfortunately extracting this information, is not independent of the effort
to fix other cosmological parameters such as and from lensing
observations.Comment: 13 pages plus figures (not included
Long-lived π-cation radicals of bilindionato zinc complexes
The title compounds have been prepared by I 2-oxidation in benzene-pyridine solutions and characterized by uv-vis and esr spectroscopy
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