Sunday, October 21, 2012

Galaxy Evolution: Surprising Trend Found by Astronomers

ScienceDaily (Oct. 19, 2012) — A comprehensive study of hundreds of galaxies observed by the Keck telescopes in Hawaii and NASA's Hubble Space Telescope has revealed an unexpected pattern of change that extends back 8 billion years, or more than half the age of the universe.



This plot shows the fractions of settled disk galaxies in four time spans, each about 3 billion years long. There is a steady shift toward higher percentages of settled galaxies closer to the present time. At any given time, the most massive galaxies are the most settled. More distant and less massive galaxies on average exhibit more disorganized internal motions, with gas moving in multiple directions, and slower rotation speeds. (Credit: NASA's Goddard Space Flight Center)

"Astronomers thought disk galaxies in the nearby universe had settled into their present form by about 8 billion years ago, with little additional development since," said Susan Kassin, an astronomer at NASA's Goddard Space Flight Center in Greenbelt, Md., and the study's lead researcher. "The trend we've observed instead shows the opposite, that galaxies were steadily changing over this time period."

More - Link >>> http://www.sciencedaily.com/releases/2012/10/121019135427.htm?utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+sciencedaily%2Fspace_time+%28ScienceDaily%3A+Space+%26+Time+News%29&utm_content=Yahoo!+Mail

Source: ScienceDaily.com .

gaw

Glenn A. Walsh, Project Director,
Friends of the Zeiss < http://friendsofthezeiss.org >
Electronic Mail - < gawalsh@planetarium.cc >
SPACE & SCIENCE NEWS, ASTRONOMICAL CALENDAR:
< http://buhlplanetarium.tripod.com/#news >
Twitter: < http://twitter.com/spacewatchtower >
Facebook: < http://www.facebook.com/pages/SpaceWatchtower/238017839577841?sk=wall >
Blog: < http://spacewatchtower.blogspot.com/ >
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
< http://www.planetarium.cc >
* Adler Planetarium, Chicago:
< http://adlerplanetarium.tripod.com >
* Astronomer, Educator, Optician John A. Brashear:
< http://johnbrashear.tripod.com >
* Andrew Carnegie & Carnegie Libraries:
< http://www.andrewcarnegie.cc >
* Civil War Museum of Andrew Carnegie Free Library:
< http://garespypost.tripod.com >
* Duquesne Incline cable-car railway, Pittsburgh:
< http://inclinedplane.tripod.com >
* Public Transit:
< http://andrewcarnegie2.tripod.com/transit >

No comments:

Post a Comment