Galactic Cannibalism

Gas finger pierces galaxy

The giant finger of hydrogen gas.

Photo: John Rowe Animations

Chee Chee LeungFebruary 6, 2008

AUSTRALIAN astronomers have spotted a giant finger of hydrogen gas poking through the Milky Way galaxy that might provide clues about the future of our closest galactic companions.

The gas finger comes from two nearby galaxies known as the Large and Small Magellanic Clouds. The CSIRO described it as ploughing into the main disc of our galaxy "like a fork piercing through a fried egg".

Observations from radio telescopes showed the collision is occurring much closer than scientists had expected — about 70,000 light years away in the direction of the Southern Cross.

Research leader Dr Naomi McClure-Griffiths said the findings suggested the Magellanic Clouds were orbiting the Milky Way and might eventually be "slowly sucked apart by our galaxy".

"We will trickle gas off them and degrade the orbits of the clouds so they move slower and slower," she said. "So they eventually merge in with our own galaxy."
Such a merger was unlikely to be felt on Earth, but a "galactic cannibalism" episode such as this would help to provide fuel for star formation.

Dr McClure-Griffiths said the findings had surprised scientists, given recent research based on Hubble Space Telescope measurements had implied the clouds were zooming past the Milky Way rather than orbiting it.

The Australian observations — published in the latest Astrophysical Journal Letters — are more in line with an earlier theory that the clouds are doomed to be swallowed up by our galaxy, which they have orbited many times.

http://www.csiro.au

http://www.theage.com.au/news/national/gas-finger-pierces-galaxy/2008/02/05/1202090421869.html