The "dark matter" that comprises a still-undetected one-quarter of the universe is not a uniform cosmic fog, says a University of California, Berkeley, astrophysicist, but instead forms dense clumps that move about like dust motes dancing in a shaft of light.
Computer simulation of the initial Hubble expansion and subsequent formation of a galaxy-size halo of dark matter over the last 13.5 billion years — 99 percent of the lifetime of the universe. The simulation shows an intricate pattern of swarming dark matter clumps, some of which may not host luminous matter such as stars and gas.
(Credit: Chung-Pei Ma, Ed Bertschinger)
In a paper submitted this week to Physical Review D, Chung-Pei Ma, an associate professor of astronomy at UC Berkeley, and Edmund Bertschinger of the Massachusetts Institute of Technology (MIT), prove that the motion of dark matter clumps can be modeled in a way similar to the Brownian motion of air-borne dust or pollen.
Their findings should provide astrophysicists with a new way to calculate the evolution of this ghost universe of dark matter and reconcile it with the observable universe, Ma said.
Robert Sanders | UC Berkeley News
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