See

close
Loading Image...
ScienceDaily: Your source for the latest research news and science breakthroughs -- updated daily
Science News
Share Blog Cite
Print Email Bookmark
Cosmic Dance Helps Galaxies Lose Weight

ScienceDaily (July 29, 2009) — A study published July 30 in the journal Nature offers an explanation for the origin of dwarf spheroidal galaxies. The research may settle an outstanding puzzle in understanding galaxy formation.
See also:
Space & Time

* Galaxies
* Stars
* Astrophysics
* Cosmology
* Eris (Xena)
* Kuiper Belt

Reference

* Local Group
* Magellanic Clouds
* Barred spiral galaxy
* Galaxy formation and evolution

Dwarf spheroidal galaxies are small and very faint, containing few stars relative to their total mass. They appear to be made mostly of dark matter - a mysterious substance detectable only by its gravitational influence, which outweighs normal matter by a factor of five to one in the universe as a whole.

Astronomers have found it difficult to explain the origin of dwarf spheroidal galaxies. Previous theories require that dwarf spheroidals orbit near large galaxies like the Milky Way, but this does not explain how dwarfs that have been observed in the outskirts of the "Local Group" of galaxies could have formed.

"These systems are 'elves' of the early universe, and understanding how they formed is a principal goal of modern cosmology," said lead author Elena D'Onghia of the Harvard-Smithsonian Center for Astrophysics (CfA).

D'Onghia and her colleagues used computer simulations to examine two scenarios for the formation of dwarf spheroidals: 1) an encounter between two dwarf galaxies far from giants like the Milky Way, with the dwarf spheroidal later accreted into the Milky Way, and 2) an encounter between a dwarf galaxy and the forming Milky Way in the early universe.

The team found that the galactic encounters excite a gravitational process which they term "resonant stripping," leading to the removal of stars from the smaller dwarf over the course of the interaction and transforming it into a dwarf spheroidal.

"Like in a cosmic dance, the encounter triggers a gravitational resonance that strips stars and gas from the dwarf galaxy, producing long visible tails and bridges of stars," explained D'Onghia.

"This mechanism explains the most important characteristic of dwarf spheroidals, which is that they are dark-matter dominated," added co-author Gurtina Besla.

The long streams of stars pulled off by gravitational interactions should be detectable. For example, the recently discovered bridge of stars between Leo IV and Leo V, two nearby dwarf spheroidal galaxies, may have resulted from resonant stripping.
Adapted from materials provided by Harvard-Smithsonian Center for Astrophysics.
Email or share this story:
| More
Need to cite this story in your essay, paper, or report? Use one of the following formats:
APA

MLA
Harvard-Smithsonian Center for Astrophysics (2009, July 29). Cosmic Dance Helps Galaxies Lose Weight. ScienceDaily. Retrieved August 24, 2009, from http://www.sciencedaily.com­ /releases/2009/07/090729140927.htm
enlarge

This simulation illustrates the resonant stripping process. Stars of a dwarf galaxy (at the bottom) orbiting around a larger system (at the top) are stripped off by gravity, forming long tails of stars. (Credit: Elena D'Onghia (CfA))
Ads by Google
Advertise here
Moartea microscopica
Un virus necrutator ameninta femeile. Afla mai mult!
www.informarehpv.ro
Horoscope & future 2009 ?
Free horoscope year 2009 birthdate requiered. You'll be surprised !
www.pasqualina.com/Horoscope_Free
Int. Diabetes Monitor
A free online review journal on trends in clinical diabetes.
InternationalDiabetesMonitor.com
Levemir®
Info for health care professionals on Levemir® and reduced weight gain
www.NovoNordisk.com
"How To Lose Belly Fat"
Lose 1 Jean Size Every 7 Days! As Seen on CNN.
www.AppliedNutritionalResearch.com
Related Stories
Dwarf Galaxies Need Dark Matter Too, Astronomers Say (Oct. 28, 2007) — Stars in dwarf spheroidal galaxies behave in a way that suggests the galaxies are utterly dominated by dark matter, astronomers have found. Astronomers measured the velocity of 6,804 stars in seven ... > read more
A Cosmic Fossil? Brilliant But Fuzzy Galaxy May Be Aftermath Of Multi-Galaxy Collision (Feb. 7, 2008) — The galaxy NGC 1132 is most likely a cosmic fossil -- the aftermath of an enormous multi-galactic pile-up, where the carnage of collision after collision has built up a brilliant but fuzzy giant ... > read more
When Worlds Collide: Cornell Astronomers Investigate Cosmic Forces That Produce New Galaxies (Dec. 1, 2005) — When galaxies collide (as our galaxy, the Milky Way, eventually will with the nearby Andromeda galaxy), what happens to matter that gets spun off in the collision's wake? With help from the Spitzer ... > read more
Hubble Spies Galaxy Silhouettes (Sep. 25, 2008) — NASA's Hubble Space Telescope has captured a rare alignment between two spiral galaxies. The outer rim of a small, foreground galaxy is silhouetted in front of a larger background galaxy. Skeletal ... > read more
Search ScienceDaily
Number of stories in archives: 44,032
Find with keyword(s):

