REVIEW Life has a funny symmetry, don’t you think? When you’re born, you’re short, toothless and bald. You spend the first part of your life gaining height, teeth and hair and the last part losing them again. Believe it or not, Microsoft Office is following the same trajectory. (This might sound like the stretched analogy of the year, but bear with me.) Microsoft spent the first dozen years of Office’s life piling on new features. Over time, the humble word processor...

Streams of glittering stellar gems on the outer edges of Andromeda are remnants of an ancient galactic collision that helped shape the spiral galaxy.

Astronomers using the DEIMOS spectrograph on the Keck II Telescope in Hawaii determined this by surveying Andromeda, our galaxy’s nearest large galactic neighbor, and discovered a trail of http://www.space.com/stars/ which they believe were part of a different galaxy that merged with Andromeda some 700 million years ago.

The findings support previous computer simulations of a dwarf galaxy merging with Andromeda and could help astronomers calculate Andromedas total mass, a slippery value that, once arrived at, could help shed light on the elusive http://www.space.com/scienceastronomy/astronomy/dark_matter_sidebar_010105.html that pervades the http://www.space.com/universe/.

Also known as http://www.space.com/php/multimedia/imagegallery/igviewer.php?imgid=3808&gid=277, Andromeda is located only 2.5 million light-years from Earth. Like other spiral galaxies, Andromeda is made up of a flat disk of stars and gas, a bright central bulge of densely concentrated stars, and at times, a dim, spherical skirt of stars that extends to large distances.

The visible matter is just fluff, however, in terms of mass. The bulk of the mass in a spiral galaxy comes from dark matter, an exotic entity detectible only through its gravitational force. Scientists estimate that http://www.space.com/scienceastronomy/070108_mm_darkmatter_map.html makes up five-sixths of the matter in the entire universe.

http://www.space.com/scienceastronomy/061012_spiderweb_galaxy.html are believed to be built partly by the http://www.space.com/scienceastronomy/060123_andromeda_plane.html of smaller galaxies, an event that destroys the smaller galaxy, said Karoline Gilbert, a graduate student at the University of California, Santa Cruz, who presented the Andromeda findings at the American Astronomical Society meeting in Seattle earlier this month.

The strong gravitational forces of a large galaxy, Gilbert explained, can rip apart a small galaxy, producing loose streams of stars that astronomers call .

‘Measuring the amount of the tidal debris that exists in present-day galaxies allows astronomers to examine the role mergers play in galaxy formation,’ she said.

Several twinkling areasincluding a stream of stars located south of the galaxy, called the “giant southern stream,” and a faint extension of Andromedas disk called the “northeast shelf” in the galaxys outskirts are most likely tidal debris from previous http://www.space.com/scienceastronomy/060307_galaxy_sonicboom.html.

The discovered tidal debris features are almost an exact match with the features predicted in the computer simulations, Gilbert said. This implies that this new stellar stream and the giant southern stream, as well as the other stellar features reproduced in the simulations, came from the same parent galaxy.

Because they are moving together, astronomers can use the stars in the tidal debris to measure the strength of gravity around the Andromeda galaxy, said Mark Fardal of the University of Massachusetts Amherst who created the computer models.

Gilberts discovery of a new tidal debris feature, combined with velocity measurements of the other related tidal debris, will provide observations necessary to measure how much dark matter is in Andromeda, he said, and how it is distributed. 2007 Space.com. All rights reserved. More from Space.com.

BY REUTERS Posted 1/22/2007 Treasury debt prices rose in light trade on Monday as bonds garnered modest bids due to weaker stocks. “Weakness in stocks helped Treasuries to rally today,” said Chris Rupkey, vice president and senior financial economist at Bank of Tokyo-Mitsubishi. But Rupkey said there was a limit on how much bonds could capitalize on the weakness in stocks because equity investors were worried about the possibility of higher interest rates, which could...