Cannibalism among galaxies

There was an old theory that described the most intriguing thing about galaxies and now it was proved, the theory that bigger galaxies try to feed on smaller galaxies when they come near, is no more an unproved theory but is a fact today. A recent study on the cannibalism of the galaxies helps the astronomers to hop in to some new areas that remained untouched so far.

Scientists who studied this phenomenon even confirmed that it happens and is already happened once in our close-by sister galaxy, Andromeda. However, it never happened with our Milky Way, as there are no wimpy galaxies nearby.

The process is so simple: when an wimpy galaxies tries to cross the bigger or not so wimpy galaxy, the not so lucky weaklings--stars--of the wimpy one are slowly swallowed up by the bigger one leaving behind the traces in the form of so-called tidal streams.

These tidal streams or trails that left behind can help us find the way the smaller galaxy once moved before getting ripped off. These paths can help us measure the bigger galaxies weight--if you are a maths geek--and the way they spread their mass--the bigger the weight, the sharper the change, in the path. They can even help us to know the way the galaxies are evolved...

"You can see these very complex systems of shells and plumes of tidal debris that mark the past accretion history of the galaxy," said astronomer Chris Mihos of case western Reserve University in Cleaveland, Ohio.

I don't know whether he is a geek of some sort or not but he definitely had found some tidal tails recently around some of the galaxies in the Virgo cluster, a relatively near by collection of galaxies about 50 million light years away.

There is one more study and is more interesting since it was not only led by Puragra Guhathakurtha of the University of California, Santa Cruz, but was regarding the cannibalism of Andromeda--our most near by galaxy, 2.5 million light-years away(It doesn't in any way mean that Mihos is less interesting).

He had found some tidal strams around the Andromeda galaxy and says that..

"The tidal steams gives you a window in time during which the events happened: the last couple billion years. If it was earlier, it's unlikely we'd still see the stars"

His discovery helps to set Andromeda apart from the Milky way.

"It looks like our sister galaxy has led a more exciting life," he said. "In contrast the Milky Way has had a relatively quiet, quiescent last couple billion years."

There are no signs of cannibalism around the Milky Way as it happens with Andromeda once. And I guess, we must feel happy for that. :)