Enter a keyword or phrase to search ScienceDaily's archives for related news topics,
the latest news stories, reference articles, science videos, images, and books.
Ads by Google
Advertise here
Bed & Breakfast Berlin
Rooms and Apartments right in the Center of Berlin
www.stars-guesthouse.com
5 Tricks to Lose Body Fat
Ab exercises don't burn body fat, but this unique method does.
TruthAboutAbs.com
Space Newsfeed
satellite broadcasting news from around the world
www.SpaceNewsFeed.co.uk

Just In:
Lightning's Mirror Image ... Only Much Bigger
Using Light To Teach Magnets New Tricks
Microchip Does 1,000 Chemical Reactions At Once
Naming Evolution's Winners And Losers
Inner 'Fingerprint' For Personal Medical Care
Why Sleep? To Boost Efficiency, Minimize Risk
Ultrathin LEDs: New Class Of Displays
Oxycholesterol: Greatest Heart Disease Risk?
Oxycholesterol: Greatest Heart Disease Risk?
Science Video News
Einstein Rings
Images from the Hubble telescope reveal eight new Einstein rings, joining only three others previously known. Einstein rings are pairs of galaxies,. ... > full story

* Astronomers And Computer Scientists Reveal Astronomical Events In Real Time
* Physicists Spot Interstellar Shock Wave Using Spitzer Telescope
* Astronomers Spot Black Holes Using NASA's Chandra X-Ray Observatory
* more science videos

Breaking News
... from NewsDaily.com

* Encyclopedia of Life grows; clues on ageing, pests
* Satellites put into orbit for Japan and Australia
* Scientists make "sugar bug" drug for bowel disease
* Gene swap experiment makes altering bugs easier
* Mercury-tainted fish found widely in U.S. streams
* more science news

In Other News ...

* Justice Dept advises pursuing CIA abuses: report
* U.S. point man on sanctions to press North Korea
* Suspect in U.S. model murder found dead in Canada
* Singapore shoots down "rumor" of APEC attack plot
* Malaysia frees woman sentenced to caning
* Hurricane Bill kills 2 in U.S., drenches eastern Canada
* China trials over Xinjiang riot "likely this week"
* Fit-looking Fidel Castro appears on Cuban TV
* more top news

Copyright Reuters 2008. See Restrictions.
Free Subscriptions
... from ScienceDaily
Get the latest science news with our free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

* Email Newsletters
* RSS Newsfeeds

Feedback
... we want to hear from you!
Tell us what you think of the new ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?

* Your Name:
* Your Email:
* Comments:
* Click button to submit feedback:

About This Site | Editorial Staff | Awards & Reviews | Contribute News | Advertise With Us | Privacy Policy | Terms of Use
Copyright © 1995-2009 ScienceDaily LLC — All rights reserved — Contact: editor@sciencedaily.com

