Dark star

Science News,  April 12, 2008  by Eugene (Gene) Cater,  Ron Cowen

• E-mail
• Print
• Link

In "From Dark Matter to Light: New models of galaxy formation show the gastro in physics" (SN: 3/22/08, p. 186), Ron Cowen says that gas is where the action is since dark matter predominantly responds to only gravity. Because dark matter responds to gravity, wouldn't it, like gas, be pulled into the star-making process and become part of the resulting star? Why is our sun not predominantly dark matter?

EUGENE (GENE) CATER, EASLEY, S.C.

On the largest scales, the amount of dark matter is much greater than the amount of baryons--ordinary atoms. But on the scale of individual planets or stars, there is more ordinary matter: That's because baryons can radiate away their energy (ridding" them of heat that would fight gravity) and therefore clump move tightly under the influence of gravity than can dark matter (which can't radiate), says theorist Piero Madau of the University of California, Santa Cruz.

COPYRIGHT 2008 Science Service, Inc.
COPYRIGHT 2008 Gale, Cengage Learning