Evolution of the cosmological constant
Article Abstract:
Recent cosmological research has indicated that the gravitational effect of a particular type of quintessence takes a long time to become comparable with the impact of ordinary matter and radiation. It is argued that, in simple theoretical models of lambda-like matter, or quintessence, a wide range of initial conditions in the early Universe develop to a situation in which the gravitational impact of quintessence is less than that of ordinary matter. This situation persists for a long time. This implies that lambda would become significant again only late in the history of the Universe, possibly around now.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1999
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The history of the galaxies
Article Abstract:
Advances in astronomical spectroscopy and imaging reveal the history of galaxies since their formation. Images from the Hubble Deep Field permit measurements of brightness, broadband color and morphology and information about the spatial organization during the evolution of galaxies. Measurements of the redshift (z) provide information about the conditions necessary for the formation of galaxies. Changes in the composition of materials, the alterations in the structure and growth in clustering reveal that the redshift interval of z = 1-3 is probably the age of formation of galaxies.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
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Robert Henry Dicke (1916-97)
Article Abstract:
Physicist Robert Henry Dicke, who died in Mar 4, 1997, will be remembered for his work on thermal radiation and for inventing the Dicke radiometer, most famously used to detect thermal radiation from the Big Bang. Dicke turned to gravity physics in the mid-1950s and his pioneering work included the motion of pulsars and planets.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1997
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