Andromeda galaxy is a "cosmic cannibal"

       Earth's nearest major galactic neighbour is a cosmic cannibal.And it is heading this way.
       Astronomers have long suspected that Andromeda is a space predator, consuming dwarf galaxies that wander too close. Now, cosmic detectives are doing a massive search of the neighbourhood and have found proof of Andromeda's sordid past: They have spotted leftovers in Andromeda's wake.
       Early results of a massive telescope scan of Andromeda and its surroundings found about a half-dozen remnants of Andromeda's galactic appetite. Stars and dwarf galaxies that got too close to Andromeda were ripped from their usual surroundings.
       "What we're seeing right now are the signs of cannibalism," said the study's lead author Alan McConnachie of the Herzberg Institute of Astrophysics in Victoria, British Columbia."We're finding things that have been destroyed ... partly digested remains."
       Andromeda and the Milky Way, Earth's galaxy, are the two big dogs of this galactic neighbourhood. Andromeda is about 2.5 million light years away. A light year is about 9.4 trillion kilometres.
       Astronomers have known for decades that galaxies consume each other, some-times violently, sometimes just creating new mega-galaxies. But this study is different because "of the scale of the cannibalism, and we've found evidence directly in front of our eyes", said coauthor Mike Irwin, an astrophysicist at the University of Cambridge in England.
       And just because Andromeda consumes a galaxy, it does not make the victim disappear, he said.
       The cannibalistic behaviour often just strips stars from where they had been,rearranging the night sky. Most of a galaxy is empty space, so there is little if any crashing of stars and planets going on, Mr Irwin said