* Health & Medicine
o Allergy
o Alternative Medicine
o Bird Flu
o Birth Control
o Breast Cancer
o Cancer
o Diabetes
o Diet and Weight Loss
o Diseases and Conditions
o Fitness
o Gene Therapy
o Heart Disease
o HIV and AIDS
o Lung Cancer
o Men's Health
o Nutrition
o Obesity
o Pharmacology
o Pregnancy and Childbirth
o Sexual Health
o Skin Care
o Stem Cells
o Women's Health
o ... more topics
* Mind & Brain
o ADD and ADHD
o Addiction
o Alzheimer's
o Anxiety
o Autism
o Depression
o Gender Difference
o Headaches
o Insomnia
o Intelligence
o Language Acquisition
o Parkinson's
o Perception
o Psychology
o Relationships
o Schizophrenia
o Social Psychology
o ... more topics
* Plants & Animals
o Agriculture and Food
o Animals
o Behavior
o Biology
o Biotechnology
o Cell Biology
o Cloning
o Developmental Biology
o Dogs
o Dolphins and Whales
o Endangered Animals
o Extinction
o Frogs and Reptiles
o Genetically Modified
o Marine Biology
o Microbes and More
o Nature
o New Species
o Pests and Parasites
o Spiders
o Zoology
o ... more topics
* Earth & Climate
o Air Quality
o Climate
o Coral Reefs
o Earthquakes
o Ecology
o Environmental Science
o Geography
o Geology
o Global Warming
o Hurricanes and Cyclones
o Ice Ages
o Oceanography
o Ozone Holes
o Pollution
o Renewable Energy
o Tsunamis
o Weather
o Wildfires
o ... more topics
* Space & Time
o Astronomy
o Astrophysics
o Big Bang
o Black Holes
o Dark Matter
o ESA
o Extrasolar Planets
o Mars
o Moon
o NASA
o Pluto
o Saturn
o Solar System
o Space Missions
o Space Station
o Space Telescopes
o Stars
o Sun
o ... more topics
* Matter & Energy
o Alternative Fuels
o Aviation
o Biochemistry
o Biometric
o Chemistry
o Detectors
o Electronics
o Energy Technology
o Forensics
o Fossil Fuels
o Inorganic Chemistry
o Nanotechnology
o Organic Chemistry
o Physics
o Quantum Physics
o Solar Energy
o Technology
o Wind Energy
o ... more topics
* Computers & Math
o Artificial Intelligence
o Communications
o Computer Graphics
o Computer Modeling
o Computer Science
o Encryption
o Hacking
o Mathematics
o Quantum Computers
o Robotics
o Software
o Statistics
o Video Games
o Virtual Reality
o ... more topics
* Fossils & Ruins
o Ancient Civilizations
o Anthropology
o Archaeology
o Dinosaurs
o Early Climate
o Early Humans
o Early Mammals
o Evolution
o Human Evolution
o Lost Treasures
o Origin of Life
o Paleontology
o Tyrannosaurus Rex
o ... more topics



* News
o Front Page
o Today's Summaries
o Latest Headlines
o Search Archives
o Email Newsletters
o RSS Newsfeeds
o News Sections
o Health & Medicine
o Mind & Brain
o Plants & Animals
o Space & Time
o Earth & Climate
o Matter & Energy
o Computers & Math
o Fossils & Ruins
* Articles
o Health & Medicine
o Mind & Brain
o Plants & Animals
o Space & Time
o Earth & Climate
o Matter & Energy
o Computers & Math
o Fossils & Ruins
* Videos
o Health & Medicine
o Mind & Brain
o Plants & Animals
o Space & Time
o Earth & Climate
o Matter & Energy
o Computers & Math
o Fossils & Ruins
* Images
o Health & Medicine
o Mind & Brain
o Plants & Animals
o Space & Time
o Earth & Climate
o Matter & Energy
o Computers & Math
o Fossils & Ruins
* Books
o Health & Medicine
o Mind & Brain
o Plants & Animals
o Space & Time
o Earth & Climate
o Matter & Energy
o Computers & Math
o Fossils & Ruins

Post this page to your favorite social bookmarking site:
close

* del.icio.us
* Digg
* Furl
* Netscape
* Yahoo! My Web
* StumbleUpon
* Google Bookmarks
* Technorati
* BlinkList
* Newsvine
* ma.gnolia
* reddit
* Facebook
* Tailrank
* Slashdot
* Fark

Include this item in your blog or web site:
close

* Title:
* Link:
* Summary:
* Click button to copy above text for pasting into your site:

Cite this article in your essay, paper, or report:
close

* APA style:
* MLA style:
* Click button to copy above text for pasting into your document:

Email this page's link to a friend or colleague:
close

* To Email:
* Your Name:
* Your Email:
* cc to self

Am vazut multe ceasuri superbe pe www.topceas.ro Am vazut multe ceasuri superbe pe www.topceas.ro Am vazut multe ceasuri superbe pe www.topceas.ro Am vazut multe ceasuri superbe pe www.topceas.ro Am vazut multe ceasuri superbe pe www.topceas.ro Am vazut multe ceasuri superbe pe www.topceas.ro Am vazut multe ceasuri superbe pe www.topceas.ro Am vazut multe ceasuri superbe pe www.topceas.ro Am vazut multe ceasuri superbe pe www.topceas.ro Am vazut multe ceasuri superbe pe www.topceas.roAm vazut multe ceasuri superbe pe www.topceas.ro
Am vazut multe ceasuri superbe pe www.topceas.ro
Am vazut multe ceasuri superbe pe www.topceas.roAm vazut multe ceasuri superbe pe www.topceas.roAm vazut multe ceasuri superbe pe www.topceas.roImi doresc un HTC MagicHTC Magic