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アルカディア翻訳会2,008年7月例会課題                奥村義治
 
暑気払い(19:00~21:00)の前に例会を行います。7月といえば「天の川」ということで、天の川の形に関する記事をUSATODAYから拾いました。課題範囲は①~④。訳せる範囲でお願いします。
日時:2008年7月19日(土)18:00~19:00
会場:渋谷区立大向区民会館 和室
 
Posted 1/9/2006 10:04 PM     Updated 1/10/2006 7:45 AM
Astronomers may have reason for Milky Way's 'lumpiness'
By Dan Vergano, USA TODAY
WASHINGTON — A mysterious lumpiness in the Milky Way Galaxy, home to our own solar system, might be caused by the gravitational pull of passing galaxies, astronomers reported Monday.
An artist's rendering of the Milky Way galaxy.
NASA
①『Galaxies are islands of stars in space. Each one is home to tens of millions of stars, including our own sun, which resides in the outer reaches of the disc-shaped Milky Way. The Milky Way is shaped just like many others, but it has a warp that has defied explanation for five decades, says astronomer Evan Levine of the University of California-Berkeley.
"It's not just that our galaxy is lopsided in a sense. The fact is that it has a special shape," says Levine, who spoke Monday at the American Astronomical Society meeting. 』
②『Levine's colleague, Leo Blitz, compares the galaxy's shape to the tipped brim of a fedora. On the galaxy's northern side, stars and gas bulge more than 16,000 light-years above the galactic disc. (One light-year equals about 5.9 trillion miles.) In the southern sky, it dips about 3,200 light-years.
Astronomers suggested long ago that a smaller pair of passerby galaxies, the Large and Small Magellanic Clouds, were bending the Milky Way through a tidal pull, much like the moon raises tides on Earth. But those two small galaxies do not weigh enough to have that kind of pull, so astronomers ruled them out as a reason. 』
③『But those same galaxies are indeed behind the warping, Levine says. Decades ago, astronomers did not know that a ring of "dark matter," 10 times heavier than the normal matter that makes up stars and planets, surrounds our galaxy. Astronomers disagree on what dark matter is, but most see it as a collection of exotic particles that give off very little light.
Analysis by the two astronomers reveals that the nearby galaxies churn up a wake in that dark-matter ring, "plowing through them like a boat," Blitz says. In turn, the gravitational pull of that wake twists the shape of our galaxy.
Other galaxies show similarly warped structures, Levine says. 』
④『Understanding how dwarf galaxies and dark matter distort galaxies helps astronomers understand how such structures arise in the universe and perhaps answer fundamental questions about the origins of stars and planets.
The Milky Way's warping is a well-known phenomenon, says astronomer Robert Lupton of Princeton University. He is part of the Sloan Digital Sky Survey effort, an astronomical atlas of galaxies. His team found another lump in our galaxy, the remains of another dwarf galaxy. But those lumpy remains are much farther out. 』
Contributing: Jess Zielinski