Experiments suggest that
the universe has been governed by the same physical laws and constants
throughout its extent and history. The dominant force at cosmological
distances is
gravity, and
general relativity is currently the most accurate
theory of gravitation. The remaining three
fundamental forces and the particles on which
they act are described by the
Standard Model.
Physical cosmology, as a branch of astronomy, is the study of the large-scale
structure of the universe and is concerned with fundamental questions about its
formation and evolution. Astronomers try to measure it all the time. They use a
special instrument called a spectroscope to tell whether an object is moving
away from Earth or toward Earth. The age of the Universe can also be estimated
from a cosmological model based on the Hubble constant and the densities of
matter and dark energy. As the early universe developed the stars were drawn
together into large clusters called galaxies. And hundred billion stars in our
galaxy, hundreds of billions of galaxies in the observable universe.
Astronomy is one of the oldest sciences. Astronomers
of early civilizations performed methodical observations
of the night sky, and astronomical artifacts have been
found from much earlier periods. However, the invention
of the telescope was required before astronomy was able
to develop into a modern science. Historically,
astronomy has included disciplines as diverse as
astrometry, celestial navigation, observational
astronomy, the making of calendars, and even astrology,
but professional astronomy is nowadays often considered
to be synonymous with astrophysics.
Cosmology is
often an important aspect of the creation myths of
religions that seek to explain the existence and nature
of reality. In some cases, views about the creation
(cosmogony) and destruction (eschatology) of the
universe play a central role in shaping a framework of
religious cosmology for understanding humanity's role in
the universe.
Links
Runaway
Universe-http://www.pbs.org/wgbh/nova/universe/
Companion website for a PBS NOVA program originally
broadcast in 2000, which examines the size, future and fate
of the universe. Contains background material on mapping the
universe, supernovae as standard
candles, and a virtual tour of the universe.
Cosmology: A Research Briefing - http://www.nap.edu/catalog.php?record_id=9293 Online book from the National Academy
of Sciences, published in 1995 by the National Research
Council's Board on Cosmology as a re-assessment of the
cosmological research earlier examined by the Physics Survey
Committee. Includes chapters on the cosmic background
radiation, the large scale structure of universe, and the
physics of the early universe.
The Planetary Society- http://planetary.org A
nonprofit organization that promotes exploration of the
solar system and the search for extraterrestrial
intelligence.
