cold dark matter


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cold dark matter

(CDM) See dark matter.

cold dark matter

[¦kōld ′därk ‚mad·ər]
(astronomy)
A hypothetical type of dark matter consisting of particles that would have been in thermal equilibrium while traveling at nonrelativistic velocities in the early universe; possibilities include axions, photinos, gravitinos, heavy magnetic monopoles, and weakly interacting massive particles.
References in periodicals archive ?
have an explanation that would fit with cold dark matter theory, but it requires combining gastrophysies with dark matter.
Even if the theory of cold dark matter survives this onslaught, the new observations of big galaxies in the most ancient of times have important implications.
Stars forming in the cold dark matter are massive, about 100 times the mass of the Sun.
That's because cold dark matter, say theorists, reacts only to gravity and is impervious to pressure.
The theory of cold dark matter, first advanced in the mid 1980s, holds that the vast majority of the matter in the universe-as much as 75 percent- is made up of "dark" material that does not interact with electrons and protons and so cannot be observed from electromagnetic radiation.
Computer simulations of cold dark matter create universes that are far lumpier on these smaller scales than the real universe appears to be.
In addition, standard cold dark matter in these simulations makes more small galaxies than astronomers see.
By providing a natural explanation for the origin of galaxies, the simulations support the view that cold dark matter is the best candidate for the mysterious material believed to make up the majority of our Universe.
However, even though computer simulations suggest that cold dark matter forms filaments, the resulting structures end up fatter than those observed with telescopes, Turner says.
Lanzetta admits that such a model of galaxy formation hasn't been popular for several decades, since it violates a widely held view of the universe in which most mass is made of an unseen, slow-moving type of matter called cold dark matter, in the simplest cold-dark-matter theories, the dark matter is the first to clump together under the influence of gravity, and the ordinary material that comprises the visible, starlit parks of galaxies takes much longer to assemble.