Subscribe free to our newsletters via your
. 24/7 Space News .

New Research Resolves Conflict In Theory Of How Galaxies Form
by Staff Writers
Seattle WA (SPX) Jan 14, 2010

With so much mass suddenly removed from the center of the galaxy, the pull of gravity on the dark matter there is diminished and the dark matter drifts away, Governato said. It is similar to what would happen if our sun suddenly disappeared and the loss of its gravitational pull allowed the Earth to drift off into space.

For more than two decades, the cold dark matter theory has been used by cosmologists to explain how the smooth universe born in the big bang more than 13 billion years ago evolved into the filamentary, galaxy-rich cosmic web that we see today.

There's been just one problem: the theory suggested most galaxies should have far more stars and dark matter at their cores than they actually do. The problem is most pronounced for dwarf galaxies, the most common galaxies in our own celestial neighborhood. Each contains less than 1 percent of the stars found in large galaxies such as the Milky Way.

Now an international research team, led by a University of Washington astronomer, reports in Nature that it resolved the problem using millions of hours on supercomputers to run simulations of galaxy formation (1 million hours is more than 100 years).

The simulations produced dwarf galaxies very much like those observed today by satellites and large telescopes around the world.

"Most previous work included only a simple description of how and where stars formed within galaxies, or neglected star formation altogether," said Fabio Governato, a UW research associate professor of astronomy and lead author of the Nature paper.

"Instead we performed new computer simulations, run over several national supercomputing facilities, and included a better description of where and how star formation happens in galaxies."

The simulations showed that as the most massive new stars exploded as supernovas, the blasts generated enormous winds that swept huge amounts of gas away from the center of what would become dwarf galaxies, preventing millions of new stars from forming.

With so much mass suddenly removed from the center of the galaxy, the pull of gravity on the dark matter there is diminished and the dark matter drifts away, Governato said. It is similar to what would happen if our sun suddenly disappeared and the loss of its gravitational pull allowed the Earth to drift off into space.

The cosmic explosions proved to be the missing piece of the puzzle, and adding them to the simulations generated formation of galaxies with substantially lower densities at their cores, closely matching the observed properties of dwarf galaxies.

"The cold dark matter theory works amazingly well at telling where, when and how many galaxies should form," Governato said. "What we did was find a better description of processes that we know happen in the real universe, resulting in more accurate simulations."

The theory of cold dark matter, first advanced in the mid 1980s, holds that the vast majority of the matter in the universe - as much as 75 percent - is made up of "dark" material that does not interact with electrons and protons and so cannot be observed from electromagnetic radiation.

The term "cold" means that immediately following the big bang these dark matter particles have speeds far lower than the speed of light.

In the cold dark matter theory, smaller structures form first, then they merge with each other to form more massive halos, and finally galaxies form within the halos.

Coauthors of the Nature paper are Chris Brook of the Jeremiah Horrocks Institute in the United Kingdom; Lucio Mayer of the Institut fur Astronomie and the Institute for Theoretical Physics in Switzerland; Alyson Brooks of the California Institute of Technology; George Rhee of the University of Nevada; James Wadsley and Gregory Stinson of McMaster University in Canada; Patrik Jonsson and Piero Madau of the University of California, Santa Cruz; Beth Willman of Haverford College in Pennsylvania and Thomas R. Quinn of the UW.


Related Links
University of Washington
Stellar Chemistry, The Universe And All Within It

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

SMU Hosts NOvA Scientists
Dallas TX (SPX) Jan 11, 2010
Physicists may see data as soon as late summer from the prototype for a $278 million science experiment in northern Minnesota that is being designed to find clues to some fundamental mysteries of the universe, including dark matter. But it could take years before the nation's largest "neutrino" detector answers the profound questions that matter to scientists. Construction is underwa ... read more

Planning Our Phases On The Moon

Space Systems Loral To Supply Lunar Mission Propulsion System

Lava tube could house moon colony

Moon Mission In Running For Next Big Space Venture

Just A Few More Approaches To Try For Extrication

Hints Of Hesperian Lakes

Martian Landform Observations Fill Special Journal Issue

NASA plans for Mars laboratory

Spectacular Years Ahead In Space

Galactic GPS Possible With Pulsars And Gravity Waves

US still has space ambitions: NASA chief

Chairman Gordon Comments On President's Budget Request

US official questions China space intentions

China's Space Pioneers Hit New High

China Building Large Radio Telescope For Space Observation

China To Launch Civil HD Survey Satellite In 2011

How To Live Long And Prosper In Space

Russia Set To Launch Another Space Truck To ISS

Obama budget extends US commitment to space station

Mini-Research Module MRM1 At Cape For Shuttle Processing

Roscosmos Reserves Site For Vostochny Spaceport

USAF Awards ULA WGS-4 Satellite Launch

ISRO Plans Special Launch Pad At Sriharikotta

Arianespace Poised For 2010 Boost

Unprecedented Details Imaged On The Surface Of Betelgeuse

Satellite Could Locate Hundreds Of Earth-Sized Planets

Second Smallest Exoplanet Found To Date Discovered At Keck

Massive Stars Easy Targets For Planet Hunters

Change-2 Satellite's Camera Resolution Reaches One Meter

China places record order for Taiwan flat screens

Lego expands its universe with online game

New sunglasses can also be used for 3-D viewing

The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement