Milky way smashup on the way?

<body leftmargin="0" bgcolor="#000060" text="#FFFFFF" link="#FFFF00" vlink="#FF9900"> <p class="MsoNormal"><b><font face="Arial" size="4">Galactic smash-up on the way for our galaxy?</font></b> </p> <p class="MsoNormal"><font face="Arial" size="1">Posted Sept. 9, 2004<br> Courtesy NASA<br> and World Science Staff</font> </p> <p class="MsoNormal"> <font size="2" face="Arial"><b>A NASA's telescope has set its sights on a major galactic collision and witnessed the future of our own Milky Way galaxy. Sixty-eight million light-years away, two other galaxies called the Antennae galaxies are locked in a dance of death, with stars being ripped from their orbits and spiral arms being shredded into streamers that dangle in space. Several billion years from now, our home might look the same as the Andromeda galaxy smashes into the Milky Way like a bulldozer through a condemned building.<br> <br> Yet this distant galactic collision we see today is not yielding death, but creating new life. With its heat-seeking eyes, NASA's Spitzer Space Telescope was able to see past the dark storm of dust that blankets the heart of the merging Antennae galaxies to a hidden population of new stars emerging inside.<br> <br> "This more complete picture of star formation in the Antennae will help us better understand the evolution of colliding galaxies, and the eventual fate of our own," said Dr. Giovanni Fazio, a co author of the research and an astronomer at the Harvard-Smithsonian Center for Astrophysics (CfA). Fazio is principal investigator for the Infrared Array Camera on Spitzer, which captured the new Antennae image.<br> <br> In the latest Antennae galaxies study, Spitzer found a new generation of stars at the site where the two galaxies clash. The telescope "sees" only infrared light, a type of light with energy too low to be visible.<br> <br> "We theorized that there were stars forming at that site, but we weren't sure to what degree," said Dr. Zhong Wang, lead author of the new paper and a CfA astronomer. "Now we see that the majority of star-forming activity in both galaxies occurs in the overlap regions where the two meet."<br> <br> The Antennae galaxies are a classic example of a galactic merger in action. These two spiral galaxies, located 68 million light-years away, began falling into each other around a common center of gravity about 800 million years ago. As they continue to crash together, clouds of gas are shocked and compressed in a process thought to trigger the birth of new stars. Astronomers believe that the two galaxies will ultimately merge into one spheroidal-shaped galaxy, leaving only hints of their varied pasts.<br> <br> Galactic mergers are common throughout the universe and play a key role in determining how galaxies grow and evolve. Our own Milky Way galaxy, for example, will eventually collide with our closest neighbor, the Andromeda galaxy.<br> <br> Previous images of the Antennae taken by visible-light telescopes show striking views of the swirling duo, with bright pockets of young stars dotting the spiral arms. At the center of the galaxies, however, where the two overlap, only a dark cloud of dust can be seen. In the new false-color Spitzer image, which has been combined with an image from a ground-based, visible light telescope to highlight new features, this cloud of buried stars appears bright red. Visible data, on the other hand, is colored blue and indicates regions containing older stars. The nuclei, or centers, of the two galaxies are white.<br> <br> The new Spitzer image is reported in one of 86 Spitzer papers published in the September issue of The Astrophysical Journal Supplement. This special all-Spitzer issue comes just after the one year anniversary of the observatory's launch, and testifies to its tremendously successful first year in space.<br> <br> "This abundance of Spitzer papers just one year after launch shows that the telescope is truly providing a new window on the universe," said Dr. Michael Werner, project scientist for Spitzer at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "These papers report the earliest results, so the best is yet to come."</b></font> </p> <p class="MsoNormal"> <font size="2" face="Arial"><b>* * * * *</b></font> </p> <p class="MsoNormal"> <font size="2" face="Arial"><b>Send us a <a href="mailto:editor@world-science.net">comment</a> about this story<br> </b></font> </p> </body>