ScienceDaily: Galaxies News

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Red stars and big bulges: How black holes shape galaxies Posted: 22 Apr 2014 05:46 AM PDT The universe we can see is made up of thousands of millions of galaxies, each containing anywhere from hundreds of thousands to hundreds of billions of stars. Large numbers of galaxies are elliptical in shape, red and mostly made up of old stars. Another (more familiar) type is the spiral, where arms wind out in a blue thin disk from a central red bulge. On average stars in spiral galaxies tend to be much younger than those in ellipticals. Now a group of astronomers has found a (relatively) simple relationship between the color of a galaxy and the size of its bulge: the more massive the bulge, the redder the galaxy.

'Upside-down planet' reveals new method for studying binary star systems Posted: 21 Apr 2014 06:13 PM PDT What looked at first like a sort of upside-down planet has instead revealed a new method for studying binary star systems. Astronomers confirmed the first "self-lensing" binary star system -- one in which the mass of the closer star can be measured by how powerfully it magnifies light from its more distant companion star. Though our sun stands alone, about 40 percent of similar stars are in binary (two-star) or multi-star systems, orbiting their companions in a gravitational dance.

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