Featured Research

from universities, journals, and other organizations

Mapping The Invisible: Dark Matter Charted Out To Five Billion Light Years

Date:
April 22, 2007
Source:
Royal Astronomical Society
Summary:
Most of the matter in the Universe is not the ordinary kind made up of protons, neutrons, and electrons, but an elusive "dark matter" detectable only from its gravity. Like a tenuous gas, dark matter is all around us - it goes through us all the time without us noticing - but tends to collect in large quantities around galaxies and clusters of galaxies and makes up about one-sixth of the mass of the Universe.

The relationship between ordinary and dark matter in a galaxy. On the left is the ordinary matter that makes up the galaxy and its shape indicates how it was assembled. On the right the map of dark matter shows how it extends over a much larger area than the visible part of the galaxy.
Credit: Image courtesy of Royal Astronomical Society

Most of the matter in the Universe is not the ordinary kind made up of protons, neutrons, and electrons, but an elusive "dark matter" detectable only from its gravity. Like a tenuous gas, dark matter is all around us - it goes through us all the time without us noticing - but tends to collect in large quantities around galaxies and clusters of galaxies and makes up about one-sixth of the mass of the Universe.

In his talk at the Royal Astronomical Society National Astronomy Meeting in Preston, Dr Ignacio Ferreras of King’s College London presented maps of the distribution of "ordinary" and dark matter in nine galaxies out to a distance of five billion light-years from the Sun.

Dr Ferreras worked with Dr Prasenjit Saha (University of Zurich, Switzerland) and Professor Scott Burles (Massachusetts Institute of Technology, USA) to take advantage of a rare astronomical phenomenon known as 'gravitational lensing'. The galaxies they studied serendipitously lie in front of quasars, which are bright sources of light at even greater distances. The gravity of the nearer galaxy and dark matter distorts the quasar light, causing the quasar to be seen as two or four images. The placement of these mirage images, studied using new theoretical techniques in gravitational lensing, makes it possible to measure the total mass and effectively gives scientists a telescope for dark matter!

By analysing the starlight from the galaxies using stellar evolution theory, it is possible to measure the mass of the stars they contain. Combining these ideas with archival data from the Hubble Space Telescope, Dr Ferreras and his colleagues were able to make dark-matter maps.

Current theories of galaxy formation can explain some but not all of these new findings. After the Big Bang, gas should have fallen towards the centres of dark-matter halos, there igniting to form the stars that go on to make up a galaxy. But why is there a higher proportion of dark matter in more massive galaxies? And had these galaxies already finished forming five billion years ago? These questions will only be answered by future theories of galaxy formation.


Story Source:

The above story is based on materials provided by Royal Astronomical Society. Note: Materials may be edited for content and length.


Cite This Page:

Royal Astronomical Society. "Mapping The Invisible: Dark Matter Charted Out To Five Billion Light Years." ScienceDaily. ScienceDaily, 22 April 2007. <www.sciencedaily.com/releases/2007/04/070419130004.htm>.
Royal Astronomical Society. (2007, April 22). Mapping The Invisible: Dark Matter Charted Out To Five Billion Light Years. ScienceDaily. Retrieved September 22, 2014 from www.sciencedaily.com/releases/2007/04/070419130004.htm
Royal Astronomical Society. "Mapping The Invisible: Dark Matter Charted Out To Five Billion Light Years." ScienceDaily. www.sciencedaily.com/releases/2007/04/070419130004.htm (accessed September 22, 2014).

Share This



More Space & Time News

Monday, September 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

NASA's MAVEN Spacecraft Has Finally Reached Mars

NASA's MAVEN Spacecraft Has Finally Reached Mars

Newsy (Sep. 22, 2014) After a 10-month voyage through space, NASA's MAVEN spacecraft is now orbiting the Red Planet. Video provided by Newsy
Powered by NewsLook.com
Raw: SpaceX Rocket Carries 3-D Printer to Space

Raw: SpaceX Rocket Carries 3-D Printer to Space

AP (Sep. 22, 2014) A SpaceX Rocket launched from Cape Canaveral, carrying a custom-built 3-D printer into space. NASA envisions astronauts one day using the printer to make their own spare parts. (Sept. 22) Video provided by AP
Powered by NewsLook.com
SpaceX Cargo Ship Blasts Off Toward Space Station

SpaceX Cargo Ship Blasts Off Toward Space Station

AFP (Sep. 21, 2014) SpaceX's unmanned Dragon cargo ship blasts off toward the International Space Station, carrying a load of supplies and science experiments for the astronauts living there. Duration: 00:35 Video provided by AFP
Powered by NewsLook.com
NASA's MAVEN To Study Martian Atmosphere

NASA's MAVEN To Study Martian Atmosphere

Newsy (Sep. 21, 2014) NASA's Maven will soon give information that could explain what happened to Mars' atmosphere. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins