Our cosmic horizons. Part two: The search for dark matter

Journal Article · Mon Feb 29 23:00:00 EST 1988 · Astronomy; (USA)

OSTI ID:5918281

Trimble, V ^[1]

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1. Univ. of California, Irvine (USA)

In this second article in the series on cosmology, the author discusses dark matter. Observational evidence collected over the last fifty years strongly indicates that all we can see in the form of planets, gas, stars, and galaxies amounts to only 10 percent of the entire universe. The remaining 90 percent is nonluminous and virtually undetectable, except for its gravitational effects on the visible universe. In a real sense we don't know what most of the universe is made of. The recognition of dark matter in the universe had some aspects of what science historians call a paradigm shift. That is, it involved not just new data but also a new way of looking at old data and problems that had been around a long time, especially questions about the formation, evolution, and structure of galaxies. The seminal event in this paradigm shift was a pair of short papers published by trios of American and Soviet astronomers. Neither presented much new data. But each had disparate bits of information, the collective import of which was that the mass associated with a typical galaxy extends out to much larger distances from the center than does the light. Thus the total mass of a galaxy depends on the distance from the center at which you are able to probe and increases linearly with that distance out to 100 kiloparsecs. Today's evidence for dark matter is based on the same kinds of research pioneered by Oort and Zwicky, but of course there is more information in each research area. Let's look into some of these areas, beginning with the smallest scales and objects closest to use, and see what the data look like and what the data imply about the nature of the dark matter.

• OSTI ID: 5918281
• Journal Information: Astronomy; (USA), Journal Name: Astronomy; (USA) Vol. 16:3; ISSN ASTRD; ISSN 0091-6358
• Country of Publication: United States
• Language: English

Related Subjects

640106* -- Astrophysics & Cosmology-- Cosmology
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHEMICAL COMPOSITION
COOLING
COSMOLOGY
DENSITY
DETECTION
ELEMENTARY PARTICLES
EXPANSION
GALACTIC EVOLUTION
GALAXIES
GALAXY CLUSTERS
GRAVITATION
MAGNETIC MONOPOLES
MASS
MILKY WAY
MONOPOLES
MOTION
NONLUMINOUS MATTER
NUCLEOSYNTHESIS
ORIGIN
PHYSICAL PROPERTIES
POSTULATED PARTICLES
ROTATION
SYNTHESIS
UNIVERSE